Java JSP MySQL Class.forName错误_Java_Mysql_Jsp_Jakarta Ee_Jdbc

Java JSP MySQL Class.forName错误

java mysql jsp jakarta-ee jdbc

Java JSP MySQL Class.forName错误,java,mysql,jsp,jakarta-ee,jdbc,Java,Mysql,Jsp,Jakarta Ee,Jdbc,我不熟悉JSP。我正在尝试使用ADT Eclipse编写JSP和MySQL连接的基本程序。在运行index.jsp页面时，我得到以下信息： HTTP Status 500 - An exception occurred processing JSP page /index.jsp at line 24 type Exception report message An exception occurred processing JSP page /index.jsp at line 24 d

我不熟悉JSP。我正在尝试使用ADT Eclipse编写JSP和MySQL连接的基本程序。在运行index.jsp页面时，我得到以下信息：

HTTP Status 500 - An exception occurred processing JSP page /index.jsp at line 24

type Exception report

message An exception occurred processing JSP page /index.jsp at line 24

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 /index.jsp at line 24

21: String sql = "select usertype from userdetail";
22: 
23: try {
24: Class.forName("com.mysql.jdbc.Driver");
25: con = DriverManager.getConnection(url, user, password);
26: ps = con.prepareStatement(sql);
27: rs = ps.executeQuery(); 


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:455)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
root cause

javax.servlet.ServletException: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:912)
    org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:841)
    org.apache.jsp.index_jsp._jspService(index_jsp.java:141)
    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:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
root cause

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    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(Class.java:190)
    org.apache.jsp.index_jsp._jspService(index_jsp.java:85)
    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:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.30 logs.

Apache Tomcat/7.0.30

我下载了MySQL连接器JJAR并将其包含在项目中

提前感谢…

不要添加外部jar。下载并复制到project中

将其复制到

WEB-INF--->lib（文件夹）

不要添加外部jar。下载并复制到project中

将其复制到

WEB-INF--->lib（文件夹）

错误

javax.servlet.ServletException:java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

表示找不到类文件

因此，您应该使用

项目属性->添加jar

在此之前，将jar放在项目内的某个文件夹中，或者通过外部jar选项添加

如果您已经添加了。再次尝试删除并添加jar文件

有关错误的附加参考，请参见和