javabean(15分)

D影子D · 2004-02-06

<%@ page import="bean.*"%>
<html><body>
<center>
<%
TestBean testBean=new TestBean("This is a test java bean.");
%>
Java bean name is: <%=testBean.getName()%>
</center></body></html>
这个正确，而下面的就不能使用bean，为什么？
<%@ page import="bean.*"%>
<html><body>
<jsp:useBean id="testBean" scope="application" class="TestBean" />
<center>
Java bean name is: <%=testBean.getName()%>
</center></body></html>

springson · 2004-02-06

下面的根本就沒有創建，或者你的bean沒有做好。

D影子D · 2004-02-06

bean.java
package bean;
public class TestBean{
String name = null;
public TestBean(String strName_p){
this.name=strName_p;
}
public void setName(String strName_p){
this.name=strName_p;
}
public String getName(){
return this.name;
}
}
已经<jsp:useBean id="testBean" scope="application" class="TestBean" />
为什么没有创建？
怎么做？

D影子D · 2004-02-06

异常提示：javax.servlet.ServletException: Cannot create bean of class TestBean
代码如下：
<%@ page import="bean.*"%>
<html><body>
<jsp:useBean id="testBean" scope="application" class="TestBean" />
<center>
<%
//TestBean testBean=new TestBean("This is a test java bean.");
%>
<%
testBean.setName("ok");
%>
Java bean name is:<%=testBean.getName()%>
</center></body></html>

springson · 2004-02-06

因為你的創建類需要有參數，你還需建個無參的才行。或引用時加入也行。
public TestBean(String strName_p){
this.name=strName_p;
}

h_o_u_l_i · 2004-02-07

bean要求为无参数的创建函数.
bean改为:
......
public class TestBean{
private String name;
public TestBean()
{this.name="";}
public void setName(String strName_p){
this.name=strName_p;
}
public String getName(){
return this.name;
}
}
在<jsp:useBean id="testBean" scope="application" class="TestBean" />后加
<jsp:setProperty name="testBean" property="*"/>
调用jsp时要传入name参数

D影子D · 2004-02-10

接受答案了.

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