Question

jsp 运行出错，请问高手，在线等.........

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 /confirm.jsp at line 18

15:
16: Statement stat=null;
17: try {
18: stat=conn.createStatement();
19: } catch (SQLException e1) {
20: // TODO Auto-generated catch block
21: e1.printStackTrace();

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:515)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:426)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

root cause

java.lang.NullPointerException
org.apache.jsp.confirm_jsp._jspService(confirm_jsp.java:74)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:384)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.10 logs.
static String drivename="com.microsoft.jdbc.sqlserver.SQLServerDriver";
static String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=messageb";
static String name="sa";
static String pwd="";
static{
try {
Class.forName(drivename);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.print("加载驱动失败");
}
}
public static Connection getConnection(){
Connection conn=null;
try{
conn=(Connection)DriverManager.getConnection(url,name,pwd);
System.out.println("创建连接成功");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("创建连接失败");
}
return conn;
}

Answer 1

java.lang.NullPointerException
即是说你的程序中使用了空对象，stat=conn.createStatement();
的conn 对象为空，你得结合你其他的程序 看看这个conn 是否正确的创建了 ，只有这个不是null那就可以了

Answer 2

空指针错误
conn是从外部引用的吧?看看包含进去没有

Answer 3

明显是没获得数据库连接，没得到conn

Answer 4

空指针异常就是你的对象里头没有添值你需要看看你的数据库获取的连接对象是否为空,到你的tomcat下有个work的文件夹里头找到root cause：下所指定的地方是什么错误这样就可以自己进行测试修改了。