java对象和json的来回转换知识点总结

strArray:[{“address”:”北京市西城区”,”age”:”23”,”name”:”JSON”}]

strJson:{“address”:”北京市西城区”,”age”:”23”,”name”:”JSON”}

//1、使用JSONObject
JSONObject json = JSONObject.fromObject(stu);
//2、使用JSONArray
JSONArray array=JSONArray.fromObject(stu);  
String strJson=json.toString();
String strArray=array.toString();

JSONObject obj = new JSONObject().fromObject(jsonStr);//将json字符串转换为json对象

Person jb = (Person)JSONObject.toBean(obj,Person.class);//将建json对象转换为Person对象

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
public class MainClass {
 public static void main(String[] args) {
  TestJsonBean();
  TestJsonAttribute();
  TestJsonArray();
 }
 @SuppressWarnings("rawtypes")
 private static void TestJsonArray() {
  Student student1 = new Student();
  student1.setId(1);
  student1.setName("jag");
  student1.setSex("man");
  student1.setAge(25);
  student1.setHobby(new String[]{"篮球","游戏"});
  Student student2 = new Student();
  student2.setId(2);
  student2.setName("tom");
  student2.setSex("woman");
  student2.setAge(23);
  student2.setHobby(new String[]{"上网","跑步"});
  List<Student> list = new ArrayList<Student>();
  list.add(student1);
  list.add(student2);
  JSONArray jsonArray = JSONArray.fromObject(list);
  System.out.println(jsonArray.toString());
  JSONArray new_jsonArray=JSONArray.fromObject(jsonArray.toArray());
  Collection java_collection=JSONArray.toCollection(new_jsonArray);
  if(java_collection!=null && !java_collection.isEmpty())
  {
   Iterator it=java_collection.iterator();
   while(it.hasNext())
   {
    JSONObject jsonObj=JSONObject.fromObject(it.next());
    Student stu=(Student) JSONObject.toBean(jsonObj,Student.class);
    System.out.println(stu.getName());
   }
  }
 }
 private static void TestJsonAttribute() {
  /**
   * 创建json对象并为该对象设置属性
   */
  JSONObject jsonObj = new JSONObject();
  jsonObj.put("Int_att",25);//添加int型属性
  jsonObj.put("String_att","str");//添加string型属性
  jsonObj.put("Double_att",12.25);//添加double型属性
  jsonObj.put("Boolean_att",true);//添加boolean型属性
  //添加JSONObject型属性
  JSONObject jsonObjSon = new JSONObject();
  jsonObjSon.put("id", 1);
  jsonObjSon.put("name", "tom");
  jsonObj.put("JSONObject_att",jsonObjSon);
  //添加JSONArray型属性
  JSONArray jsonArray = new JSONArray();
  jsonArray.add("array0");
  jsonArray.add("array1");
  jsonArray.add("array2");
  jsonArray.add("array3");
  jsonObj.put("JSONArray_att", jsonArray);
  System.out.println(jsonObj.toString());
  System.out.println("Int_att:"+jsonObj.getInt("Int_att"));
  System.out.println("String_att:"+jsonObj.getString("String_att"));
  System.out.println("Double_att:"+jsonObj.getDouble("Double_att"));
  System.out.println("Boolean_att:"+jsonObj.getBoolean("Boolean_att"));
  System.out.println("JSONObject_att:"+jsonObj.getJSONObject("JSONObject_att"));
  System.out.println("JSONArray_att:"+jsonObj.getJSONArray("JSONArray_att"));
 }
 /**
  * java对象与json对象互相转换
  */
 private static void TestJsonBean() {
  /**
   * 创建java对象
   */
  Student student = new Student();
  student.setId(1);
  student.setName("jag");
  student.setSex("man");
  student.setAge(25);
  student.setHobby(new String[]{"篮球","上网","跑步","游戏"});
  /**
   * java对象转换成json对象，并获取json对象属性
   */
  JSONObject jsonStu = JSONObject.fromObject(student);
  System.out.println(jsonStu.toString());
  System.out.println(jsonStu.getJSONArray("hobby"));
  /**
   * json对象转换成java对象，并获取java对象属性
   */
  Student stu = (Student) JSONObject.toBean(jsonStu, Student.class);
  System.out.println(stu.getName());
  /**
   * 创建json对象
   */
  JSONObject jsonObj = new JSONObject();
  jsonObj.put("id",1);
  jsonObj.put("name","张勇");
  jsonObj.put("sex","男");
  jsonObj.put("age",24);
  //jsonObj.put("hobby",new String[]{"上网","游戏","跑步","音乐"});
  //System.out.println(jsonObj.toString());
  /**
   * json对象转换成java对象
   */
  Student stud = (Student) JSONObject.toBean(jsonObj,Student.class);
  System.out.println(stud.getName());
 }
}