菜鸟救助jsp与javabean的问题，急！！谢谢~

davidcoffee 2009-11-14 10:40:49

一共3个页面ClientFormBean.java; clientForm.jsp; processForm.jsp
第一个
package jspbean;

public class ClientFormBean {
private String name = "NoNameYet";
private String birthday = "00/00/0000";
private int height = 0;
//access name property
public String getName() {
return name;
}
public void setName(String newValue) {
if(newValue != null){
name = newValue;
}
}
public int getHeight() {
return height;
}
public void setHeight(int newValue) {
height = newValue;
}

public String getBirthday() {
return birthday;
}
public void setBirthday(String newValue) {
if(newValue != null){
birthday = newValue;
}
}

}
第二个
<html>
<head>
<title>ClientForm</title>
</head>
<body bgcolor="#ffffff">
<form action="processForm.jsp">
User name:<input type="text" id="userName" name="userName"/>
<br/>
<br/>
Birthday:<input type="text" id="birthday" name="birthday"/>
<br/>
<br/>
Height:<input type="text" id=""height" name="height"/>
<br/>
<br/>
<br/>
<input type="reset" value="reset">
<input type="submit" value="submit">
</form>
</body>
</html>
第三个
<html>
<head>
<title>processForm</title>
</head>
<%--<jsp:setProperty name="clientFormBeanId" property="*"/> --%>
<body bgcolor="#ffffff">
<jsp:useBean id="clientFormBeanId" scope="request" class="jspbean.ClientFormBean"/>
<jsp:setProperty name="clientFormBean" param="userName" property="name"/>
<jsp:setProperty name="clientFormBean" param="height" property="height"/>
<jsp:setProperty name="clientFormBean" param="birthday" property="birthday"/>
<table border="1">
<tr>
<th>Name<th>Height<th>Birthday
<td><jsp:getProperty name="clientFormBeanId" property="name"/>
<td><jsp:getProperty name="clientFormBeanId" property="height"/>
<td><jsp:getProperty name="clientFormBeanId" property="birthday"/>
</table>
</body>
</html>
按书上打的为什么报500错误
错误如下：
HTTP Status 500 -

--------------------------------------------------------------------------------

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /processForm.jsp at line 9

6: <%--<jsp:setProperty name="clientFormBeanId" property="*"/> --%>
7: <body bgcolor="#ffffff">
8: <jsp:useBean id="clientFormBeanId" scope="request" class="jspbean.ClientFormBean"/>
9: <jsp:setProperty name="clientFormBean" param="userName" property="name"/>
10: <jsp:setProperty name="clientFormBean" param="height" property="height"/>
11: <jsp:setProperty name="clientFormBean" param="birthday" property="birthday"/>
12: <table border="1">

Stacktrace:
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:505)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:398)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

root cause

org.apache.jasper.JasperException: java.lang.NullPointerException
org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:361)
org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:308)
org.apache.jsp.processForm_jsp._jspService(processForm_jsp.java:72)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

root cause

java.lang.NullPointerException
org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:322)
org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:308)
org.apache.jsp.processForm_jsp._jspService(processForm_jsp.java:72)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.

谢谢各位大牛帮忙解决下~小弟万分感谢~

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sangshusen_1988 2009-11-15

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name修改成clientFormBeanId

gouxiongyaya 2009-11-15

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不是吧，很明显的错误啊
8: <jsp:useBean id="clientFormBeanId"scope="request"class="jspbean.ClientFormBean"/>
9: <jsp:setProperty name="clientFormBean" param="userName" property="name"/>
你看你第8行的id是clientFormBeanId，而你第9行的name是clientFormBean
name值应该和id值一样，改为clientFormBeanId,所以出现空指针异常
不用改楼上的，不用把userName改为name

ttwings 2009-11-14

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看错了......不好意思。。
把userName改为 name看看。。

zhang_yu_cvicse 2009-11-14

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后面的异常提示了错误：org.apache.jasper.JasperException: An exception occurred processing JSP page /processForm.jsp at line 9

8: <jsp:useBean id="clientFormBeanId" scope="request" class="jspbean.ClientFormBean"/>
9: <jsp:setProperty name="clientFormBean" param="userName" property="name"/>

错误说clientFormBean没有找到，只要把第八行的id="clientFormBeanId"改成id="clientFormBean"就行了

试试看

ttwings 2009-11-14

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顺序反了吧，先要 useBean 下来才可以 setproperty
6: <%-- <jsp:setProperty name="clientFormBeanId" property="*"/> --%>
7: <body bgcolor="#ffffff">
8: <jsp:useBean id="clientFormBeanId" scope="request" class="jspbean.ClientFormBean"/>

6行和 8行换一下位置，看行不行。。

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