Question

我在jsf项目中有例外，如果你可以帮助我谢谢！遵循以下错误：

javax.servlet.ServletException
javax.faces.webapp.FacesServlet.service(Unknown Source)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

java.lang.NullPointerException
DAO.TestDAO.getPersonne(TestDAO.java:26)
TestMB.TestMB.getAllData(TestMB.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)
javax.el.BeanELResolver.getValue(BeanELResolver.java:94)
com.sun.faces.el.DemuxCompositeELResolver._getValue(Unknown Source)
com.sun.faces.el.DemuxCompositeELResolver.getValue(Unknown Source)
org.apache.el.parser.AstValue.getValue(AstValue.java:169)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184)
com.sun.faces.facelets.el.TagValueExpression.getValue(Unknown Source)
javax.faces.component.ComponentStateHelper.eval(Unknown Source)
javax.faces.component.ComponentStateHelper.eval(Unknown Source)
javax.faces.component.UIData.getValue(Unknown Source)
javax.faces.component.UIData.getDataModel(Unknown Source)
javax.faces.component.UIData.setRowIndexWithoutRowStatePreserved(Unknown Source)
javax.faces.component.UIData.setRowIndex(Unknown Source)
com.sun.faces.renderkit.html_basic.TableRenderer.encodeBegin(Unknown Source)
javax.faces.component.UIComponentBase.encodeBegin(Unknown Source)
javax.faces.component.UIData.encodeBegin(Unknown Source)
javax.faces.component.UIComponent.encodeAll(Unknown Source)
javax.faces.component.UIComponent.encodeAll(Unknown Source)
javax.faces.component.UIComponent.encodeAll(Unknown Source)
com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(Unknown Source)
com.sun.faces.application.view.MultiViewHandler.renderView(Unknown Source)
com.sun.faces.lifecycle.RenderResponsePhase.execute(Unknown Source)
com.sun.faces.lifecycle.Phase.doPhase(Unknown Source)
com.sun.faces.lifecycle.LifecycleImpl.render(Unknown Source)
javax.faces.webapp.FacesServlet.service(Unknown Source)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

这是我的托管bean类

我把jsf注释

package TestMB;

import DAO.TestDAO;

import Test.Test;


import java.util.List;

import javax.faces.bean.ManagedBean;

import javax.faces.bean.SessionScoped;

@ManagedBean(name="TestM")

@SessionScoped

public class TestMB {


public List<Test> getAllData (){
    return new TestDAO().getPersonne();
}

}

这是我的xhtml页面，用于显示数据库中的数据

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
  xmlns:f="http://java.sun.com/jsf/core"
  xmlns:h="http://java.sun.com/jsf/html">
 <h:body>
 <h:dataTable  value="#{TestM.allData}" var="test">

 <h:column>

  <f:facet name="nom">

     <h:outputText value="#{test.nom}"/>

  </f:facet>

  </h:column>

  <h:column>

  <f:facet name="prenom">

     <h:outputText value="#{test.prenom}"/>

  </f:facet>

</h:column>

</h:dataTable>

</h:body>
</html>

这是我的数据库函数，用于将数据从数据库显示到此xhtml页面：

package DAO;
import Test.Test;
import DAO.DBConn;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;


public class TestDAO {

public TestDAO() {

}

public List<Test> getPersonne() {
      ResultSet rs = null;
      PreparedStatement pst = null;
      Connection con = DBConn.getConnection();
      String stm = "Select nom,prenom from t";
      List<Test> records = new ArrayList<Test>();

      try {   
         pst = con.prepareStatement(stm);
         pst.execute();
         rs = pst.getResultSet();

         while(rs.next()) {
            Test pers = new Test();
            pers.setNom(rs.getString(1));
            pers.setPrenom(rs.getString(2));
            records.add(pers);              
         }
      } catch (SQLException e) {
         e.printStackTrace();
       }
         return records;
       }
 }

感谢您提供帮助，如果可能的话！：d

异常javax.servlet.ServletException javax.faces.webapp.FacesServlet.service（未知来源）

0 个答案: