Question

嗨，我是jsp＆amp;的新手。试图从mysql db显示一些数据。为此我已经安装了JDK1.7，MySQL Server 5.5，mysql-connector-java-5.1.19-bin.jar作为tomcat 7服务器上的连接器。我在％CATALINA_HOME％webapps / ROOT / ws / 文件夹中创建了一个文件，即 index.jsp ，代码为

<%@ page import="java.sql.*" %>
<%
String connectionURL = "jdbc:mysql://localhost:test?user=root;password=sumant";
Connection connection = null;
Statement statement = null;
ResultSet rs = null;
%>


<html><body>


<%
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
connection = DriverManager.getConnection(connectionURL, "", "");
statement = connection.createStatement();
rs = statement.executeQuery("SELECT name FROM store");

while (rs.next()) {
out.println(rs.getString("name")+"<br>");
}

rs.close();
%>


</body></html>

并且在调用url： http：// localhost：8080 / ws / index.jsp 我正在

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /ws/index.jsp at line 14

11: 
12: 
13: <%
14: Class.forName("org.gjt.mm.mysql.Driver").newInstance();
15: connection = DriverManager.getConnection(connectionURL, "", "");
16: statement = connection.createStatement();
17: rs = statement.executeQuery("SELECT name FROM store");


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:567)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:456)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

javax.servlet.ServletException: java.lang.ClassNotFoundException: org.gjt.mm.mysql.Driver
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:911)
    org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:840)
    org.apache.jsp.ws.index_jsp._jspService(index_jsp.java:98)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:433)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

java.lang.ClassNotFoundException: org.gjt.mm.mysql.Driver
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1678)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1523)
    org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:126)
    org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:63)
    java.lang.Class.forName0(Native Method)
    java.lang.Class.forName(Unknown Source)
    org.apache.jsp.ws.index_jsp._jspService(index_jsp.java:78)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:433)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

现在我不知道这里有什么问题。请帮我连接mysql数据库。感谢。

Answer 1

使用com.mysql.jdbc.Driver类（所谓的JDBC驱动程序）而不是org.gjt.mm.mysql.Driver进行连接。需要在类路径中添加任何第三方API才能使用它。因此，需要在Tomcat中显示JAR。因此，我建议将mysql-connector-java-5.1.19-bin.jar放置在项目的/WEB-INF/lib目录的物理位置，在您的情况下 ws 。

在早些时候，如果jar不在物理位置，我会遇到ClassNotFoundException。然后重启Tomcat应该可以工作。

Answer 2

将mysql_connector / j驱动程序jar文件放在类路径中。然后使用

连接

Class.forName("com.mysql.jdbc.Driver");

你的连接url也应该有mysql端口3306

String connectionURL = "jdbc:mysql://localhost:3306/test?user=root;password=sumant";

JSP无法连接到tomcat7上的mysql数据库

2 个答案: