[JSON] JavaWeb basis

JSON

JavaScript Object Notation (JavaScript Object Notation);

JSON is a lightweight text data exchange format;

JSON language independent, self-descriptive, easier to understand;

JSON syntax rules

Data described by a key (key) / value (value), separated by commas
A complete object braces representatives, have more key / value pairs
Brackets backup array, a plurality of objects separated by commas

{
    "site":[
        {"name":"慕课网", "url":"www.imooc.com"},
        {"name":"百度", "url":"www.baidu.com"},
        {"name":"网易", "url":"www.163.com"}
    ]
}

JSON string conversion

The JSON.parse () method to convert the string to an object JSON
The JSON.stringify () method to convert the string to an object JSON

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
    <!--JS中将字符串转换成JSON-->
    var str = "{\"class_name\" : \"五年级一班\"}";
    var json = JSON.parse(str);
    console.log(str);
    console.log(json);
    document.write("班级:" + json.class_name + "<br>");
    
    <!--JS中将JSON转换成字符串-->
    var json2 = {"class_name" : "五年级二班"};
    var str2 = JSON.stringify(json2);
    console.info(json2);
    console.info(str2);
    document.write(str2 + "<br>");
    
    <!--JS中JSON对象初始化-->
    var json3 = {};
    json3.class_name = "五年级三班";
    console.log(json3);
    document.write("班级:" + json3.class_name);
</script>
</head>
<body>

</body>
</html>

JSON interact with Java

Java's JSON toolkit also FastJson, Jackson, Gson, Json-lib ...
FastJson Alibaba famous JSON serialization and de-serialization Kit
FastJson the country has a large number of users, with a simple API, high efficiency

FastJSON object serialization and deserialization

Employee.java

package demo;

import java.util.Date;

import com.alibaba.fastjson.annotation.JSONField;

public class Employee {
    @JSONField(serialize = false) //serialize属性:不对该成员序列化
    private int empId;
    
    private String empName;
    
    @JSONField(name = "hiredate", format = "yyyy-MM-dd") //JSON注解，name属性:说明key，format属性:将日期格式化
    private Date empIn;
    
    public int getEmpId() {
        return empId;
    }
    public void setEmpId(int empId) {
        this.empId = empId;
    }
    public String getEmpName() {
        return empName;
    }
    public void setEmpName(String empName) {
        this.empName = empName;
    }
    public Date getEmpIn() {
        return empIn;
    }
    public void setEmpIn(Date empIn) {
        this.empIn = empIn;
    }
    
    public Employee(int empId, String empName, Date empIn) {
        super();
        this.empId = empId;
        this.empName = empName;
        this.empIn = empIn;
    }
    
    @Override
    public String toString() {
        return "Employee [empId=" + empId + ", empName=" + empName + ", empIn=" + empIn + "]";
    }
    
}

FastJsonSample.java

package demo;

import java.util.Calendar;

import com.alibaba.fastjson.JSON;

public class FastJsonSample {

    public static void main(String[] args) {
        Calendar c = Calendar.getInstance();
        c.set(2019, 1, 24);
        Employee emp = new Employee(007, "星海", c.getTime());
        String json = JSON.toJSONString(emp); //将Java对象转换成JSON字符串
        System.out.println(json);
        Employee emp2 = JSON.parseObject(json, Employee.class); //将JSON字符串转换成Java对象
        System.out.println(emp2);
    }

}

Console output:

{"empName":"星海","hiredate":"2019-02-24"}
Employee [empId=0, empName=星海, empIn=Sun Feb 24 00:00:00 CST 2019]

FastJSON array of objects and deserialize serialized

JSON.toJSONString(list)The array of objects serialized
JSON.parseArray(json, Employee.class)The JSON array deserialization

[JSON] JavaWeb basis

JSON

JSON syntax rules

JSON string conversion

JSON interact with Java

FastJSON object serialization and deserialization

FastJSON array of objects and deserialize serialized

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