Android GSON使用

new Gson().fromJson(String json, Class<T> classOfT)

三、测试结果

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import androidx.appcompat.app.AppCompatActivity;



import android.os.Bundle;

import android.util.Log;



import com.google.gson.Gson;



import java.util.ArrayList;

import java.util.List;



/**

 * @author by t, Date on 2019-10-23.

 * note: Gson使用

 */

public class MainActivity extends AppCompatActivity {



    private final String TAG = "MainActivity";



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);



        Gson gson = new Gson();



        Person person = new Person();

        person.setName("张三");

        person.setAge(22);



        Log.d(TAG, "toJson:" + gson.toJson(person));



        String jsonStr = "{\"age\":22,\"name\":\"张三\"}";



        Log.d(TAG, "fromJson:" + new Gson().fromJson(jsonStr, Person.class).toString());



        //来个复杂点的



        CompanyInfo companyInfo = new CompanyInfo();

        companyInfo.setCompanyName("公司名字");

        companyInfo.setCompanyOwner("老板");



        List<Person> personList = new ArrayList<>();

        personList.add(new Person("张三", 22));

        personList.add(new Person("李四", 23));

        personList.add(new Person("王五", 24));

        companyInfo.setPersonList(personList);



        String toJson = gson.toJson(companyInfo);



        Log.d(TAG, "toJson:" + toJson);



        Log.d(TAG, "fromJson:" + gson.fromJson(toJson, CompanyInfo.class));

    }





    public class Person {

        private String name;

        private int age;



        public Person() {

        }



        public Person(String name, int age) {

            this.name = name;

            this.age = age;

        }



        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 "Person{" +

                    "name='" + name + '\'' +

                    ", age=" + age +

                    '}';

        }

    }





    public class CompanyInfo {

        private String companyName;

        private String companyOwner;

        private List<Person> personList;



        public String getCompanyName() {

            return companyName;

        }



        public void setCompanyName(String companyName) {

            this.companyName = companyName;

        }



        public String getCompanyOwner() {

            return companyOwner;

        }



        public void setCompanyOwner(String companyOwner) {

            this.companyOwner = companyOwner;

        }



        public List<Person> getPersonList() {

            return personList;

        }



        public void setPersonList(List<Person> personList) {

            this.personList = personList;

        }



        @Override

        public String toString() {

            return "CompanyInfo{" +

                    "companyName='" + companyName + '\'' +

                    ", companyOwner='" + companyOwner + '\'' +

                    ", personList=" + personList +

                    '}';

        }

    }



}

Gson处理空对象场景

=========================================================================

//        UserInfo userInfo = new UserInfo();

//        userInfo.setId(0);

//        userInfo.setName("张三");

//        userInfo.setAddress(null);



//        {"id":0,"name":"张三"}





//        UserInfo userInfo = new UserInfo();

//        userInfo.setId(0);

//        userInfo.setName("张三");

//

//        {"id":0,"name":"张三"}



//        UserInfo userInfo = new UserInfo();

//        userInfo.setId(0);

//        userInfo.setName("张三");

//        userInfo.setAddress("");

//        

//        {"address":"","id":0,"name":"张三"}