java JSONObject jar 下载 jsonobject jar包

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mob64ca140d96d9 2024-04-11 21:08:00

文章标签 JSONObject json User System 文章分类 Java 后端开发

注意来自不同3个jar包的JSONObject的区别

com.alibaba.fastjson.JSONObject
net.sf.json.JSONObject
org.json.JSONObject

java对象和json数据之间的转换方式一般有两种，一种是引用第三方的jar包，如Gson（谷歌）、Fastjson（阿里）、Jackson等，这种方式优点是语法精练，可以实现一句话转化，但缺点是会引入庞大的第三方库，第二种是直接使用Java自带的org.json解析，但这个库功能比较基础，解析会写很多重复的代码

一、com.alibaba.fastjson.JSONObject的使用

1 POM.xml

<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.51</version>
</dependency>

2 附上代码例子

2.1 创建2个实体类，供后面例子使用

public class School {
     private String id;
     private String name;
     List<User> students = new ArrayList<User>();
     public String getId() {
          return id;
     }
     public void setId(String id) {
         this.id = id;
     }
     public String getName() {
        return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public List<User> getStudents() {
         return students;
     }
     public void setStudents(List<User> students) {
         this.students = students;
     }
}

public class User {
     private String id;
     private String name;
     
     public User(){
         
     }
     public User(String id, String name){
         this.id = id;
         this.name = name;
     }
     
     public String getId() {
         return id;
     }
     public void setId(String id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
}

2.2 Json字符串与Map、List、object之间的相互转换

import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import com.alibaba.fastjson.JSON;
  import com.alibaba.fastjson.JSONArray;
  import com.alibaba.fastjson.JSONObject;
   
 public class TestFastJson {
  
      public static void main(String[] args){
          json2JsonObject();//将Json字符串转换为JSONObject对象
          json2JavaBean();//将Json字符串转换为JavaBean对象
          json2JsonArray();//将Json字符串转换为JSONArray对象
          json2JavaBeanList();//将Json字符串转换为JavaBean的集合
          javaBean2Json();//将JavaBean转换为Json格式的数据
          javaBean2JsonObject();//将JavaBean转换为JSONObject对象
          json2ListInMap();//从Json字符串的Map中获取List对象
          list2JsonInMap();//将含list的Map对象转换为Json字符串
          stringToMap();//json字符串转map
          mapToString();//map转json字符串
          mapToJsonObject();//map转json对象
          testList2String()；//list转json字符串
      }
      
      private static void json2JsonObject() {
          String s = "{\"name\":\"peter\"}";
          JSONObject object = JSON.parseObject(s);
          System.out.println(object.get("name"));
      }
     
     private static void json2JavaBean() {
         String s = "{\"id\":\"17051801\",\"name\":\"lucy\"}";
         User user = JSON.parseObject(s, User.class);
         System.out.println(user.getId());
         System.out.println(user.getName());
     }
     
     private static void json2JsonArray() {
         String s = "[{\"id\":\"17051801\",\"name\":\"lucy\"},{\"id\":\"17051802\",\"name\":\"peter\"}]";
         JSONArray array = JSON.parseArray(s);
         for (int i = 0; i < array.size(); i++) {
             //JSONArray中的数据转换为String类型需要在外边加"";不然会报出类型强转异常！
             String str = array.get(i)+"";
             JSONObject object = JSON.parseObject(str);
             System.out.println(object.get("name"));
         }
     }
     
     private static void json2JavaBeanList() {
         String s = "[{\"id\":\"17051801\",\"name\":\"lucy\"},{\"id\":\"17051802\",\"name\":\"peter\"}]";
         List<User> list = JSON.parseArray(s, User.class);
         for (User user : list) {
             System.out.println(user.getName());
         }
     }
     
      private static void javaBean2Json() {
         User user = new User("17051801", "lucy");
         String string = JSON.toJSONString(user);
         System.out.println(string);
     }
     
     private static void javaBean2JsonObject() {
         User user = new User("17051801", "lucy");
         JSONObject json = (JSONObject) JSON.toJSON(user);
         System.out.println(json.get("id"));
     }
     
     private static void json2ListInMap() {
         String s = "{json:[{id:\"17051801\",\"name\":\"lucy\"},{id:\"17051802\",\"name\":\"peter\"},"
                 + "{id:\"17051803\",\"name\":\"tom\"},{id:\"17051804\",\"name\":\"lily\"}]}";
         //将Json字符串转换为JSONObject对象,并取出list对象的值
         JSONObject object = JSON.parseObject(s);
         Object objArray = object.get("json");
         String str = objArray+"";
         //方式1:转换成JSONArray对象形式
         JSONArray array = JSON.parseArray(str);
         for (int i = 0; i < array.size(); i++) {
             JSONObject obj = JSON.parseObject(array.get(i)+"");
             System.out.println(obj.get("name"));
         }
         //方式2:转换成List<JavaBean>形式
         List<User> list = JSON.parseArray(str, User.class);
         for (User user : list) {
             System.out.println(user.getName());
         }
     }
     
     private static void list2JsonInMap() {
         //方式1:构建一个带有list的JavaBean对象
         School school = new School();
         school.setId("1");
         school.setName("schoolA");
         
         User user1 = new User();
         user1.setId("17051801");
         user1.setName("lucy");
         User user2 = new User();
         user2.setId("17051802");
         user2.setName("peter");
         
         school.getStudents().add(user1);
         school.getStudents().add(user2);
         //将JavaBean对象转换成Json字符串
         String string1 = JSON.toJSONString(school);
         System.out.println(string1);
         
         //方式2:构建一个带有list的Map对象
         Map<String, Object> map1 = new HashMap<String,Object>();
         map1.put("id", "17051801");
         map1.put("name", "lucy");
         
         Map<String, Object> map2 = new HashMap<String,Object>();
         map2.put("id", "17051802");
         map2.put("name", "peter");
         
         List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
         list.add(map1);
         list.add(map2);
         
         Map<String, Object> map = new HashMap<String,Object>();
         map.put("id", "1");
         map.put("name", "schoolA");
         map.put("students", list);
         //将map对象转换成Json字符串
         String string2 = JSON.toJSONString(map);
         System.out.println(string2);
     }
 
      private static void stringToMap(){
          String str = "{\"age\":\"24\",\"name\":\"cool_summer_moon\"}";
          JSONObject  jsonObject = JSONObject.parseObject(str);
          //json对象转Map
          Map<String,Object> map = (Map<String,Object>)jsonObject;
          System.out.println("map对象是：" + map);
          Object object = map.get("age");
          System.out.println("age的值是"+object);
     }
     
     private static void mapToString(){
         Map<String,Object> map = new HashMap<>();
         map.put("age", 24);
         map.put("name", "cool_summer_moon");
         String jsonString = JSON.toJSONString(map);
         System.out.println("json字符串是："+jsonString);
     }
 
     private static void mapToJsonObject(){
        Map<String,Object> map = new HashMap<>();
        map.put("age", 24);
        map.put("name", "cool_summer_moon");
        JSONObject json = new JSONObject(map);
        System.out.println("Json对象是：" + json);
 
     }
 
     /** 
     * 测试包装类型的List转换为json字符串 
     */   
    public static void testList2String() {  
        List<Long> longs = new ArrayList<Long>();  
        longs.add(1L);  
        longs.add(2L);  
        longs.add(3L);  
        String actual = JSON.toJSONString(longs);  
        Assert.assertEquals("[1,2,3]", actual);  
    }
 
}

二、org.json.JSONObject的使用

1.引入org.json依赖

<!-- 引入org.json所需依赖 -->
		<dependency>
			<groupId>org.json</groupId>
			<artifactId>json</artifactId>
			<version>20160810</version>
		</dependency>

2 构建JSONObject (3种)

2.1 直接构建

可以直接使用 new 关键字实例化一个JSONObject对象，然后调用它的 put() 方法对其字段值进行设置。

java JSONObject jar 下载 jsonobject jar包_JSONObject

范例

JSONObject jsonObj = new JSONObject();
		jsonObj.put("female", true);
		jsonObj.put("hobbies", Arrays.asList(new String[] { "yoga", "swimming" }));
		jsonObj.put("discount", 9.5);
		jsonObj.put("age", "26");
		jsonObj.put("features", new HashMap<String, Integer>() {
			private static final long serialVersionUID = 1L;
			{
				put("height", 175);
				put("weight", 70);
			}
		});
		System.out.println(jsonObj);

结果

{
	"features": {
		"weight": 70,
		"height": 175
	},
	"hobbies": ["yoga", "swimming"],
	"discount": 9.5,
	"female": true,
	"age": 26
}

2.2 使用Map构建

范例

Map<String, Object> map = new HashMap<String, Object>();
		map.put("female", true);
		map.put("hobbies", Arrays.asList(new String[] { "yoga", "swimming" }));
		map.put("discount", 9.5);
		map.put("age", "26");
		map.put("features", new HashMap<String, Integer>() {
			private static final long serialVersionUID = 1L;
			{
				put("height", 175);
				put("weight", 70);
			}
		});
		JSONObject jsonObj = new JSONObject(map);
		System.out.println(jsonObj);

结果

{
	"features": {
		"weight": 70,
		"height": 175
	},
	"hobbies": ["yoga", "swimming"],
	"discount": 9.5,
	"female": true,
	"age": 26
}

2.3 使用JavaBean构建

范例

import java.util.Map;
 
public class UserInfo {
 
	private Boolean female;
	private String[] hobbies;
	private Double discount;
	private Integer age;
	private Map<String, Integer> features;
 
	public Boolean getFemale() {
		return female;
	}
 
	public void setFemale(Boolean female) {
		this.female = female;
	}
 
	public String[] getHobbies() {
		return hobbies;
	}
 
	public void setHobbies(String[] hobbies) {
		this.hobbies = hobbies;
	}
 
	public Double getDiscount() {
		return discount;
	}
 
	public void setDiscount(Double discount) {
		this.discount = discount;
	}
 
	public Integer getAge() {
		return age;
	}
 
	public void setAge(Integer age) {
		this.age = age;
	}
 
	public Map<String, Integer> getFeatures() {
		return features;
	}
 
	public void setFeatures(Map<String, Integer> features) {
		this.features = features;
	}
 
}

UserInfo userInfo = new UserInfo();
		userInfo.setFemale(true);
		userInfo.setHobbies(new String[] { "yoga", "swimming" });
		userInfo.setDiscount(9.5);
		userInfo.setAge(26);
		userInfo.setFeatures(new HashMap<String, Integer>() {
			private static final long serialVersionUID = 1L;
			{
				put("height", 175);
				put("weight", 70);
			}
		});
		JSONObject jsonObj = new JSONObject(userInfo);
		System.out.println(jsonObj);

结果

{
	"features": {
		"weight": 70,
		"height": 175
	},
	"hobbies": ["yoga", "swimming"],
	"discount": 9.5,
	"female": true,
	"age": 26
}

3.解析JSONObject

JSONObject为每一种数据类型都提供了一个getXXX(key)方法，例如：获取字符串类型的字段值就使用getString()方法，获取数组类型的字段值就使用getJSONArray()方法。

java JSONObject jar 下载 jsonobject jar包_User_02

范例

// 获取基本类型数据
		System.out.println("Female: " + jsonObj.getBoolean("female"));
		System.out.println("Discount: " + jsonObj.getDouble("discount"));
		System.out.println("Age: " + jsonObj.getLong("age"));
		
		// 获取JSONObject类型数据
		JSONObject features = jsonObj.getJSONObject("features");
		String[] names = JSONObject.getNames(features);
		System.out.println("Features: ");
		for (int i = 0; i < names.length; i++) {
			System.out.println("\t"+features.get(names[i]));
		}
 
		// 获取数组类型数据
		JSONArray hobbies = jsonObj.getJSONArray("hobbies");
		System.out.println("Hobbies: ");
		for (int i = 0; i < hobbies.length(); i++) {
			System.out.println("\t"+hobbies.get(i));
		}

结果

Female: true
Discount: 9.5
Age: 26
Features: 
	70
	175
Hobbies: 
	yoga
	swimming

三 net.sf.json.JSONObject的使用

1 引入maven依赖

最后一行需要保留，有两个jdk版本的实现：json-lib-2.1-jdk13.jar和json-lib-2.1-jdk15.jar

<dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>

使用范例

JSONObject_1_3
package json;

import net.sf.json.JSON;
import net.sf.json.JSONObject;
import net.sf.json.xml.XMLSerializer;

public class JSONObject_1_3 {
public static void javaToJSON() {
System.out.println("java代码封装为json字符串");
JSONObject jsonObj = new JSONObject();
jsonObj.put("username", "张三");
jsonObj.put("password", "123456");
System.out.println("java--->json \n" + jsonObj.toString());
}

public static void jsonToJAVA() {
System.out.println("json字符串转java代码");
String jsonStr = "{\"password\":\"123456\",\"username\":\"张三\"}";
JSONObject jsonObj = JSONObject.fromString(jsonStr);
String username = jsonObj.getString("username");
String password = jsonObj.optString("password");
System.out.println("json--->java\n username=" + username
+ "\t password=" + password);
}

public static void jsonToXML() {
System.out.println("json字符串转xml字符串");
String jsonStr = "{\"password\":\"123456\",\"username\":\"张三\"}";
JSONObject json = JSONObject.fromString(jsonStr);
XMLSerializer xmlSerializer = new XMLSerializer();
xmlSerializer.setRootName("user_info");
xmlSerializer.setTypeHintsEnabled(false);
String xml = xmlSerializer.write(json);
System.out.println("json--->xml \n" + xml);
}

public static void javaBeanToJSON() {
System.out.println("javabean转json字符串");
UserInfo userInfo = new UserInfo();
userInfo.setUsername("张三");
userInfo.setPassword("123456");
JSONObject json = JSONObject.fromBean(userInfo);
System.out.println("javabean--->json \n" + json.toString());
}

public static void javaBeanToXML() {
System.out.println("javabean转xml字符串");
UserInfo userInfo = new UserInfo();
userInfo.setUsername("张三");
userInfo.setPassword("123456");
JSONObject json = JSONObject.fromBean(userInfo);
XMLSerializer xmlSerializer = new XMLSerializer();
String xml = xmlSerializer.write(json, "UTF-8");
System.out.println("javabean--->xml \n" + xml);
}

public static void xmlToJSON(){
System.out.println("xml字符串转json字符串");
String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><user_info><password>123456</password><username>张三</username></user_info>";
JSON json=XMLSerializer.read(xml);
System.out.println("xml--->json \n"+json.toString());
}

public static void main(String args[]) {
// javaToJSON();
// jsonToJAVA();
// jsonToXML();
// javaBeanToJSON();
// javaBeanToXML();
xmlToJSON();
}
}

UserInfo
package json;

public class UserInfo {
public String username;
public String password;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}

}

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