Dozer小试

 

一、简介

       分析多层架构的JEE系统,经常存在JavaBean直接的拷贝，典型的解决方案就是手动拷贝,弊端很明显,代码中充斥大量Set Get方法,真正的业务没埋藏与值的拷贝之中.另一种方案就是使用BeanUtil,但BeanUtil不够很好的灵活性,又时候还不得不手动拷贝。

       Dozer提供了一种非常好的解决方案。

       Dozer 是一个对象转换工具。 Dozer可以在JavaBean到JavaBean之间进行递归数据复制,并且这些JavaBean可以是不同的复杂的类型。 所有的mapping，Dozer将会很直接的将名称相同的fields进行复制，如果field名不同，或者有特别的对应要求，则可以在xml中进行定义。 更多详细请参考dozer官网：http://dozer.sourceforge.net/documentation/about.html 。

 

二、下载

       1、http://sourceforge.net/projects/dozer/files/

       2、在maven中，pom文中加入：

 

<dependency>
	<groupId>net.sf.dozer</groupId>
	<artifactId>dozer</artifactId>
	<version>5.4.0</version>
</dependency>

 

三、示例

      po Book类

package dozer;

import java.util.Date;

/**
 * @author zhuc
 * @create 2013-3-28 下午1:57:50
 */
public class Book {

	private Integer id;

	private String name;

	private String author;

	private String capacity;

	private Date birthday;

	private String bookTypeName;

	private Integer source;

	/**
	 * @return the name
	 */
	public String getName() {
		return name;
	}

	/**
	 * @return the author
	 */
	public String getAuthor() {
		return author;
	}

	/**
	 * @param name the name to set
	 */
	public void setName(String name) {
		this.name = name;
	}

	/**
	 * @param author the author to set
	 */
	public void setAuthor(String author) {
		this.author = author;
	}

	/**
	 * @return the capacity
	 */
	public String getCapacity() {
		return capacity;
	}

	/**
	 * @param capacity the capacity to set
	 */
	public void setCapacity(String capacity) {
		this.capacity = capacity;
	}

	/**
	 * @return the id
	 */
	public Integer getId() {
		return id;
	}

	/**
	 * @param id the id to set
	 */
	public void setId(Integer id) {
		this.id = id;
	}

	/**
	 * @return the birthday
	 */
	public Date getBirthday() {
		return birthday;
	}

	/**
	 * @param birthday the birthday to set
	 */
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

	/**
	 * @return the bookTypeName
	 */
	public String getBookTypeName() {
		return bookTypeName;
	}

	/**
	 * @param bookTypeName the bookTypeName to set
	 */
	public void setBookTypeName(String bookTypeName) {
		this.bookTypeName = bookTypeName;
	}

	/**
	 * @return the source
	 */
	public Integer getSource() {
		return source;
	}

	/**
	 * @param source the source to set
	 */
	public void setSource(Integer source) {
		this.source = source;
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return "Book [id=" + id + ", name=" + name + ", author=" + author + ", capacity=" + capacity + ", birthday="
				+ birthday + ", bookTypeName=" + bookTypeName + ", source=" + source + "]";
	}

}

 

      vo BookVo类

package dozer;

/**
 * @author zhuc
 * @create 2013-3-28 下午1:58:34
 */
public class BookVo {

	private Integer id;

	private String nameVo;

	private String authorVo;

	private Integer capacity;

	private String day;

	private BookType bookType;

	private String source;

	/**
	 * @return the nameVo
	 */
	public String getNameVo() {
		return nameVo;
	}

	/**
	 * @return the authorVo
	 */
	public String getAuthorVo() {
		return authorVo;
	}

	/**
	 * @param nameVo the nameVo to set
	 */
	public void setNameVo(String nameVo) {
		this.nameVo = nameVo;
	}

	/**
	 * @param authorVo the authorVo to set
	 */
	public void setAuthorVo(String authorVo) {
		this.authorVo = authorVo;
	}

	/**
	 * @return the capacity
	 */
	public Integer getCapacity() {
		return capacity;
	}

	/**
	 * @param capacity the capacity to set
	 */
	public void setCapacity(Integer capacity) {
		this.capacity = capacity;
	}

	/**
	 * @return the id
	 */
	public Integer getId() {
		return id;
	}

	/**
	 * @param id the id to set
	 */
	public void setId(Integer id) {
		this.id = id;
	}

	/**
	 * @return the day
	 */
	public String getDay() {
		return day;
	}

	/**
	 * @param day the day to set
	 */
	public void setDay(String day) {
		this.day = day;
	}

	/**
	 * @return the bookType
	 */
	public BookType getBookType() {
		return bookType;
	}

	/**
	 * @param bookType the bookType to set
	 */
	public void setBookType(BookType bookType) {
		this.bookType = bookType;
	}

	/**
	 * @return the source
	 */
	public String getSource() {
		return source;
	}

	/**
	 * @param source the source to set
	 */
	public void setSource(String source) {
		this.source = source;
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return "BookVo [id=" + id + ", nameVo=" + nameVo + ", authorVo=" + authorVo + ", capacity=" + capacity
				+ ", day=" + day + ", bookType=" + bookType + ", source=" + source + "]";
	}

}

 

其中vo中包含复杂对象BookType类

 

package dozer;

/**
 * @author zhuc
 * @create 2013-3-28 下午2:43:16
 */
public class BookType {

	private String name;

	private String desc;

	/**
	 * @return the name
	 */
	public String getName() {
		return name;
	}

	/**
	 * @return the desc
	 */
	public String getDesc() {
		return desc;
	}

	/**
	 * @param name the name to set
	 */
	public void setName(String name) {
		this.name = name;
	}

	/**
	 * @param desc the desc to set
	 */
	public void setDesc(String desc) {
		this.desc = desc;
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return "BookType [name=" + name + ", desc=" + desc + "]";
	}

}

 

这里在复制对象，我们发现有类型不一致、名称不一样或者都不一样的需要自定义映射的字段等，我们需要自定义mapping.xml 映射文件。

 

<?xml version="1.0" encoding="UTF-8"?>
<mappings xmlns="http://dozer.sourceforge.net" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://dozer.sourceforge.net 
 	http://dozer.sourceforge.net/schema/beanmapping.xsd">
	
	<mapping date-format="yyyy-MM-dd HH:mm:ss">
		<class-a>dozer.Book</class-a>
		<class-b>dozer.BookVo</class-b>
		<field>
			<a>name</a>
			<b>nameVo</b>
		</field>
		<field>
			<a>author</a>
			<b>authorVo</b>
		</field>
		<field>
			<a>birthday</a>
			<b>day</b>
		</field>
		<field>
			<a>bookTypeName</a>
			<b>bookType.name</b>
		</field>
		<field custom-converter="dozer.MyCustomConverter">
			<a>source</a>
			<b>source</b>
		</field>
	</mapping>
	
</mappings>

 

 

package dozer;

import org.dozer.CustomConverter;

/**
 * 自定义转换类
 * @author zhuc
 * @create 2013-3-28 下午2:49:39
 */
public class MyCustomConverter implements CustomConverter {

	@Override
	public Object convert(Object existingDestinationFieldValue, Object sourceFieldValue, Class<?> destinationClass,
			Class<?> sourceClass) {
		Object obj = null;
		if (null != sourceFieldValue) {
			if (sourceFieldValue instanceof Integer) {
				if (((Integer) sourceFieldValue).intValue() == 1900) {
					obj = "20世纪";
				} else if (((Integer) sourceFieldValue).intValue() == 2000) {
					obj = "21世纪";
				}
			} else if (sourceFieldValue instanceof String) {
				if ("20世纪".equals(sourceFieldValue)) {
					obj = 1900;
				} else if ("21世纪".equals(sourceFieldValue)) {
					obj = 2000;
				}
			}
		}
		return obj;
	}

}

 

 

 

到这里，我们来看下真正的代码转换测试类：

 

package dozer;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.dozer.DozerBeanMapper;

/**
 * @author zhuc
 * @create 2013-3-28 下午3:15:49
 */
public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		List<String> mappers = new ArrayList<String>();
		mappers.add("mapper.xml");

		DozerBeanMapper dozer = new DozerBeanMapper();
		dozer.setMappingFiles(mappers);

		Book book = new Book();
		book.setId(100); // id	2个JavaBean一致
		book.setName("明天"); // Book:name(String)  <->  BookVo:nameVo(String)	类型一致,名称不一致
		book.setAuthor("James"); // Book:author(String)  <->  BookVo:authorVo(String)	类型一致,名称不一致
		book.setCapacity("123"); // Book:capacity(String)  <->  BookVo:capacity(Integer)	类型不一致,名称一致
		book.setBirthday(new Date()); // Book:birthday(Date)  <->  BookVo:day(String)	类型名称都不一致,且Date<->String互转
		book.setBookTypeName("科教类"); // Book:bookTypeName(String)  <->  BookVo:BookType:name(String)	源类的字段映射为目标类的复杂对象的字段。
		book.setSource(1900); // Book:source(Integer)  <->  BookVo:source(String)	自定义的转换,需要实现dozer的CustomConverter接口

		BookVo vo = new BookVo();
		dozer.map(book, vo);

		System.out.println(book);
		System.out.println(vo);
	}

}

 

 

输出结果：

Book [id=100, name=明天, author=James, capacity=123, birthday=Thu Mar 28 16:00:20 CST 2013, bookTypeName=科教类, source=1900]
BookVo [id=100, nameVo=明天, authorVo=James, capacity=123, day=2013-03-28 16:00:20, bookType=BookType [name=科教类, desc=null], source=20世纪]