六个架包（666）

首先我们系统中要用到JSON解析，所以要引入这六个架包。饱饱

不引入这六个架包的话，使用JSONObject.fromObject  和 SONObject.toBean会报错，而且有的时候编译器不会告诉你是架包缺少的错误哦！

JSON 对象  与  JAVA对象的转换

1. JSONObject   json = JSONObject.fromObject(String);//java转json

2. JSONObject.toBean()//json转java

（1）java对象转json对象。

                ——HashMap转为JSON对象：JSONObject.fromObject()

          json对象又再次转换成java对象

                 ——JSON转为Map<String,String>：JSON强制转换

栗子1

public class JSONTest
{public static void main(String[] args){HashMap<String,String> map=new HashMap<String,String>();map.put("A", "B");//map={A=B}JSONObject json = JSONObject.fromObject(map);//json={"A":"B"}System.out.println(json.toString());//{"A":"B"}//再将json强转成mapMap<String,String> map2=(Map<String,String>)json;//{"A":"B"}System.out.println(map2.toString());}
}

忽然发现两件事：

一件事：HashMap中key值相同的话，前一个会被后一个覆盖。（原谅我太渣，现在才知道）

第二件事：相比于有道笔记，饱饱更爱写CSDN啊！

public class JSONTest
{public static void main(String[] args){HashMap<String,String> map=new HashMap<String,String>();map.put("A", "B");//map={A=B}map.put("A", "C");//map={A=C}JSONObject json = JSONObject.fromObject(map);//json={"A":"C"}System.out.println(json.toString());//{"A":"C"}//再将json强转成mapMap<String,String> map2=(Map<String,String>)json;//{"A":"C"}System.out.println(map2.toString());}
}

栗子2

public class JSONTest
{public static void main(String[] args){HashMap<String,String> map=new HashMap<String,String>();map.put("A", "B");//map={A=B}map.put("C", "D");//map={A=B, C=D}JSONObject json = JSONObject.fromObject(map);//json={"A":"B","C":"D"}System.out.println(json.toString());//再将json强转成mapMap<String,String> map2=(Map<String,String>)json;//{"A":"B","C":"D"}System.out.println(map2.toString());}
}

（2）java对象转json对象。

                ——String转为JSON对象：JSONObject.fromObject()

          json对象又再次转换成java对象

                 ——JSON转为Map<String,Object>：JSON强制转换

mapString =
{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""}
}

public class JSONTest
{public static void main(String[] args){//将string类型的map数据转换为json的数据格式，在将json的数据格式的转换成java的    Map<String,Object>的数据类型String mapString = "{\"errmsg\":\"ok\",\"ErrorCode\":0,\"messageId\":\"f5d4566c4c833152b3feb42a8092ee6c\",\"invaliduser\":\"\",\"forbiddenUserId\":\"\",\"resJson\":{\"errmsg\":\"ok\",\"ErrorCode\":0,\"messageId\":\"f5d4566c4c833152b3feb42a8092ee6c\",\"invaliduser\":\"\",\"forbiddenUserId\":\"\"}}";//mapString={"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""}}JSONObject json = JSONObject.fromObject(mapString);//json	   ={"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""}}Map<String, Object> map = (Map<String, Object>)json;//map      ={"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""}}System.out.println("-----map:---"+map.toString());}
}

（3）java对象转json对象。

                 ——String转为JSON对象：JSONObject.fromObject()

          json对象又再次转换成java对象

                  ——JSON转为Student对象：JSONObject.toBean()

public class JSONTest
{public static void main(String[] args){String mapString = "{id:'211415034',name:'徐妍',age:'24'}";Student student = new Student();JSONObject json = JSONObject.fromObject(mapString);//json={"id":"211415034","name":"徐妍","age":"24"}student = (Student)JSONObject.toBean(json, Student.class);//曾经的学号：211415034    姓名：徐妍    年龄：24//JSONObject.toBean() 方法意为：从JSONObject 对象转换为 JAVA 对象。System.out.println(student);}
}

public class Student
{private int id;private String name;private int age;public int getId(){return id;}public void setId(int id){this.id = id;}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;}	public String toString(){return "曾经的学号："+this.id+"    姓名："+this.name+"    年龄："+this.age;}
}