servlet與jsp的分工協作
阿新 • • 發佈：2018-11-03
servlet和jsp都是前段語言的一種，但是servlet一般用於與伺服器之間的互動，而jsp一般用於實現頁面內容的顯示
el表示式：
全程：expression language 用來在jsp用來展示結果的語言
語法：${ 表示式語言 }
登陸驗證的案例：
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2018/9/19 Time: 22:11 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <form action="/s1" method="post"> <input type="text" name="username" placeholder="請輸入使用者名稱"> <input type="password" name="password" placeholder="請輸入密碼"> <input type="submit" value="登入"> </form> </body> </html>
package controller; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet(urlPatterns = "/s1") public class servlet1 extends HttpServlet { @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String name = req.getParameter("username"); String password = req.getParameter("password"); if ("zhangsan".equals(name)&&"123".equals(password)){ req.getRequestDispatcher("2.jsp").forward(req, resp); }else { req.getRequestDispatcher("1.jsp").forward(req, resp); } } }
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2018/9/19 Time: 22:36 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" import="java.util.*,controller1.shop8" %> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> <head> <title>Title</title> </head> <body> 歡迎您，恭喜您登陸成功！ </body> </html>
實現的登陸功能：
密碼如果正確則會進入成功的頁面：
反之，如果使用者名稱或者密碼不正確，則會返回到登陸的頁面：
jstl標籤庫：
全程：java standard tag library，主要的工具就是配合el表示式來更加便捷的實現jsp的頁面的現實功能，但是前提是要正確的加入jstl的jar包，並在jsp的頁面上加入程式碼
<%@ taglib uri="標籤庫唯一標識" prefix="字首" %>常用的jstl的方法一般有c:forEach以及c:if方法，通過下文的案例來進行說明:
package controller1;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
@WebServlet(urlPatterns = "/q1")
public class ServletTest extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
List<Student> students = new ArrayList<>();
Student student = new Student(1, "zhangsan", "男");
Student student1 = new Student(2, "lisi", "女");
Student student2 = new Student(3, "wangwu", "男");
students.add(student);
students.add(student1);
students.add(student2);
req.setAttribute("aaa",students);
req.getRequestDispatcher("2.jsp").forward(req, resp);
}
}
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2018/9/19
Time: 22:36
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" import="java.util.*,controller1.shop8" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<table border="1" width="100%">
<tbody>
<c:forEach items="${aaa}" var="d">
<tr>
<td><input type="text" name="sid" value="${d.id}"></td>
<td><input type="text" name="sname" value="${d.name}"></td>
<td><input type="text" name="ssex" value="${d.sex}"></td>
<td><c:if test="${d.id>2}">編號大於2</c:if></td>
</tr>
</c:forEach>
</tbody>
</table>
</body>
</html>
效果展示如下：
