gson在android中的应用

首先需要建一个实体类 Person.java 来对应json

需要注意的是实体类中的变量名必须和json传过来的key值完全一样（大小写）

 public class Person {
     private String name;
     private int age;
     private String city;

     public Person(String name, int age, String city){
         this.name = name;
         this.age = age;
         this.city = city;
     }

     public Person(){}

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

     public String getName() {
         return name;
     }

     public void setAge(int age) {
         this.age = age;
     }

     public int getAge() {
         return age;
     }

     public void setCity(String city) {
         this.city = city;
     }

     public String getCity() {
         return city;
     }
 }

然后这是编码和解码的具体实现

 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.util.Log;

 import com.google.gson.Gson;
 import com.google.gson.reflect.TypeToken;

 import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;

 public class MainActivity extends AppCompatActivity {

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         List<Person> list = new ArrayList<Person>();
         Person person = new Person("Thh", 23, "CHENGDU");
         list.add(person);
         person = new Person("CBB", 22, "CHENGDU");
         list.add(person);
         person = new Person("CMT", 18, "TIANJIN");
         list.add(person);

         Gson gson = new Gson();

         Log.e("ABC", "" + gson.toJson(list));

         Person person1 = new Person();
         Gson gson1 = new Gson();

         String s=gson.toJson(list);
         Type lt=new TypeToken<List<Person>>(){}.getType();//获取一个泛型的数据类型
         List<Person> l=gson1.fromJson(s,lt);
         for(Person p1:l){
             Log.e("ABC",p1.getName() + " " + p1.getAge() + " " + p1.getCity());
         }
     }
 }

Logcat中显示结果：

10-22 01:22:01.444 16669-16669/? E/ABC: [{"age":23,"city":"CHENGDU","name":"Thh"},{"age":22,"city":"CHENGDU","name":"CBB"},{"age":18,"city":"TIANJIN","name":"CMT"}]
10-22 01:22:01.448 16669-16669/? E/ABC: Thh 23 CHENGDU
10-22 01:22:01.448 16669-16669/? E/ABC: CBB 22 CHENGDU
10-22 01:22:01.449 16669-16669/? E/ABC: CMT 18 TIANJIN