Dozer是一个JavaBean到JavaBean之间的转换工具。它就可以递归的将数据从一个对象复制到另一个对象。

Dozer的官方文档：http://dozer.sourceforge.net/documentation/whymap.html
Dozer的github地址：https://github.com/DozerMapper/dozer

Dozer转换好处：

• 如果两个类型属性名称一致，不论类型是否一致。dozer都可以自动配置
• 如果类中有null property，dozer可以默认将属性指为null，不会抛出nullPointerExeception异常。

Dozer整合项目（有三种：xml形式/注解配置/API配置）

引入jar

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

xml配置

• xml头部文件

<?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">

</mappings> 

xml中mapping配置（将a中对应的属性名转换为b中对应的属性名，<a>标签转换为<b>标签）

<mapping>
        <class-a>com.qding.brick.pojo.biz.Project</class-a>
        <class-b>com.qding.openapi.call.stage.struct.Project</class-b>
        <field>
            <a>id</a>
            <b>projectId</b>
        </field>
        <field>
            <a>name</a>
            <b>projectName</b>
        </field>
        <field>
            <a>address</a>
            <b>addr</b>
        </field>
</mapping>

注：官网着重建议：在现实应用中，最好不要每次映射对象时都创建一个Mapper实例来工作，这样会产生不必要的开销。如果你不使用IoC容器（如：spring）来管理你的项目，那么，最好将Mapper定义为单例模式。

• 测试：

Mapper mapper = new DozerBeanMapper();
DestinationObject destObject =  mapper.map(sourceObject, DestinationObject.class);

• 补充：单例模式例子

public class DozerMapperConstant {
    private static final Mapper mapper= new org.dozer.DozerBeanMapper();
    public static DozerBeanMapper getDozerBeanMapper() {
        return mapper;
    }
}

Mapper announcementDozerMapper =  DozerMapperConstant.dozerMapper;

API方式

import static org.dozer.loader.api.FieldsMappingOptions.*;
import static org.dozer.loader.api.TypeMappingOptions.*;

...

BeanMappingBuilder builder = new BeanMappingBuilder() {
      protected void configure() {
        mapping(Bean.class, Bean.class,
                TypeMappingOptions.oneWay(),
                mapId("A"),
                mapNull(true)
        )
                .exclude("excluded")
                .fields("src", "dest",
                        copyByReference(),
                        collectionStrategy(true, 
                            RelationshipType.NON_CUMULATIVE),
                        hintA(String.class),
                        hintB(Integer.class),
                        FieldsMappingOptions.oneWay(),
                        useMapId("A"),
                        customConverterId("id")
                )
                .fields("src", "dest",
                    customConverter("org.dozer.CustomConverter")
                );
      }
    };

使用

DozerBeanMapper mapper = new DozerBeanMapper();
mapper.addMapping(builder);

注解方式 （mapping自动注入）

a类

public class SourceBean {

    private Long id;

    private String name;

    @Mapping("binaryData")
    private String data;

    @Mapping("pk")
    public Long getId() {
        return this.id;
    }

    public String getName() {
        return this.name;
    }
}

b类

public class TargetBean {

    private String pk;

    private String name;

    private String binaryData;

    public void setPk(String pk) {
        this.pk = pk;
    }

    public void setName(String name) {
        this.name = name;
    }
}