今天在运行书里的JSTL标签代码的时候出错,总结一下:
问题1.The JSP specification requires that an attribute name is preceded by whitespace
解决:<c:forEach var="book" items="${requestScope.books}"varStatus="status">出错
改为:<c:forEach var="book" items="${requestScope.books}" varStatus="status">
原因:varStatus="status"前加空格
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问题2.Property 'isbn' not found on type java.lang.String
解决:<c:forEach var="book" items=" ${requestScope.books}" varStatus="status">出错
改为:<c:forEach var="book" items="${requestScope.books}" varStatus="status">
原因:${requestScope.books}前去掉空格
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问题3.程序能运行了,jsp能访问,但是EL表达式读取不到想要的信息
解决:没有在.无法调用servlet向jsp传对象。
在.
<servlet> <servlet-name>BooksServlet</servlet-name> <servlet-class>com.controller.BooksServlet</servlet-class></servlet><servlet-mapping> <servlet-name>BooksServlet</servlet-name> <url-pattern>/BooksServlet</url-pattern></servlet-mapping>
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jstl标签练习代码:
1.BooksServlet.java
1 package com.controller; 2 import java.io.IOException; 3 import javax.servlet.RequestDispatcher; 4 import javax.servlet.ServletException; 5 import javax.servlet.annotation.WebServlet; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 import java.util.List;10 import java.util.ArrayList;11 import com.model.Book;12 //@WebServlet("/BooksServlet")13 public class BooksServlet extends HttpServlet {14 @Override15 public void doGet(HttpServletRequest request, HttpServletResponse response) 16 throws ServletException, IOException {17 List<Book> books = new ArrayList<Book>();18 Book book1 = new Book("978-7-302-23059-5","Java语言程序设计",45.00);19 Book book2 = new Book("978-7-302-21540-0","Java Web编程技术",39.00);20 Book book3 = new Book("978-7-302-24130-0","C #入门经典",99.80);21 books.add(book1);22 books.add(book2);23 books.add(book3);24 request.setAttribute("books", books);25 RequestDispatcher rd = request.getRequestDispatcher("/books.jsp");26 rd.forward(request, response);27 }28 }
2.Book.java(javaBean类)
1 package com.model; 2 3 public class Book { 4 private String isbn; 5 private String title; 6 private double price; 7 public Book(String isbn, String title, double price) { 8 super(); 9 this.isbn = isbn;10 this.title = title;11 this.price = price;12 }13 public String getIsbn() {14 return isbn;15 }16 public void setIsbn(String isbn) {17 this.isbn = isbn;18 }19 public String getTitle() {20 return title;21 }22 public void setTitle(String title) {23 this.title = title;24 }25 public double getPrice() {26 return price;27 }28 public void setPrice(double price) {29 this.price = price;30 }31 32 33 }
3.books.jsp
1 package com.model; 2 3 public class Book { 4 private String isbn; 5 private String title; 6 private double price; 7 public Book(String isbn, String title, double price) { 8 super(); 9 this.isbn = isbn;10 this.title = title;11 this.price = price;12 }13 public String getIsbn() {14 return isbn;15 }16 public void setIsbn(String isbn) {17 this.isbn = isbn;18 }19 public String getTitle() {20 return title;21 }22 public void setTitle(String title) {23 this.title = title;24 }25 public double getPrice() {26 return price;27 }28 public void setPrice(double price) {29 this.price = price;30 }31 32 33 }
4.配置文件.xm
1 <? 2 <web-app 3 <display-name>Ex_JSTL_tag</display-name> 4 <servlet> 5 <servlet-name>BooksServlet</servlet-name> 6 <servlet-class>com.controller.BooksServlet</servlet-class> 7 </servlet> 8 <servlet-mapping> 9 <servlet-name>BooksServlet</servlet-name>10 <url-pattern>/BooksServlet</url-pattern>11 </servlet-mapping>12 <welcome-file-list>13 <welcome-file>index.html</welcome-file>14 <welcome-file>index.htm</welcome-file>15 <welcome-file>books.jsp</welcome-file>16 <welcome-file>default.htm</welcome-file>17 <welcome-file>default.jsp</welcome-file>18 </welcome-file-list>19 </web-app>
5.运行时注意加入 http://localhost/Ex_JSTL_tag/BooksServlet
只有在url中加入/BooksServlet才能调用到servlet想jsp传参数
截图:
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原标题:JSTL标签出错:c:forEach var=book items=${requestScope.books} varStatus=status
关键词:JS