我正在研究 struts2 应用程序，我必须上传文件并将其保存到数据库中。但每次显示NullPointerException我的代码都在这里
堆栈跟踪是-
java.lang.NullPointerException
dao.Clientdao.registration(Clientdao.java:31)
action.client.Clientaction.execute(Clientaction.java:18)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:452)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:291)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:254)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:314)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:485)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
模型类是
import java.io.File;
public class Clientmodel {
private String Aggrement;
private String date;
private String rate;
private String maturitydate;
private String detail;
private String taxno;
private File imagefile;
public File getImagefile() {
return imagefile;
}
public void setImagefile(File imagefile) {
this.imagefile = imagefile;
}
public String getRate() {
return rate;
}
public void setRate(String rate) {
this.rate = rate;
}
public String getDetail() {
return detail;
}
public void setDetail(String detail) {
this.detail = detail;
}
public String getTaxno() {
return taxno;
}
public void setTaxno(String taxno) {
this.taxno = taxno;
}
public String getAggrement() {
return Aggrement;
}
public void setAggrement(String aggrement) {
Aggrement = aggrement;
}
public String getMaturitydate() {
return maturitydate;
}
public void setMaturitydate(String maturitydate) {
this.maturitydate = maturitydate;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
}
struts.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<constant name="struts.enable.DynamicMethodInvocation" value="true"/>
<constant name="struts.devmode" value="true"/>
<package name="loginmodel" extends ="struts-default">
<action name="clientlogin" class="action.client.Clientaction" >
<interceptor-ref name="exception"/>
<interceptor-ref name="i18n"/>
<interceptor-ref name="fileUpload">
<param name="allowedTypes">text/plain</param>
<param name="maximumSize">10240</param>
</interceptor-ref>
<interceptor-ref name="params">
<param name="excludeParams">dojo\..*,^struts\..*</param>
</interceptor-ref>
<interceptor-ref name="validation">
<param name="excludeMethods">input,back,cancel,browse</param>
</interceptor-ref>
<interceptor-ref name="workflow">
<param name="excludeMethods">input,back,cancel,browse</param>
</interceptor-ref>
<result name="input">/Registration/clientregistration.jsp </result>
<result name ="success">/Registration/success.jsp </result>
</action>
</package>
</struts>
客户端注册.jsp
<%@ page language ="java" contentType ="text/html; charset=ISO-8859-1" pageEncoding ="ISO-8859-1"%>
<%@ taglib uri ="/struts-tags" prefix="s"%>
<%@ taglib uri ="/struts-dojo-tags" prefix="sx" %>
<%@ taglib prefix="sj" uri="/struts-jquery-tags"%>
<html>
<head>
<sj:head jqueryui="true" jquerytheme="redmond" />
<style>
div.ui-datepicker {
font-size: 82.5%;
}
</style>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>CLIENT</title>
<link rel="stylesheet" type="text/css" href="css/emp.css">
</head>
<body >
<div id ="did" align="center"> <h1 style="color: red"> CLIENT REGISTRATION FORM</h1>
<s:form action ="clientlogin" method="post" enctype="multipart/form-data">
<s:select name="Aggrement" label ="Type of Aggrement" list ="{'ORAL', 'written'} "/>
<sj:datepicker name="date" label="Aggrement DATE" changeMonth="true" changeYear="true"/>
<s:select name ="rate" list="{'1','2','3'}" label ="Aggrement rate"/>
<s:textarea name ="detail" label ="Aggrement Detail"></s:textarea>
<s:textfield name ="taxno" label="Tax No "></s:textfield>
<s:file name ="imagefile" label ="Upload Document" />
<tr><td> </td></tr>
<tr>
<td> </td>
<s:submit align="center"></s:submit>
</s:form>
</div>
</body>
</html>
客户 dao 是
package dao;
import java.sql.Blob;
import java.sql.SQLException;
import model.Clientmodel;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.ResultSet;
public class Clientdao {
java.sql.Connection connection =null;
PreparedStatement pst = null;
ResultSet rs =null;
private java.sql.Connection getConnection() throws SQLException{
java.sql.Connection conn;
conn = Connectionfactory.getInstance().getConntection();
return conn;
}
public int registration(Clientmodel model){
int i= 0;
try{
String str = "insert into " + "clientdata(Aggrement,aggrementDate,rate,maturitydate,detail,taxno,image)"+
"values(?,?,?,?,?,?)";
connection =getConnection();
pst =(PreparedStatement) connection.prepareStatement(str);
pst.setString(1, model.getAggrement());
pst.setString(2, model.getDate());
pst.setString(3, model.getRate());
pst.setString(4, model.getMaturitydate());
pst.setString(5, model.getDetail());
pst.setString(6, model.getTaxno());
pst.setBlob(7,(Blob) model.getImagefile());
i = pst.executeUpdate();
System.out.println("Result " +i);
}
catch (SQLException se){
se.printStackTrace();
}
return i;
}
}