compile 'com.google.code.gson:gson:2.7'

package com.zyj.app.util;

import com.google.gson.Gson;

import com.google.gson.JsonArray;

import com.google.gson.JsonElement;

import com.google.gson.JsonParser;

import java.util.ArrayList;

import java.util.List;

/**

 * Created by ${zyj} on 2016/8/24.

 */

public class JsonUitl {

    private static Gson mGson = new Gson();

    /**

     * 将json字符串转化成实体对象

     * @param json

     * @param classOfT

     * @return

     */

    public static Object stringToObject( String json , Class classOfT){

        return  mGson.fromJson( json , classOfT ) ;

    }

    /**

     * 将对象准换为json字符串 或者 把list 转化成json

     * @param object

     * @param <T>

     * @return

     */

    public static <T> String objectToString(T object) {

        return mGson.toJson(object);

    }

    /**

     * 把json 字符串转化成list

     * @param json

     * @param cls

     * @param <T>

     * @return

     */

    public static <T>  List<T> stringToList(String json ,Class<T> cls  ){

        Gson gson = new Gson();

        List<T> list = new ArrayList<T>();

        JsonArray array = new JsonParser().parse(json).getAsJsonArray();

        for(final JsonElement elem : array){

            list.add(gson.fromJson(elem, cls));

        }

        return list ;

    }

}

package com.zyj.app.bean;

/**

 * Created by ${zyj} on 2016/9/5.

 */

public class Me {

    String name ;

    String age ;

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public String getAge() {

        return age;

    }

    public void setAge(String age) {

        this.age = age;

    }

}

        List<Me> list = new ArrayList<>() ;

        Me me1 = new Me() ;

        me1.setName( "name111");

        me1.setAge( "age111");

        Me me2 = new Me() ;

        me2.setName( "name222");

        me2.setAge( "age222");

        Me me3 = new Me() ;

        me3.setName( "name333");

        me3.setAge( "age333");

        list.add( me1 ) ;

        list.add( me2 ) ;

        list.add( me3 ) ;

        //测试一：把list对象转换成json字符串

        String json1 = JsonUitl.objectToString( list  ) ;

        //日志打印

         KLog.d( "测试一 " + json1 );

       //测试二：把json字符串转化成list集合

        List<Me> listMe = JsonUitl.stringToList( json1 , Me.class ) ;

        //日志打印

        for ( Me meTest : listMe ){

            KLog.d( "测试二 " + "name: " + meTest.getName() + " age: " + meTest.getAge() );

            //测试三 ： 把对象转化成json字符串

            String jsonTest3 = JsonUitl.objectToString( meTest ) ;

            KLog.d( "测试三 " + jsonTest3  );

        }

测试一 [{"age":"age111","name":"name111"},{"age":"age222","name":"name222"},{"age":"age333","name":"name333"}]

测试二 name: name111 age: age111

测试三 {"age":"age111","name":"name111"}

测试二 name: name222 age: age222

测试三 {"age":"age222","name":"name222"}

测试二 name: name333 age: age333

测试三 {"age":"age333","name":"name333"}