java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at com.neiguan.tools.BaseServlet.service(BaseServlet.java:55)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2503)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2492)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$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)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.neiguan.tools.BaseServlet.service(BaseServlet.java:35)
... 22 more
Caused by: java.lang.NullPointerException
at com.neiguan.web.servlet.LoginServlet.login(LoginServlet.java:21)
... 27 more
這是例外資訊
public class LoginServlet extends BaseServlet {
private LoginService loginService;
public String login(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
String username = req.getParameter("id")；
String password = req.getParameter("password");
User user = loginService.findById(username);
if(user==null){
req.setAttribute("msg", "您輸入的工號錯誤！");
return "login.jsp";
}else if (!user.getPassword().equals(password)) {
req.setAttribute("msg", "您輸入的密碼錯誤！");
return "login.jsp";
}else{
return "/jsps/main.jsp";
}
}
}
這是servlet的代碼，我還沒寫什么邏輯就是想測驗一下，結果在紅字處例外了，打了斷點，壓根進不了service和dao，直接一到這行就進了例外，然后baseServlet就反射方法例外出來了，找了好久找不到解決辦法，class檔案正常，jar包也正常！請大神們給瞅瞅！！
uj5u.com熱心網友回復：
空指標錯誤，也就是loginService物件還沒有new就使用了你用了什么框架了嗎，如spring？如果用了要加上注解spring才會幫你注入；如果沒用框架，要自己寫代碼new來生成實體。
uj5u.com熱心網友回復：
private LoginService loginService; 這里加@Autowired注解uj5u.com熱心網友回復：
大哥，謝謝啊，解決了，一直以為是方法的問題，沒想到是這么個小問題，太謝謝了
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標籤：Java EE