JSONObject

前言

fastjson2 是 FASTJSON 项目的重要升级，目标是为下一个十年提供一个高性能的JSON库， fastjson2 性能相比原先旧的 fastjson 有了很大提升,并且 fastjson2 更安全，完全删除autoType白名单，提升了安全性。

一、导入fastjson2依赖

maven如下：

pom(本文所有代码仅使用这一个依赖即可):

    <dependencies>
        <dependency>
            <groupId>com.alibaba.fastjson2</groupId>
            <artifactId>fastjson2</artifactId>
            <version>2.0.26</version>
        </dependency>
    </dependencies>

二、json对象与json数组的创建

json对象创建

public class JsonTest {
    public static void main(String[] args) {
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("name","瓜怂");
        jsonObject.put("age",25);
        jsonObject.put("sex","男");
        jsonObject.put("phone","1234567890");
        System.out.println(jsonObject);//{"phone":"1234567890","sex":"男","name":"瓜怂","age":25}
    }
}

json数组创建 

public class JsonTest {
    public static void main(String[] args) {
        //对象创建
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("name","瓜怂");
        jsonObject.put("age",25);
        JSONObject jsonObject1 = new JSONObject();
        jsonObject1.put("name","瓜皮");
        jsonObject1.put("age",25);
        //数组创建
        JSONArray objects = new JSONArray();
        objects.put(jsonObject);
        objects.put(jsonObject1);
        System.out.println(objects);//[{"name":"瓜怂","age":25},{"name":"瓜皮","age":25}]
    }
}

三、json对象取值与json数组遍历取值

json对象取值

        //遍历
        JSONObject jsonObject2 = new JSONObject();
        jsonObject2.put("A",jsonObject1);
        jsonObject2.put("b",objects);
        System.out.println(jsonObject.get("name"));//瓜怂
        System.out.println(jsonObject.get("age"));//25
        System.out.println(jsonObject2);//{"A":{"name":"瓜皮","age":25},"b":[{"name":"瓜怂","age":25},{"name":"瓜皮","age":25}]}
        System.out.println(jsonObject2.getJSONObject("A"));//{"name":"瓜皮","age":25}
        System.out.println(jsonObject2.getJSONArray("b"));//[{"name":"瓜怂","age":25},{"name":"瓜皮","age":25}]

json数组遍历取值 

        //遍历数组
        for(int i=0;i<objects.length();i++){
            JSONObject json = objects.getJSONObject(i);//
            System.out.println(json);
            System.out.println(json.get("name"));
            System.out.println(json.get("age"));
        }

四、json对象与字符串的转换

json对象与字符串的转换

        //JSON对象转字符串
        String jsonString = JSON.toJSONString(jsonObject);
        String jsonString1 = JSON.toJSONString(jsonObject1);
        System.out.println(jsonString);
        System.out.println(jsonString1);
        //JSON字符串转JSON对象
        System.out.println(JSON.parse(jsonString));
        System.out.println(JSON.parse(jsonString1));
       

json字符串转json对象 

       String str ="{\n" +
                "  \"name\": \"Cainfly\",\n" +
                "  \"age\": 18,\n" +
                "  \"地理\": \"70\",\n" +
                "  \"英语\": \"60\"\n" +
                "}";
        com.alibaba.fastjson.JSONObject jsonObject3 = JSON.parseObject(str);
        System.out.println(jsonObject3);//{"name":"Cainfly","英语":"60","地理":"70","age":18}

        //json字符串转json数组
        com.alibaba.fastjson.JSONArray objects1 = JSON.parseArray(jsonString1);
        //json数组转json字符串
        String jsonString2 = com.alibaba.fastjson.JSONArray.toJSONString(objects1);

五、json字符串转java对象的转换

Student类如下：

package com.amarsoft.lease;

public class Student {
    private String name;
    private int age;
    private String sex;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Student(String name, int age,String sex) {
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

}

        Student student = new Student("lpf", 25, "男");
        System.out.println(student);//com.amarsoft.lease.Student@5d5eef3d
        //Student对象转JSON字符串
        String s1 = JSON.toJSONString(student);
        System.out.println(s1);//{"age":25,"name":"lpf","sex":"男"}
        //JSON字符串转Student对象
        Student data = JSON.parseObject(s1, Student.class);
        System.out.println(data);//com.amarsoft.lease.Student@e320068

六、json字符串与Map转换

json字符串转Map

 

        String str = "{\n" +
                "  \"gradle\": \"高一\",\n" +
                "  \"number\": \"2\",\n" +
                "  \"people\": [\n" +
                "    {\n" +
                "      \"sex\": \"男\",\n" +
                "      \"name\": \"张三\",\n" +
                "      \"age\": 15\n" +
                "    },\n" +
                "    {\n" +
                "      \"sex\": \"女\",\n" +
                "      \"name\": \"李四\",\n" +
                "      \"age\": 16\n" +
                "    }\n" +
                "  ]\n" +
                "}";
        System.out.println(JSON.parse(str));//{"gradle":"高一","number":"2","people":[{"sex":"男","name":"张三","age":15},{"sex":"女","name":"李四","age":16}]}
        Map<String,Object> map = JSON.parseObject(str, new TypeReference<Map<String, Object>>(){});
        System.out.println(map);
        System.out.println(map.get("gradle"));
        System.out.println(map.get("number"));
        System.out.println(map.get("people"));
        String people = map.get("people").toString();
        JSONArray objects = JSON.parseArray(people);
        for(int i=0;i<objects.size();i++){
            JSONObject jsonObject = objects.getJSONObject(i);
            String name = jsonObject.getString("name");
            Integer age = Integer.valueOf(jsonObject.getString("age"));
            String sex = jsonObject.getString("sex");
            Student s = new Student(name, age, sex);
            String jsonString = JSON.toJSONString(s);
            /**
             * {"age":15,"name":"张三","sex":"男"}
             * {"age":16,"name":"李四","sex":"女"}
             */
            System.out.println(jsonString);
        }

七、json数组转List 

        String str = "{\n" +
                "  \"gradle\": \"高一\",\n" +
                "  \"number\": \"2\",\n" +
                "  \"people\": [\n" +
                "    {\n" +
                "      \"sex\": \"男\",\n" +
                "      \"name\": \"张三\",\n" +
                "      \"age\": 15\n" +
                "    },\n" +
                "    {\n" +
                "      \"sex\": \"女\",\n" +
                "      \"name\": \"李四\",\n" +
                "      \"age\": 16\n" +
                "    }\n" +
                "  ]\n" +
                "}";
        JSONObject jsonObject = JSON.parseObject(str);
        System.out.println(jsonObject);//{"gradle":"高一","number":"2","people":[{"sex":"男","name":"张三","age":15},{"sex":"女","name":"李四","age":16}]}
        JSONArray people = jsonObject.getJSONArray("people");
        //转list
        List<JSONObject> javaList = people.toJavaList(JSONObject.class);
        System.out.println(javaList);//[{"sex":"男","name":"张三","age":15}, {"sex":"女","name":"李四","age":16}]
        javaList.forEach(json->{
            //也可以在添加新的数据
            Map<String, ? extends Serializable> stringMap = MapKit.mapOf("phone", 12232323, "address", "甘肃省");
            json.putAll(stringMap);
            System.out.println(json);
            /**
             * {"address":"甘肃省","phone":12232323,"sex":"男","name":"张三","age":15}
             * {"address":"甘肃省","phone":12232323,"sex":"女","name":"李四","age":16}
             */
        });

 

原文地址：https://blog.csdn.net/lpf11214/article/details/137549297

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