如何修复“ DriverManager.getConnection(connectionURL, UN, PW); ”上的错误？

Question

我是 MYSQL 和 JSP 的新手。我正在尝试检查 mysql 数据库和 jsp 之间的连接。当我运行服务器上的项目时，它抛出异常。我找不到代码上的错误。

我已经在mysql和UN上创建了oop数据库，PW也正确。

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"  pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*" %> 
<%@ page import="java.io.*" %> 
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

<h1>Connection status </h1>
<% 

/* Create string of connection url within specified format with machine name, 
port number and database name. Here machine name id localhost and 
database name is oop. */ 
String connectionURL = "jdbc:mysql://localhost:3306/oop"; 

// declare a connection by using Connection interface 
Connection connection = null; 

// Load JBBC driver "com.mysql.jdbc.Driver" 
Class.forName("com.mysql.jdbc.Driver").getDeclaredConstructors(); 

/* Create a connection by using getConnection() method that takes parameters of 
string type connection url, user name and password to connect to database. */ 
connection = DriverManager.getConnection(connectionURL, "root", "raviya");

// check weather connection is established or not by isClosed() method 
if(!connection.isClosed()){

%>
<font size="+3" color="green">
<% 
out.println("Successfully connected to " + "MySQL server using TCP/IP...");
connection.close();
}

else{

%>
</font>
<font size="+3" color="red">

<%
out.println("Unable to connect to database.");
}
%>
</font>
</body>
</html>

错误： enter image description here

Answer 1

如果您未导入 mysql 连接器 jar 文件，则可能会发生此类错误。因此，您可以下载与您的版本相关的 jar 文件，并将其粘贴到您自己的项目 /WEB-INF/lib 文件夹中。

如何修复“ DriverManager.getConnection(connectionURL, UN, PW); ”上的错误？

how to fix an error on " DriverManager.getConnection(connectionURL, UN, PW); "?

mysql

database

jsp

database-connection

http-status-code-500