JarCasting1. 概述
在我们日常开发过程中，会存在大量需要对领域对象转换为dto的场景，程序员往往使用getter和setter来对对象进行赋值，当对象的字段过多，手写赋值过程将变得非常麻烦，遗漏字段的事情也常常发生。为发减轻程序员的工作，automapper可以自动完成对象之间的互相转换工作。
2. 快速应用AutoMapper
使用maven添加引用
<dependency>
<groupId>com.zhaofujun.automapper</groupId>
<artifactId>automapper</artifactId>
<version>1.0.release</version>
</dependency>
// 省略对象定义和赋值部分...
IMapper mapper = new AutoMapper();
UserDo userDo = mapper.map(dto, UserDo.class);
直接使用automapper进行对象转换时，automapper将使用默认的转换规则进行转换，具体转换规则见 3.2 默认转换规则
3. 转换演示
3.1 准备工作
为了模拟各场景下的对象转换过程，我们需要先准备两个对象。
UserDto
package com.zhaofujun.automapper;
public class UserDto {
private String id;
private String sex;
private int age;
private String realName;
private String contactAddress;
private String contactTel;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getRealName() {
return realName;
}
public void setRealName(String realName) {
this.realName = realName;
}
public String getContactAddress() {
return contactAddress;
}
public void setContactAddress(String contactAddress) {
this.contactAddress = contactAddress;
}
public String getContactTel() {
return contactTel;
}
public void setContactTel(String contactTel) {
this.contactTel = contactTel;
}
}
UserDo
package com.zhaofujun.automapper;
public class UserDo {
enum Sex{
female,male
}
private String id;
private Sex sex;
private int age;
private String name;
private Contact contact;
public String getId() {
return id;
}
public Sex getSex() {
return sex;
}
public void setSex(Sex sex) {
this.sex = sex;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Contact getContact() {
return contact;
}
public void setContact(Contact contact) {
this.contact = contact;
}
}
Contact
public class Contact {
private String address;
private int tel;
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public int getTel() {
return tel;
}
public void setTel(int tel) {
this.tel = tel;
}
}
3.2 默认转换规则
默认转换规则只转换目标对象中字段带有setter并且在源对象中有同名字段的所有字段信息。
@Test
public void defaultMapper() {
UserDo userDo=new UserDo();
userDo.setAge(100);
IMapper mapper=new AutoMapper();
UserDto userDto = mapper.map(userDo, UserDto.class);
Assert.assertEquals(userDo.getAge(),userDto.getAge());
}
3.3 映射目标对象中字段没有setter的方式
当目标对象中的字段名与源对象中的字段名相同，但目标对象没有setter方法时，可以在配置两个对象的映射关系时设置允许私有字段为true
IMapper接口定义的配置方式
//自动匹配所有带setter，并且同名的字段
ClassMappingBuilder mapping(Class sourceClass,Class targetClass);
//自动匹配所有同名字段
ClassMappingBuilder mapping(Class sourceClass,Class targetClass,boolean allowPrivate);
演示代码
@Test
public void noSetterMap(){
UserDto userDto=new UserDto();
userDto.setId("idid");
IMapper mapper=new AutoMapper();
//允许映射包括没有setter的字段
mapper.mapping(UserDto.class,UserDo.class,true);
UserDo userDo = mapper.map(userDto, UserDo.class);
Assert.assertEquals(userDo.getId(),userDto.getId());
}
3.4 源对象与目标对象字段名不同时的映射方式
当源对象与目标对象中有不同名字段时，需要为源对象与目标对象配置字段映射关系。
ClassMappingBuilder定义的配置方式
ClassMappingBuilder field( String sourceFieldName,String targetFieldName);
演示代码
@Test
public void differentFieldMap(){
UserDto userDto=new UserDto();
userDto.setRealName("name");
IMapper mapper=new AutoMapper();
//允许映射包括没有setter的字段
mapper.mapping(UserDto.class,UserDo.class,true)
.field("realName","name");
UserDo userDo = mapper.map(userDto, UserDo.class);
Assert.assertEquals(userDo.getName(),userDto.getRealName());
}
3.5 排除不需要映射的字段
当目标对象中有的字段不需要映射出去时，可以手动排除指定的字段。
ClassMappingBuilder定义的配置方式
ClassMappingBuilder excludes(String... targetFieldNames);
演示代码
@Test
public void excludeField(){
UserDto userDto=new UserDto();
userDto.setRealName("name");
userDto.setAge(10);
IMapper mapper=new AutoMapper();
//允许映射包括没有setter的字段
mapper.mapping(UserDto.class,UserDo.class,true)
.field("realName","name")
.excludes("age");
UserDo userDo = mapper.map(userDto, UserDo.class);
Assert.assertEquals(userDo.getAge(),0);
}
3.6 映射复杂对象到简单对象
当源对象中的字段是一个子对象时，可以将子对象下的字段映射到目标对象的字段中。 只需自动配置field映射关系时，指定字段名时用“.”来指向子对象下的字段信息。
演示代码
@Test
public void complexToSimple() {
IMapper mapper = new AutoMapper();
mapper.mapping(UserDo.class, UserDto.class)
.field("contact.address", "contactAddress")
.field("contact.tel", "contactTel");
Contact contact = new Contact();
contact.setAddress("address");
contact.setTel(11);
UserDo userDo = new UserDo();
userDo.setContact(contact);
UserDto userDto = mapper.map(userDo, UserDto.class);
Assert.assertEquals(userDo.getContact().getAddress(), userDto.getContactAddress());
}
3.7 简单对象映射到复杂对象
当目标对象中的字段是一个子对象时，可以将源对象的字段映射到目标对象子对象下的字段。 只需自动配置field映射关系时，指定字段名时用“.”来指向子对象下的字段信息。
演示代码
@Test
public void SimpleToComplex() {
IMapper mapper = new AutoMapper();
mapper.mapping(UserDto.class, UserDo.class)
.field("contactTel", "contact.tel")
.field("contactAddress", "contact.address");
UserDto userDto = new UserDto();
userDto.setContactTel("123");
userDto.setContactAddress("address");
UserDo userDo = mapper.map(userDto, UserDo.class);
Assert.assertEquals(userDo.getContact().getAddress(), userDto.getContactAddress());
}
3.8 允许添加自定义转换器，用于解决任何类型之间的自定义转换
当两个类型的转换比较通用，可以自定义转换器，
IMapper定义的配置方式
IMapper registerConverter(Converter converter);
演示代码
// 创建字符串与性别枚举的转换器
class SexAndStringConverter extends Converter<String, UserDo.Sex> {
@Override
protected Class<String> getSourceClass() {
return String.class;
}
@Override
protected Class<UserDo.Sex> getTargetClass() {
return UserDo.Sex.class;
}
@Override
public UserDo.Sex toTarget(String source) {
if (source.equals("男"))
return UserDo.Sex.male;
else
return UserDo.Sex.female;
}
@Override
public String toSource(UserDo.Sex target) {
if (target.equals(UserDo.Sex.male))
return "男";
else
return "女";
}
}
枚举转换成字符串
@Test
public void EnumToString() {
IMapper mapper = new AutoMapper();
mapper.registerConverter(new SexAndStringConverter());
UserDo userDo = new UserDo();
userDo.setSex(UserDo.Sex.female);
UserDto userDto = mapper.map(userDo, UserDto.class);
Assert.assertEquals(userDto.getSex(), "女");
}
字符串转枚举
@Test
public void StringToEnum() {
IMapper mapper = new AutoMapper();
mapper.registerConverter(new SexAndStringConverter());
UserDto userDto = new UserDto();
userDto.setSex("女");
UserDo userDo = mapper.map(userDto, UserDo.class);
Assert.assertEquals(userDo.getSex(), UserDo.Sex.female);
}
3.9 支持对子类的映射
配置的对象是父类，而实际转换是使用的子类时，automapper也自动支持
演示代码
UserDoSubClass
package com.zhaofujun.automapper;
public class UserDoSubClass extends UserDo {
}
UserDtoSubClass
package com.zhaofujun.automapper;
public class UserDtoSubClass extends UserDto {
}
@Test
public void subClassTest() {
IMapper mapper = new AutoMapper();
mapper.mapping(UserDto.class, UserDo.class)
.field("contactTel", "contact.tel")
.field("contactAddress", "contact.address");
UserDtoSubClass userDto = new UserDtoSubClass();
userDto.setContactTel("123");
userDto.setContactAddress("address");
UserDo userDo = mapper.map(userDto, UserDo.class);
Assert.assertEquals(userDo.getContact().getAddress(), userDto.getContactAddress());
}
#4 更新日志
1.3.5 更新日志
新增map时的过滤字段，该过滤当前映射有效