Gson使用样例代码
package com.hand.json;
import com.google.gson.*;
import com.google.gson.reflect.TypeToken;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.*;
/**
* Created by ljh on 2016/7/30.
*/
public class ParseJSON {
public static void main(String args[]) {
// parseList();
// parseMap();
parseMapList();
}
public static void readJsonFromFile() {
try {
JsonParser parser = new JsonParser();
JsonObject object = (JsonObject) parser.parse(new FileReader("test.json"));
System.out.println("cat = " + object.get("cat").getAsString());
System.out.println("pop = " + object.get("pop").getAsBoolean());
JsonArray array = object.get("languages").getAsJsonArray();
for (int i = 0; i < array.size(); i++) {
System.out.println("--------------------");
JsonObject jo = array.get(i).getAsJsonObject();
System.out.println("id = " + jo.get("id").getAsInt());
System.out.println("name = " + jo.get("name").getAsString());
System.out.println("ide = " + jo.get("ide").getAsString());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
public static void createJsonStr() {
JsonObject jsonObject = new JsonObject();
jsonObject.addProperty("cat", "it");
JsonArray array = new JsonArray();
JsonObject lan1 = new JsonObject();
lan1.addProperty("id", 1);
lan1.addProperty("name", "java");
lan1.addProperty("ide", "Eclipse");
array.add(lan1);
JsonObject lan2 = new JsonObject();
lan2.addProperty("id", 2);
lan2.addProperty("name", "java");
lan2.addProperty("ide", "Eclipse");
array.add(lan2);
JsonObject lan3 = new JsonObject();
lan3.addProperty("id", 1);
lan3.addProperty("name", "java");
lan3.addProperty("ide", "Eclipse");
array.add(lan3);
jsonObject.add("languages", array);
jsonObject.addProperty("pop", true);
System.out.println(jsonObject);
}
/**
* 简单的解析 JavaBean
*/
public static void parseBean() {
Gson gson = new Gson();
Student stu1 = new Student(1, "张三", new Date(), false);
System.out.println(stu1);
// 简单的bean转为json
String g1 = gson.toJson(stu1);
System.out.println(g1);
// 简单的json转为 bean
Student stu2 = gson.fromJson(g1, Student.class);
System.out.println(stu2);
}
/**
* 将 List 转化为 Json数据
*/
public static void parseList() {
Gson gson = new Gson();
List stus = new ArrayList();
Student stu1 = new Student(1, "张三", new Date(), false);
Student stu2 = new Student(2, "李四", new Date(201608080), true);
Student stu3 = new Student(3, "王五", new Date(20150909), false);
stus.add(stu1);
stus.add(stu2);
stus.add(stu3);
// 带泛型的list转化为json
String gs = gson.toJson(stus);
System.out.println(gs);
// json转为带泛型的list
System.out.println("#########################");
List stus_gson = gson.fromJson(gs,
new TypeToken>(){}.getType());
for(Student s : stus_gson) {
System.out.println(s.toString());
}
}
/**
* 简单的 将 Map 的数据转化为 JSON
*/
public static void parseMap() {
Gson gson = new GsonBuilder().enableComplexMapKeySerialization().create();
// 使用LinkedHashMap将结果按先进先出顺序排列
Map map1 = new LinkedHashMap();
map1.put(1000, new Student(1, "张三", new Date(), false));
map1.put(1001, new Student(2, "李四", new Date(201608080), true));
map1.put(1002, new Student(3, "王五", new Date(20150909), false));
// map 转化为 json
String s = gson.toJson(map1);
System.out.println(s);
System.out.println("-----------------");
// json 转化为 map
Map retMap1 = gson.fromJson(s,
new TypeToken>(){}.getType());
for(Integer i : retMap1.keySet()) {
System.out.println("key: " + i + ", value:" + retMap1.get(i).toString());
}
System.out.println("########################");
// 使用LinkedHashMap将结果按先进先出顺序排列
Map map2 = new LinkedHashMap();
map2.put(new Student(1, "张三", new Date(), false), 1000);
map2.put(new Student(2, "李四", new Date(201608080), true), 1001);
map2.put(new Student(3, "王五", new Date(20150909), false), 1002);
// map 转化为 json
String s2 = gson.toJson(map2);
System.out.println(s2);
System.out.println("-----------------");
// json 转化为 map
Map retMap2 = gson.fromJson(s2,
new TypeToken>(){}.getType());
for(Student st : retMap2.keySet()) {
System.out.println("key: " + st.toString() + ", value:" + map2.get(st));
}
}
/***
* 将 Map转化为 JSON
*/
public static void parseMapList() {
List stu_list = new ArrayList();
stu_list.add(new Student(1, "张三", new Date(), false));
stu_list.add(new Student(2, "李四", new Date(201608080), true));
stu_list.add(new Student(3, "王五", new Date(20150909), false));
Map map = new LinkedHashMap();
map.put("students", stu_list);
Gson gson = new Gson();
String s = gson.toJson(map);
System.out.println(s);
System.out.println("-----------------");
Map retMap = gson.fromJson(s,
new TypeToken>(){}.getType());
for(String i : retMap.keySet()) {
System.out.println("key: " + i + ", value: " + retMap.get(i).toString());
}
}
}
Student.java
import java.util.Date;
/**
* Created by ljh on 2016/7/30.
*/
public class Student {
private int id;
private String name;
private Date birthday;
private boolean sex;
public Student() {
}
public Student(int id, String name, Date birthday, boolean sex) {
this.id = id;
this.name = name;
this.birthday = birthday;
this.sex = sex;
}
public int getId() {
return id;
}
public String getName() {
return name;
}
public Date getBirthday() {
return birthday;
}
public boolean isSex() {
return sex;
}
public void setId(int id) {
this.id = id;
}
public void setName(String name) {
this.name = name;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public void setSex(boolean sex) {
this.sex = sex;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", birthday=" + birthday +
", sex=" + sex +
'}';
}
}
Json转换利器Gson之实例一-简单对象转化和带泛型的List转化 (http://blog.csdn.net/lk_blog/article/details/7685169)
Json转换利器Gson之实例二-Gson注解和GsonBuilder (http://blog.csdn.net/lk_blog/article/details/7685190)
Json转换利器Gson之实例三-Map处理(上) (http://blog.csdn.net/lk_blog/article/details/7685210)
Json转换利器Gson之实例四-Map处理(下) (http://blog.csdn.net/lk_blog/article/details/7685224)
Json转换利器Gson之实例五-实际开发中的特殊需求处理 (http://blog.csdn.net/lk_blog/article/details/7685237)
Json转换利器Gson之实例六-注册TypeAdapter及处理Enum类型 (http://blog.csdn.net/lk_blog/article/details/7685347)