实体属性映射框架mapstruct
1. 框架介绍
mapstruct框架是一种实体类间的映射框架，能够通过JAVA注解的形式将一个实体类的属性安全的赋值给另一个实体类。通过一系列注解可以定义实体类属性之间的映射关系，mapstruct会在编译期间生成映射实现类，而非通过反射的方式进行实体类赋值。
（1）安全性高，编译期就实现源对象到目标对象的映射，如果编译器能够通过，运行期就不会报错。
（2）速度快，运行期间直接调用实现类的方法，不会在运行期间使用反射进行转化。
2. 项目依赖
- 实体Getter和Setter方法生成依赖
- 实体映射依赖
- JSON依赖
- 单元测试依赖
<dependencies>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.28version>
dependency>
<dependency>
<groupId>org.mapstructgroupId>
<artifactId>mapstructartifactId>
<version>1.4.2.Finalversion>
dependency>
<dependency>
<groupId>org.mapstructgroupId>
<artifactId>mapstruct-processorartifactId>
<version>1.4.2.Finalversion>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>fastjsonartifactId>
<version>1.2.83version>
dependency>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.13.2version>
<scope>testscope>
dependency>
dependencies>
3. 基础映射
单一实体映射 + 批量实体映射
3.1 持久层实体类
@Getter
@Setter
public class SysUserDO implements Serializable {
/**
* 用户编号
*/
private Long userId;
/**
* 用户姓名
*/
private String realName;
/**
* 用户年龄
*/
private Integer age;
/**
* 用户性别
*/
private Boolean sex;
/**
* 出生日期
*/
private LocalDate birthday;
@Override
public String toString() {
return JSON.toJSONString(this);
}
}
3.2 业务层实体类
@Getter
@Setter
public class SysUserBO {
/**
* 用户编号
*/
private Long userId;
/**
* 用户姓名
*/
private String realName;
/**
* 用户年龄
*/
private Integer age;
/**
* 用户性别
*/
private Boolean sex;
/**
* 出生日期
*/
private LocalDate birthday;
@Override
public String toString() {
return JSON.toJSONString(this);
}
}
3.3 转换层接口
@Mapper
public interface SysUserTransfer {
/**
* 实体转换
*
* @param user 持久层-系统用户实体
* @return 业务层-系统用户实体
*/
@Mappings({
@Mapping(source = "userId", target = "userId"),
@Mapping(source = "realName", target = "realName"),
@Mapping(source = "age", target = "age"),
@Mapping(source = "sex", target = "sex"),
@Mapping(source = "birthday", target = "birthday")
})
SysUserBO transfer(SysUserDO user);
/**
* 实体列表转换
*
* @param users 持久层-系统用户实体列表
* @return 业务层-系统用户实体列表
*/
@Mappings({
@Mapping(source = "userId", target = "userId"),
@Mapping(source = "realName", target = "realName"),
@Mapping(source = "age", target = "age"),
@Mapping(source = "sex", target = "sex"),
@Mapping(source = "birthday", target = "birthday")
})
List<SysUserBO> transfers(List<SysUserDO> users);
}
3.4 接口测试类
public class SysUserTransferTest {
@Test
public void transfer() {
// 1.构造持久层系统用户实例
SysUserDO sysUserDO = new SysUserDO();
sysUserDO.setUserId(10001L);
sysUserDO.setRealName("亡灵天灾");
sysUserDO.setAge(26);
sysUserDO.setSex(true);
sysUserDO.setBirthday(LocalDate.now());
// 2.获取转换接口实例并转换实体
SysUserTransfer sysUserTransfer = Mappers.getMapper(SysUserTransfer.class);
SysUserBO sysUserBO = sysUserTransfer.transfer(sysUserDO);
// 3.打印实体内容
System.out.println("sysUserDO = " + sysUserDO);
System.out.println("sysUserBO = " + sysUserBO);
}
@Test
public void transfers() {
// 1.批量构造持久层系统用户实例
List<SysUserDO> sysUserDOS = new ArrayList<>();
for (int i = 0; i < 10; i++) {
SysUserDO sysUserDO = new SysUserDO();
sysUserDO.setUserId(Long.valueOf(10000 + i));
sysUserDO.setRealName("亡灵天灾" + i);
sysUserDO.setAge(26);
sysUserDO.setSex(true);
sysUserDO.setBirthday(LocalDate.now());
sysUserDOS.add(sysUserDO);
}
// 2.获取转换接口实例并批量转换实体
SysUserTransfer sysUserTransfer = Mappers.getMapper(SysUserTransfer.class);
List<SysUserBO> sysUserBOS = sysUserTransfer.transfers(sysUserDOS);
// 3.批量打印实体内容
for (int i = 0; i < 10; i++) {
System.out.println("sysUserDO = " + sysUserDOS.get(i));
System.out.println("sysUserBO = " + sysUserBOS.get(i));
System.out.println("-----------------------------------------------------------------------------");
}
}
}
- 单一实体转换结果
- 批量实体转换结果
4. 嵌套映射
系统用户实体中包含系统角色属性的嵌套实体转换
4.1 持久层实体类
- 持久层系统角色实体类
@Getter
@Setter
public class SysRoleDO implements Serializable {
/**
* 角色编号
*/
private Long roleId;
/**
* 角色描述
*/
private String roleDesc;
@Override
public String toString() {
return JSON.toJSONString(this);
}
}
- 持久层系统用户实体类
@Getter
@Setter
public class SysUserDO implements Serializable {
/**
* 用户编号
*/
private Long userId;
/**
* 用户姓名
*/
private String realName;
/**
* 用户角色
*/
private List<SysRoleDO> roles;
@Override
public String toString() {
return JSON.toJSONString(this);
}
}
4.2 业务层实体类
- 业务层系统角色实体类
@Getter
@Setter
public class SysRoleBO {
/**
* 角色编号
*/
private Long roleId;
/**
* 角色描述
*/
private String roleDesc;
@Override
public String toString() {
return JSON.toJSONString(this);
}
}
- 业务层系统用户实体类
@Getter
@Setter
public class SysUserBO {
/**
* 用户编号
*/
private Long userId;
/**
* 用户姓名
*/
private String realName;
/**
* 用户角色
*/
private List<SysRoleBO> roles;
@Override
public String toString() {
return JSON.toJSONString(this);
}
}
4.3 转换层接口
- 系统角色实体转换接口
@Mapper
public interface SysRoleTransfer {
/**
* 实体转换
*
* @param role 持久层-系统角色实体
* @return 业务层-系统角色实体
*/
@Mappings({
@Mapping(source = "roleId", target = "roleId"),
@Mapping(source = "roleDesc", target = "roleDesc")
})
SysRoleBO transfer(SysRoleDO role);
/**
* 实体列表转换
*
* @param roles 持久层-系统角色实体列表
* @return 业务层-系统角色实体列表
*/
@Mappings({
@Mapping(source = "roleId", target = "roleId"),
@Mapping(source = "roleDesc", target = "roleDesc")
})
List<SysRoleBO> transfers(List<SysRoleDO> roles);
}
- 系统用户实体转换接口
@Mapper
public interface SysUserTransfer {
/**
* 实体转换
*
* @param user 持久层-系统用户实体
* @return 业务层-系统用户实体
*/
@Mappings({
@Mapping(source = "userId", target = "userId"),
@Mapping(source = "realName", target = "realName"),
@Mapping(source = "roles", target = "roles")
})
SysUserBO transfer(SysUserDO user);
/**
* 实体列表转换
*
* @param users 持久层-系统用户实体列表
* @return 业务层-系统用户实体列表
*/
@Mappings({
@Mapping(source = "userId", target = "userId"),
@Mapping(source = "realName", target = "realName"),
@Mapping(source = "roles", target = "roles")
})
List<SysUserBO> transfers(List<SysUserDO> users);
}
4.4 接口测试类
public class SysUserTransferTest {
@Test
public void transfer() {
SysUserDO sysUserDO = new SysUserDO();
sysUserDO.setUserId(10001L);
sysUserDO.setRealName("亡灵天灾");
SysRoleDO role1 = new SysRoleDO();
role1.setRoleId(10001L);
role1.setRoleDesc("超级管理员");
SysRoleDO role2 = new SysRoleDO();
role2.setRoleId(10002L);
role2.setRoleDesc("系统管理员");
sysUserDO.setRoles(new ArrayList() {{
add(role1);
add(role2);
}});
SysUserTransfer sysUserTransfer = Mappers.getMapper(SysUserTransfer.class);
SysUserBO sysUserBO = sysUserTransfer.transfer(sysUserDO);
System.out.println("sysUserDO = " + sysUserDO);
System.out.println("sysUserBO = " + sysUserBO);
}
}
5. 合并映射
将多个实例映射成一个实例
5.1 转换层接口
@Mapper
public interface SysUserTransfer {
/**
* 实体转换
*
* @param user 持久层-系统用户实体
* @param roles 持久层-系统角色实体列表
* @return 业务层-系统用户实体
*/
@Mappings({
@Mapping(source = "user.userId", target = "userId"),
@Mapping(source = "user.realName", target = "realName"),
@Mapping(source = "roles", target = "roles")
})
SysUserBO transfer(SysUserDO user, List<SysRoleDO> roles);
}
5.2 接口测试类
public class SysUserTransferTest {
@Test
public void transfer() {
SysUserDO sysUserDO = new SysUserDO();
sysUserDO.setUserId(10001L);
sysUserDO.setRealName("亡灵天灾");
SysRoleDO role1 = new SysRoleDO();
role1.setRoleId(10001L);
role1.setRoleDesc("超级管理员");
SysRoleDO role2 = new SysRoleDO();
role2.setRoleId(10002L);
role2.setRoleDesc("系统管理员");
List<SysRoleDO> roles = new ArrayList() {{
add(role1);
add(role2);
}};
SysUserTransfer sysUserTransfer = Mappers.getMapper(SysUserTransfer.class);
SysUserBO sysUserBO = sysUserTransfer.transfer(sysUserDO, roles);
System.out.println("sysUserDO = " + sysUserDO);
System.out.println("sysUserBO = " + sysUserBO);
}
}
6. 特殊映射
（1）常量
（2）默认值
（3）表达式
（4）自定义映射
6.1 转换层接口
@Mapper(imports = {UUID.class})
public interface SysUserTransfer {
/**
* 实体转换
*
* @param user 持久层-系统用户实体
* @return 业务层-系统用户实体
*/
@Mappings({
@Mapping(target = "userId", constant = "1001L"),
@Mapping(source = "age", target = "age", defaultValue = "25"),
@Mapping(target = "realName", expression = "java(UUID.randomUUID().toString())"),
@Mapping(source = "hight", target = "hight", qualifiedByName = "hightHandle")
})
SysUserBO transfer(SysUserDO user);
/**
* 用户身高特殊处理
*
* @param sourceHight 原始身高
* @return 结果身高
*/
@Named(value = "hightHandle")
default Double hightHandle(Double sourceHight) {
return Objects.nonNull(sourceHight) ? sourceHight + 10 : sourceHight;
}
}
6.2 接口测试类
public class SysUserTransferTest {
@Test
public void transfer() {
SysUserDO sysUserDO = new SysUserDO();
sysUserDO.setUserId(10002L);
sysUserDO.setRealName("亡灵天灾");
sysUserDO.setHight(171.50);
SysUserTransfer sysUserTransfer = Mappers.getMapper(SysUserTransfer.class);
SysUserBO sysUserBO = sysUserTransfer.transfer(sysUserDO);
System.out.println("sysUserDO = " + sysUserDO);
System.out.println("sysUserBO = " + sysUserBO);
}
}
7. 切面处理
（1）映射前置处理
（2）映射后置处理
7.1 转换层接口
@Mapper
public interface SysUserTransfer {
/**
* 实体转换
*
* @param user 持久层-系统用户实体
* @return 业务层-系统用户实体
*/
@Mappings({
@Mapping(source = "userId", target = "userId"),
@Mapping(source = "realName", target = "realName"),
@Mapping(source = "age", target = "age"),
@Mapping(source = "hight", target = "hight")
})
SysUserBO transfer(SysUserDO user);
/**
* 前置处理
*
* @param sourceUser 原始系统用户
*/
@BeforeMapping
default void beforeMapping(SysUserDO sourceUser) {
System.out.println("sourceUser = " + sourceUser);
}
/**
* 后置处理
* @param targetUser 目标系统用户
*/
@AfterMapping
default void afterMapping(@MappingTarget SysUserBO targetUser) {
System.out.println("targetUser = " + targetUser);
}
}
7.2 接口测试类
public class SysUserTransferTest {
@Test
public void transfer() {
SysUserDO sysUserDO = new SysUserDO();
sysUserDO.setUserId(10001L);
sysUserDO.setRealName("亡灵天灾");
sysUserDO.setAge(25);
sysUserDO.setHight(171.50);
SysUserTransfer sysUserTransfer = Mappers.getMapper(SysUserTransfer.class);
SysUserBO sysUserBO = sysUserTransfer.transfer(sysUserDO);
System.out.println("sysUserDO = " + sysUserDO);
System.out.println("sysUserBO = " + sysUserBO);
}
}
