2022年0514文章的内容Json前后端的交互数据.从最基本的Servlect开始.文章重在实操.关顾的去看是不明白的.

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第一点:JSON的定义:JSON(JavaScript Object Notation, JS 对象简谱) 是一种轻量级的数据交换格式。它基于 ECMAScript (欧洲计算机协会制定的js规范)的一个子集，采用完全独立于编程语言的文本格式来存储和表示数据。简洁和清晰的层次结构使得 JSON 成为理想的数据交换语言。

第二点在这之前你要会Ajax的内容.首先回顾Ajax的内容。

2022年5月12号:Asynchronous JavaScript And XML简称AJAX.(第一课）在这之前你的知道JavaScript Jquery 数组实体类集合._@Live@And@Learn@#的博客-CSDN博客Ajax的简介:Ajax即Asynchronous Javascript And XML（异步JavaScript和XML）在 2005年被Jesse James Garrett提出的新术语，用来描述一种使用现有技术集合的‘新’方法，包括: HTML 或 XHTML, CSS, JavaScript, DOM, XML, XSLT, 以及最重要的XMLHttpRequest。使用Ajax技术网页应用能够快速地将增量更新呈现在用户界面上，而不需要重载（https://blog.csdn.net/qq_56248592/article/details/124737776?spm=1001.2014.3001.5501

第三点在这之前要知道的JSON的两句话.

1.{}：当需要保存的是一个实体中不同属性的数据，就需要一对大括号套起来.{}

2.[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

案例一:使用的是当需要保存的是一个实体中不同属性的数据，就需要一对大括号套起来.{}这里我们使用了三种方案

方案一：利用Map集合开始JSON数据格式的学习。

@WebServlet(urlPatterns = "/A5Servlet")public class A5Servlet extends HttpServlet {    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("application/json"); response.setCharacterEncoding("UTF-8"); /*JSON*/ //当html页面点击发送a.jax过来的时候 // 学生信息  姓名  年龄  性别  学校  专业   、爱好 //AAA  20  XX  江西青年职业学院  BBB    CCCb Map map = new HashMap(); map.put("id","100890657"); map.put("name", "胡大胜"); map.put("age", "21"); map.put("sex", "男"); map.put("school", "清华大学"); map.put("height","1187"); //将map集合自动转为json的格式  一行代码 new ObjectMapper().writeValue(response.getWriter(), map);    }

我们在html中定义三个按钮.

      /*获得Ajax的内容*/ function btn() {     $.ajax({  url:"A5Servlet",  type:"POST",  data:"",  success:function (json) {     error:function () {      alert("连接服务器失败");  },  dataType:"json"//要求服务器返回的数据格式为json格式     }); }

运行效果我们在审查元素中看结果.

你会发现运行结果显示的JSON结果是下面的样子.

那么如何解析上面的数据在浏览器中显示呢？

  /*获得Ajax的内容*/ function btn() {     $.ajax({  url:"A5Servlet",  type:"POST",  data:"",  success:function (json) { var a=json.name;      var b=json.age;      var c=json.sex;      var d=json.school;      $("#pc").html(a+"-"+b+"-"+c+"-"+d);  },  error:function () {      alert("连接服务器失败");  },  dataType:"json"//要求服务器返回的数据格式为json格式     }); }

结果为下面的内容:

方案二利用实体类的方式。

package Entity;public class Student {    private String name;    private int age;    private String sex;    private String school;    public Student() {    }    public Student(String name, int age, String sex, String school) { this.name = name; this.age = age; this.sex = sex; this.school = school;    }    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 String getSchool() { return school;    }    public void setSchool(String school) { this.school = school;    }    @Override    public String toString() { return "Student{" +  "name='" + name + '\'' +  ", age=" + age +  ", sex='" + sex + '\'' +  ", school='" + school + '\'' +  '}';    }}

你会发现实体类的方式更简单.

运行效果

在审查元素的运行结果

{"name":"哈喽","age":20,"sex":"男","school":"清华大学"}

方案三:利用Properties的方式存放数据。

运行结果:JSON格式

{age: "19", school: "江西农业大学", name: "小咩咩", sex: "女"}

接下来学第二句话

2.[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

同样也有三种方式。数组集合 set集合。同一属性不同的值。

第一种方式：

运行结果

JSON：[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

["红色","蓝色","绿色","黄色","白色","粉色","天蓝色"]

第二种方式:list集合方式。

运行结果

JSON格式：

["《Python从入门到放弃》","《Html从入门到精通》","《Jquery框架技术》","《MySQL从入门到出家》"]

第三种方式Set集合:

["《Python从入门到放弃》","《Html从入门到精通》","《Jquery框架技术》","《MySQL从入门到出家》"]

         input {     height: 20%;     width: 60%;     border-radius: 20px;     font-family: 微软雅黑;     font-size: 16px;     line-height: 100px;     margin: 2px;     background-color: black;     color: red;     font-size: 23px;     font-family: 微软雅黑;     font-weight: bold;     border-radius: 12px; } ul{     list-style: none; }        ASON格式的使用             /*获得Ajax的内容*/ function btn() {     $.ajax({  url:"A5Servlet",  type:"POST",  data:"",  success:function (json) {      //{"school":"江西青年职业学院","sex":"男","name":"杜康","age":20}      var a=json.name;      var b=json.age;      var c=json.sex;      var d=json.school;      $("#pc").html(a+"-"+b+"-"+c+"-"+d);  },  error:function () {      alert("连接服务器失败");  },  dataType:"json"//要求服务器返回的数据格式为json格式     }); }         function btn1() {     $.ajax({  url:"A5Servlet",  type:"GET",  data:"",  success:function (json) {      //{"school":"江西青年职业学院","sex":"男","name":"杜康","age":20}      var a=json.name;      var b=json.age;      var c=json.sex;      var d=json.school;      $("#pc").html(a+"-"+b+"-"+c+"-"+d);  },  error:function () {      alert("连接服务器失败");  },  dataType:"json"//要求服务器返回的数据格式为json格式     }); }         function btn2() {     $.ajax({  url:"A6Servlet",  type:"POST",  data:"",  success:function (json) {      //{"school":"江西青年职业学院","sex":"男","name":"杜康","age":20}      var a=json.name;      var b=json.age;      var c=json.sex;      var d=json.school;      $("#pc").html(a+"-"+b+"-"+c+"-"+d);  },  error:function () {      alert("连接服务器失败");  },  dataType:"json"//要求服务器返回的数据格式为json格式     }); }             
       
    function btn3() { $.ajax({     url: "A6Servlet",     type: "GET",     data: "",     success: function (json) {  //["红色","蓝色","绿色","黄色"],把该格式的数据当做数组来获得数据  for (var i = 0; i < json.length; i++) {      $("#u").append("" + json[i] + "
");  }     },     error: function () {     },     dataType: "json" });    }     function btn4() {     $.ajax({  url: "A7Servlet",  type: "POST",  data: "",  success: function (json) {      //["红色","蓝色","绿色","黄色"],把该格式的数据当做数组来获得数据      for (var i = 0; i < json.length; i++) {   $("#u").append("" + json[i] + "
");      }  },  error: function () {  },  dataType: "json"     }); }         function btn5() {     $.ajax({  url: "A7Servlet",  type: "GET",  data: "",  success: function (json) {      //["红色","蓝色","绿色","黄色"],把该格式的数据当做数组来获得数据      for (var i = 0; i < json.length; i++) {   $("#u").append("" + json[i] + "
");      }  },  error: function () {  },  dataType: "json"     }); }         function btn6() {     $.ajax({  url: "two",  type: "GET",  data: "",  success: function (json) {      //["红色","蓝色","绿色","黄色"],把该格式的数据当做数组来获得数据      for (var i = 0; i < json.length; i++) {   $("#u").append("" + json[i] + "
");      }  },  error: function () {      alert("链接的地址错误请查看地址的信息内容")  },  dataType: "json"     }); }

1.{}：当需要保存的是一个实体中不同属性的数据，就需要一对大括号套起来.{}

2.[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

综合上面的两种方案灵活运用：先思考一个问题.{}[]""，这些符号如何运用呢？

JSON的难度在哪里？

{"pageNum":1,    (第几页)"pageSize":10,   （每页显示多少条数据）"size":10,（条数）"startRow":1,    （展示在页面的是从第一行开始）"endRow":10,（展示在页面的是到第十行结束）"total":11,  （从数据库中查询的总记录数11条）"pages":2,   （分页的总数为两页）"list":（当前页要展示的数据）[{"birthday":439833600000,"userPassword":"0000000","address":"北京市东城区前门东大街9号","gender":2,"phone":"13688884457","createdBy":1,"id":2,"userName":"李明","userRole":2,"userCode":"liming"},{"birthday":455212800000,"userPassword":"0000000","address":"北京市朝阳区北辰中心12号","gender":2,"phone":"18567542321","createdBy":1,"id":5,"userName":"韩路彪","userRole":2,"creationDate":1420026729000,"userCode":"hanlubiao"},{"birthday":424454400000,"userPassword":"0000000","address":"北京市海淀区学院路61号","gender":1,"phone":"13544561111","createdBy":1,"id":6,"userName":"张华","userRole":3,"creationDate":1360551077000,"userCode":"zhanghua"},{"birthday":410112000000,"userPassword":"0000000","address":"北京市海淀区西二旗辉煌国际16层","gender":2,"phone":"13444561124","createdBy":1,"id":7,"userName":"王洋","userRole":3,"creationDate":1402484947000,"userCode":"wangyang"},{"birthday":510508800000,"userPassword":"0000000","address":"北京市海淀区回龙观小区10号楼","gender":1,"phone":"18098764545","createdBy":1,"id":8,"userName":"赵燕","userRole":3,"creationDate":1461218047000,"userCode":"zhaoyan"},{"birthday":347385600000,"userPassword":"0000000","address":"北京市朝阳区管庄新月小区12楼","gender":2,"phone":"13387676765","createdBy":1,"id":10,"userName":"孙磊","userRole":3,"creationDate":1430880727000,"userCode":"sunlei"},{"birthday":258480000000,"userPassword":"0000000","address":"北京市朝阳区建国门南大街10号","gender":2,"phone":"13367890900","createdBy":1,"id":11,"userName":"孙兴","userRole":3,"creationDate":1478681477000,"userCode":"sunxing"},{"birthday":512323200000,"modifyBy":1,"userPassword":"0000000","address":"朝阳区管庄路口北柏林爱乐三期13号楼","gender":1,"modifyDate":1460614536000,"userName":"张晨","creationDate":1470693157000,"userCode":"zhangchen","phone":"18098765434","createdBy":1,"id":12,"userRole":3},{"birthday":373651200000,"userPassword":"0000000","address":"北京市海淀区北航家属院10号楼","gender":2,"phone":"13689674534","createdBy":1,"id":13,"userName":"邓超","userRole":3,"creationDate":1468195367000,"userCode":"dengchao"},{"birthday":315504000000,"userPassword":"0000000","address":"北京市朝阳区北苑家园茉莉园20号楼","gender":2,"phone":"13388886623","createdBy":1,"id":14,"userName":"杨过","userRole":3,"creationDate":1422733927000,"userCode":"yangguo"}],"prePage":0,（上一页的页码为0）"nextPage":2,（下一页的页码为2）"isFirstPage":true,（当前页码为第一页）"isLastPage":false,（当前页码是否为最后一页）"hasPreviousPage":false,（判断是否有上一页）"hasNextPage":true,（判断是否有下一页）"navigatePages":8,"navigatepageNums":[1,2],（页码数组）"navigateFirstPage":1,（获得第一页的页码）"navigateLastPage":2,（获得最后一页的页码）"firstPage":1,"lastPage":2}

上面的代码看的懂吗？这又是JSON格式.不要看表面要看他的内涵.

{{},{},{},{},{}}

{[],[],[],[],[]}

[[],[],[],[],[]]

[{},{},{},{},]

{[{},{},{},{},]}

[{[],[],[],[],[]} ]

案例一:先看结果后想思路.

[{name: "张三", age: 22, sex: "男", school: "北京大学"}, {name: "小明", age: 21, sex: "男", school: "清华大学"},…]0: {name: "张三", age: 22, sex: "男", school: "北京大学"}1: {name: "小明", age: 21, sex: "男", school: "清华大学"}2: {name: "小王", age: 20, sex: "女", school: "南京大学"}3: {name: "李武", age: 20, sex: "女", school: "南昌大学"}

案例二:先看结果后想思路.

{"fruits":["苹果 ","香蕉","梨子"," 橘子 "],"foots":["薯片","瓜子","饮料 "," 火腿","赖条"],"Pents":["水彩笔 ","钢笔","圆珠笔"]}

{"fruits":["苹果 ","香蕉","梨子"," 橘子 "],"foots":["薯片","瓜子","饮料 "," 火腿","赖条"],"Pents":["水彩笔 ","钢笔","圆珠笔"]}

案例一的综合运用的分析流程:

[{name: "张三", age: 22, sex: "男", school: "北京大学"}, {name: "小明", age: 21, sex: "男", school: "清华大学"},…]

第一步创建学生对象：中在创建四个学生对象，然后将四个学生对象利用数组的方式存放起来。

Student[] students = {student1, student2, student3, student4};

new ObjectMapper().writeValue(response.getWriter(), students);//转换成JSON格式。

[{name: "张三", age: 22, sex: "男", school: "北京大学"}, {name: "小明", age: 21, sex: "男", school: "清华大学"},…]

        json格式综合运用    function btn() {    $.ajax({ url:"three", type:"POST", data:"", success:function (json) {     console.log(json)     for (let i = 0; i < json.length; i++) {  //将每次循环的数据显示在表格中  $("#tb").append("" +      ""+json[i].name+"" +      ""+json[i].age+"" +      ""+json[i].sex+"" +      ""+json[i].school+"" +      "")     } }, error:function () { alert("失败") }, dataType:"json"    })    }     姓名  年龄  性别  学校

JSON解析:

 success:function (json) {     console.log(json)     for (let i = 0; i < json.length; i++) {  //将每次循环的数据显示在表格中  $("#tb").append("" +      ""+json[i].name+"" +      ""+json[i].age+"" +      ""+json[i].sex+"" +      ""+json[i].school+"" +      "")     } },

案例二的综合运用的分析流程:

 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); response.setCharacterEncoding("UTF-8"); //大{[][][]} //{"fruits":["苹果 ","香蕉","梨子"," 橘子 "],"foots":["薯片","瓜子","饮料 "," 火腿","赖条"],"Pents":["水彩笔 ","钢笔","圆珠笔"]} response.setContentType("text/html"); response.setCharacterEncoding("UTF-8"); //小明去 goshoping //1 苹果  香蕉  梨子  橘子 String[] fruits={"苹果 ","香蕉","梨子"," 橘子 "}; //2  五种零食  薯片  瓜子  饮料    火腿  赖条 String[] foots={"薯片","瓜子","饮料 "," 火腿","赖条"}; //3  袋子 :水彩笔  钢笔  圆珠笔 String[] Pents={"水彩笔 ","钢笔","圆珠笔"}; //4收银员 给了一个大袋子 Map map=new HashMap(); map.put("fruits",fruits); map.put("foots",foots); map.put("Pents",Pents); //{"fruits":[],"foots":[],"Pents":[]} new ObjectMapper().writeValue(response.getWriter(), map);    }

        json格式的综合运用         function btn() {     $.ajax({  url:"three",  type:"GET",  data:"",  success:function (json) {      console.log(json)  } ,  error:function () {      alert("连接服务器失败");  },  dataType:"json"     }); }

{"fruits":["苹果 ","香蕉","梨子"," 橘子 "],"foots":["薯片","瓜子","饮料 "," 火腿","赖条"],"Pents":["水彩笔 ","钢笔","圆珠笔"]}

综合案例三:这才是日后工作使用JSON解析。

package Entity;/** * @author MZFAITHDREAM * 一个标准类的封装 */public class People {    private     String  Id;   //身份证号    private String name;      //身份证的姓名    private int age;   //省份证的年龄    private String sex;//省份证的性别    private String x;  //省份证的人物所在名族    private  String address;  //省份的家庭地址    private  int height;      //身高    private  int weight;      //体重    private  String  job;     //工作    private  String   n;      //爱好    //在一个标准类的 无惨 有参    public People() { System.out.println("无参构造");    }    public People(String id, String name, int age, String sex, String x, String address, int height, int weight, String job, String n) { Id = id; this.name = name; this.age = age; this.sex = sex; this.x = x; this.address = address; this.height = height; this.weight = weight; this.job = job; this.n = n;    }    public String getId() { return Id;    }    public void setId(String id) { Id = id;    }    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 String getX() { return x;    }    public void setX(String x) { this.x = x;    }    public String getAddress() { return address;    }    public void setAddress(String address) { this.address = address;    }    public int getHeight() { return height;    }    public void setHeight(int height) { this.height = height;    }    public int getWeight() { return weight;    }    public void setWeight(int weight) { this.weight = weight;    }    public String getJob() { return job;    }    public void setJob(String job) { this.job = job;    }    public String getN() { return n;    }    public void setN(String n) { this.n = n;    }    @Override    public String toString() { return "People{" +  "Id='" + Id + '\'' +  ", name='" + name + '\'' +  ", age=" + age +  ", sex='" + sex + '\'' +  ", x='" + x + '\'' +  ", address='" + address + '\'' +  ", height=" + height +  ", weight=" + weight +  ", job='" + job + '\'' +  ", n='" + n + '\'' +  '}';    }}

package Com;import Entity.People;import Entity.Student;import com.fasterxml.jackson.databind.ObjectMapper;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;@WebServlet(urlPatterns = "/A8Servlet")public class A8Servlet extends HttpServlet {    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.setContentType("text/html"); response.setCharacterEncoding("UTF-8"); //  public People(int id, String name, int age, String sex, String x, String address, int height, int weight, String job, String n) //1 创建人类的对象 一个实体类中部同属性{} People people1=new People("360429200310080977","张三",22,"女","白领","九江",178,68,"上海东区","王者"); People people2=new People("360429200310080978","李四",24,"男","红领","南昌",175,69,"上海西区","排球"); People people3=new People("360429200310080979","王五",20,"女","黑领","北京",168,66,"上海南区","睡觉"); People people4=new People("360429200310080980","李留",26,"男","陆玲","上海",158,37,"上海北区","篮球"); People people5=new People("360429200310080981","李子璇",28,"男","普通工人","南昌",178,67,"上海中部","写字"); //将上面的实体类中创建一维数组  People[] people {} People[] people = {people1,people2,people3,people4,people5}; new ObjectMapper().writeValue(response.getWriter(),people );    }    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {    }}

        json格式综合运用    function btn() { $.ajax({     url:"A8Servlet",     type:"POST",     data:"",     success:function (json) {  console.log(json)  for (let i = 0; i < json.length; i++) {      //将每次循环的数据显示在表格中      $("#tb").append("" +   ""+json[i].id+"" +   ""+json[i].name+"" +   ""+json[i].age+"" +   ""+json[i].sex+"" +   ""+json[i].x+"" +   ""+json[i].address+"" +   ""+json[i].height+"" +   ""+json[i].weight+"" +   ""+json[i].job+"" +   ""+json[i].n+"" +   "")      //int id, String name, int age, String sex, String x, String address, int height, int weight, String job, String n  }     },     error:function () {  alert("失败")     },     dataType:"json" })    }                  身份证号      姓名      年龄      性别      名族      地址      身高      体重      工作地      爱好

[,…]
1. 0: {name: "张三", age: 22, sex: "女", x: "白领", address: "九江", height: 178, weight: 68, job: "上海东区", n: "王者",…}
2. 1: {name: "李四", age: 24, sex: "男", x: "红领", address: "南昌", height: 175, weight: 69, job: "上海西区", n: "排球",…}
  1. address: "南昌"
  2. age: 24
  3. height: 175
  4. id: "360429200310080978"
  5. job: "上海西区"
  6. n: "排球"
  7. name: "李四"
  8. sex: "男"
  9. weight: 69
  10. x: "红领"
3. 2: {name: "王五", age: 20, sex: "女", x: "黑领", address: "北京", height: 168, weight: 66, job: "上海南区", n: "睡觉",…}
  1. address: "北京"
  2. age: 20
  3. height: 168
  4. id: "360429200310080979"
  5. job: "上海南区"
  6. n: "睡觉"
  7. name: "王五"
  8. sex: "女"
  9. weight: 66
  10. x: "黑领"
4. 3: {name: "李留", age: 26, sex: "男", x: "陆玲", address: "上海", height: 158, weight: 37, job: "上海北区", n: "篮球",…}
  1. address: "上海"
  2. age: 26
  3. height: 158
  4. id: "360429200310080980"
  5. job: "上海北区"
  6. n: "篮球"
  7. name: "李留"
  8. sex: "男"
  9. weight: 37
  10. x: "陆玲"
5. 4: {name: "李子璇", age: 28, sex: "男", x: "普通工人", address: "南昌", height: 178, weight: 67, job: "上海中部",…}
  1. address: "南昌"
  2. age: 28
  3. height: 178
  4. id: "360429200310080981"
  5. job: "上海中部"
  6. n: "写字"
  7. name: "李子璇"
  8. sex: "男"
  9. weight: 67
  10. x: "普通工人"

JSON的第一课今天到这里了.

面向对象案例：

package Entity;import java.util.Objects;/** * 经典案例 */public class Dog {    private  String object;    private Integer ID;    private String name;    private Integer age;    private String sex;    private String height;    private String weight;    private String fuColor;    private String x;    private String y;    private String footColor;    private String dogYEyes;    private String a;    private String b;    private String c;    private String d;    private String e;    private String f;    private String g;    private String h;    private String i;    private String j;    private String k;    private String l;    private String m;    private String n;    private String o;    private String p;    private String q;    private String r;    private String s;    private String t;    private String u;    private String v;    private String w;    private String ss;    private String yy;    private String z;/*无惨*/    public Dog() { System.out.println("无惨构造");    }/*有参构造*/    public Dog(String object, Integer ID, String name, Integer age, String sex, String height, String weight, String fuColor, String x, String y, String footColor, String dogYEyes, String a, String b, String c, String d, String e, String f, String g, String h, String i, String j, String k, String l, String m, String n, String o, String p, String q, String r, String s, String t, String u, String v, String w, String ss, String yy, String z) { this.object = object; this.ID = ID; this.name = name; this.age = age; this.sex = sex; this.height = height; this.weight = weight; this.fuColor = fuColor; this.x = x; this.y = y; this.footColor = footColor; this.dogYEyes = dogYEyes; this.a = a; this.b = b; this.c = c; this.d = d; this.e = e; this.f = f; this.g = g; this.h = h; this.i = i; this.j = j; this.k = k; this.l = l; this.m = m; this.n = n; this.o = o; this.p = p; this.q = q; this.r = r; this.s = s; this.t = t; this.u = u; this.v = v; this.w = w; this.ss = ss; this.yy = yy; this.z = z;    }    public String getObject() { return object;    }    public void setObject(String object) { this.object = object;    }    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 String getSex() { return sex;    }    public void setSex(String sex) { this.sex = sex;    }    public String getHeight() { return height;    }    public void setHeight(String height) { this.height = height;    }    public String getWeight() { return weight;    }    public void setWeight(String weight) { this.weight = weight;    }    public String getFuColor() { return fuColor;    }    public void setFuColor(String fuColor) { this.fuColor = fuColor;    }    public String getX() { return x;    }    public void setX(String x) { this.x = x;    }    public String getY() { return y;    }    public void setY(String y) { this.y = y;    }    public String getFootColor() { return footColor;    }    public void setFootColor(String footColor) { this.footColor = footColor;    }    public String getDogYEyes() { return dogYEyes;    }    public void setDogYEyes(String dogYEyes) { this.dogYEyes = dogYEyes;    }    public String getA() { return a;    }    public void setA(String a) { this.a = a;    }    public String getB() { return b;    }    public void setB(String b) { this.b = b;    }    public String getC() { return c;    }    public void setC(String c) { this.c = c;    }    public String getD() { return d;    }    public void setD(String d) { this.d = d;    }    public String getE() { return e;    }    public void setE(String e) { this.e = e;    }    public String getF() { return f;    }    public void setF(String f) { this.f = f;    }    public String getG() { return g;    }    public void setG(String g) { this.g = g;    }    public String getH() { return h;    }    public void setH(String h) { this.h = h;    }    public String getI() { return i;    }    public void setI(String i) { this.i = i;    }    public String getJ() { return j;    }    public void setJ(String j) { this.j = j;    }    public String getK() { return k;    }    public void setK(String k) { this.k = k;    }    public String getL() { return l;    }    public void setL(String l) { this.l = l;    }    public String getM() { return m;    }    public void setM(String m) { this.m = m;    }    public String getN() { return n;    }    public void setN(String n) { this.n = n;    }    public String getO() { return o;    }    public void setO(String o) { this.o = o;    }    public String getP() { return p;    }    public void setP(String p) { this.p = p;    }    public String getQ() { return q;    }    public void setQ(String q) { this.q = q;    }    public String getR() { return r;    }    public void setR(String r) { this.r = r;    }    public String getS() { return s;    }    public void setS(String s) { this.s = s;    }    public String getT() { return t;    }    public void setT(String t) { this.t = t;    }    public String getU() { return u;    }    public void setU(String u) { this.u = u;    }    public String getV() { return v;    }    public void setV(String v) { this.v = v;    }    public String getW() { return w;    }    public void setW(String w) { this.w = w;    }    public String getSs() { return ss;    }    public void setSs(String ss) { this.ss = ss;    }    public String getYy() { return yy;    }    public void setYy(String yy) { this.yy = yy;    }    public String getZ() { return z;    }    public void setZ(String z) { this.z = z;    }    @Override    public String toString() { return "Dog{" +  "object='" + object + '\'' +  ", ID=" + ID +  ", name='" + name + '\'' +  ", age=" + age +  ", sex='" + sex + '\'' +  ", height='" + height + '\'' +  ", weight='" + weight + '\'' +  ", fuColor='" + fuColor + '\'' +  ", x='" + x + '\'' +  ", y='" + y + '\'' +  ", footColor='" + footColor + '\'' +  ", dogYEyes='" + dogYEyes + '\'' +  ", a='" + a + '\'' +  ", b='" + b + '\'' +  ", c='" + c + '\'' +  ", d='" + d + '\'' +  ", e='" + e + '\'' +  ", f='" + f + '\'' +  ", g='" + g + '\'' +  ", h='" + h + '\'' +  ", i='" + i + '\'' +  ", j='" + j + '\'' +  ", k='" + k + '\'' +  ", l='" + l + '\'' +  ", m='" + m + '\'' +  ", n='" + n + '\'' +  ", o='" + o + '\'' +  ", p='" + p + '\'' +  ", q='" + q + '\'' +  ", r='" + r + '\'' +  ", s='" + s + '\'' +  ", t='" + t + '\'' +  ", u='" + u + '\'' +  ", v='" + v + '\'' +  ", w='" + w + '\'' +  ", ss='" + ss + '\'' +  ", yy='" + yy + '\'' +  ", z='" + z + '\'' +  '}';    }    @Override    public boolean equals(Object o1) { if (this == o1) return true; if (o1 == null || getClass() != o1.getClass()) return false; Dog dog = (Dog) o1; return Objects.equals(object, dog.object) &&  Objects.equals(ID, dog.ID) &&  Objects.equals(name, dog.name) &&  Objects.equals(age, dog.age) &&  Objects.equals(sex, dog.sex) &&  Objects.equals(height, dog.height) &&  Objects.equals(weight, dog.weight) &&  Objects.equals(fuColor, dog.fuColor) &&  Objects.equals(x, dog.x) &&  Objects.equals(y, dog.y) &&  Objects.equals(footColor, dog.footColor) &&  Objects.equals(dogYEyes, dog.dogYEyes) &&  Objects.equals(a, dog.a) &&  Objects.equals(b, dog.b) &&  Objects.equals(c, dog.c) &&  Objects.equals(d, dog.d) &&  Objects.equals(e, dog.e) &&  Objects.equals(f, dog.f) &&  Objects.equals(g, dog.g) &&  Objects.equals(h, dog.h) &&  Objects.equals(i, dog.i) &&  Objects.equals(j, dog.j) &&  Objects.equals(k, dog.k) &&  Objects.equals(l, dog.l) &&  Objects.equals(m, dog.m) &&  Objects.equals(n, dog.n) &&  Objects.equals(o, dog.o) &&  Objects.equals(p, dog.p) &&  Objects.equals(q, dog.q) &&  Objects.equals(r, dog.r) &&  Objects.equals(s, dog.s) &&  Objects.equals(t, dog.t) &&  Objects.equals(u, dog.u) &&  Objects.equals(v, dog.v) &&  Objects.equals(w, dog.w) &&  Objects.equals(ss, dog.ss) &&  Objects.equals(yy, dog.yy) &&  Objects.equals(z, dog.z);    }    @Override    public int hashCode() { return Objects.hash(object, ID, name, age, sex, height, weight, fuColor, x, y, footColor, dogYEyes, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, ss, yy, z);    }}

package Com;import Entity.Dog;public class DogTest {    public static void main(String[] args) { Dog dog=new Dog(); dog.setA("AAAAAA"); System.out.println("获得Dog的A的属性为《"+dog.getA()+"》"); dog.setID(1009001); dog.setAge(23); dog.setName("网效果"); dog.setHeight("162"); dog.setDogYEyes("黑色"); dog.setFootColor("白色"); dog.setObject("万物皆object"); dog.setB("BBB"); dog.setC("CCC"); dog.setD("DDD"); dog.setE("EEE"); dog.setF("FFF"); dog.setG("GGG"); dog.setH("HHH"); dog.setI("III"); dog.setJ("JJJ"); dog.setK("KKK"); dog.setL("LLL"); dog.setM("MMM"); dog.setN("NNN"); dog.setO("OOO"); dog.setP("PPP"); dog.setQ("QQQ"); dog.setR("RRR"); dog.setS("SSS"); dog.setT("TTT"); dog.setU("UUU"); dog.setV("VVV"); dog.setW("WWW"); String a=dog.getA()+dog.getB()+dog.getC()+dog.getN()+dog.getM(); System.out.println(a); System.out.println("------------------------------------------------"); System.out.println("获得Dog的A的属性为《"+dog.getA()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getB()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getC()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getD()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getE()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getF()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getG()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getH()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getI()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getJ()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getK()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getL()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getM()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getN()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getO()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getP()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getQ()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getU()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getV()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getW()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getS()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getY()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getZ()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getName()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getAge()+"》"); System.out.println("获得Dog的A的属性为《"+dog.getSex()+"》"); }    }

2022年0514文章的内容Json前后端的交互数据.从最基本的Servlect开始.文章重在实操.关顾的去看是不明白的.

第二点在这之前你要会Ajax的内容.首先回顾Ajax的内容。

第三点在这之前要知道的JSON的两句话.

1.{}：当需要保存的是一个实体中不同属性的数据，就需要一对大括号套起来.{}

2.[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

案例一:使用的是当需要保存的是一个实体中不同属性的数据，就需要一对大括号套起来.{}这里我们使用了三种方案

方案一：利用Map集合开始JSON数据格式的学习。

我们在html中定义三个按钮.

运行效果我们在审查元素中看结果.

你会发现运行结果显示的JSON结果是下面的样子.

那么如何解析上面的数据在浏览器中显示呢？

结果为下面的内容:

方案二利用实体类的方式。

你会发现实体类的方式更简单.

运行效果

在审查元素的运行结果

{"name":"哈喽","age":20,"sex":"男","school":"清华大学"}

方案三:利用Properties的方式存放数据。

运行结果:JSON格式

{age: "19", school: "江西农业大学", name: "小咩咩", sex: "女"}

接下来学第二句话

2.[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

同样也有三种方式。数组 集合 set集合。同一属性不同的值。

第一种方式：

运行结果

JSON：[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

["红色","蓝色","绿色","黄色","白色","粉色","天蓝色"]

第二种方式:list集合方式。

运行结果

JSON格式：

["《Python从入门到放弃》","《Html从入门到精通》","《Jquery框架技术》","《MySQL从入门到出家》"]

第三种方式Set集合:

["《Python从入门到放弃》","《Html从入门到精通》","《Jquery框架技术》","《MySQL从入门到出家》"]

1.{}：当需要保存的是一个实体中不同属性的数据，就需要一对大括号套起来.{}

2.[]: 当需要保存的数据是同一个属性不同的值，就需要一对中括号套起来.[]

综合上面的两种方案灵活运用：先思考一个问题.{}[]""，这些符号如何运用呢？

JSON的难度在哪里？

上面的代码看的懂吗？这又是JSON格式.不要看表面要看他的内涵.

{{},{},{},{},{}}

{[],[],[],[],[]}

[[],[],[],[],[]]

[{},{},{},{},]

{[{},{},{},{},]}

[{[],[],[],[],[]} ]

案例一:先看结果后想思路.

案例二:先看结果后想思路.

{"fruits":["苹果 ","香蕉","梨子"," 橘子 "],"foots":["薯片","瓜子","饮料 "," 火腿","赖条"],"Pents":["水彩笔 ","钢笔","圆珠笔"]}

案例一的综合运用的分析流程:

[{name: "张三", age: 22, sex: "男", school: "北京大学"}, {name: "小明", age: 21, sex: "男", school: "清华大学"},…]

第一步创建学生对象：中在创建四个学生对象，然后将四个学生对象利用数组的方式存放起来。

Student[] students = {student1, student2, student3, student4};

new ObjectMapper().writeValue(response.getWriter(), students);//转换成JSON格式。

[{name: "张三", age: 22, sex: "男", school: "北京大学"}, {name: "小明", age: 21, sex: "男", school: "清华大学"},…]

JSON解析:

案例二的综合运用的分析流程:

{"fruits":["苹果 ","香蕉","梨子"," 橘子 "],"foots":["薯片","瓜子","饮料 "," 火腿","赖条"],"Pents":["水彩笔 ","钢笔","圆珠笔"]}

综合案例三:这才是日后工作使用JSON解析。

JSON的第一课今天到这里了.

面向对象案例：

运行结果

相关问题

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同样也有三种方式。数组集合 set集合。同一属性不同的值。