JAvaにおけるjsonの使用

json列の例
[{"id":1,"name":"name1","password":"password1","remark":"remark1"},{"id":2,"name":"name2","password":"password2","remark":"remark2"},{"id":3,"name":"name3","password":"password3","remark":"remark3"}]
主に以下の種類に分けられます.
1.json列を直接構築し、主なコード;
2.json列->javaオブジェクト;
3.javaオブジェクト->json列/jsonオブジェクト;
4. List -> json列;
5.オブジェクト配列->json列.
手順は次のとおりです.
TestJson.java

import java.util.*;

import net.sf.json.*;

import com.hs.sig.ui.sgms.vo.User;

public class TestJson {

/**

*    userList  

*/

public static final int USERLISTSIZE = 3; 

/**

*     json 

* @return

*/

public String toJsonString() {

//     User   

User user = null;

List<User> userList = this.initUserList(USERLISTSIZE);

//    json  

StringBuffer json = new StringBuffer();

json.append("[");

for (int i = 0; i < userList.size(); i++) {

user = userList.get(i);

json.append("{");

json.append("\"id\":\"").append(user.getId()).append("\",");

json.append("\"name\":\"").append(user.getName()).append("\",");

json.append("\"password\":\"").append(user.getPassword()).append("\",");

json.append("\"remark\":\"").append(user.getRemark()).append('"');

json.append("},");

}

json.deleteCharAt(json.lastIndexOf(","));

json.append("]");

//System.out.println("     json    ：" + json.toString());

return json.toString();

}

/**

* json  -> java  

* @return

*/

public String jsonToObject() {

StringBuffer info = new StringBuffer();

if(this.isArray(this.toJsonString())){

JSONArray jSONArray = JSONArray.fromObject(this.toJsonString());

JsonConfig jsonConfig = new JsonConfig();

jsonConfig.setArrayMode(JsonConfig.MODE_LIST);

jsonConfig.setRootClass(User.class);

List<User> userList = (List<User>) JSONSerializer.toJava(jSONArray, jsonConfig);

User user = null;

for (int i = 0; i < userList.size(); i++) {

user = userList.get(i);

info.append("user" + (i + 1) + ".id=" + user.getId());

info.append(",user" + (i + 1) + ".name=" + user.getName());

info.append(",user" + (i + 1) + ".password=" + user.getPassword());

info.append(",user" + (i + 1) + ".remark=" + user.getRemark());

info.append("
");

}

//System.out.println("json  -> java  ：" + info.toString());

}

return info.toString();

}

/**

* java   -> json /json  

* @return

*/

public String objectToJson() {

//      user  

User user = null;

List<User> userList = this.initUserList(USERLISTSIZE);

user = userList.get(0);

//   user     

JsonConfig jsonConfig = new JsonConfig();

//              

jsonConfig.setExcludes(new String[]{"id"});

//    user   json 

JSONArray jsonArray = JSONArray.fromObject(user, jsonConfig);

//jsonArray = JSONArray.fromObject(user);

//    json  

//JSONObject jsonObject = JSONObject.fromObject(user, jsonConfig);

//jsonObject = JSONObject.fromObject(user);

return jsonArray.toString();

}

/**

* List<User> -> json 

* @return

*/

public String listToJson(){

List<User> userList = this.initUserList(USERLISTSIZE);

// list   JSON 

JSONArray jsonArray = JSONArray.fromObject(userList);

//System.out.println("List<User> -> json ：" + jsonArray.toString());

return jsonArray.toString();

}

/**

*      -> json 

* @return

*/

public String arrayToJson() {

List<User> userList = this.initUserList(USERLISTSIZE);

User[] userArray = new User[userList.size()];

for(int i = 0 ; i < userList.size() ; i++){

userArray[i] = userList.get(i);

}

// user    json 

JSONArray jsonArray = JSONArray.fromObject(userArray);

//System.out.println("     -> json ：" + jsonArray.toString());

return jsonArray.toString();

}

/**

*      

* @param userListSize list    

* @return

*/

private List<User> initUserList(int userListSize) {

User user = null;

List<User> userList = new ArrayList<User>();

for (int i = 0; i < userListSize; i++) {

user = new User();

user.setId(i + 1);

user.setName("name" + (i + 1));

user.setPassword("password" + (i + 1));

user.setRemark("remark" + (i + 1));

userList.add(user);

}

return userList;

}

/**

*   JSON    "["  ，     jsonArray，     jsonObject

* @param str

* @return

*/

private boolean isArray(String str) {

return str.startsWith("[") ? true : false;

}

public static void main(String[] args) {

TestJson testJson = new TestJson();

System.out.println("    json ：" + testJson.toJsonString());

System.out.println("json  -> java  ：" + testJson.jsonToObject());

System.out.println("java   -> json ：" + testJson.objectToJson());

System.out.println("List<User> -> json ：" + testJson.listToJson());

System.out.println("     -> json ：" + testJson.arrayToJson());

}

}

 User.java
 

public class User {

private Integer id;

private String name;

private String password;

private String remark;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

public String getRemark() {

return remark;

}

public void setRemark(String remark) {

this.remark = remark;

}

public Integer getId() {

return id;

}

public void setId(Integer id) {

this.id = id;

}

}

 
json列を直接構築する:[{"id":"1","name":"name 1","password":"password 1","remark":"remark 1"},{"id":"id":"2","name":"name 2","password":"password 2","password 2","remark":"remark":"remark 2"},{"id":"3","name":"name":"name":"name 3","password":"password 3","remark","remark":""remark":"remark 3"}]
json列->javaオブジェクト:user 1.id=1,user 1.name=name 1,user 1.password=password 1,user 1.remark=remark 1
user2.id=2,user2.name=name2,user2.password=password2,user2.remark=remark2
user3.id=3,user3.name=name3,user3.password=password3,user3.remark=remark3
JAvaオブジェクト->json列:[{“name”:“name 1”,“password”:“password 1”,“remark”:“remark 1”}]
リスト＜User＞＞＞＞＞＞json列:[{“id”:1,“name”:“name 1”,“password”:“password 1”,“remark”:“remark 1”｝,｛“id”:2,“name”:“name 2”,“password”:“password 2”,“password d 2”,“remark”:“remark 2”,｛“id”:3,“name”:“name 3”,“password”:“password 3”,“remark”:“remark”:“remark”:“remark”:“remark”:“remark”:“remark”:“3,“id”:“mark 3"}]
オブジェクト配列->json列:[{"id":1,"name":"name 1","password":"password 1","remark":"remark 1"},{"id":2,"name":"name 2","password":"password":"password 2","remark":"remark":"remark 2"},{"id":3,"name":"name 3","password":"password 3","remark":"remark":"remark":"remark":"remark":remark 3"},{id":"id":3,"name":"name":"}]