Java 使链接转到 servlet 以重定向到另一个页面
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Making link go to servlet to redirect to another page
提问by user3457789
SO first off let me begin by saying that my servlet loads the option lists in a form i have just fine. The problem is when i start from the index.jsp like i want, the lists dont load. So basically, i want to click a link on the index.jsp to take me to the servlet to then redirect me to the correct page based on the link clicked. Maybe I have been looking at this too long and just need fresh eyes but I cant get why it wont work.
所以首先让我首先说我的 servlet 以一种我很好的形式加载选项列表。问题是当我像我想要的那样从 index.jsp 开始时，列表不会加载。所以基本上，我想单击 index.jsp 上的链接将我带到 servlet，然后根据单击的链接将我重定向到正确的页面。也许我已经看这个太久了，只需要新的眼睛，但我不明白为什么它不起作用。
I have included my Index.jsp and servlet
我已经包含了我的 Index.jsp 和 servlet
Index.jsp
索引.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.util.ArrayList" %>
<!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">
<title>Insert title here</title>
</head>
<body>
<form method="get" action="customerServlet">
<a href="customerServlet?addCustomer">Add Customer</a>
<br/>
<a href="customerServlet?addPet">Add Pet</a>
</form>
</body>
</html>
Servlet
小服务程序
package edu.witc.Assignment03.controller;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//import javax.servlet.annotation.WebServlet;
//import javax.servlet.http.HttpServlet;
//import javax.servlet.http.HttpServletRequest;
//import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import edu.witc.Assignment03.model.Customer;
import edu.witc.Assignment03.model.Phone;
import edu.witc.Assignment03.model.States;
@WebServlet(description = "servlet to get act as controller between form and models", urlPatterns = { "/customerServlet","/addCustomer","/addPet" })
public class CustomerServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public CustomerServlet() {
super();
}
private void processRequest(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
HttpSession session = request.getSession();
Phone phone = new Phone();
States state = new States();
Collection<Phone> phones = phone.getPhoneCollection();
Collection<States> states = state.getStateCollection();
session.setAttribute("phones", phones);
session.setAttribute("states", states);
request.getRequestDispatcher("/customerManagement.jsp").forward(request, response);
//}
}
private List<edu.witc.Assignment03.model.Customer> customers = new ArrayList<Customer>();
private void addCustomer(HttpServletResponse response, HttpServletRequest request)//redirect to index
throws IOException, ServletException {
String url = "/customerManagement.jsp";
processRequest(request, response);
request.getRequestDispatcher(url).forward(request,response);
}
private void addPet(HttpServletResponse response, HttpServletRequest request)//redirect to index
throws IOException, ServletException {
String url = "/pets.jsp";
request.getRequestDispatcher(url).forward(request,response);
}
private Customer getCustomer(int customerId) {
for (Customer customer : customers) {
if (customer.getCustomerId() == customerId) {
return customer;
}
}
return null;
}
private void sendEditCustomerForm(HttpServletRequest request,
HttpServletResponse response) throws IOException, ServletException {
String url = "/customerManagement.jsp";
request.setAttribute("customers", customers);
request.getRequestDispatcher(url).forward(request,response);
}
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String uri = request.getRequestURI();
if (uri.endsWith("/addCustomer")) {
addCustomer(response, request);
} else if (uri.endsWith("/addPet")) {
addPet(response, request);
}
}
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
// update customer
int customerId = 0;
try {
customerId =
Integer.parseInt(request.getParameter("id"));
} catch (NumberFormatException e) {
}
Customer customer = getCustomer(customerId);
if (customer != null) {
customer.setFirstName(request.getParameter("firstName"));
customer.setLastName(request.getParameter("lastName"));
customer.setEmail(request.getParameter("email"));
customer.setPhone(request.getParameter("phone"));
customer.setAddress(request.getParameter("address"));
customer.setCity(request.getParameter("city"));
customer.setZip(request.getParameter("zip"));
}
}
}
采纳答案by developerwjk
It would be easier to use one parameter and check the value than to manually parse the URL:
使用一个参数并检查值比手动解析 URL 更容易：
<a href="customerServlet?action=addCustomer">Add Customer</a>
<br/><a href="customerServlet?action=addPet">Add Pet</a>
In your servlet:
在您的 servlet 中：
String action = request.getParameter("action");
if("addCustomer".equals(action)) { ... }
else if("addPet".equals(action)) { ... }
回答by Naoto Aguilar Morita
if you are using "forms", this could be the solution to send params to servlet.
如果您使用“表单”，这可能是将参数发送到 servlet 的解决方案。
<form action="ServletName" method="POST">
<input type="text" name="paramName">
<input type="submit" value="Add">
</form>
In Servlet:
在 Servlet 中：
String costumerName = request.getParameter("paramName");
If you just use a link like href, you should send the param like:
如果您只使用 href 之类的链接，则应发送如下参数：
<a href="ServletName?ID=12345">
In servlet, same.
在 servlet 中，相同。
String costumerName = request.getParameter("ID");
