setCycleDetectionStrategy 防止自包含

package com.wzw.jsonConfig;

/**
 * @ProjectName: Zwen_Demo
 * @Package: com.wzw.jsonConfig
 * @ClassName: User
 * @Author: WangZunWen
 * @Description: ${description}
 * @Date: 2020/5/4 17:02
 */
public class User {
    private String username;
    private Integer age;
    private  User user = this;
    
    //get
    //set
    
}
//错误展示
public class Test1 {
    public static void main(String[] args) {
        User user = new User();
        user.setUsername("userName");
        user.setAge(20);
        JsonConfig jsonConfig = new JsonConfig();
        JSONObject json = JSONObject.fromObject(user);
        System.out.println(json);

    }
}
/*
Exception in thread "main" net.sf.json.JSONException: There is a cycle in the hierarchy!
    at net.sf.json.util.CycleDetectionStrategy$StrictCycleDetectionStrategy.handleRepeatedReferenceAsObject(CycleDetectionStrategy.java:97)
    at net.sf.json.JSONObject._fromBean(JSONObject.java:859)
    at net.sf.json.JSONObject.fromObject(JSONObject.java:194)
    at net.sf.json.JSONObject._processValue(JSONObject.java:2793)
    at net.sf.json.JSONObject._setInternal(JSONObject.java:2817)
    at net.sf.json.JSONObject.setValue(JSONObject.java:1527)
    at net.sf.json.JSONObject._fromBean(JSONObject.java:946)
    at net.sf.json.JSONObject.fromObject(JSONObject.java:194)
    at net.sf.json.JSONObject.fromObject(JSONObject.java:156)
    at com.wzw.jsonConfig.Test1.main(Test1.java:22)

Process finished with exit code 1
*/





public class Test2 {
    public static void main(String[] args) {
        User user = new User();
        user.setUsername("userName");
        user.setAge(20);
        JsonConfig jsonConfig = new JsonConfig();
        jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);
        JSONObject json = JSONObject.fromObject(user,jsonConfig);
        System.out.println(json);

    }
}
/*
{"user":null,"age":20,"username":"userName"}

Process finished with exit code 0
*/