javaee ajax请求后台不刷新页面

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摇滚侠 2023-06-24 00:07:53 ©著作权

文章标签 java-ee ajax servlet java sql 文章分类 HarmonyOS 后端开发

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javaee ajax请求后台不刷新页面_ajax

jsp页面

Reg.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script src="js/jquery1.11.3.min.js"></script>
<script src="js/reg.js"></script>
</head>
<body>
  <form action="TestRegServlet" method="post">
   <pre>
    用户名:<input type='text' name='uname' /><span id="s1"></span>
   密码:<input type='password' name='pwd' />
   确认密码:<input type='password' name='repwd' />
 <input type='submit' name='sub' value='注册' />
  
  </pre>
  </form>


</body>
</html>

js代码

reg.js

/**
 * 
 */

$(function(){
	
	$(":text[name='uname']").blur(function(){
		
		//1.获得用户名
		var uname=$(this).val();
		
		//2.通过异步传输对象将用户名传到服务器，服务器查询数据库得到结果并返回
		
		$.get("CheckUnameServlet?uname="+uname,function(data){
			
			  if(data=="1")
				  $("#s1").html("该用户已存在");
			  else
				  $("#s1").html("可以注册");
		})
		
		
	})
	
	
})

后台代码

CheckUnameServlet

package com.yyy.servlet;

import java.io.IOException;
import java.util.ArrayList;
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.test.util.DbHelper;


/**
 * Servlet implementation class CheckUnameSevlet
 */
@WebServlet("/CheckUnameServlet")
public class CheckUnameServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CheckUnameServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//禁止缓存
				response.setHeader("Pragma", "No-cache");
				response.setHeader("Cache-Control", "no-cache");
				response.setDateHeader("Expires", 0);
				
				
				String uname=request.getParameter("uname");
				
				String sql="select * from user where uname=?";
				
				List<Object> paramList=new ArrayList<Object>();
				
				paramList.add(uname);
				
				DbHelper dbHelper=new DbHelper();
				
				List<Map<String, Object>> list=  dbHelper.executeQuery(sql, paramList);
				
				if(list!=null && list.size()>0)
				    response.getWriter().print("1");
				else
					response.getWriter().print("0");
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

TestRegServlet

package com.yyy.servlet;

import java.io.IOException;
import java.util.ArrayList;
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.test.util.DbHelper;


/**
 * Servlet implementation class RegServlet
 */
@WebServlet("/TestRegServlet")
public class TestRegServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public TestRegServlet() {
        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());
			
				request.setCharacterEncoding("utf-8");
				response.setContentType("text/html;charset=utf-8");
				
				//1.获得用户输入
				String uname=request.getParameter("uname");
				String pwd=request.getParameter("pwd");
				
				//2.先判断用户名是否已存在 
				
				DbHelper dbHelper=new DbHelper();
				
				String sql="select * from user where uname=?";
				
				List<Object> paramList=new ArrayList<Object>();
				
				paramList.add(uname);
				
				List<Map<String, Object>> list=  dbHelper.executeQuery(sql, paramList);
				
				//3.不存在 则可以注册
				if(list==null || list.size()==0)
				{
					  String sql2="insert into user values(null,?,?)";
					  
					  List<Object> paramList2=new ArrayList<Object>();
					  
					  paramList2.add(uname);
					  
					  paramList2.add(pwd);
					  
					//4.处理结果
					  if(dbHelper.executeUpdate(sql2, paramList2)>0)
						  response.getWriter().println("注册成功");
					  else
						  response.getWriter().println("注册失败");			  
				}
				else
					response.getWriter().println("该用户已注册");
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

DbHelper

package com.test.util;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import javax.print.attribute.standard.RequestingUserName;

public class DbHelper {
	private Connection connection;
	
	private PreparedStatement preparedStatement;
	
	private ResultSet resultSet;
	
	public DbHelper()
	{
		getConnection();
	}
	//打开连接
	public void getConnection()
	{
		 try {			
			  if(connection==null || connection.isClosed())
			  {
				//将文件中的数据转到集合中 再从集合取数据
				Properties properties=new Properties();
				
				InputStream iStream=this.getClass().getResourceAsStream("/db2.properties");
				
			    properties.load(iStream);
			    
			    //获得集合中数据
			    String driver=properties.getProperty("driver");
			    
			    String url=properties.getProperty("url");
			    
			    String uname=properties.getProperty("uname");
			    
			    String pwd=properties.getProperty("pwd");
				  
				  
			    Class.forName(driver);
			 
			    this.connection= DriverManager.getConnection(url, uname, pwd);
			  }
			
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}		 
		 
	}	
	
	//执行 增 删 改 语句 返回受影响的行数
	public int executeUpdate(String sql,List<Object> paramList)
	{
		 getConnection();   //打开连接
		 
		 try {
			
			 this.preparedStatement=connection.prepareStatement(sql);
			
			 //给sql语句的参数赋值
			 if(paramList!=null)
			 {
				  for(int i=0;i<paramList.size();i++)
				  {
					  this.preparedStatement.setObject(i+1, paramList.get(i));
				  }
			 }
			 
			 return this.preparedStatement.executeUpdate();
			 
			 
			
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			close();
		}
		 
		return 0;
	}
	
	//执行查询
	public List<Map<String, Object>> executeQuery(String sql,List<Object> paramList)
	{
		 getConnection();
		 
		 try {
			 this.preparedStatement=connection.prepareStatement(sql);
			
			 //给sql的参数赋值
			 if(paramList!=null)
			 {
				  for(int i=0;i<paramList.size();i++)
				  {
					    this.preparedStatement.setObject(i+1, paramList.get(i));
				  }
			 }
			 
			 //执行查询
			 this.resultSet= this.preparedStatement.executeQuery();
			 
			 //定义一个集合用来存放结果集中的数据
			 List<Map<String, Object>> resultList=new ArrayList<Map<String,Object>>();
			 
			 //读取结果集中的数据存入到集合resultList中
			 
			 //获得结果集中的列名
			 ResultSetMetaData resultSetMetaData= this.resultSet.getMetaData();
			 
			 
			 while(resultSet.next())
			 {
				 //存放结果集中的每一条记录  uid=1 uname="zhangsan" pwd="123"
				 Map<String, Object> map=new HashMap<String,Object>();
				 
				 for(int i=1;i<=resultSetMetaData.getColumnCount();i++)
				 {
					   //获得第i列的名称
					   String columnname=  resultSetMetaData.getColumnName(i);
				       //获得第i列的值
					   Object columnvalue=resultSet.getObject(columnname);
					   
					   map.put(columnname, columnvalue);
					   
				 }
				 
				 //将map存入到list中
				 resultList.add(map);
				 
			 }
			 
			 return resultList;
			
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			close();
		}
		 
		return null;
		 
	}
	
	//关闭连接
	public void close()
	{
		 if(resultSet!=null)
			try {
				resultSet.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		 
		 if(preparedStatement!=null)
			try {
				preparedStatement.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		 
		 if(connection!=null)
			try {
				connection.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
	}
}

properties文件

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/itstar?characterEncoding=utf-8
uname=itstar
pwd=yyy123456

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javaee ajax请求后台 不刷新页面

javaee ajax请求后台 不刷新页面

jsp页面

Reg.jsp

js代码

reg.js

后台代码

CheckUnameServlet

TestRegServlet

DbHelper

properties文件

51CTO博客

javaee ajax请求后台不刷新页面

javaee ajax请求后台不刷新页面