将自定义对象从servlet传递到JSP [英] Passing custom objects from servlet to JSP
问题描述
我想将Student类型的自定义对象从servlet传递到JSP. 我创建了一个Student bean类. Student包含2个属性firstname和lastName.
学生bean:
import java.io.Serializable;
public class Student implements Serializable {
public Student() {
}
String firstName;
String lastName;
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
用于从用户获取名字和姓氏的HTML文件:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
</head>
<body>
<form id="myForm" method="POST" action="MyFormServlet">
FirstName<input type="text" id="firstName" name="FirstName"/><br>
LastName<input type="text" id="lastName" name="LastName"/><br>
<button type="submit" />Submit</button>
</form>
</body>
</html>
Servlet代码:
import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class MyFormServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) {
Student s = new Student();
s.setFirstName(request.getParameter("FirstName"));
s.setLastName(request.getParameter("LastName"));
HttpSession session =request.getSession();
session.setAttribute("student", s);
try {
RequestDispatcher rd = getServletContext().getRequestDispatcher("/myJsp.jsp");
rd.forward(request, response);
} catch (Exception e) {
e.printStackTrace();
}
}
}
myJsp.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
</head>
<body>
<%
// I want to do something like this :
//Student student =(Student)session.getAttribute("student");
//String fullName=student.firstName + student.lastName;
%>
<h1><%=fullName%></h1>
</body>
</html>
我想获取学生"对象，访问其属性并将其存储在JSP变量中以进行进一步处理.
request，session和servletContext上的setAttribute()方法已经可以作为JSP / EL 变量.
在您的特定情况下，该servlet中包含以下行，
session.setAttribute("student", s);
在JSP/EL中以${student}形式提供.因此，只需这样做:
<body>
<h1>${student.firstName} ${student.lastName}</h1>
</body>
如果要将其存储为JSP中的另一个变量，以便可以多次重用，请使用 JSTL <c:set>.
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
...
<body>
<c:set var="fullName" value="${student.firstName} ${student.lastName}" />
<h1>${fullName}</h1>
</body>
I want to pass a custom object of type Student from a servlet to JSP. I have created a Student bean class. Student contains 2 properties firstname and lastName.
Student bean:
import java.io.Serializable;
public class Student implements Serializable {
public Student() {
}
String firstName;
String lastName;
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
HTML file for taking FirstName and LastName from the user:
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
</head>
<body>
<form id="myForm" method="POST" action="MyFormServlet">
FirstName<input type="text" id="firstName" name="FirstName"/><br>
LastName<input type="text" id="lastName" name="LastName"/><br>
<button type="submit" />Submit</button>
</form>
</body>
</html>
Servlet Code:
import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class MyFormServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request,
HttpServletResponse response) {
Student s = new Student();
s.setFirstName(request.getParameter("FirstName"));
s.setLastName(request.getParameter("LastName"));
HttpSession session =request.getSession();
session.setAttribute("student", s);
try {
RequestDispatcher rd = getServletContext().getRequestDispatcher("/myJsp.jsp");
rd.forward(request, response);
} catch (Exception e) {
e.printStackTrace();
}
}
}
myJsp.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
</head>
<body>
<%
// I want to do something like this :
//Student student =(Student)session.getAttribute("student");
//String fullName=student.firstName + student.lastName;
%>
<h1><%=fullName%></h1>
</body>
</html>
I want to get the 'student' object, access its attributes and store it in a JSP variable for further processing.
The setAttribute() method on request, session and servletContext will already make it available as a JSP/EL variable by the attribute name.
In your particular case, with the following line in the servlet,
session.setAttribute("student", s);
it's available in JSP/EL as ${student}. So, just this should do:
<body>
<h1>${student.firstName} ${student.lastName}</h1>
</body>
If you want to store it as another variable in JSP so that you can reuse it multiple times, use JSTL <c:set>.
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
...
<body>
<c:set var="fullName" value="${student.firstName} ${student.lastName}" />
<h1>${fullName}</h1>
</body>
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