tomcat连接jsp文件出错。我找了很久，不知道错误在哪。

Question

这是什么问题呢？大家帮忙解决一下。[code="java"]type Exception report

message

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

exception

javax.servlet.ServletException: java.lang.NullPointerException
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

root cause

java.lang.NullPointerException
com.tools.ConnDB.executeQuery(ConnDB.java:55)
com.dao.ScripDao.query(ScripDao.java:25)
com.action.ScripAction.scripQuery(ScripAction.java:43)
com.action.ScripAction.execute(ScripAction.java:26)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.20 logs.

[/code]

Answer 1

试试，看哪一行为空？
[code="java"] public ResultSet executeQuery(String sql) {
try { // 捕捉异常
conn = getConnection();
System.out.println("conn:"+conn);
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
System.out.println("stmt:"+stmt);
rs = stmt.executeQuery(sql);
System.out.println("rs:"+rs);
} catch (SQLException ex) {
System.err.println(ex.getMessage()); // 输出异常信息
}
return rs; // 返回结果集对象
}
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