JSTLのCoreライブラリ c:forEach の利用についてわかりやすく説明します。JSP/Servlet

1. package controller;
3. import java.io.IOException;
4. import java.util.ArrayList;
5. import java.util.List;
7. import javax.servlet.ServletException;
8. import javax.servlet.annotation.WebServlet;
9. import javax.servlet.http.HttpServlet;
10. import javax.servlet.http.HttpServletRequest;
11. import javax.servlet.http.HttpServletResponse;
13. import dto.User;
15. /**
16. ＊Servlet implementation class UserList
17. */
18. @WebServlet(“/user”)
19. public class UserListServlet extends HttpServlet {
20. private static final long serialVersionUID = 1L;
22. /**
23. ＊@see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
24. */
25. protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
26. List userList = new ArrayList<>();
27. userList.add(new User(“山田”, 25));
28. userList.add(new User(“佐藤”, 27));
29. userList.add(new User(“田中”, 21));
30. request.setAttribute(“userList”, userList); request.getRequestDispatcher(“/WEB-INF/view/user.jsp”).forward(request, response);
31. }
32. }

User.java

1. package dto;
3. public class User {
4. private String name;
5. private int age;
7. public User(String name, int age) {
8. this.name = name;
9. this.age = age;
10. }
12. public String getName() {
13. return name;
14. }
16. public void setName(String name) {
17. this.name = name;
18. }
20. public int getAge() {
21. return age;
22. }
24. public void setAge(int age) {
25. this.age = age;
26. }
27. ｝

user.jsp

1. <%@ page pageEncoding=”UTF-8″%>
2. <%@ taglib prefix=”c” uri=”http://java.sun.com/jsp/jstl/core” %>
3. <%@ taglib prefix=”fmt” uri=”http://java.sun.com/jsp/jstl/fmt” %>
5. ＜ｈｔｍｌ＞
6. ＜ｈｅａｄ＞＜／ｈｅａｄ＞
7. ＜ｂｏｄｙ＞
8. ＜ｈ１＞生徒名簿＜／ｈ１＞
10. ＜table border=”1″>
11. ＜ｔｒ＞
12. ＜ｔｈ＞番号＜／ｔｈ＞
13. ＜ｔｈ＞名前＜／ｔｈ＞
14. ＜ｔｈ＞年齢＜／ｔｈ＞
15. ＜／ｔｒ＞
17. ＜c:forEach items=”${userList}” var=”user” varStatus=”vs”＞
18. ＜ｔｒ＞
19. ＜ｔｄ＞＜c:out value=”${vs.count}” /＞＜／ｔｄ＞
20. ＜ｔｄ＞＜c:out value=”${user.name}” /＞＜／ｔｄ＞
21. ＜ｔｄ＞＜c:out value=”${user.age}” /＞才＜／ｔｄ＞
22. ＜／ｔｒ＞
23. ＜/c:forEach＞
24. ＜/table＞
25. ＜／ｂｏｄｙ＞
26. ＜／ｈｔｍｌ＞