如何获取url的参数设置

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如何获取url的参数设置

来源：6-2 项目作业

weixin_慕仰6475988

2020-07-12 08:29:25

在UpdateBook.jsp中

String paraId=request.getParameter("bookId");

这个paraId一直是空的

//bookList.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

<html>

<head>

<title>图书后台管理</title>

</head>

<body>

<nav>

<a href="bookList.jsp" >图书信息管理</a>

</nav>

<nav>

</nav>

</div>

</header>

<div>

<h1>图书管理系统</h1>

<p>图书信息管理</p>

</div>

</section>

</div>

<input name="searchContent" class="form-control" id="searchContent"

placeholder="输入要查询的分类" style="width: 250px">

</div>

</form>

</div>

<thead>

<tr>

</tr>

</thead>

<tbody>

<c:forEach items="${applicationScope.bookList }" var="curBook" varStatus="idx">

<td>${idx.index+1 }</td>

<td>${curBook.id }</td>

<td>${curBook.bookName }</td>

<td>${curBook.className }</td>

<td>￥${curBook.price }</td>

<td>

</td>

</tr>

</c:forEach>

</tbody>

</table>

</div>

</section>

</div>

</section>

copy@慕课网

</footer>

</body>

</html>

//updateBook.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<html>

<head>

<title>修改图书信息</title>

</head>

<body>

图书信息管理

</a>

</div>

</nav>

<h1>Hello, ${sessionScope.existUser.username }!</h1>

<p>请小心的修改图书信息。。。</p>

</div>

</div>

</div>

</div>

</select>

</div>

</div>

</div>

</div>

</div>

</form>

</div>

copy@imooc

</footer>

</body>

</html>

//UpdateBook

package com.imooc.addanddelete;

import java.io.IOException;

import java.util.List;

import javax.servlet.ServletContext;

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 com.imooc.domain.Book;

/**

* Servlet implementation class UpdateBook

@WebServlet("/UpdateBook")

public class UpdateBook extends HttpServlet {

private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String bookName = request.getParameter("bookName");

String categoryId = request.getParameter("categoryId");

* if (categoryId.equals("ca0001")) categoryId = "计算机类"; else if

* (categoryId.equals("ca0002")) categoryId = "文学类"; else categoryId = "历史类";

String bookPrice = request.getParameter("bookPrice");

String bookPic = request.getParameter("bookPic");

String temp = "img/";

bookPic = temp + bookPic;

String remarks = request.getParameter("remarks");

// public Book(int id, String bookName, String className, Float price, String bookCover, String remark) {

// Book b = new Book(bookId, bookName, categoryId, Float.parseFloat(bookPrice), bookPic,

// remarks);

ServletContext context = request.getServletContext();

List<Book> book = (List<Book>) context.getAttribute("bookList");

String paraId = request.getParameter("bookId");

for(Book curBook:book) {

if(curBook.getId().equals(paraId)) {

curBook.setBookCover(bookPic);

curBook.setBookName(bookName);

curBook.setClassName(categoryId);

curBook.setPrice(Float.parseFloat(bookPrice));

curBook.setRemark(remarks);

}

context.setAttribute("bookList", book);

response.sendRedirect(request.getContextPath() + "/bookList.jsp");

}

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

写回答

4回答

好帮手慕阿园

2020-07-12

同学你好，因为新增图书信息时有文件上传项，所以建议同学使用上传文件的方式来接收数据，可以参考课程中的第三章来完成，如下

关于修改图书的代码同学可参考以下这个问答中老师的代码
http://class.imooc.com/course/qadetail/225742

祝学习愉快

weixin_慕仰6475988

提问者

2020-07-12

我的添加图书是这样实现的

所以不会你说的方法

可以给个示例的代码?

//addBook.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<html>

<head>

<title>新建图书信息</title>

</head>

<body>

图书信息管理

</a>

</div>

</nav>

<h1>Hello, ${sessionScope.existUser.username }!</h1>

<p>请小心地新增图书信息，要是建了一个错误的就不好了。。。</p>

</div>

</div>

</div>

</div>

</select>

</div>

</div>

</div>

</div>

</div>

</form>

</div>

copy@imooc

</footer>

</body>

</html>

//AddBook.java

package com.imooc.addanddeleteandsearch;

import java.io.IOException;

import java.util.List;

import javax.servlet.ServletContext;

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 com.imooc.domain.Book;

import com.imooc.domain.Category;

/**

* Servlet implementation class AddBook

@WebServlet("/AddBook")

public class AddBook extends HttpServlet {

private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

ServletContext context = request.getServletContext();

List<Category> categoryList = (List<Category>) context.getAttribute("categoryList");

String bookId = request.getParameter("bookId");

String bookName = request.getParameter("bookName");

String categoryId = request.getParameter("categoryId");

String categoryName;

if (categoryId.equals("ca0001"))

categoryName = "计算机类";

else if (categoryId.equals("ca0002"))

categoryName = "文学类";

else

categoryName = "历史类";

boolean flag = true;

for (Category curCategory : categoryList) {

if (curCategory.getClassName().equals(categoryName)) {

flag = false;

break;

}

if (flag)

categoryList.add(new Category(categoryId, categoryName));

String bookPrice = request.getParameter("bookPrice");

String bookPic = request.getParameter("bookPic");

String temp = "img/";

bookPic = temp + bookPic;

String remarks = request.getParameter("remarks");

// public Book(int id, String bookName, String className, Float price, String bookCover, String remark) {

Book b = new Book(bookId, bookName, categoryName, Float.parseFloat(bookPrice), bookPic, remarks,categoryId);

System.out.println(b);

List<Book> book = (List<Book>) context.getAttribute("bookList");

book.add(b);

context.setAttribute("bookList", book);

context.setAttribute("categoryList", categoryList);

response.sendRedirect(request.getContextPath() + "/bookList.jsp");

}

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doGet(request, response);

}

好帮手慕阿园

2020-07-12

同学你好，编程题实现的方式有很多种，每个人的思路也不一样，所以老师这里也没有标准答案，
修改的Servlet与添加图书的Servlet相似，同学可以参考添加图书的servlet来实现接收页面中提交的内容，比如：

2）接收完数据内容后，封装成一个Book对象，调用update修改方法，将这个Book对象传入，调用修改方法。

3）调用update修改方法，需要将封装好的Book对象传入，遍历所有图书，判断每个图书id与传入的图书id是否一致，如果一致，则对该对象的属性进行判断，比如同学的代码：

祝学习愉快

heixin_慕仰6475988

h 然而用我的方法,不能获得url中的参数bookId,所以我不会呀能不能给个示例代码呀

h020-07-12

共2条回复

好帮手慕阿园

2020-07-12

同学你好，获取修改后的图书信息应该以上传文件的方式接收数据，并且在jsp页面的form表单中增加enctype属性enctype="multipart/form-data"，设置post提交
UpdateBookServlet文件上传参考代码如下

jsp页面的form表单中添加enctype属性，如下

祝学习愉快

heixin_慕仰6475988

h 可以提供下UpdateBookServlet的代码?

h020-07-12

共1条回复

0 学习 · 9666 问题

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