function check() {//js表單驗證方法
var text = document.getElementById("xh").value;//通過id獲取需要驗證的表單元素的值
if (text == "") {
alert("請輸入學號！");//彈出提示
return false;//返回false（不提交表單）
}
if (!(/(^[1-9]\d*$)/.test(text))) {
alert("請輸入學號！");//彈出提示
return false;//返回false（不提交表單）
}
var student_id = $("#student_id").val();
$.ajax({
url : "<%=basePath%>user/queryByUser",
type : "post",
data : {
"student_id" : student_id
},
dataType : "json",
success : function(data) {
if (data != null) {
alert("有");
} else if (data == null && student_id != '') {
alert("沒有");
return false;
}
}
});
return true;//提交表單
}
</script>
<body>
<div class="listDIV">
<table id="FileTable" border="1" width="50%" height="50%"
style="text-align: center;">
<form action="<%=basePath%>user/one" method="post">
<input type="text" id="xh" name="student_id" placeholder="根據學號查詢">
<button class="glyphicon glyphicon-select" onclick="return check();">查詢</button>
</form>
@ResponseBody
@RequestMapping(value="/queryByUser", method=RequestMethod.POST,produces="application/json;charset=UTF-8")
public Student queryByName(Integer student_id,HttpServletRequest request){
Student s= userService.getStudent_id(student_id);
s.getStudent_id();
return s;
}
<!-- 查詢student_id是否存在 -->
<select id="getStudent_id" resultMap="studentMap" parameterType="int">
SELECT * from student where student_id = #{student_id}
</select>
報錯信息
嚴重: Servlet.service() for servlet [springMVC] in context with path [/StudentManagementSSM] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.zmk.controller.UserTestController.queryByName(UserTestController.java:66)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:777)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
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:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1139)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
ajax數據校驗前臺沒有獲取數據
慕工程0101907
2019-01-17 01:03:46