1、Manage and Configure POJOs with the Spring IoC Container
创建POPJ Class
package com.apress.springrecipes.sequence;
public class SequenceGenerator {
private String prefix;
private String suffix;
private int initial;
private int counter;
public SequenceGenerator() {}
public SequenceGenerator(String prefix, String suffix, int initial) {
this.prefix = prefix;
this.suffix = suffix;
this.initial = initial;
}
public void setPrefix(String prefix) {
this.prefix = prefix;
}
public void setSuffix(String suffix) {
this.suffix = suffix;
}
public void setInitial(int initial) {
this.initial = initial;
}
public synchronized String getSequence() {
StringBuffer buffer = new StringBuffer();
buffer.append(prefix);
buffer.append(initial + counter++);
buffer.append(suffix);
return buffer.toString();
}
}
XML配置
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator">
<property name="prefix" value="30" />
<property name="suffix" value="A" />
<property name="initial" value="100000" />
</bean
</beans>
实例化Spring IoC Container，并通过IoC Container创建POPJ
package com.apress.springrecipes.sequence;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
public class Main {
public static void main(String[] args) {
ApplicationContext context =
new GenericXmlApplicationContext("beans.xml");
SequenceGenerator generator =
(SequenceGenerator) context.getBean("sequenceGenerator");
System.out.println(generator.getSequence());
System.out.println(generator.getSequence());
}
}
2、Create POJOs by Invoking a Constructor
Product.java
package com.apress.springrecipes.shop;
public abstract class Product {
private String name;
private double price;
public Product() {}
public Product(String name, double price) {
this.name = name;
this.price = price;
}
// Getters and Setters
public void setName(String name) {
this.name = name;
}
public void setPrice(double price) {
this.price = price;
}
public String getName() {
return name;
}
public double getPrice() {
return price;
}
public String toString() {
return name + " " + price;
}
}
Dis.java
package com.apress.springrecipes.shop;
public class Disc extends Product {
private int capacity;
public Disc() {
super();
}
public Disc(String name, double price) {
super(name, price);
}
// Getters and Setters
public void setCapacity(int capacity) {
this.capacity = capacity;
}
public int getCapacity() {
return capacity;
}
}
Battery.java
package com.apress.springrecipes.shop;
public class Battery extends Product {
private boolean rechargeable;
public Battery() {
super();
}
public Battery(String name, double price) {
super(name, price);
}
// Getters and Setters
public void setRechargeable(boolean rechargeable) {
this.rechargeable = rechargeable;
}
public boolean getRechargeable() {
return rechargeable;
}
}
配置beans.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<!--
当没有constructor-arg时，调用默认构造器创建bean，否则寻找最合适的构造器；
然后再property的属性通过setter方法初始化
-->
<!--
Product aaa = new Battery();
aaa.setName("AAA");
aaa.setPrice(2.5);
aaa.setRechargeable(true);
Product cdrw = new Disc();
cdrw.setName("CD-RW");
cdrw.setPrice(1.5);
cdrw.setCapacity(700);
-->
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
<property name="capacity" value="700" />
</bean>
<!--
Product aaa = new Battery("AAA", 2.5);
aaa.setRechargeable(true);
Product cdrw = new Disc("CD-RW", 1.5);
cdrw.setCapacity(700);
-->
<!--
constructor-arg标签可以通过添加type属性（int、java.lang.String等）、
name属性（形参名词）、index属性（参数顺序）等来进一步限定，进而找到最合适的构造器。
-->
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<constructor-arg value="AAA" />
<constructor-arg value="2.5" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<constructor-arg value="CD-RW" />
<constructor-arg value="1.5" />
<property name="capacity" value="700" />
</bean>
</beans>
实例化
package com.apress.springrecipes.shop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
public class Main {
public static void main(String[] args) throws Exception {
ApplicationContext context =
new GenericXmlApplicationContext("beans.xml");
Product aaa = (Product) context.getBean("aaa");
Product cdrw = (Product) context.getBean("cdrw");
System.out.println(aaa);
System.out.println(cdrw);
}
}
3、Use POJO References, Auto-Wiring, and Imports to Interact with Other POJOs
SequenceGenerator引用了一个PrefixGenerator
package com.apress.springrecipes.sequence;
public interface PrefixGenerator {
public String getPrefix();
}
package com.apress.springrecipes.sequence;
import java.text.SimpleDateFormat;
import java.text.DateFormat;
import java.util.Date;
public class DatePrefixGenerator implements PrefixGenerator {
private DateFormat formatter;
public void setPattern(String pattern) {
this.formatter = new SimpleDateFormat(pattern);
}
public String getPrefix() {
return formatter.format(new Date());
}
}
package com.apress.springrecipes.sequence;
public class SequenceGenerator {
private PrefixGenerator prefixGenerator;
private String suffix;
private int initial;
private int counter;
public SequenceGenerator() {}
public SequenceGenerator(PrefixGenerator prefixGenerator, String suffix, int initial) {
this.prefixGenerator = prefixGenerator;
this.suffix = suffix;
this.initial = initial;
}
public void setPrefixGenerator(PrefixGenerator prefixGenerator) {
this.prefixGenerator = prefixGenerator;
}
public void setSuffix(String suffix) {
this.suffix = suffix;
}
public void setInitial(int initial) {
this.initial = initial;
}
public synchronized String getSequence() {
StringBuffer buffer = new StringBuffer();
buffer.append(prefixGenerator.getPrefix());
buffer.append(initial + counter++);
buffer.append(suffix);
return buffer.toString();
}
}
配置XML
<!-- 引用一个bean -->
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="datePrefixGenerator" class="com.apress.springrecipes.sequence.DatePrefixGenerator">
<property name="pattern" value="yyyyMMdd" />
</bean>
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator">
<property name="initial" value="100000" />
<property name="suffix" value="A" />
<property name="prefixGenerator" ref="datePrefixGenerator" />
</bean>
</beans>
<!--constructor-arg 引用bean-->
<!--
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator">
<constructor-arg ref="datePrefixGenerator" />
<property name="initial" value="100000" />
<property name="suffix" value="A" />
</bean>
-->
<!-- 用一个自定义的标签p声明 -->
<!--
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="datePrefixGenerator" class="com.apress.springrecipes.sequence.DatePrefixGenerator">
<property name="pattern" value="yyyyMMdd" />
</bean>
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator"
p:suffix="A" p:initial="1000000"
p:prefixGenerator-ref="datePrefixGenerator" />
</beans>
-->
<!-- 引用内部bean-->
<!--
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator">
<property name="initial" value="100000" />
<property name="suffix" value="A" />
<property name="prefixGenerator">
<bean class="com.apress.springrecipes.sequence.DatePrefixGenerator">
<property name="pattern" value="yyyyMMdd" />
</bean>
</property>
</bean>
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator">
<constructor-arg>
<bean class="com.apress.springrecipes.sequence.DatePrefixGenerator">
<property name="pattern" value="yyyyMMdd" />
</bean>
</constructor-arg>
<property name="initial" value="100000" />
<property name="suffix" value="A" />
</bean>
-->
使用bean
package com.apress.springrecipes.sequence;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
public class Main {
public static void main(String[] args) {
ApplicationContext context =
new GenericXmlApplicationContext("beans.xml");
SequenceGenerator generator =
(SequenceGenerator) context.getBean("sequenceGenerator");
System.out.println(generator.getSequence());
System.out.println(generator.getSequence());
}
}
4、Configure POJOs with Java Collection Attributes
有集合属性的POPJ Class
package com.apress.springrecipes.sequence;
import java.util.List;
public class SequenceGenerator {
private String prefix;
private List<Object> suffixes;
private int initial;
private int counter;
public SequenceGenerator() {}
public SequenceGenerator(String prefix, List<Object> suffixes, int initial) {
this.prefix = prefix;
this.suffixes = suffixes;
this.initial = initial;
}
public void setPrefix(String prefix) {
this.prefix = prefix;
}
public void setSuffixes(List<Object> suffixes) {
this.suffixes = suffixes;
}
public void setInitial(int initial) {
this.initial = initial;
}
public synchronized String getSequence() {
StringBuffer buffer = new StringBuffer();
buffer.append(prefix);
buffer.append(initial + counter++);
for (Object suffix : suffixes) {
buffer.append("-");
buffer.append(suffix);
}
return buffer.toString();
}
}
XML配置
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<!--
List标签下的每一项可以是value（常量值）、ref（引用的bean）、
idref、<bean>（匿名内部bean）、<null/>（空值）；
Set与List的唯一区别是Set中的元素不会重复，也就意味着相同的值会被覆盖
-->
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator">
<property name="prefix" value="30" />
<property name="initial" value="100000" />
<property name="suffixes">
<list>
<value>A</value>
<bean class="java.net.URL">
<constructor-arg value="http" />
<constructor-arg value="www.apress.com" />
<constructor-arg value="/" />
</bean>
<null />
</list>
</property>
</bean>
<!--
Map的定义方式为<key>和Value
-->
<!--
<bean id="sequenceGenerator"class="com.apress.springrecipes.sequence.SequenceGenerator">
<property name="prefix" value="30" />
<property name="initial" value="100000" />
<property name="suffixes">
<map>
<entry>
<key>
<value>type</value>
</key>
<value>A</value>
</entry>
<entry key="type1" value="A" />
<entry>
<key>
<value>url</value>
</key>
<bean class="java.net.URL">
<constructor-arg value="http" />
<constructor-arg value="www.apress.com" />
<constructor-arg value="/" />
</bean>
</entry>
<entry key="url1">
<bean class="java.net.URL">
<constructor-arg value="http" />
<constructor-arg value="www.apress.com" />
<constructor-arg value="/" />
</bean>
</entry>
</map>
</property>
</bean>
-->
<!--
Properties与Map的区别为：Properties要求键值对均为String
-->
<!--
<bean id="sequenceGenerator"class="com.apress.springrecipes.sequence.SequenceGenerator">
<property name="prefix" value="30" />
<property name="initial" value="100000" />
<property name="suffixes">
<props>
<prop key="type">A</prop>
<prop key="url">http://www.apress.com/</prop>
<prop key="null">null</prop>
</props>
</property>
</bean>
-->
<!--
指定集合元素类型type
-->
<!--
<property name="suffixes">
<list>
<value type="int">5</value>
<value type="int">10</value>
<value type="int">20</value>
</list>
</property>
-->
<!--
指定具体使用的集合对象，例如指定Set为TreeSet
-->
<!--
<property name="suffixes">
<bean class="org.springframework.beans.factory.config.SetFactoryBean">
<property name="targetSetClass">
<value>java.util.TreeSet</value>
</property>
<property name="sourceSet">
<set>
<value>5</value>
<value>10</value>
<value>20</value>
</set>
</property>
</bean>
</property>
-->
<!--
指定具体使用的集合对象，例如指定Set为TreeSet，使用util标签
-->
<!--
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-3.2.xsd">
<bean id="sequenceGenerator" class="com.apress.springrecipes.sequence.SequenceGenerator">
<property name="prefix" value="30" />
<property name="initial" value="100000" />
<property name="suffixes">
<util:set set-class="java.util.TreeSet">
<value>5</value>
<value>10</value>
<value>20</value>
</util:set>
</property>
</bean>
</beans>
-->
</beans>
使用bean
package com.apress.springrecipes.sequence;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
public class Main {
public static void main(String[] args) {
ApplicationContext context =
new GenericXmlApplicationContext("beans.xml");
SequenceGenerator generator =
(SequenceGenerator) context.getBean("sequenceGenerator");
System.out.println(generator.getSequence());
System.out.println(generator.getSequence());
}
}
5、Set a POJOs Scope
Spring中Scope分以下几种：
singleton -- Creates a single bean instance per Spring IoC container
prototype -- Creates a new bean instance each time when requested
request -- Creates a single bean instance per HTTP request; only valid in the context of a web application
session -- Creates a single bean instance per HTTP session; only valid in the context of a web application
globalSession -- Creates a single bean instance per global HTTP session; only valid in the context of a portalapplication
package com.apress.springrecipes.shop;
public abstract class Product {
private String name;
private double price;
public Product() {}
public Product(String name, double price) {
this.name = name;
this.price = price;
}
// Getters and Setters
public void setName(String name) {
this.name = name;
}
public void setPrice(double price) {
this.price = price;
}
public String getName() {
return name;
}
public double getPrice() {
return price;
}
public String toString() {
return name + " " + price;
}
}
package com.apress.springrecipes.shop;
public class Disc extends Product {
private int capacity;
public Disc() {
super();
}
public Disc(String name, double price) {
super(name, price);
}
// Getters and Setters
public void setCapacity(int capacity) {
this.capacity = capacity;
}
public int getCapacity() {
return capacity;
}
}
package com.apress.springrecipes.shop;
public class Battery extends Product {
private boolean rechargeable;
public Battery() {
super();
}
public Battery(String name, double price) {
super(name, price);
}
// Getters and Setters
public void setRechargeable(boolean rechargeable) {
this.rechargeable = rechargeable;
}
public boolean getRechargeable() {
return rechargeable;
}
}
package com.apress.springrecipes.shop;
import java.util.List;
import java.util.ArrayList;
public class ShoppingCart {
private List<Product> items = new ArrayList<Product>();
public void addItem(Product item) {
items.add(item);
}
public List<Product> getItems() {
return items;
}
}
配置XML，默认scope为singleton
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
<property name="capacity" value="700" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="3.0" />
<property name="capacity" value="700" />
</bean>
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" />
</beans>
main方法，执行结果为：
Shopping cart 1 contains [AAA 2.5, CD-RW 1.5]
Shopping cart 2 contains [AAA 2.5, CD-RW 1.5, DVD-RW 3.0]
package com.apress.springrecipes.shop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
public class Main {
public static void main(String[] args) throws Exception {
ApplicationContext context =
new GenericXmlApplicationContext("beans.xml");
Product aaa = (Product) context.getBean("aaa");
Product cdrw = (Product) context.getBean("cdrw");
Product dvdrw = (Product) context.getBean("dvdrw");
ShoppingCart cart1 = (ShoppingCart) context.getBean("shoppingCart");
cart1.addItem(aaa);
cart1.addItem(cdrw);
System.out.println("Shopping cart 1 contains " + cart1.getItems());
ShoppingCart cart2 = (ShoppingCart) context.getBean("shoppingCart");
cart2.addItem(dvdrw);
System.out.println("Shopping cart 2 contains " + cart2.getItems());
}
}
以上shoppingCart的配置相当于：
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" scope="singleton" />
如果shoppingCart配置为：
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" scope="prototype" />
main方法执行结果为：
Shopping cart 1 contains [AAA 2.5, CD-RW 1.5]
Shopping cart 2 contains [DVD-RW 3.0]
2.6 Use Data from External Resources
读取java classpath路径下的properties文件，文件内容：
specialcustomer.discount=0.1 summer.discount=0.15 endofyear.discount=0.2
在配置文件中读取properties的内容：
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="discountPropertyConfigurer" class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
<property name="location">
<value>classpath:discounts.properties</value>
</property>
<property name="ignoreResourceNotFound" value="true"/>
<property name="ignoreUnresolvablePlaceholders" value="true"/>
</bean>
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
<property name="discount" value="${specialcustomer.discount:0}" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
<property name="discount" value="${summer.discount:0}" />
<property name="capacity" value="700" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="3.0" />
<property name="discount" value="${endofyear.discount:0}" />
<property name="capacity" value="700" />
</bean>
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" scope="prototype" />
</beans>
也可以在java代码中读取：
public class Main {
public static void main(String[] args) throws Exception {
Resource resource = new ClassPathResource("discounts.properties");
Properties props = PropertiesLoaderUtils.loadProperties(resource);
System.out.println("And don't forget our discounts!");
System.out.println(props);
}
}
也可以直接加载某路径下的文件 或者 URL获取的文件：
Resource resource = new FileSystemResource("c:/shop/banner.txt")
Resource resource = new UrlResource("http://www.apress.com/context/banner.txt")
读取classpath下的文件：
************************* * Welcome to My Shop! * *************************
设置一个POPJ类：
package com.apress.springrecipes.shop;
import org.springframework.core.io.Resource;
import java.io.IOException;
import java.io.InputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class BannerLoader {
private Resource banner;
public void setBanner(Resource banner) {
this.banner = banner;
}
public void showBanner() throws IOException {
InputStream in = banner.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
while (true) {
String line = reader.readLine();
if (line == null)
break;
System.out.println(line);
}
reader.close();
}
}
初始化bean时，读取数据：
<bean id="bannerLoader"
class="com.apress.springrecipes.shop.BannerLoader"
init-method="showBanner">
<property name="banner">
<value>classpath:banner.txt</value>
</property>
</bean>
设置路径时候，还可以是：
file:c:/shop/banner.txt
classpath:banner.txt
http://springrecipes.apress.com/shop/banner.txt
2.7 Resolve I18N Text Messages for Different Locales in Properties Files
国际化文件：
配置国际化文件对应的bean
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
<property name="basenames">
<list>
<value>classpath:messages</value>
</list>
</property>
<property name="cacheSeconds" value="1"/>
</bean>
</beans>
使用国际化：
package com.apress.springrecipes.shop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
import java.util.Locale;
import java.util.Date;
public class Main {
public static void main(String[] args) throws Exception {
ApplicationContext context =
new GenericXmlApplicationContext("beans.xml");
String alert = context.getMessage("alert.checkout", null, Locale.US);
String alert_inventory = context.getMessage("alert.inventory.checkout", new Object[] { "[DVD-RW 3.0]", new Date() }, Locale.US);
System.out.println("The I18N message for alert.checkout is: " + alert);
System.out.println("The I18N message for alert.inventory.checkout is: " + alert_inventory);
}
}
2-8. Customize POJO Initialization and Destruction
初始化bean时的方法init-method和销毁bean时的方法destroy-method
Product.java、Battery.java、Disc.java同上
package com.apress.springrecipes.shop;
import java.util.List;
import java.util.ArrayList;
public class ShoppingCart {
private List<Product> items = new ArrayList<Product>();
public void addItem(Product item) {
items.add(item);
}
public List<Product> getItems() {
return items;
}
}
package com.apress.springrecipes.shop;
import java.io.IOException;
import java.io.File;
import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
import java.io.FileOutputStream;
import java.util.Date;
public class Cashier {
private String fileName;
private String path;
private BufferedWriter writer;
public void setFileName(String fileName) {
this.fileName = fileName;
}
public void setPath(String path) {
this.path = path;
}
public void openFile() throws IOException {
File targetDir = new File(path);
if (!targetDir.exists()) {
targetDir.mkdir();
}
File checkoutFile = new File(path, fileName + ".txt");
if(!checkoutFile.exists()) {
checkoutFile.createNewFile();
}
writer = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream(checkoutFile, true)));
}
public void checkout(ShoppingCart cart) throws IOException {
writer.write(new Date() + "\t" +cart.getItems() + "\r\n");
writer.flush();
}
public void closeFile() throws IOException {
writer.close();
}
}
配置XML
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
<property name="capacity" value="700" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="3.0" />
<property name="capacity" value="700" />
</bean>
<bean id="shoppingCart" lazy-init="true" class="com.apress.springrecipes.shop.ShoppingCart" scope="prototype" />
<bean id="cashier" class="com.apress.springrecipes.shop.Cashier" init-method="openFile" destroy-method="closeFile">
<property name="fileName" value="checkout" />
<property name="path" value="c:/Windows/Temp/cashier" />
</bean>
</beans>
lazy-init默认为false，如果为true，意味着，如果bean一直没有被应用初始化，那么，bean不会被初始化。
初始化bean时候会执行init-method，在bean最后销毁时会执行destroy-method。
package com.apress.springrecipes.shop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.GenericXmlApplicationContext;
public class Main {
public static void main(String[] args) throws Exception {
ApplicationContext context =
new GenericXmlApplicationContext("beans.xml");
Product aaa = (Product) context.getBean("aaa");
Product cdrw = (Product) context.getBean("cdrw");
Product dvdrw = (Product) context.getBean("dvdrw");
ShoppingCart cart1 = (ShoppingCart) context.getBean("shoppingCart");
cart1.addItem(aaa);
cart1.addItem(cdrw);
System.out.println("Shopping cart 1 contains " + cart1.getItems());
ShoppingCart cart2 = (ShoppingCart) context.getBean("shoppingCart");
cart2.addItem(dvdrw);
System.out.println("Shopping cart 2 contains " + cart2.getItems());
Cashier cashier = (Cashier) context.getBean("cashier");
cashier.checkout(cart1);
cashier.checkout(cart2);
}
}
如果希望一个bean初始化时比另外一个先，可以：
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="sequenceGenerator"
class="com.apress.springrecipes.sequence.SequenceGenerator"
autowire="byType" depends-on="datePrefixGenerator">
<property name="initial" value="100000" />
<property name="suffix" value="A" />
</bean>
<bean id="datePrefixGenerator" primary="true"
class="com.apress.springrecipes.sequence.DatePrefixGenerator">
</bean>
<bean id="numberprefixGenerator"
class="com.apress.springrecipes.sequence.NumberPrefixGenerator">
</bean>
</beans>
示例中datePrefixGenerator会比sequenceGenerator先创建。
2.9 Create Post Processors to Validate and Modify POJOs
处理每个bean，可以继承BeanPostProcessor
Product.java、Battery.java、Disc.java、Cashier.java 、ShoppingCart.java 、Main.java均同2.8例，添加如下两个类，这两个类均继承BeanPostProcessor，这意味着每个bean都会被这两个类处理，该类有两方法，一个是初始化之前处理，一个是之后。
package com.apress.springrecipes.shop;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
public class AuditCheckBeanPostProcessor implements BeanPostProcessor {
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
System.out.println("In AuditCheckBeanPostProcessor.postProcessBeforeInitialization, processing bean type: " + bean.getClass());
return bean;
}
public Object postProcessAfterInitialization(Object bean, String beanName)
throws BeansException {
return bean;
}
}
package com.apress.springrecipes.shop;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
public class ProductCheckBeanPostProcessor implements BeanPostProcessor {
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
if (bean instanceof Product) {
String productName = ((Product) bean).getName();
System.out.println("In ProductCheckBeanPostProcessor.postProcessBeforeInitialization, processing Product: " + productName);
}
return bean;
}
public Object postProcessAfterInitialization(Object bean, String beanName)
throws BeansException {
if (bean instanceof Product) {
String productName = ((Product) bean).getName();
System.out.println("In ProductCheckBeanPostProcessor.postProcessAfterInitialization, processing Product: " + productName);
}
return bean;
}
}
在配置文件中需要配置相应的bean
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean class="com.apress.springrecipes.shop.ProductCheckBeanPostProcessor"/>
<bean class="com.apress.springrecipes.shop.AuditCheckBeanPostProcessor"/>
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
<property name="capacity" value="700" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="3.0" />
<property name="capacity" value="700" />
</bean>
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" scope="prototype" />
<bean id="cashier" class="com.apress.springrecipes.shop.Cashier" init-method="openFile" destroy-method="closeFile">
<property name="fileName" value="checkout" />
<property name="path" value="c:/Windows/Temp/cashier" />
</bean>
</beans>
2-9. Create Post Processors to Validate and Modify POJOs
使用静态工厂方法初始化bean
package com.apress.springrecipes.shop;
public class ProductCreator {
public static Product createProduct(String productId) {
if ("aaa".equals(productId)) {
return new Battery("AAA", 2.5);
} else if ("cdrw".equals(productId)) {
return new Disc("CD-RW", 1.5);
} else if ("dvdrw".equals(productId)) {
return new Disc("DVD-RW", 3.0);
}
throw new IllegalArgumentException("Unknown product");
}
}
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="aaa" class="com.apress.springrecipes.shop.ProductCreator"
factory-method="createProduct">
<constructor-arg value="aaa" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.ProductCreator"
factory-method="createProduct">
<constructor-arg value="cdrw" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.ProductCreator"
factory-method="createProduct">
<constructor-arg value="dvdrw" />
</bean>
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" scope="prototype" />
</beans>
通过某个bean的方法创建新的bean，例如
package com.apress.springrecipes.shop;
import java.util.Map;
public class ProductCreator {
private Map<String, Product> products;
public void setProducts(Map<String, Product> products) {
this.products = products;
}
public Product createProduct(String productId) {
Product product = products.get(productId);
if (product != null) {
return product;
}
throw new IllegalArgumentException("Unknown product");
}
}
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean id="productCreator"
class="com.apress.springrecipes.shop.ProductCreator">
<property name="products">
<map>
<entry key="aaa">
<bean class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
</bean>
</entry>
<entry key="cdrw">
<bean class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
</bean>
</entry>
<entry key="dvdrw">
<bean class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="3.0" />
</bean>
</entry>
</map>
</property>
</bean>
<bean id="aaa" factory-bean="productCreator"
factory-method="createProduct">
<constructor-arg value="aaa" />
</bean>
<bean id="cdrw" factory-bean="productCreator"
factory-method="createProduct">
<constructor-arg value="cdrw" />
</bean>
<bean id="dvdrw" factory-bean="productCreator"
factory-method="createProduct">
<constructor-arg value="dvdrw" />
</bean>
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" scope="prototype" />
</beans>
配置中，'aaa','cdrw','dvdrw'是通过id为productCreator的bean 的createProduct方法创建的。
2-11. Use Spring Environments and Profiles to Load Different Sets of POJOs
可以通过profile的给不同的配置加标签，然后根据实际情况激活。示例中profile分为五中：spring、summer、autumn、winter以及global，
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<beans profile="spring">
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
<property name="capacity" value="700" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="3.0" />
<property name="capacity" value="700" />
</bean>
</beans>
<beans profile="summer,winter">
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.0" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.0" />
<property name="capacity" value="700" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="2.5" />
<property name="capacity" value="700" />
</bean>
</beans>
<beans profile="autumn">
<bean id="aaa" class="com.apress.springrecipes.shop.Battery">
<property name="name" value="AAA" />
<property name="price" value="2.5" />
<property name="rechargeable" value="true" />
</bean>
<bean id="cdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="CD-RW" />
<property name="price" value="1.5" />
<property name="capacity" value="700" />
</bean>
<bean id="dvdrw" class="com.apress.springrecipes.shop.Disc">
<property name="name" value="DVD-RW" />
<property name="price" value="3.0" />
<property name="capacity" value="700" />
</bean>
</beans>
<beans profile="global">
<bean id="shoppingCart" class="com.apress.springrecipes.shop.ShoppingCart" scope="prototype" />
<bean id="cashier" class="com.apress.springrecipes.shop.Cashier" init-method="openFile" destroy-method="closeFile">
<property name="fileName" value="checkout" />
<property name="path" value="c:/Windows/Temp/cashier" />
</bean>
</beans>
</beans>
激活global和winter
package com.apress.springrecipes.shop;
import org.springframework.context.support.GenericXmlApplicationContext;
public class Main {
public static void main(String[] args) throws Exception {
GenericXmlApplicationContext context = new GenericXmlApplicationContext();
context.getEnvironment().setActiveProfiles("global","winter");
context.load("beans.xml");
context.refresh();
Product aaa = (Product) context.getBean("aaa");
Product cdrw = (Product) context.getBean("cdrw");
Product dvdrw = (Product) context.getBean("dvdrw");
ShoppingCart cart1 = (ShoppingCart) context.getBean("shoppingCart");
cart1.addItem(aaa);
cart1.addItem(cdrw);
System.out.println("Shopping cart 1 contains " + cart1.getItems());
ShoppingCart cart2 = (ShoppingCart) context.getBean("shoppingCart");
cart2.addItem(dvdrw);
System.out.println("Shopping cart 2 contains " + cart2.getItems());
Cashier cashier = (Cashier) context.getBean("cashier");
cashier.checkout(cart1);
cashier.checkout(cart2);
}
}
也可以用java命令的参数：-Dspring.profiles.active="global,winter"来执行。也可以在Spring的Servlet的 web.xml的配置来激活：
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