Bean Mapping Utils--Dozer初探

最近从springside3项目里看到个值对象拷贝框架 dozer 学习了一下，发现还是满有用的，写点学习小结

适用情况：分层架构时对DTO，VO，Pojo之间值属性的拷贝，并且这种拷贝可以跨属性的，即两个对象可以完全不一样（字段名称，字段属性）

比如将基本类型转为包装类型，数组转字符串，各种Collection集合类型之间互相转化，举个例子页面有个产品form有个关键词属性 是个String数组，对应页面一排输入框，而在数据库里是用逗号（，）分隔的字符串，一般都是在程序里用

String.split(","),StringUtils.join(String[]s)这样的方法进行转化,现在将这两个互相转化的方法定义的pojo中

写道

public void setWords(String words) {
this.keyWords = words.split(",");
}
public String getWords(){
return StringUtils.join(keyWords);
}

 在相应的dozer-bean-mapping.xml文件中定义get，set方法

写道

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mappings PUBLIC "-//DOZER//DTD MAPPINGS//EN"
"http://dozer.sourceforge.net/dtd/dozerbeanmapping.dtd">
<mappings>
<configuration>
<stop-on-errors>true</stop-on-errors>
<date-format>yyyy-MM-dd</date-format>
<wildcard>true</wildcard>
<trim-strings>true</trim-strings>
</configuration>
<mapping map-null="false">
<class-a>com.spring.bean.Students</class-a>
<class-b>com.spring.view.command.StudentCommand</class-b>
<field>
<a>word</a>
<b set-method="setWords(java.lang.String)" get-method="getWords">keyWords</b>
</field>
</mapping>
</mappings>

 测试代码

写道

package com.spring.test;

import static java.lang.System.out;

import java.util.Date;

import net.sf.dozer.util.mapping.DozerBeanMapper;

import org.apache.commons.lang.builder.ReflectionToStringBuilder;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.spring.bean.Students;
import com.spring.view.command.StudentCommand;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class BaseTest {

@Autowired
private DozerBeanMapper dozer;

@Test
public void fristDozerTetst() {
Students stu = new Students();
stu.setAge(" dff ");
stu.setId("dd");
stu.setDate(new Date());
stu.setWord("1,2,3,4,5,6");
StudentCommand studentCommand = (StudentCommand) dozer.map(stu,
StudentCommand.class);
out.println(ReflectionToStringBuilder.toString(studentCommand));
StudentCommand sc1 = new StudentCommand();
sc1.setAge("444");
sc1.setName("");
sc1.setValue(5555);
sc1.setDate("2008-08-08");
sc1.setKeyWords(new String[] { "a", "b", "c", "d", "e", "f" });
Students stu1 = (Students) dozer.map(sc1, Students.class);
out.println(ReflectionToStringBuilder.toString(stu1));
String s=stu1.getWord();
out.println(stu1.getWord());
}

 

控制台输出

写道

com.spring.view.command.StudentCommand@f9c40[id=dd,name=<null>,age=dff,value=0,date=2008-06-03,keyWords={1,2,3,4,5,6}]
com.spring.bean.Students@1bb5c09[id=<null>,name=,age=444,value=5555,order=<null>,date=Fri Aug 08 00:00:00 CST 2008,orderByType=<null>,word=abcdef]
abcdef

  可见 dozer将原来的字符串"1,2,3,4,5,6"转化为字符数组={1,2,3,4,5,6}

而字符数组{ "a", "b", "c", "d", "e", "f" }则变为word=abcdef；

另外dozer也可格式化时间

<date-format>yyyy-MM-dd</date-format>
date=2008-06-03

sc1.setDate("2008-08-08");

date=Fri Aug 08 00:00:00 CST 2008

若两个需要互相拷贝的java对象有相同的字段名，则在配置文件中无需在指出就可以自带的copy，很方便

在程序里再也不用出现一堆的setXXX（XXX.getXXX)了

最后是spring的context文件

写道

<?xml version="1.0" encoding="UTF-8"?>
<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-2.5.xsd">
<bean id="net.sf.dozer.util.mapping.MapperIF"
class="net.sf.dozer.util.mapping.DozerBeanMapper" scope="singleton">
<property name="mappingFiles">
<list>
<value>dozer-bean-mapping.xml</value>
</list>
</property>
</bean>
</beans>