Java前后端的JSON传输方式(前后端JSON格式转换)

	JSONObject zhangsan = new JSONObject();
        try {
            //添加
            zhangsan.put("name", "张三");
            zhangsan.put("age", 18.4);
            zhangsan.put("birthday", "1900-20-03");
            zhangsan.put("majar", new String[] {"哈哈","嘿嘿"});
            zhangsan.put("null", null);
            zhangsan.put("house", false);
            System.out.println(zhangsan.toString());
        } catch (JSONException e) {
            e.printStackTrace();
        }

   HashMap<String, Object> zhangsan = new HashMap<>();        
   zhangsan.put("name", "张三");
   zhangsan.put("age", 18.4);
   zhangsan.put("birthday", "1900-20-03");
   zhangsan.put("majar", new String[] {"哈哈","嘿嘿"});
   zhangsan.put("null", null);
   zhangsan.put("house", false);
   System.out.println(new JSONObject(zhangsan).toString());

  Student student = new Student();
  student.setId(1);
  student.setAge("20");
  student.setName("张三");
  // 生成 JSONObject
  System.out.println(JSON.toJSON(student));

String studentString = "{\"id\":1,\"age\":2,\"name\":\"zhang\"}";
 
//JSON字符串转换成 JSONObject 
JSONObject jsonObject1 = JSONObject.parseObject(stuString); 
System.out.println(jsonObject1);

 { "firstName": "Brett", "lastName":"McLaughlin", "email": "aaaa" } 

{ "people": [
{ "firstName": "Brett", "lastName":"McLaughlin", "email": "aaaa" },
{ "firstName": "Jason", "lastName":"Hunter", "email": "bbbb"}, 
{ "firstName": "Elliotte", "lastName":"Harold", "email": "cccc" }
]} 

var people = { "programmers": [ { "firstName": "Brett", "lastName":"McLaughlin", "email": "aaaa" },

{ "firstName": "Jason", "lastName":"Hunter", "email": "bbbb" },

{ "firstName": "Elliotte", "lastName":"Harold", "email": "cccc" }

],

"authors": [

{ "firstName": "Isaac", "lastName": "Asimov", "genre": "science fiction" },

{ "firstName": "Tad", "lastName": "Williams", "genre": "fantasy" },

{ "firstName": "Frank", "lastName": "Peretti", "genre": "christian fiction" }

],

"musicians": [

{ "firstName": "Eric", "lastName": "Clapton", "instrument": "guitar" },

{ "firstName": "Sergei", "lastName": "Rachmaninoff", "instrument": "piano" }

] }

people.programmers[0].lastName;

people.musicians[1].lastName = "Rachmaninov";

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.9</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.9</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.9</version>
        </dependency>

    @RequestMapping(value="/returnJson")
    //@ResponseBody注解将JSON数据写入响应流中返回到前端
    @ResponseBody
    public String returnJson(){
        ObjectMapper objectMapper=new ObjectMapper();
        Student student=new Student();
        //writeValueAsString()函数将对象转换为JSON字符串
        return objectMapper.writeValueAsString(student);
    }

    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.4</version>
    </dependency>

// 将 JSON 字符串反序列化成 JavaBean 
public static final Object parse(String text); 
// 将 JSON 字符串反序列化成 JSONObject    
public static final JSONObject parseObject(String text)； 
// 将 JSON 字符串反序列化成 JavaBean 或 JSONObject 
public static final <T> T parseObject(String text, Class<T> clazz); 
// 将 JSON 字符串反序列化成JSONObject 的数组
public static final JSONArray parseArray(String text); 
// 将 JSON 字符串反序列化成 JavaBean 的数组
public static final <T> List<T> parseArray(String text, Class<T> clazz); 
// 将 Java 对象序列化为JSON 字符串 
public static final String toJSONString(Object object); 
// 将 Java 对象序列化为带格式的 JSON 字符串 
public static final String toJSONString(Object object, boolean prettyFORMat); 
 //将 JavaBean 转换为 JSONObject 或者 JSONArray。
public static final Object toJSON(Object javaObject);

    @RequestMapping(value="/returnJson")
    @ResponseBody
    public Student returnJson(){
        Student student=new Student();
        student.setName("林俊杰");
        student.setBirth(new Date(1996-03-15));
        student.setPassword("123456");
        String[] lan= {"Java","python"};
        student.setLanguage(lan);
        return student;
    }

var jsonVar = {key: value}
 //将JS对象转换为JSON字符串
var jsonString = JSON.stringify(jsonVar) 
//将JSON字符串转换为JSON对象
var jsonObject = JSON.parse(jsonString)  

var jsonVar = [value1,..,value]
//将JS数组转换为JSON字符串
var jsonString = JSON.stringify(jsonVar)  
//将JSON字符串转换为数组对象
var jsonObject = JSON.parse(jsonString)  

var json = '{"name":"James"}';
var obj = eval( '(' + json + ')' );  //注意需要在json字符外包裹一对小括号
alert( obj.name );

var json = '{"name":"James"}';
var obj = $.parseJSON(json);  
alert( obj.name );  

var obj = {"plugin":"jquery-json","version":2.4};
//json = '{"plugin":"jquery-json","version":2.4}'
var json = $.toJSON( obj );
// 得到name值为："jquery-json"
var name = $.evalJSON( json ).plugin;
// 得到version值为：2.4
var version = $.evalJSON( json ).version;