我是Struts 2的新手.我正在创建一个演示Web应用程序,它允许用户在jsp上提交员工详细信息并在下一个jsp上显示它们.以下是代码:
在struts.xml
<struts>
<constant name="struts.custom.i18n.resources" value="ApplicationResources" />
<!-- Configuration for the default package. -->
<package name="default" extends="struts-default" namespace="/">
<action name="empDetails" class="com.webapp.test.action.MyAction"
method="employeeDetails">
<result name="success">jsp/employeeDetails.jsp</result>
</action>
<action name="addEmployee" class="com.webapp.test.action.MyAction"
method="addEmployee">
<result name="success">jsp/addEmployee.jsp</result>
</action>
</package>
</struts>
动作类
public class MyAction extends ActionSupport{
private static final long serialVersionUID = 1L;
private Employee emp = null;
public String addEmployee(){
System.out.println("In addEmployee");
return SUCCESS;
}
public String employeeDetails(){
System.out.println("In employeeDetails");
System.out.println("Employee ID: "+emp.getEmployeeID());
return SUCCESS;
}
}
在上面的操作类中,Employee是一个单独的模型类,具有以下属性:
String employeeID;
String name;
String department;
以下是我添加员工的JSP页面:
<%@taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Add Employee</title>
</head>
<body>
<s:form action="empDetails">
<s:textfield name="emp.employeeID" label="Employee ID"></s:textfield>
<s:textfield name="emp.name" label="Name"></s:textfield>
<s:textfield name="emp.department" label="Department"></s:textfield>
<s:submit></s:submit>
</s:form>
</body>
</html>
单击Submit按钮后填写员工详细信息后,我在employeeDetails()方法中得到一个nullpointer异常:
java.lang.NullPointerException
com.webapp.test.action.MyAction.employeeDetails(MyAction.java:19)
并且服务器控制台显示以下异常:
ognl.OgnlException: target is null for setProperty(null, "department", [Ljava.lang.String;@acd4c9)
.....
ognl.OgnlException: target is null for setProperty(null, "employeeID", [Ljava.lang.String;@c5dd98)
....
ognl.OgnlException: target is null for setProperty(null, "name", [Ljava.lang.String;@5753b0)
请解释问题是什么以及如何从JSP填充员工模型对象.我不想在Action类中创建getter setter方法,也不想使用ModelDriven接口.