【发布时间】：2019-05-25 02:50:04
【问题描述】：
我创建了一个 JSP 服务器 (tomcat) 并将它链接到我的 Eclipse IDE。我还创建了一个 PostgreSQL 服务器，并试图弄清楚如何通过我的 JSP 服务器连接到它。
这是我的 JSP 文件的样子：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<%@ page import="helloWorldJSP.Test" %>
<%@ page import="helloWorldJSP.SQLTest" %>
</head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
//Test testThing = new Test();
//out.println( testThing.caps("thing") );
SQLTest test = new SQLTest();
System.out.println("FINISH");
%>
</body>
</html>
我已经对其进行了测试并且可以正常工作，所以我认为错误不在此页面内。
这是我的 SQLTest 类的代码：
package helloWorldJSP;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
public class SQLTest
{
public SQLTest()
{
Connection conn = null;
System.out.println("STARTING");
try
{
String url = "jdbc:postgresql://localhost:5432/deama_db";
String user = "deama1295";
String password = "1295";
conn = DriverManager.getConnection(url, user, password);
if (conn != null)
{
System.out.println("Connected to the database postgres");
}
}
catch (SQLException ex)
{
System.out.println("An error occurred. Maybe user/password is invalid");
ex.printStackTrace();
}
}
}
在我的 tomcat 服务器 lib 文件夹中，我查找了 JDBC 驱动程序，它就在那里。 我正在从 virtualBox 虚拟机运行 Ubuntu-18.10-desktop-amd64。
我尝试将数据库和用户名更改为“postgres”（我相信默认设置？）但这并没有改变我的错误（我很确定我将 postgres 的密码设置为 1295）。
这是完整的错误信息：
java.sql.SQLException: No suitable driver found for jdbc:postgresql://localhost/deama_db
at java.sql.DriverManager.getConnection(DriverManager.java:689)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at helloWorldJSP.SQLTest.<init>(SQLTest.java:26)
at org.apache.jsp.NewFile_jsp._jspService(NewFile_jsp.java:127)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
【问题讨论】：
-
你需要将JDBC驱动放在WAR的/WEB-INF/lib中并执行..Class.forName("com.example.jdbc.Driver"); .. 在第一次 DriverManager#getConnection() 调用之前的代码中
-
@ZhaoGang 只有第一部分。从 JDBC 4 (Java 6) 开始就不需要
Class.forName。
标签： java sql postgresql jsp ubuntu