java对象与json对象间的相互转换

1.解析json字符串
将json字符串转换为json对象，然后再解析json对象:。
JSONObjectjsonObject = JSONObject.fromObject(jsonStr);
 根据json中的键得到它的值
Stringname = jsonObject.getString("name");
int age = jsonObject.getInt("age");
 
2.将json字符串转换为java对象
同样先将json字符串转换为json对象，再将json对象转换为java对象，如下所示。
JSONObjectobj = new JSONObject().fromObject(jsonStr);//将json字符串转换为json对象
将json对象转换为java对象
Personjb = (Person)JSONObject.toBean(obj,Person.class);//将建json对象转换为Person对象
 

3.将java对象转换为json字符串
先将java对象转换为json对象，在将json对象转换为json字符串
JSONObjectjson = JSONObject.fromObject(obj);//将java对象转换为json对象
Stringstr = json.toString();//将json对象转换为字符串

实例代码：
package Test3;

public class Person {

private int age;
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
private String name;
public String toString() {
return "Person [age=" + age + ", name=" + name + "]";
}
public Person(int age, String name) {
super();
this.age = age;
this.name = name;
}

public Person(String personStr){

}

public Person(){

}
}

package Test3;
import net.sf.json.JSONObject;

public class JsonToObject {

/**
* @param args
*/
public void test(){

System.out.println("将object对象，字符串转为json对象");

Person person = new Person(1, "cgf");

JSONObject json = JSONObject.fromObject(person);

System.out.println(json);

System.out.println("将字符串转成JSON对象，再转为自定义对象");

String jsonString = "{" + "age" + ":1" + "," + "name" + ":" + "'wbj'" + "}";

JSONObject jsonObject = JSONObject.fromObject(jsonString);

System.out.println(jsonObject);

Person person1 = (Person) JSONObject.toBean(jsonObject, Person.class);

System.out.println("名字："+person1.getAge() + "年龄:" + person1.getName());

System.out.println("将Java对象转为json字符串");

JSONObject json1 = JSONObject.fromObject(person);

String jsonString1 = json1.toString();

System.out.println(jsonString1);

}

public static void main(String[] args) {
// TODO Auto-generated method stub

JsonToObject json = new JsonToObject();

json.test();

}

}