比beanutil更加灵活的dto转换工具dozer

准确的说，是因为pojo无法一招走天下或者说内外部隔离的原因，所以有些时候，不得不在两个bean之间做copy或者转换映射。对于直接性的属性拷贝beanutil以及能够满足大部分要求，但是如果遇到字段不一致或者需要二次处理的情况下，就需要进行人工代码处理了。而且这些重复除非通过某种方式管理起来，不然系统中会有大量的复制粘贴。

周六的时候，一个同事说他们那边使用的dozer，还挺好用的，于是看了下官方手册http://dozer.sourceforge.net/dozer-user-guide.pdf，确实比较灵活，有点类似于mybatis之余jdbc原生代码。DEMO示例（实际使用中建议使用spring IOC方式，以及classpath加载，故非以教程式，而是直接可用的代码为例子）如下。

原bean:

package test;

public class SourceObject {
    private String srcName;
    private int age;
    private String notMatch;
    public String getSrcName() {
        return srcName;
    }
    public void setSrcName(String srcName) {
        this.srcName = srcName;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getNotMatch() {
        return notMatch;
    }
    public void setNotMatch(String notMatch) {
        this.notMatch = notMatch;
    }
}

目标bean:

package test;

public class DestinationObject {
    private String destName;
    private int age;
    private String notExist;
    private String dictName;
    public String getDestName() {
        return destName;
    }
    public void setDestName(String destName) {
        this.destName = destName;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getNotExist() {
        return notExist;
    }
    public void setNotExist(String notExist) {
        this.notExist = notExist;
    }
    public String getDictName() {
        return dictName;
    }
    public void setDictName(String dictName) {
        this.dictName = dictName;
    }
    
    public void dictSet(String destName) {
        this.dictName = "dict " + destName;
    }
}

转换映射文件：

<?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">
  <configuration>
    <stop-on-errors>true</stop-on-errors>
    <date-format>MM/dd/yyyy HH:mm</date-format>  <!-- 设置java.util.Date的默认格式, 用于 -->
    <wildcard>true</wildcard>
  </configuration>

  <mapping>
    <class-a>test.SourceObject</class-a>
    <class-b>test.DestinationObject</class-b>
      <field>
        <a>srcName</a>
        <b>destName</b>
      </field>
      <field>
        <a>srcName</a> <!-- 一个属性可以映射到多个目标 -->
        <b set-method="dictSet">dictName</b> <!-- 会将destName作为参数传递给dictSet方法 -->
      </field>
  </mapping> 
  <!--  other custom class mappings would go here....... -->   
                   
</mappings>

spring配置文件：

<?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-4.0.xsd"
       default-autowire="byName" 
default-lazy-init="false">

  <bean id="mapper" class="org.dozer.spring.DozerBeanMapperFactoryBean">
    <property name="mappingFiles">
      <list>
        <value>classpath*:*DTOMapper.xml</value>
      </list>
    </property>
  </bean>
</beans>

测试类：

package test;

import org.dozer.DozerBeanMapper;
import org.dozer.Mapper;
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 org.springframework.test.context.transaction.TransactionConfiguration;

import com.alibaba.fastjson.JSON;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:spring-dozer.xml"})
@TransactionConfiguration(defaultRollback = false)
public class DozerBeanMapperTest {
    @Autowired
    Mapper mapperNotDefault;

    @Test
    public void testDozerBeanMapper(){
        SourceObject sourceObject = new SourceObject();
        sourceObject.setAge(1);
        sourceObject.setNotMatch("notmatch");
        sourceObject.setSrcName("name1");
        DestinationObject destObject;
        Mapper mapper = new DozerBeanMapper();
        destObject = mapper.map(sourceObject, DestinationObject.class);
        System.out.println(JSON.toJSONString(sourceObject));
        System.out.println(JSON.toJSONString(destObject));

        destObject = mapperNotDefault.map(sourceObject, DestinationObject.class);
        System.out.println(JSON.toJSONString(sourceObject));
        System.out.println(JSON.toJSONString(destObject));
    }
}

输出如下：

{"age":1,"notMatch":"notmatch","srcName":"name1"}
{"age":1}
{"age":1,"notMatch":"notmatch","srcName":"name1"}
{"age":1,"destName":"name1","dictName":"dict name1"}