Java学习笔记（一）

最新推荐文章于 2021-02-16 16:15:45 发布

yysmall

最新推荐文章于 2021-02-16 16:15:45 发布

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分类专栏： Java 文章标签： java string action path deprecated input

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本文围绕Struts应用程序展开，执行功能时抛出'No input attribute for mapping path'错误。分析了ExamOwnBatchAddForm.java中validate和reset方法缺少参数、ExamOwnBatchAddAction.java缺少返回语句的问题，还探讨了perform和execute方法的区别及perform方法使用时的弃用提示。

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在写应用程序时Struts时当在执行该功能时，抛出以下错误；

HTTP Status 500 - No input attribute for mapping path /examOwnBatchAddAction
--------------------------------------------------------------------------------
type Status report

message No input attribute for mapping path /examOwnBatchAddAction

description The server encountered an internal error (No input attribute for mapping path /examOwnBatchAddAction) that prevented it from fulfilling this request.

//ExamOwnBatchAddForm.java
import org.apache.struts.action.*;
import javax.servlet.http.*;

public class ExamOwnBatchAddForm extends ActionForm {

private String qcode;
private String ucode;
private String action;

public String getQcode() {
    return qcode;
}
public void setQcode(String qcode) {
    this.qcode = qcode;
}
   public String getUcode() {
    return ucode;
}
public void setUcode(String ucode) {
    this.ucode = ucode;
}
public String getAction() {
    return action;
}
public void setAction (String action) {
    this.action = action;
}
public ActionErrors validate(ActionMapping actionMapping, HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) {
    /**@todo: finish this method, this is just the skeleton.*/
    ActionErrors errors = new ActionErrors();
    if (ucode==null||ucode.equals("")){
      errors.add(ucode, new ActionError("error.exam.nullucode"));
    }
    return errors;
}
public void reset(ActionMapping actionMapping, HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) {
}
}

//ExamOwnBatchAddAction.java
public class ExamOwnBatchAddAction extends Action {
   public ActionForward perform(ActionMapping actionMapping,
                                ActionForm actionForm,
                                HttpServletRequest httpServletRequest,
                                HttpServletResponse httpServletResponse){
   //execute perform
     ExamOwnBatchAddForm examOwnBatchAddForm = (ExamOwnBatchAddForm) actionForm;
     String action = httpServletRequest.getParameter("action");

     HttpSession session = httpServletRequest.getSession();
     String ucode = (String) session.getAttribute("ucode");
     String qcode = (String) session.getAttribute("qcode");
     String target = "";
     if ((ucode==null)||(ucode.equals("")))
     {
       target = "login";
     }
     else if (action.equals("BatchAdd"))
     {
     Exam exam = new Exam();
      exam.setBatchAddExamDetail(ucode,qcode);
      target = "success";
     }
    return actionMapping.findForward(target);
   }
}

//Struts-conifg.xml
<struts-config>
<form-beans>
    <form-bean name="examOwnBatchAddForm" type="ExamOwnBatchAddForm" />
  </form-beans>
<global-forwards>
    <forward name="errors" path="/insertError.jsp" />
    <forward name="login" path="/index.jsp" />
</global-forwards>
<action-mappings>
    <action name="examOwnBatchAddForm" type="ExamOwnBatchAddAction" validate="true" scope="request" path="/examOwnBatchAddAction">
      <forward name="success" path="/examListAction.do" />
    </action>

问题1：当在ExamOwnBatchAddForm.java中的public ActionErrors validate( )和public void reset( )中缺少“HttpServletResponse httpServletResponse”时即会抛出开头错误；当在validate( )中写入后则程序执行正常。

问题2：在ExamOwnBatchAddAction.java 中如果不写入return actionMapping.findForward(target); 则编译时提示missing return statement 。

问题3：在public ActionForward perform( ) 和 public ActionForward execute( ) 两者的区别？使用perform编译后会提示
Note: ExamOwnBatchAddAction.java uses or overrides a deprecated API.
Note: Recompile with -deprecation for details.