JSP Web应用开发-数据库链接
主要问题com.mysql.jdbc.exceptions.jdbc4.CommunicationsException 通信异常
次要问题IDEA out.print 报红
问题1图片
问题2图片
代码功能读取数据表的内容
<%--
Created by IntelliJ IDEA.
User: 26316
Date: 2023/3/19
Time: 16:24
To change this template use File | Settings | File Templates.
--%>
<%@ page language="java" import="java.util.*" contentType="text/html;charset=utf-8" %>
<%@ page import="java.sql.*" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<%
Connection con = null;
Statement sql = null;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver");
}
catch (Exception e){
out.println("没有把MySQL数据库的JDBC数据库驱动程序复制到JDK的扩展目录中"); //加载MySQL的JDBC数据库驱动程序
}
try {
String url = "jdbc:mysql://localhost:3306/jqe_school";
String user = "root";
String password = "newpassword";
con = DriverManager.getConnection(url,user,password); //连接数据库
sql = con.createStatement(); //创建结果集
rs = sql.executeQuery("SELECT * FROM score"); //读取表数据
out.print(""); //输出表格
out.print("");
out.print(""+"编号");
out.print(" "+"学号");
out.print(" "+"课程名");
out.print(" "+"分数");
out.print(" ");
while(rs.next()){ //循环输出表中的数据
out.print("");
out.print(""+rs.getInt("id")+" ");
out.print(""+rs.getInt("stu_id")+" ");
out.print(""+rs.getString("c_name")+" ");
out.print(""+rs.getInt("grade")+" ");
out.print(" ");
}
out.print("
");
con.close(); //关闭连接
}
catch (SQLException e){
out.print(e);
}
%>
</body>
</html>
这个文件不知道怎么上传
数据库
