java对象和json互相转换

落日映苍穹つ 2022-02-04 12:51 298阅读 0赞

## jar包 ##

![在这里插入图片描述][20190507193217279.png]

## pom.xml ##

<project 
    xmlns="http://maven.apache.org/POM/4.0.0" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    
      
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
    http://maven.apache.org/xsd/maven-4.0.0.xsd">
    
      <modelVersion>4.0.0</modelVersion>
    
    
    
      <groupId>com.java1234</groupId>
    
      <artifactId>TestDemo</artifactId>
    
      <version>0.0.1-SNAPSHOT</version>
    
      <packaging>jar</packaging>
    
    
    
      <name>TestDemo</name>
    
      <url>http://maven.apache.org</url>
    
    
    
      <properties>
    
        
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    
      </properties>
    
    
    
      <dependencies>
    
        <dependency>
    
          <groupId>junit</groupId>
    
          <artifactId>junit</artifactId>
    
          <version>3.8.1</version>
    
          <scope>test</scope>
    
        </dependency>
    
        
    
         <dependency>
    
            <groupId>commons-lang</groupId>
    
            <artifactId>commons-lang</artifactId>
    
            <version>2.5</version>
    
        </dependency>
    
        
    
        <dependency>
    
            <groupId>commons-beanutils</groupId>
    
            <artifactId>commons-beanutils</artifactId>
    
            <version>1.8.0</version>
    
        </dependency>
    
        
    
        <dependency>
    
            <groupId>commons-collections</groupId>
    
            <artifactId>commons-collections</artifactId>
    
            <version>3.2.1</version>
    
        </dependency>
    
        
    
        <dependency>
    
            <groupId>commons-logging</groupId>
    
            <artifactId>commons-logging</artifactId>
    
            <version>1.1.1</version>
    
        </dependency>
    
        
    
        <dependency>
    
            <groupId>net.sf.ezmorph</groupId>
    
            <artifactId>ezmorph</artifactId>
    
            <version>1.0.6</version>
    
        </dependency>
    
        
    
      </dependencies>
    
    </project>

其中的json-lib-2.4-jdk15.jar是单独下载的，在maven仓库里没有

### Student.java ###

package com.java1234;
    
    
    
    public class Student {
    
    
    
        private Integer id;
    
        private String name;
    
        private Integer age;
    
        public Integer getId() {
    
            return id;
    
        }
    
        public void setId(Integer id) {
    
            this.id = id;
    
        }
    
        public String getName() {
    
            return name;
    
        }
    
        public void setName(String name) {
    
            this.name = name;
    
        }
    
        public Integer getAge() {
    
            return age;
    
        }
    
        public void setAge(Integer age) {
    
            this.age = age;
    
        }
    
        public Student(Integer id, String name, 
    Integer age) {
    
            super();
    
            this.id = id;
    
            this.name = name;
    
            this.age = age;
    
        }
    
        public Student() {
    
            super();
    
            // TODO Auto-generated constructor stub
    
        }
    
        
    
        
    
    }

测试类：

package com.java1234.test;
    
    
    
    import java.util.ArrayList;
    
    import java.util.HashMap;
    
    import java.util.List;
    
    import java.util.Map;
    
    
    
    import org.junit.After;
    
    import org.junit.Before;
    
    import org.junit.Test;
    
    
    
    import com.java1234.Student;
    
    
    
    import net.sf.json.JSONArray;
    
    import net.sf.json.JSONObject;
    
    
    
    public class Test1 {
    
    
    
        @Before
    
        public void setUp() throws Exception {
    
        }
    
    
    
        @After
    
        public void tearDown() throws Exception {
    
        }
    
    
    
        /**
    
         * 测试单个对象转<u>json</u>，用JSONObject
    
         */
    
        @Test
    
        public void test() {
    
            Student student=new Student(1,"小王",23);
    
            JSONObject 
    jsonObject=JSONObject.fromObject(student);
    
            String json=jsonObject.toString();
    
            System.out.println(json);//{"age":23,"id":1,"name":"小王"}
    
        }
    
    
    
        /**
    
         * 测试list转JSON，转集合用JSONArray，会产生[]
    
         */
    
        @Test
    
        public void test2() {
    
            List<Student> list=new 
    ArrayList<Student>();
    
            list.add(new Student(1,"小刘",22));
    
            list.add(new Student(2,"李大全",42));
    
            list.add(new Student(3,"大刘",32));
    
            JSONArray 
    jsonArray=JSONArray.fromObject(list);
    
            String json=jsonArray.toString();
    
            System.out.println(json);//[{"age":22,"id":1,"name":"小刘"},{"age":42,"id":2,"name":"李大全"},{"age":32,"id":3,"name":"大刘"}]
    
    
    
        }
    
        
    
        /**
    
         * 测试map转JSON，转单个对象用JSONObject
    
         */
    
        @Test
    
        public void test3() {
    
    
    
            Map<String,Student> map=new 
    HashMap<String,Student>();
    
            map.put("1", new Student(1,"小刘",22));
    
            map.put("2",new Student(2,"李大全",42));
    
            map.put("3",new Student(3,"大刘",32));
    
            JSONObject 
    jsonObject=JSONObject.fromObject(map);
    
            String json=jsonObject.toString();
    
            System.out.println(json);//{"1":{"age":22,"id":1,"name":"小刘"},"2":{"age":42,"id":2,"name":"李大全"},"3":{"age":32,"id":3,"name":"大刘"}}
    
    
    
        }
    
        
    
        /**
    
         * 手动创建JSONObject与JSONOArray
    
         */
    
        @Test
    
        public void test4() {
    
    
    
            JSONObject jsonObject=new JSONObject();
    
            jsonObject.put("id","1");
    
            jsonObject.put("name","小华");
    
            jsonObject.put("age",23);
    
            System.out.println(jsonObject.toString());//{"id":"1","name":"小华","age":23}
    
    
    
            JSONObject jsonObject2=new JSONObject();
    
            jsonObject2.put("id","2");
    
            jsonObject2.put("name","小华2");
    
            jsonObject2.put("age",33);
    
            System.out.println(jsonObject2.toString()); 
    //{"id":"2","name":"小华2","age":33}
    
            
    
            JSONArray jsonArray=new JSONArray();
    
            jsonArray.add(jsonObject);
    
            jsonArray.add(jsonObject2);
    
            System.out.println(jsonArray.toString());//[{"id":"1","name":"小华","age":23},{"id":"2","name":"小华2","age":33}]
    
        }
    
        
    
    }

[20190507193217279.png]: /images/20220204/071b49fe619040ad86425ab1ecc2a0a2.png