你必須使用<jsp:useBean/>
行動request
或session
範圍來實例化BeanClass
在JSP。
樣本 - EmpServlet.java
package com.me;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class EmpServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
PrintWriter pw=response.getWriter();
Emp emp=(Emp)request.getAttribute("emp");
pw.print(emp);
}
}
Emp.java:的Emp豆
package com.me;
public class Emp {
private int age;
private String name;
public Emp() {
name="";
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public boolean valid()
{
return age!=0 && name.length()!=0;
}
@Override
public String toString() {
return "Emp{" + "age=" + age + ", name=" + name + '}';
}
}
emp.jsp(視圖)
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<jsp:useBean id="emp" class="com.me.Emp" scope="request">
<jsp:setProperty name="emp" property="*"/>
</jsp:useBean>
<c:if test="${emp.valid()}">
<jsp:forward page="emp"/>
</c:if>
<form method="post" action="emp.jsp">
<br/><input type="text" name="age"/>
<br/><input type="text" name="name"/>
<br/><input type="submit"/>
</form>
的web.xml
<servlet>
<servlet-name>EmpServlet</servlet-name>
<servlet-class>com.me.EmpServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>EmpServlet</servlet-name>
<url-pattern>/emp</url-pattern>
</servlet-mapping>
我可以在index.jsp中使用這個語句嗎?如果是這樣的話,在jsp頁面中放置這個語句..我也嘗試從servlet中使用getter方法獲取val,但是iam獲得了空值 – user636207