exception
org.apache.jasper.JasperException: An exception occurred processing JSP page /article.jsp at line 7
4: <%!
5: private void tree(List<Article> articles, Connection conn, int id, int grade) {
6: String sql = "select * from article where pid = " + id;
7: Statement stmt = DB.createStmt(conn);
8: ResultSet rs = DB.executeQuery(stmt, sql);
9: try {
10: while(rs.next()) {
DB.java的一些相关方法
public static Statement createStmt(Connection conn) {
Statement stmt = null;
try {
stmt = conn.createStatement();
} catch (SQLException e) {
e.printStackTrace();
}
return stmt;
}
后台报错:
严重: Servlet.service() for servlet [jsp] in context with path [/BBS] threw exception [An exception occurred processing JSP page /article.jsp at line 7
4: <%!
5: private void tree(List<Article> articles, Connection conn, int id, int grade) {
6: String sql = "select * from article where pid = " + id;
7: Statement stmt = DB.createStmt(conn);
8: ResultSet rs = DB.executeQuery(stmt, sql);
9: try {
10: while(rs.next()) {
Stacktrace:] with root cause
java.lang.NullPointerException
at com.bjsxt.bbs.DB.createStmt(DB.java:29)
at org.apache.jsp.article_jsp.tree(article_jsp.java:24)
at org.apache.jsp.article_jsp._jspService(article_jsp.java:96)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
急啊，这个问题我也是弄半天了，好无奈啊
