类或集合的转换(model-dto之间的转换)

1.User.class

package com.demo.model;

import lombok.Data;

/**
 * @date 2018/4/14
 * 注意User中的name和UserVo中的username属性名不同，age的类型也不同
 */
@Data
public class User {
    private String name;
    private String age;
    private String sex;
    
}

2.UserVo.class

package com.demo.vo;

import lombok.Data;

/**
 * @date 2018/4/14
 */
@Data
public class UserVo {

    private String username;
    private Integer age;
    private String  sex;
}

3.User1.class

package com.demo.model;
import lombok.Data;

/**
 * @date 2018/4/14
 * 注意age的类型不同
 */
@Data
public class User1 {
    private String username;
    private String age;
    private String  sex;
    
}

4.UserVo1.class

package com.demo.vo;

import lombok.Data;

/**
 * @date 2018/4/14
 */
@Data
public class UserVo1 {
    private String username;
    private Integer age;
    private String  sex;
}

5.User2.class

package com.demo.model;
import lombok.Data;

/**
 * @date 2018/4/14
 * 注意User中的name和UserVO中的username属性名不同，age的类型也不同
 */
@Data
public class User2 {
    private String name;
    private String age;
    private String  sex;
}

6.UserVo2.class

package com.demo.vo;

import lombok.Data;

/**
 * @date 2018/4/14
 */
@Data
public class UserVo2 {
    private String username;
    private Integer age;
    private String  sex;
}

7.pom.xml

<!-- https://mvnrepository.com/artifact/ma.glasnost.orika/orika-core -->
        <dependency>
            <groupId>ma.glasnost.orika</groupId>
            <artifactId>orika-core</artifactId>
            <version>1.5.2</version>
        </dependency>

8.第一种方法

/**
     * 1.单个类映射单个类(字段名不完全一样,类型也可以不一样)
     */
    @Test
    public void userToUserVo(){
        User user = new User();
        user.setName("张三");
        user.setAge("20");
        user.setSex("男");

        //1.创建MapperFactory
        MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();

        //2.先注册以下映射方式
        mapperFactory.classMap(User.class, UserVo.class)
                //不一样的字段映射
                .field("name","username")
                //剩余的字段映射
                .byDefault()
                .register();
        UserVo userVo = mapperFactory.getMapperFacade().map(user, UserVo.class);
        System.out.println(user);
        System.out.println(userVo);
        //输出结果
       /* User(name=张三, age=20, sex=男)
        UserVo(username=张三, age=20, sex=男)*/
    }

    /**
     * 2. 单个类映射单个类(字段名完全一样)
     */
    @Test
    public void user1ToUserVo1(){
        User1 user1 = new User1();
        user1.setUsername("张三");
        user1.setAge("20");
        user1.setSex("男");

        //1.创建MapperFactory
        MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();

        UserVo1 userVo1 = mapperFactory.getMapperFacade().map(user1, UserVo1.class);
        System.out.println(user1);
        System.out.println(userVo1);

        //输出结果
       /* User1(username=张三, age=20, sex=男)
        UserVo1(username=张三, age=20, sex=男)*/
    }

    /**
     * 3.集合之间的映射(字段名不完全一样,类型也可以不一样)
     */
    @Test
    public void user2ListToUser2VoList(){
        List<User2> user2List = new ArrayList<User2>();
        User2 user2 = new User2();
        user2.setName("张三");
        user2.setAge("20");
        user2.setSex("男");
        user2List.add(user2);

        //1.创建MapperFactory
        MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();

        //2.手动配置不一样的属性转换
        mapperFactory.classMap(User2.class,UserVo2.class)
                //不一样的字段映射
                .field("name","username")
                //剩余的字段映射
                .byDefault()
                .register();

        //3.转换List
        List<UserVo2> userVo2List = mapperFactory.getMapperFacade().mapAsList(user2List, UserVo2.class);
        for (User2 user21 : user2List) {
            System.out.println(user21);
        }
        for (UserVo2 userVo2 : userVo2List) {
            System.out.println(userVo2);
        }
        //输出结果
       /* User2(name=张三, age=20, sex=男)
        UserVo2(username=张三, age=20, sex=男)*/
    }

9.第二种使用BeanMapper工具类

BeanMapper.class

 1 package com.demo.util;
 2 
 3 import ma.glasnost.orika.MapperFacade;
 4 import ma.glasnost.orika.MapperFactory;
 5 import ma.glasnost.orika.impl.DefaultMapperFactory;
 6 import ma.glasnost.orika.metadata.Type;
 7 import ma.glasnost.orika.metadata.TypeFactory;
 8 import java.util.List;
 9 
10 
11 /**
12  *
13  *  @date 2018/4/14
14  * 简单封装orika, 实现深度的BeanOfClasssA<->BeanOfClassB复制
15  *
16  * 不要是用Apache Common BeanUtils进行类复制，每次就行反射查询对象的属性列表, 非常缓慢.
17  *
18  * 注意: 需要参考本模块的POM文件，显式引用orika.
19  */
20 public class BeanMapper {
21 
22     private static MapperFacade mapper;
23 
24     static {
25         MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();
26         mapper = mapperFactory.getMapperFacade();
27     }
28 
29     /**
30      * 简单的复制出新类型对象.
31      *
32      * 通过source.getClass() 获得源Class
33      */
34     public static <S, D> D map(S source, Class<D> destinationClass) {
35         return mapper.map(source, destinationClass);
36     }
37 
38     /**
39      * 极致性能的复制出新类型对象.
40      *
41      * 预先通过BeanMapper.getType() 静态获取并缓存Type类型，在此处传入
42      */
43     public static <S, D> D map(S source, Type<S> sourceType, Type<D> destinationType) {
44         return mapper.map(source, sourceType, destinationType);
45     }
46 
47     /**
48      * 简单的复制出新对象列表到ArrayList
49      *
50      * 不建议使用mapper.mapAsList(Iterable<S>,Class<D>)接口, sourceClass需要反射，实在有点慢
51      */
52     public static <S, D> List<D> mapList(Iterable<S> sourceList, Class<S> sourceClass, Class<D> destinationClass) {
53         return mapper.mapAsList(sourceList, TypeFactory.valueOf(sourceClass), TypeFactory.valueOf(destinationClass));
54     }
55 
56     /**
57      * 极致性能的复制出新类型对象到ArrayList.
58      *
59      * 预先通过BeanMapper.getType() 静态获取并缓存Type类型，在此处传入
60      */
61     public static <S, D> List<D> mapList(Iterable<S> sourceList, Type<S> sourceType, Type<D> destinationType) {
62         return mapper.mapAsList(sourceList, sourceType, destinationType);
63     }
64 
65     /**
66      * 简单复制出新对象列表到数组
67      *
68      * 通过source.getComponentType() 获得源Class
69      */
70     public static <S, D> D[] mapArray(final D[] destination, final S[] source, final Class<D> destinationClass) {
71         return mapper.mapAsArray(destination, source, destinationClass);
72     }
73 
74     /**
75      * 极致性能的复制出新类型对象到数组
76      *
77      * 预先通过BeanMapper.getType() 静态获取并缓存Type类型，在此处传入
78      */
79     public static <S, D> D[] mapArray(D[] destination, S[] source, Type<S> sourceType, Type<D> destinationType) {
80         return mapper.mapAsArray(destination, source, sourceType, destinationType);
81     }
82 
83     /**
84      * 预先获取orika转换所需要的Type，避免每次转换.
85      */
86     public static <E> Type<E> getType(final Class<E> rawType) {
87         return TypeFactory.valueOf(rawType);
88     }
89 
90 }

/**
     * 4.BeanMapper工具类只是做了BeanOfClasssA<->BeanOfClassB复制，要求字段属性名完全相同，不同则为null
     *   若需要属性名不同也能转换，则需要类似于上面的特殊配置，参考userToUserVo()和user2ListToUser2VoList()
     */
    @Test
    public void beanMapperTest(){
        //类的转换(字段属性名不一样为null,字段类型可以不一样也行)
        User user = new User();
        user.setName("张三");
        user.setAge("20");
        user.setSex("男");
        UserVo userVo = BeanMapper.map(user, UserVo.class);
        System.out.println(user);
        System.out.println(userVo);
        //输出：
        /*User(name=张三, age=20, sex=男)
        UserVo(username=null, age=20, sex=男)*/

        //集合的转换(字段属性名不一样为null,字段类型可以不一样也行)
        List<User> userList = new ArrayList<User>();
        userList.add(user);
        List<UserVo> userVoList = BeanMapper.mapList(userList, User.class, UserVo.class);
        for (User user1 : userList) {
            System.out.println(user1);
        }
        for (UserVo userVo1 : userVoList) {
            System.out.println(userVo1);
        }
        //输出：
        /*User(name=张三, age=20, sex=男)
        UserVo(username=null, age=20, sex=男)*/
    }

10.第三种使用MapperFacade不需要依赖工具类BeanMapper

OrikaConfig.class

 1 package com.demo.config;
 2 
 3 import ma.glasnost.orika.MapperFacade;
 4 import ma.glasnost.orika.MapperFactory;
 5 import ma.glasnost.orika.impl.DefaultMapperFactory;
 6 import ma.glasnost.orika.metadata.ClassMapBuilder;
 7 import org.springframework.context.annotation.Bean;
 8 import org.springframework.context.annotation.Configuration;
 9 import java.util.LinkedList;
10 import java.util.List;
11 
12 
13 @Configuration
14 public class OrikaConfig {
15 
16     @Bean
17     MapperFactory mapperFactory() {
18         MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();
19         List<ClassMapBuilder> builders = new LinkedList<>();
20 
21         for (ClassMapBuilder builder : builders) {
22             builder.byDefault().register();
23         }
24         return mapperFactory;
25     }
26 
27     @Bean
28     MapperFacade mapperFacade() {
29         MapperFacade mapper = mapperFactory().getMapperFacade();
30         return mapper;
31     }
32 
33 
34 }

    @Autowired
    MapperFacade mapperFacade;

    /**
     * 5.使用MapperFacade不需要依赖工具类BeanMapper，只需要如下两步
     *   ①写配置类OrikaConfig，加入到spring容器中
     *   ②@Autowired MapperFacade mapperFacade;
     */
    @Test
    public void mapperFacadeTest(){
        System.out.println(mapperFacade);
        //类的转换(字段属性名不一样为null,字段类型可以不一样也行)
        User user = new User();
        user.setName("张三");
        user.setAge("20");
        user.setSex("男");
        UserVo userVo = mapperFacade.map(user, UserVo.class);
        System.out.println(user);
        System.out.println(userVo);
        //输出结果：
        /*User(name=张三, age=20, sex=男)
        UserVo(username=null, age=20, sex=男)*/

        //集合的转换(字段属性名不一样为null,字段类型可以不一样也行)
        List<User> userList = new ArrayList<User>();
        userList.add(user);
        List<UserVo> userVoList = mapperFacade.mapAsList(userList, UserVo.class);
        for (User user1 : userList) {
            System.out.println(user1);
        }
        for (UserVo userVo1: userVoList) {
            System.out.println(userVo1);
        }
        //输出结果
        /*User(name=张三, age=20, sex=男)
        UserVo(username=null, age=20, sex=男)*/
    }

相关阅读:
日期和时间运算：上月最后一天
 SY全局系统字段
 内表、结构赋值转换规则
 基本类型赋值转换规则表
 嵌套结构使用：struc1-struc2-XXX
TYPES、DATA、TYPE、LIKE、CONSTANTS、STATICS、TABLES
ABAP WRITE、WRITE TO、FORMAT语句
 ABAP DESCRIBE语句
 数据词典与ABAP类型映射
 Field+offset(len)
原文地址：https://www.cnblogs.com/jcjssl/p/9395091.html