package com.bjpowernode.test;
import com.bjpowernode.domain.User;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.sun.deploy.security.ValidationState;
import org.junit.Test;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;
public class TestGSONAPI {
/**
* 测试一个对象转JSON
*/
@Test
public void testOneObjectConvertToJSON(){
User user = new User(1,"zhangsan","123456","三丰大师",149) ;
Gson gson = new Gson();
//写法一
System.out.println("=======================写法一=========================");
String userJson = gson.toJson(user, User.class);
System.out.println("userJson = " + userJson);//userJson = {"id":1,"username":"zhangsan","password":"123456","nickname":"三丰大师","age":149}
//写法二
System.out.println("========================写法二=========================");
String userJson2 = gson.toJson(user);
System.out.println("userJson2 = " + userJson2);
}
/**
* 测试多个对象转JSON
*/
@Test
public void testManyObjectConvertToJSON(){
List<User> users = new ArrayList<>();
User user = null;
for (int i = 1; i <=5 ; i++) {
user = new User(i,"hhh"+i,123456+"i","哈哈哈"+i,24+i);
users.add(user);
}
Gson gson = new Gson();
String usersJson = gson.toJson(users);
System.out.println("usersJson = " + usersJson);
}
/**
* 测试JSON字符串转一个对象
*/
@Test
public void testJSONSConvertToOneObject(){
//如何将JSON字符串转换成对象
String jsonStr = "{\"id\":1,\"username\":\"zhangsan\",\"password\":\"123456\",\"nickname\":\"三丰大师\",\"age\":149}";
Gson gson = new Gson();
User user = gson.fromJson(jsonStr, User.class);
System.out.println("user = " + user);
}
/**
* 测试JSON字符串转多个对象（List）（错误案例）
*/
@Test
public void testJSONConvertManyObjectErrorInstance(){
String jsonStr = "[{\"id\":1,\"username\":\"hhh1\",\"password\":\"123456i\",\"nickname\":\"哈哈哈1\",\"age\":25},{\"id\":2,\"username\":\"hhh2\",\"password\":\"123456i\",\"nickname\":\"哈哈哈2\",\"age\":26},{\"id\":3,\"username\":\"hhh3\",\"password\":\"123456i\",\"nickname\":\"哈哈哈3\",\"age\":27},{\"id\":4,\"username\":\"hhh4\",\"password\":\"123456i\",\"nickname\":\"哈哈哈4\",\"age\":28},{\"id\":5,\"username\":\"hhh5\",\"password\":\"123456i\",\"nickname\":\"哈哈哈5\",\"age\":29}]\n";
Gson gson = new Gson();
ArrayList<User> arrayList = gson.fromJson(jsonStr, ArrayList.class);
/*上面这行代码，使得结果输出如下：
* {id=1.0, username=hhh1, password=123456i, nickname=哈哈哈1, age=25.0}
{id=2.0, username=hhh2, password=123456i, nickname=哈哈哈2, age=26.0}
{id=3.0, username=hhh3, password=123456i, nickname=哈哈哈3, age=27.0}
{id=4.0, username=hhh4, password=123456i, nickname=哈哈哈4, age=28.0}
{id=5.0, username=hhh5, password=123456i, nickname=哈哈哈5, age=29.0}
输出的结果，既不是对象，也不是JSON字符串
对象 ：User(id=1, username=zhangsan, password=123456, nickname=三丰大师, age=149)
JSON字符串 : {"id":1,"username":"zhangsan","password":"123456","nickname":"三丰大师","age":149}
*/
// for (Object o : arrayList) {
// System.out.println(o);
// }
arrayList.forEach(System.out::println);
}
/**
* 测试JSON字符串转多个对象（List）（正确案例）
* 引入TypeToken
*/
@Test
public void testJSONConvertManyObjectCorrectInstance(){
String jsonStr = "[{\"id\":1,\"username\":\"hhh1\",\"password\":\"123456i\",\"nickname\":\"哈哈哈1\",\"age\":25},{\"id\":2,\"username\":\"hhh2\",\"password\":\"123456i\",\"nickname\":\"哈哈哈2\",\"age\":26},{\"id\":3,\"username\":\"hhh3\",\"password\":\"123456i\",\"nickname\":\"哈哈哈3\",\"age\":27},{\"id\":4,\"username\":\"hhh4\",\"password\":\"123456i\",\"nickname\":\"哈哈哈4\",\"age\":28},{\"id\":5,\"username\":\"hhh5\",\"password\":\"123456i\",\"nickname\":\"哈哈哈5\",\"age\":29}]\n";
Gson gson = new Gson();
Type type = new TypeToken<ArrayList<User>>(){}.getType();
ArrayList<User> arrayList = gson.fromJson(jsonStr, type);
// for (User user : arrayList) {
// System.out.println(user);
// }
arrayList.forEach(System.out::println);
/* 输出结果如下
* User(id=1, username=hhh1, password=123456i, nickname=哈哈哈1, age=25)
User(id=2, username=hhh2, password=123456i, nickname=哈哈哈2, age=26)
User(id=3, username=hhh3, password=123456i, nickname=哈哈哈3, age=27)
User(id=4, username=hhh4, password=123456i, nickname=哈哈哈4, age=28)
User(id=5, username=hhh5, password=123456i, nickname=哈哈哈5, age=29)
*
*/
}
}
GSON入门篇（教学视频+源代码）.zip （19个子文件） 
教学视频 
2.idea中使用gson转换JSON数据 - 1.375.idea中使用gson转换JSON数据(Av470785552,P1).mp4 41.31MB 1.谷歌Gson的使用 - 1.374.谷歌Gson的使用(Av555872872,P1).mp4 41.89MB 源代码 GSON-bilibili lib 
junit-4.13.2.jar 376KB hamcrest-core-1.3.jar 44KB gson-2.8.5.jar 236KB lombok.jar 1.88MB
GSON-bilibili.iml 815B src com bjpowernode test TestGSONAPI.java 5KB domain User.java 449B out production GSON-bilibili generated com bjpowernode test TestGSONAPI.class 4KB TestGSONAPI$1.class 663B domain User.class 3KB .idea libraries hamcrest_core_1_3.xml 297B lombok.xml 210B workspace.xml 8KB misc.xml 278B compiler.xml 254B modules.xml 273B .gitignore 184B资源评论
