Struts2.2.3.1，Method "setStudent" failed for object com.city.action.UpdateAction

[wqzhang]

在自学struts2 就自己写了个小的管理程序
在对信息进行修改的时候出错了，请大家帮帮忙
struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

    <constant name="struts.enable.DynamicMethodInvocation" value="true" />
    <constant name="struts.devMode" value="false" />

    <package name="default" namespace="/" extends="struts-default">
        <default-action-ref name="index" />
        
        <action name="index" class="com.city.action.StudentAction">
        	<result name="success">/index.jsp</result>
        	<result name="update">/update.jsp</result>
        	<result name="add">/add.jsp</result>
            <result name="goback" type="redirectAction">
           		 <param name="actionName">back</param>
            	<param name="namespace">/</param>
            </result>
        </action>
        <action name="back" class="com.city.action.StudentAction">
        	<result name="success">
        	/index.jsp
        	</result>
        </action>
        <action name="add" class="com.city.action.AddAction">
        	<result name="goback" type="redirectAction">
           		 <param name="actionName">back</param>
            	<param name="namespace">/</param>
            </result>
        </action>
        <action name="update" class="com.city.action.UpdateAction">
        	<result name="goback" type="redirectAction">
           		 <param name="actionName">back</param>
            	<param name="namespace">/</param>
            </result>
            <result name="input">
            /error.jsp
            </result>
        </action>
    </package>

   

    <!-- Add packages here -->

</struts>

StudentAction

package com.city.action;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.interceptor.RequestAware;
import org.apache.struts2.interceptor.ServletRequestAware;

import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionSupport;
import com.city.model.*;
import com.city.server.StudentServer;


public class StudentAction extends ActionSupport{
	
	List<Student> list = new ArrayList<Student>();
	HttpServletRequest request=ServletActionContext.getRequest();
	private String id;
	private Student student = new Student();
	
	public HttpServletRequest getRequest() {
		return request;
	}



	public void setRequest(HttpServletRequest request) {
		this.request = request;
	}



	public Student getStudent() {
		return student;
	}



	public void setStudent(Student student) {
		this.student = student;
	}



	public List<Student> getList() {
		return list;
	}



	public void setList(List<Student> list) {
		this.list = list;
	}

//	public void setServletRequest(HttpServletRequest request){
//		this.request = request;
//	}


	public String execute(){
		list = new StudentServer().checkStuList();
		return SUCCESS;
	}
	
	public String gotoUpdate(){
		this.student = new StudentServer().checkStuById(Integer.parseInt(id));
		return "update";
	}
	
	public String gotoAdd(){	
		return "add";
	}


	public String deleteStuById(){
		new StudentServer().deleteStu(Integer.parseInt(id));
		return "goback";
	}
	

	public void setId(String id) {
		this.id = id;
	}



	public String getId() {
		return id;
	}







}

UpdateAction

package com.city.action;

import com.city.model.Student;
import com.city.server.StudentServer;
import com.opensymphony.xwork2.ActionSupport;

public class UpdateAction extends ActionSupport {
	Student student = new Student();

	public Student getStudent() {
		return student;
	}

	public void setStudent(Student student) {
		this.student = student;
	}
	
	public String updateSuccess(){
		new StudentServer().updateStu(student);
		return "goback";
	}
	
	public String updateCancle(){
		
		return "goback";
	}
	
	
	
	
	
}

update.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'update.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
    This is my update page. <br>
    <s:form action="update!updateSuccess" method="post">
    	<table>
    		<tr>
    			<td>
    			姓名：
    			</td>
    			<td>
    			<s:hidden name="student" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>
    
    			<input name="student.name" value="<s:property value="student.name"/>" ></input>
    			</td>
    		</tr>
    		<tr>
    			<td>
    			学号：
    			</td>
    			<td>
    			<input name="student.stu_no" value="<s:property value="student.stu_no"/>" ></input>
    			</td>
    		</tr>
    		<tr>
    			<td>
    			年龄：
    			</td>
    			<td>
    			<input name="student.age" value="<s:property value="student.age"/>" ></input>
    			</td>
    		</tr>
    		<tr>
    			<td>
    			<s:submit value="提交"></s:submit>
    			</td>
    			<td>
    			
    			</td>
    		</tr>
    	</table>
    </s:form>
    <table>
    	<tr><td><a href="update!updateCancle">返回</a></td></tr>
    </table>
    <br/>
    <hr/>
    <s:debug></s:debug>
  </body>
</html>

报错信息：

警告: Error setting expression 'student' with value '[Ljava.lang.String;@1d5c645'
ognl.MethodFailedException: Method "setStudent" failed for object com.city.action.UpdateAction@1f15067 [java.lang.NoSuchMethodException: com.city.action.UpdateAction.setStudent([Ljava.lang.String;)]
at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1285)
at ognl.OgnlRuntime.setMethodValue(OgnlRuntime.java:1474)
at ognl.ObjectPropertyAccessor.setPossibleProperty(ObjectPropertyAccessor.java:85)
at ognl.ObjectPropertyAccessor.setProperty(ObjectPropertyAccessor.java:162)
at com.opensymphony.xwork2.ognl.accessor.ObjectAccessor.setProperty(ObjectAccessor.java:27)
at ognl.OgnlRuntime.setProperty(OgnlRuntime.java:2245)
java.lang.NoSuchMethodException: com.city.action.UpdateAction.setStudent([Ljava.lang.String;)

。。。。
我在网上查了下，有的人说是页面有重复信息，是不是我在StudentAction里面定义了student对象 在UpdateAction里面也定义了student对象 然后都放在了udapte.jsp页面造成了冲突，但是如果这样写的话，那我UpdateAction里面怎样获得update.jsp提交的值呢？？？求帮助

[dracularking]

java.lang.NoSuchMethodException: com.city.action.UpdateAction.setStudent([Ljava.lang.String;)

他是找不到setStudent方法，是不是要定义的，查一下


<action name="index" class="com.city.action.StudentAction">
<result name="success">/index.jsp</result>
<result name="update">/update.jsp</result>
<result name="add">/add.jsp</result>
<result name="goback" type="redirectAction">
<param name="actionName">back</param>
<param name="namespace">/</param>
</result>
</action>

[chabale]

java.lang.NoSuchMethodException: com.city.action.UpdateAction.setStudent([Ljava.lang.String;)

UpdateAction中没找到setStudent方法，如果没有提供这个方法，传参数的时候肯定会报错。。。。

[leilei0932_java]

<s:hidden name="student" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>
改为
<s:hidden name="student.id" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>

[wqzhang]

[Quote=引用 8 楼 leilei0932_java 的回复:]

你的student类拿来看下，里面应该没有对应的set方法.
[/Quote]

package com.city.model;

public class Student {
	private int id;
	private String name;
	private String stu_no;
	private int age;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getStu_no() {
		return stu_no;
	}
	public void setStu_no(String stu_no) {
		this.stu_no = stu_no;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}

}

[wqzhang]

[Quote=引用 3 楼 chabale 的回复:]

java.lang.NoSuchMethodException: com.city.action.UpdateAction.setStudent([Ljava.lang.String;)

UpdateAction中没找到setStudent方法，如果没有提供这个方法，传参数的时候肯定会报错。。。。
[/Quote]
改了
报错
Error setting expression 'student.id' with value '[Ljava.lang.String;@363593'
java.lang.NoSuchMethodException: com.city.model.Student.setId([Ljava.lang.String;)
无语了

[wqzhang]

[Quote=引用 3 楼 chabale 的回复:]

java.lang.NoSuchMethodException: com.city.action.UpdateAction.setStudent([Ljava.lang.String;)

UpdateAction中没找到setStudent方法，如果没有提供这个方法，传参数的时候肯定会报错。。。。
[/Quote]

有这个方法的

package com.city.action;

import com.city.model.Student;
import com.city.server.StudentServer;
import com.opensymphony.xwork2.ActionSupport;

public class UpdateAction extends ActionSupport {
	Student student = new Student();

	public Student getStudent() {
		return student;
	}

	public void setStudent(Student student) {
		this.student = student;
	}
	
	public String updateSuccess(){
		new StudentServer().updateStu(student);
		return "goback";
	}
	
	public String updateCancle(){
		
		return "goback";
	}
	
	
	
	
	
}

[Canace_lemon]

4楼是正确的，你的setStudent的参数传递有问题。

主要是类型的错误，，， 将Student类型的数据错误的传递为String类型。


仔细检查一下传参的问题。。。

[leilei0932_java]

你的student类拿来看下，里面应该没有对应的set方法.

[leilei0932_java]

还有种可能性:
<s:hidden name="student.id" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>没有接到值，这样系统会把""当做字符串对待,你可以先用<input name="student.id" value="student.id"/>看看值接到了没有.

[wqzhang]

弄了一晚上了，去睡去了，明天来看，小弟感激不尽~！！！

[wqzhang]

[Quote=引用 9 楼 leilei0932_java 的回复:]

还有种可能性:
<s:hidden name="student.id" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>没有接到值，这样系统会把""当做字符串对待,你可以先用<input name="student.id" value="student.id"/>看看值接到了没有.
[/Quote]
我这样写：
<input name="student.id" value="<s:property value="student.id"/>" ></input>
能够看到值，但是<input name="student.id" value="student.id"/>这样写就读不出来值了

[wqzhang]

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'update.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
    This is my update page. <br>
    <s:form action="update!updateSuccess" method="post">
    	<table>
    		<tr>
    			<td>
    			AAA
    			</td>
    			<td>
    			<input name="student.id" value="<s:property value="student.id"/>" ></input>
    			<input type="hidden" value="<s:property value="student.id"/>" />
    			</td>
    		</tr>
    		<tr>
    			<td>
    			姓名：
    			</td>
    			<td>
    			<input name="student.name" value="<s:property value="student.name"/>" ></input>
    			</td>
    		</tr>
    		<tr>
    			<td>
    			学号：
    			</td>
    			<td>
    			<input name="student.stu_no" value="<s:property value="student.stu_no"/>" ></input>
    			</td>
    		</tr>
    		<tr>
    			<td>
    			年龄：
    			</td>
    			<td>
    			<input name="student.age" value="<s:property value="student.age"/>" ></input>
    			</td>
    		</tr>
    		<tr>
    			<td>
    			<s:submit value="提交"></s:submit>
    			</td>
    			<td>
    			
    			</td>
    		</tr>
    	</table>
    </s:form>
    <table>
    	<tr><td><a href="update!updateCancle">返回</a></td></tr>
    </table>
    <br/>
    <hr/>
    <s:debug></s:debug>
  </body>
</html>

改成这样就能好用了，谢谢各位了，但是还是不是很清楚这中间的值是怎样传得，特别感谢9L,我再去想想，或者各位给我说点这其中传值的问题，再回来给分，再次谢谢大家

[leilei0932_java]

那就是第二种情况了，<s:hidden name="student.id" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>的value=""系统认为空字符串不能转换为int,所以会去找返回值为String的setId方法，由于找不到此方法所以抛出异常,看看你上一步传递值有什么问题.

还有StudentAction这个类中，你没必要在写一个private String id;,因为你student中已经有这个属性了，也可能是这里的原因，传到修改页面的id就已经成为String类型了.

[EEXXTTJJSS]

9楼正解，应该是value="<s:property value='student.id'没有取到值，所以就报错“”不能转换为int,可以把student.id的值直接打印出来看看。

[arikara]

，<s:hidden name="student.id" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>
差不多就是这里出错了
public class UpdateAction extends ActionSupport {

Student student = new Student();

struts2 需要你去new 嘛？
private Student student;

[游一游走一走]

问题出在:

<s:hidden name="student.id" theme="simple" value="<s:property value='student.id'/>" ></s:hidden>

你不应该使用struts标签嵌套标签,这样会取不到值,
如果你这样写实际的html是

<input id="update!updateSuccess_student" type="hidden" value="<s:property value='student.id'/>" name="student">

所以赋值不成功的

[凡人之玲珑]

断点 看下变量有没有值

[leilei0932_java]

写这一句就行了:

<input type="hidden" name="student.id" value="<s:property value="student.id"/>" ></input>

文本框的name一定要和对象的属性名对应，之前你没有接到值有可能是name没有写对，也有可能是其他原因，一般不确定只有没有接到可以先将隐藏域type="hidden"删除这样便于测试，确认接到值后再加上就可以了。

[leilei0932_java]

还有14楼那种写法需要稍加改动,这里要用el表达式:

<input name="student.id" value="${student.id}"/>

[dracularking]

java.lang.NoSuchMethodException: com.city.action.UpdateAction.setStudent([Ljava.lang.String;)
哦 原来是因为带String参数的setStudent方法找不到
但即使当初成功传到student.id，name没改正确，也一样会报找不到方法，因为也不存在带int参数的setStudent方法