org.json下载
org.json包下载地址：https://repo1.maven.org/maven2/org/json/json/20220924/json-20220924.jar
org.json安装
1. Idea中导入json包的方法。
ctrl+alt+shift+S 打开项目结构，依次点击Libraries->+加号。
将刚才下载的jar文件导入我们的项目
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20220924</version>
</dependency>json字符串和java对象相互转换
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.util.*;
public class StringToJSON {
public static String BuildJson() throws JSONException {
// JSON格式数据解析对象
JSONObject jo = new JSONObject();
// 下面构造两个map、一个list和一个Employee对象
Map<String, String> map1 = new HashMap<String, String>();
map1.put("name", "zhangsan");
map1.put("sex", "female");
map1.put("age", "23");
Map<String, String> map2 = new HashMap<String, String>();
map2.put("name", "sili");
map2.put("sex", "male");
map2.put("age", "24");
List<Map> list = new ArrayList<Map>();
list.add(map1);
list.add(map2);
Employee employee = new Employee();
employee.setName("wangwu");
employee.setSex("female");
employee.setAge(24);
// 将Map转换为JSONArray数据
JSONArray ja = new JSONArray();
ja.put(map1);
System.out.println("JSONArray对象数据格式：");
System.out.println(ja.toString());
// 将Javabean转换为Json数据（需要Map中转）
JSONObject jo1 = JsonHelper.toJSON(employee);
System.out.println("\n仅含Employee对象的Json数据格式：");
System.out.println(jo1.toString());
// 构造Json数据，包括一个map和一个含Employee对象的Json数据
jo.put("map", ja);
jo.put("employee", jo1.toString());
System.out.println("\n最终构造的JSON数据格式：");
System.out.println(jo.toString());
return jo.toString();
}
/**
* 解析Json数据
*/
public static void ParseJson(String jsonString) throws JSONException,
ParseException {
JSONObject jo = new JSONObject(jsonString);
JSONArray ja = jo.getJSONArray("map");
System.out.println("\n将Json数据解析为Map：");
System.out.println("name: " + ja.getJSONObject(0).getString("name")
+ " sex: " + ja.getJSONObject(0).getString("sex") + " age: "
+ ja.getJSONObject(0).getInt("age"));
String jsonStr = jo.getString("employee");
Employee emp = new Employee();
JsonHelper.toJavaBean(emp, jsonStr);
System.out.println("\n将Json数据解析为Employee对象：");
System.out.println("name: " + emp.getName() + " sex: " + emp.getSex()
+ " age: " + emp.getAge());
}
public static void main(String[] args) throws JSONException, ParseException {
ParseJson(BuildJson());
}
}
class Employee{
private String name;
private String sex;
private Integer age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
/**
*
* 1:将JavaBean转换成Map、JSONObject 2:将Map转换成Javabean 3:将JSONObject转换成Map、Javabean
*
* @author zhangsan
*/
class JsonHelper {
/**
* 将Javabean转换为Map
*
* @param javaBean
* javaBean
* @return Map对象
*/
public static Map toMap(Object javaBean) {
Map result = new HashMap();
Method[] methods = javaBean.getClass().getDeclaredMethods();
for (Method method : methods) {
try {
if (method.getName().startsWith("get")) {
String field = method.getName();
field = field.substring(field.indexOf("get") + 3);
field = field.toLowerCase().charAt(0) + field.substring(1);
Object value = method.invoke(javaBean, (Object[]) null);
result.put(field, null == value ? "" : value.toString());
}
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
/**
* 将Json对象转换成Map
* @param jsonString
* @return
* @throws JSONException
*/
public static Map toMap(String jsonString) throws JSONException {
JSONObject jsonObject = new JSONObject(jsonString);
Map result = new HashMap();
Iterator iterator = jsonObject.keys();
String key = null;
String value = null;
while (iterator.hasNext()) {
key = (String) iterator.next();
value = jsonObject.getString(key);
result.put(key, value);
}
return result;
}
/**
* 将JavaBean转换成JSONObject（通过Map中转）
* @param bean
* @return
*/
public static JSONObject toJSON(Object bean) {
return new JSONObject(toMap(bean));
}
/**
* 将Map转换成Javabean
* @param javabean
* @param data
* @return
*/
public static Object toJavaBean(Object javabean, Map data) {
Method[] methods = javabean.getClass().getDeclaredMethods();
for (Method method : methods) {
try {
if (method.getName().startsWith("set")) {
String field = method.getName();
field = field.substring(field.indexOf("set") + 3);
field = field.toLowerCase().charAt(0) + field.substring(1);
method.invoke(javabean, new Object[] {
data.get(field)
});
}
} catch (Exception e) {
}
}
return javabean;
}
/**
* JSONObject到JavaBean
* @param javabean
* @param jsonString
* @throws ParseException
* @throws JSONException
*/
public static void toJavaBean(Object javabean, String jsonString)
throws ParseException, JSONException {
JSONObject jsonObject = new JSONObject(jsonString);
Map map = toMap(jsonObject.toString());
toJavaBean(javabean, map);
}
} 输出
JSONArray对象数据格式：
[{"name":"zhangsan","age":"23","sex":"female"}]
仅含Employee对象的Json数据格式：
{"name":"wangwu","age":"24","sex":"female"}
最终构造的JSON数据格式：
{"employee":"{\"name\":\"wangwu\",\"age\":\"24\",\"sex\":\"female\"}","map":[{"name":"zhangsan","age":"23","sex":"female"}]}
将Json数据解析为Map：
name: zhangsan sex: female age: 23
将Json数据解析为Employee对象：
name: wangwu sex: female age: null
[{"name":"zhangsan","age":"23","sex":"female"}]
仅含Employee对象的Json数据格式：
{"name":"wangwu","age":"24","sex":"female"}
最终构造的JSON数据格式：
{"employee":"{\"name\":\"wangwu\",\"age\":\"24\",\"sex\":\"female\"}","map":[{"name":"zhangsan","age":"23","sex":"female"}]}
将Json数据解析为Map：
name: zhangsan sex: female age: 23
将Json数据解析为Employee对象：
name: wangwu sex: female age: null