Details of adding, deleting, modifying and checking data implemented by Ajax [Java background]

Time:2020-9-29

This paper describes the Ajax implementation of data addition, deletion, modification and query operations. For your reference, the details are as follows:

Home page: index.html

<!DOCTYPE html>
<html>
 <head>
 <meta charset="UTF-8">
 <title></title>
 <script src="http://libs.baidu.com/jquery/2.1.4/jquery.min.js"></script>
 </head>
 <body>
 No.: < input type = "text" value = / > < br >
 Name: < input type = "text" value = / > < br > name
 Gender: male: < input type = "radio" name = "sex" value = "male" > female: < input type = "radio" name = "sex" value = "female" > < br > male
 Age: < Select >
  <option value="15">15</option>
  <option value="16">16</option>
  <option value="17">17</option>
  <option value="18">18</option>
  <option value="19">19</option>
  <option value="20">20</option>
  <option value="21">21</option>
  <option value="22">22</option>
  <option value="23">23</option>
  <option value="24">24</option>
  <option value="25">25</option>
 </select><br>
 Height: < input type = "text" value = / > < br > height
 Weight: < input type = "text" value = / > < br > body weight
 < input type = "button" value = insert "onclick =" submit() "/ >
 <br>
 <br>
 <br>
 
 No.: < input type = "text" value = / >
 < input type = "button" value = query "onclick =" query() "/ >
 <table>
  <tr>
  <td>No</td>
  <td>Name</td>
  <td>Gender</td>
  <td>Age</td>
  <td>Height</td>
  <td>Weight</td>
  </tr>
  <tr>
  <td></td>
  <td></td>
  <td></td>
  <td></td>
  <td></td>
  <td></td>
  </tr>
 </table>
 
 
 <br>
 <br>
 <br>
 No.: < input type = "text" value = / >
 < input type = "button" value = delete "onclick =" del() "/ >
 
 <br>
 <br>
 <br>
 No.: < input type = "text" value = / > < br >
 Name: < input type = "text" value = / > < br > name
 Gender: male: < input type = "radio" name = "sex"_ Up "value =" male "> female: < input type =" radio "name =" sex "_ Up "value =" female "> < br > < br > and
 Age: < Select >
  <option value="15">15</option>
  <option value="16">16</option>
  <option value="17">17</option>
  <option value="18">18</option>
  <option value="19">19</option>
  <option value="20">20</option>
  <option value="21">21</option>
  <option value="22">22</option>
  <option value="23">23</option>
  <option value="24">24</option>
  <option value="25">25</option>
 </select><br>
 Height: < input type = "text" value = / > < br > height
 Weight: < input type = "text" value = / > < br > body weight
 < input type = "button" value = update "onclick =" update() "/ >
 
 </body>
 
 <script type="text/javascript">
 /*
 var x = $("#queryResult").html();
 
 for(var i=0; i < 20 ; i++) {
  x += '<tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>';
 }
 $("#queryResult").html(x);*/
 function submit() {
 var pno = $("#pno").val();
 var name = $("#name").val();
 var sex = $('input[name="sex"]:checked').val();
 var age = $("#age").val();
 var height = $("#height").val();
 var weight = $("#weight").val();
 
 var data={
  
  "pno":pno,
  "name":name,
  "sex":sex,
  "age":age,
  "height":height,
  "weight" : weight
 }
 
 
 $.ajax({
  type : "post",
  url : "Hello",
  data : data,
  cache : true,
  async : true,
  success: function (data ,textStatus, jqXHR){
     if(data.code == 200){
      Alert ("inserted successfully");
     }else{
      alert(data.message);
     }
   },
     error:function (XMLHttpRequest, textStatus, errorThrown) {   
      
       alert(typeof(errorThrown));
     }
  
 });
 }
 
 
 function query() {
 
 var pno = $("#pno_query").val(); 
 Var STR = ["number", "name", "gender", "age", "height", "weight"];
 $.ajax({
  type : "post",
  url : "HelloQuery",
  data : {
  "pno": pno
  },
  cache : true,
  async : true,
  success: function (data ,textStatus, jqXHR){
  //data = $.parseJSON(data);
  var j = 0;
  var x = 1;
  //for(var i=1; i <20; i++) {
   For (VaR P in data) {// traverse each key / value pair of the JSON object, P is the key
   console.log(data[p]);
   if(j == 6) {
    j = 0;
    x++;
   }
    $("#queryResult tr:eq("+x+") td:eq("+j+")").html(data[p]);
    console.log(data[p]);
    j++;
   }
  //}
  
  
  
     
   },
     error:function (XMLHttpRequest, textStatus, errorThrown) {   
      
       alert(typeof(errorThrown));
     }
  
 });
 }
 
 function del() {
 var pno = $("#pno_del").val(); 
 
 $.ajax({
  type : "post",
  url : "HelloDelete",
  data : {
  "pno": pno
  },
  cache : true,
  async : true,
  success: function (data ,textStatus, jqXHR){
  if(data.code == 200){
      Alert ("deletion succeeded");
     }else{
      alert(data.message);
     }
   },
     error:function (XMLHttpRequest, textStatus, errorThrown) {   
      
       alert(typeof(errorThrown));
     }
  
 });
 }
 
 function update() {
 var pno = $("#pno_up").val();
 var name = $("#name_up").val();
 var sex = $('input[name="sex_up"]:checked').val();
 var age = $("#age_up").val();
 var height = $("#height_up").val();
 var weight = $("#weight_up").val();
 
 var data={
  
  "pno":pno,
  "name":name,
  "sex":sex,
  "age":age,
  "height":height,
  "weight" : weight
 }
 
 
 $.ajax({
  type : "post",
  url : "HelloUpdate",
  data : data,
  cache : true,
  async : true,
  success: function (data ,textStatus, jqXHR){
     if(data.code == 200){
      Alert ("update succeeded");
     }else{
      alert(data.message);
     }
   },
     error:function (XMLHttpRequest, textStatus, errorThrown) {   
      
       alert(typeof(errorThrown));
     }
  
 });
 }
 
 
 
 </script>
</html>

Added Serlvet: Hello.java

package com.web;
 
import java.io.IOException;
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 com.mysql.MysqlUtil;
 
/**
 * Servlet implementation class Hello
 */
@WebServlet("/Hello")
public class Hello extends HttpServlet {
 private static final long serialVersionUID = 1L;
    
  /**
   * @see HttpServlet#HttpServlet()
   */
  public Hello() {
    super();
    // TODO Auto-generated constructor stub
  }
 
 /**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 // TODO Auto-generated method stub
 response.getWriter().append("Served at: ").append(request.getContextPath());
 }
 
 /**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
 response.setCharacterEncoding("utf-8");
 response.setContentType("application/json; charset=utf-8");
 
 String pno = request.getParameter("pno");
 String name = request.getParameter("name");
 String sex = request.getParameter("sex");
 String age = request.getParameter("age");
 String height = request.getParameter("height");
 String weight = request.getParameter("weight");
 
 String sqlInsert = "INSERT INTO Person (Pno,Pname,Psex,Page,Pheight,Pweight) VALUES('";
 sqlInsert += pno +"','";
 sqlInsert += name +"','";
 sqlInsert += sex +"',";
 sqlInsert += age +",";
 sqlInsert += height +",";
 sqlInsert += weight +")";
 
 int message = MysqlUtil.add(sqlInsert);
 String rep = "";
 if(message == 1) {
  Rep = "{code \": 200, \ "message \": "successfully inserted into database \"} ";
 }else {
  Rep = "{code": "999", "message": "failed to insert"} ";
 }
 response.getWriter().write(rep);
 
 
 }
 
}

Deleted servlet: HelloDelete.java

package com.web;
 
import java.io.IOException;
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 com.mysql.MysqlUtil;
 
/**
 * Servlet implementation class HelloDelete
 */
@WebServlet("/HelloDelete")
public class HelloDelete extends HttpServlet {
 private static final long serialVersionUID = 1L;
    
  /**
   * @see HttpServlet#HttpServlet()
   */
  public HelloDelete() {
    super();
    // TODO Auto-generated constructor stub
  }
 
 /**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 // TODO Auto-generated method stub
 response.getWriter().append("Served at: ").append(request.getContextPath());
 }
 
 /**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 response.setCharacterEncoding("utf-8");
 response.setContentType("application/json; charset=utf-8");
 
 String pno = request.getParameter("pno");
 
 
 String sqlDel = "delete from Person where pno="+pno;
 
 
 int message = MysqlUtil.del(sqlDel);
 String rep = "";
 if(message == 1) {
  Rep = "{code": "200", "message": "successfully deleted"} ";
 }else {
  Rep = "{code": "999", "message": "deletion failed"} ";
 }
 response.getWriter().write(rep);
 }
 
}

Updated servlet: HelloUpdate.java

package com.web;
 
import java.io.IOException;
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 com.mysql.MysqlUtil;
 
/**
 * Servlet implementation class HelloUpdate
 */
@WebServlet("/HelloUpdate")
public class HelloUpdate extends HttpServlet {
 private static final long serialVersionUID = 1L;
    
  /**
   * @see HttpServlet#HttpServlet()
   */
  public HelloUpdate() {
    super();
    // TODO Auto-generated constructor stub
  }
 
 /**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 // TODO Auto-generated method stub
 response.getWriter().append("Served at: ").append(request.getContextPath());
 }
 
 /**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 response.setCharacterEncoding("utf-8");
 response.setContentType("application/json; charset=utf-8");
 
 String pno = request.getParameter("pno");
 String name = request.getParameter("name");
 String sex = request.getParameter("sex");
 String age = request.getParameter("age");
 String height = request.getParameter("height");
 String weight = request.getParameter("weight");
 
 String sqlupdate = "update Person set ";
// sqlupdate += "Pno='"+ pno +"',";
 sqlupdate += "Pname='"+ name +"',";
 sqlupdate += "Psex='"+ sex +"',";
 sqlupdate += "Page="+ age +",";
 sqlupdate += "Pheight="+ height +",";
 sqlupdate += "Pweight="+ weight;
 sqlupdate += " where Pno='"+pno+"'";
 System.out.println(sqlupdate);
 int message = MysqlUtil.update(sqlupdate);
 String rep = "";
 if(message == 1) {
  Rep = "{code \": "200 \", "message \": "successfully inserted into database \"} ";
 }else {
  Rep = "{code": "999", "message": "failed to insert"} ";
 }
 response.getWriter().write(rep);
 
 }
 
}

Servlets queried: HelloQuery.java

package com.web;
 
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
 
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 com.mysql.MysqlUtil;
 
/**
 * Servlet implementation class HelloQuery
 */
@WebServlet("/HelloQuery")
public class HelloQuery extends HttpServlet {
 private static final long serialVersionUID = 1L;
    
  /**
   * @see HttpServlet#HttpServlet()
   */
  public HelloQuery() {
    super();
    // TODO Auto-generated constructor stub
  }
 
 /**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 // TODO Auto-generated method stub
 response.getWriter().append("Served at: ").append(request.getContextPath());
 }
 
 /**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 response.setCharacterEncoding("utf-8");
 response.setContentType("application/json; charset=utf-8");
 String pno = request.getParameter("pno");
 String[] params = {"Pno","Pname","Psex","Page","Pheight","Pweight"};
 String sql = "select * from Person where Pno="+pno;
 String data = "{";
 
 String [] STR = {number "," name "," gender "," age "," height "," weight "};
 List<Map<String,String>> listmap = new ArrayList<>();
 listmap = MysqlUtil.show(sql, params);
 for(int i =0 ; i<listmap.size();i++) {  
  for(int j=0 ; j<listmap.get(i).size();j++) {
  data += "\""+str[j]+"\":"+"\""+listmap.get(i).get(params[j])+"\",";  
  }
 }
 data = data.substring(0, data.length()-1);
 data += "}";
 
 
 System.out.println(data);
 response.getWriter().write(data);
 }
 
 
 
}

The page is as follows:

Corresponding database:

Git clone address:https://github.com/dreamiboy/JDBCUtil.git

For more information about Ajax related content, you can check out our topic:《Summary of Ajax usage in jquery》、《Summary of Ajax operation skills in JavaScript》、《Summary of PHP + Ajax skills and Application》And《asp.net Summary of Ajax techniques

I hope this article will be helpful to everyone’s Ajax programming.