alibaba架包FastJson使用例子

　　alibaba的架包FastJson可以對json字符串進行快捷的類型轉換。下面是一些各種類型轉換的使用例子。

一、下載FastJson的架包，並導入項目中，如下：

Maven項目pom.xml配置如下：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.32</version>
</dependency>

 

二、附上代碼例子，如下：

1、創建2個實體類，供后面例子使用，如下：

public class School {
    private String id;
    private String name;
    List<User> students = new ArrayList<User>();
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public List<User> getStudents() {
        return students;
    }
    public void setStudents(List<User> students) {
        this.students = students;
    }
}

 

public class User {
    private String id;
    private String name;
    
    public User(){
        
    }
    public User(String id, String name){
        this.id = id;
        this.name = name;
    }
    
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

 

2、Json字符串與Map、List、object之間的相互轉換例子，如下：

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

public class TestFastJson {

    public static void main(String[] args){
        json2JsonObject();//將Json字符串轉換為JSONObject對象
        json2JavaBean();//將Json字符串轉換為JavaBean對象
        json2JsonArray();//將Json字符串轉換為JSONArray對象
        json2JavaBeanList();//將Json字符串轉換為JavaBean的集合
        javaBean2Json();//將JavaBean轉換為Json格式的數據
        javaBean2JsonObject();//將JavaBean轉換為JSONObject對象
        json2ListInMap();//從Json字符串的Map中獲取List對象
        list2JsonInMap();//將含list的Map對象轉換為Json字符串
    }
    
    private static void json2JsonObject() {
        String s = "{\"name\":\"peter\"}";
        JSONObject object = JSON.parseObject(s);
        System.out.println(object.get("name"));
    }
    
    private static void json2JavaBean() {
        String s = "{\"id\":\"17051801\",\"name\":\"lucy\"}";
        User user = JSON.parseObject(s, User.class);
        System.out.println(user.getId());
        System.out.println(user.getName());
    }
    
    private static void json2JsonArray() {
        String s = "[{\"id\":\"17051801\",\"name\":\"lucy\"},{\"id\":\"17051802\",\"name\":\"peter\"}]";
        JSONArray array = JSON.parseArray(s);
        for (int i = 0; i < array.size(); i++) {
            //JSONArray中的數據轉換為String類型需要在外邊加"";不然會報出類型強轉異常！
            String str = array.get(i)+"";
            JSONObject object = JSON.parseObject(str);
            System.out.println(object.get("name"));
        }
    }
    
    private static void json2JavaBeanList() {
        String s = "[{\"id\":\"17051801\",\"name\":\"lucy\"},{\"id\":\"17051802\",\"name\":\"peter\"}]";
        List<User> list = JSON.parseArray(s, User.class);
        for (User user : list) {
            System.out.println(user.getName());
        }
    }
    
    private static void javaBean2Json() {
        User user = new User("17051801", "lucy");
        String string = JSON.toJSONString(user);
        System.out.println(string);
    }
    
    private static void javaBean2JsonObject() {
        User user = new User("17051801", "lucy");
        JSONObject json = (JSONObject) JSON.toJSON(user);
        System.out.println(json.get("id"));
    }
    
    private static void json2ListInMap() {
        String s = "{json:[{id:\"17051801\",\"name\":\"lucy\"},{id:\"17051802\",\"name\":\"peter\"},"
                + "{id:\"17051803\",\"name\":\"tom\"},{id:\"17051804\",\"name\":\"lily\"}]}";
        //將Json字符串轉換為JSONObject對象,並取出list對象的值
        JSONObject object = JSON.parseObject(s);
        Object objArray = object.get("json");
        String str = objArray+"";
        //方式1:轉換成JSONArray對象形式
        JSONArray array = JSON.parseArray(str);
        for (int i = 0; i < array.size(); i++) {
            JSONObject obj = JSON.parseObject(array.get(i)+"");
            System.out.println(obj.get("name"));
        }
        //方式2:轉換成List<JavaBean>形式
        List<User> list = JSON.parseArray(str, User.class);
        for (User user : list) {
            System.out.println(user.getName());
        }
    }
    
    private static void list2JsonInMap() {
        //方式1:構建一個帶有list的JavaBean對象
        School school = new School();
        school.setId("1");
        school.setName("schoolA");
        
        User user1 = new User();
        user1.setId("17051801");
        user1.setName("lucy");
        User user2 = new User();
        user2.setId("17051802");
        user2.setName("peter");
        
        school.getStudents().add(user1);
        school.getStudents().add(user2);
        //將JavaBean對象轉換成Json字符串
        String string1 = JSON.toJSONString(school);
        System.out.println(string1);
        
        //方式2:構建一個帶有list的Map對象
        Map<String, Object> map1 = new HashMap<String,Object>();
        map1.put("id", "17051801");
        map1.put("name", "lucy");
        
        Map<String, Object> map2 = new HashMap<String,Object>();
        map2.put("id", "17051802");
        map2.put("name", "peter");
        
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
        list.add(map1);
        list.add(map2);
        
        Map<String, Object> map = new HashMap<String,Object>();
        map.put("id", "1");
        map.put("name", "schoolA");
        map.put("students", list);
        //將map對象轉換成Json字符串
        String string2 = JSON.toJSONString(map);
        System.out.println(string2);
    }
}