本文内容大多基于官方文档和网上前辈经验总结,经过个人实践加以整理积累,仅供参考。
默认情况下解析和生成 JSON 字符串要求键名称和 POJO 类的属性名一一对应,实际应用中常常出现不一致现象,
如期望字符串:{“account”:”admin”,”password”:”123456”,”age”:30}
实际字符串:{“account”:”admin”,”code”:”123456”,”age”:30}
Gson 使用 @SerializedName 注解解决 JSON 字符串键名称和 POJO 类属性名不对应的问题
示例
1 POJO 类
import com.google.gson.annotations.SerializedName;
public class User {
private String account;
@SerializedName("code")
private String password;
private String name;
private int age;
public String getAccount() {
return account;
}
public void setAccount(String account) {
this.account = account;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "User [account=" + account + ", password=" + password + ", name=" + name + ", age=" + age + "]";
}
}
2 单元测试
@Test
public void test() {
Gson gson = new Gson();
String userStr = "{\"account\":\"admin\",\"code\":\"123456\",\"age\":30}";
User user = gson.fromJson(userStr, User.class);
assertEquals(user.getAccount(), "admin");
assertEquals(user.getPassword(), "123456");
assertEquals(user.getAge(), 30);
}
如果存在多个需要解析的 JSON 字符串,每个字符串的键名称各不相同,但实际上对应的都是 POJO 对象的同一个属性,如
{“account”:”admin”,”password”:”123456”,”age”:30}
{“account”:”admin1”,”code”:”000000”,”age”:20}
{“account”:”adminX”,”xxx”:”aaaaaa”,”age”:40}
{“account”:”adminY”,”yyy”:”bbbbbb”,”age”:45}
{“account”:”adminZ”,”zzz”:”cccccc”,”age”:50}
解决方法:
1 修改 POJO 类
import com.google.gson.annotations.SerializedName;
public class User {
private String account;
@SerializedName(value = "password", alternate = {"code", "xxx", "yyy", "zzz"})
private String password;
private String name;
private int age;
public String getAccount() {
return account;
}
public void setAccount(String account) {
this.account = account;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "User [account=" + account + ", password=" + password + ", name=" + name + ", age=" + age + "]";
}
}
2 单元测试
@Test
public void test() {
Gson gson = new Gson();
String userStr = "{\"account\":\"admin\",\"password\":\"123456\",\"age\":30}";
User user = gson.fromJson(userStr, User.class);
assertEquals(user.getAccount(), "admin");
assertEquals(user.getPassword(), "123456");
assertEquals(user.getAge(), 30);
userStr = "{\"account\":\"admin1\",\"code\":\"000000\",\"age\":20}";
user = gson.fromJson(userStr, User.class);
assertEquals(user.getAccount(), "admin1");
assertEquals(user.getPassword(), "000000");
assertEquals(user.getAge(), 20);
userStr = "{\"account\":\"adminX\",\"xxx\":\"aaaaaa\",\"age\":40}";
user = gson.fromJson(userStr, User.class);
assertEquals(user.getAccount(), "adminX");
assertEquals(user.getPassword(), "aaaaaa");
assertEquals(user.getAge(), 40);
userStr = "{\"account\":\"adminY\",\"yyy\":\"bbbbbb\",\"age\":45}";
user = gson.fromJson(userStr, User.class);
assertEquals(user.getAccount(), "adminY");
assertEquals(user.getPassword(), "bbbbbb");
assertEquals(user.getAge(), 45);
userStr = "{\"account\":\"adminZ\",\"zzz\":\"cccccc\",\"age\":50}";
user = gson.fromJson(userStr, User.class);
assertEquals(user.getAccount(), "adminZ");
assertEquals(user.getPassword(), "cccccc");
assertEquals(user.getAge(), 50);
}