Controller 和 视图层编写

1. BookController 类编写 ， 方法一：查询全部书籍

@Controller
@RequestMapping("/book")
public class BookController {
    @Autowired
    @Qualifier("BookServiceImpl")
    private BookService bookService;
    @RequestMapping("/allBook")
    public String list(Model model) {
        List list = bookService.queryAllBook();
        model.addAttribute("list", list);
        return "allBook";
    }
}

2. 编写首页 index.jsp

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



    
    



    点击进入列表
        页

3. 书籍列表页面 allbook.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    
    
    
    <link
            href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"
            rel="stylesheet">



    

        

            

                

                    书籍列表 —— 显示所有书籍
                
            
        
    
    

        

            
               href="${pageContext.request.contextPath}/book/toAddBook">新增
        
    
    

        

            var="book"
                           items="${requestScope.get('list')}">
                    

                

                

                    
书籍编号
                    
书籍名字
                    
书籍数量
                    
书籍详情
                    
操作
                
                
                

                

                        
${book.getBookID()}
                        
${book.getBookName()}
                        
${book.getBookCounts()}
                        
${book.getDetail()}
                        

                            <a
                                    href="${pageContext.request.contextPath}/book/toUpdateBook?
id=${book.getBookID()}">更改 |
                            <a
                                    href="${pageContext.request.contextPath}/book/del/${book.getBookID()}">
                                删除
                        
                    
                
                
            
        
    

4. BookController 类编写 ， 方法二：添加书籍

    @RequestMapping("/toAddBook")
    public String toAddPaper() {
        return "addBook";
    }
    @RequestMapping("/addBook")
    public String addPaper(Books books) {
        System.out.println(books);
        bookService.addBook(books);
        return "redirect:/book/allBook";
    }

5. 添加书籍页面：addBook.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    
    
    
    <link
            href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"
            rel="stylesheet">



    

        

            

                

                    新增书籍
                
            
        
    
    

          method="post">
        书籍名称：



        书籍数量：



        书籍详情：



        
    

6. BookController 类编写 ， 方法三：修改书籍

    @RequestMapping("/toUpdateBook")
    public String toUpdateBook(Model model, int id) {
        Books books = bookService.queryBookById(id);
        System.out.println(books);
        model.addAttribute("book",books );
        return "updateBook";
    }
    @RequestMapping("/updateBook")
    public String updateBook(Model model, Books book) {
        System.out.println(book);
        bookService.updateBook(book);
        Books books = bookService.queryBookById(book.getBookID());
        model.addAttribute("books", books);
        return "redirect:/book/allBook";
    }

7. 修改书籍页面 updateBook.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    
    
    
    <link
            href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"
            rel="stylesheet">



    

        

            

                

                    修改信息
                
            
        
    
    

          method="post">
        
        书籍名称：
                    value="${book.getBookName()}"/>
        书籍数量：
                    value="${book.getBookCounts()}"/>
        书籍详情：
                    value="${book.getDetail() }"/>
        
    

8. BookController 类编写 ， 方法四：删除书籍

   @RequestMapping("/del/{bookId}")
    public String deleteBook(@PathVariable("bookId") int id) {
        bookService.deleteBookById(id);
        return "redirect:/book/allBook";
    }

项目结构图

实现查询书籍功能

1. 前端页面增加一个输入框和查询按钮

    

          style="float: right">
        
               placeholder="输入查询书名" required>
        
    

2. 编写查询的Controller

  @RequestMapping("/queryBook")
    public String queryBook(String queryBookName,Model model){
        System.out.println("要查询的书籍:"+queryBookName);
//业务逻辑还没有写
        return "allBook";
    }

3. 由于底层没有实现，所以我们要将底层代码先搞定

4. Mapper接口

//根据id查询,返回一个Book
Books queryBookByName(String bookName);

5. Mapper.xml

<select id="queryBookByName" resultType="Books">
select * from ssmbuild.books
where bookName = #{bookName}
select>

6. Service接口

//根据id查询,返回一个Book
Books queryBookByName(String bookName);

7. Service实现类

public Books queryBookByName(String bookName) {
    return bookMapper.queryBookByName(bookName);
}

8. 完善Controller

   @RequestMapping("/queryBook")
    public String queryBook(String queryBookName,Model model){
        System.out.println("要查询的书籍:"+queryBookName);
        Books books = bookService.queryBookByName(queryBookName);
        List list = new ArrayList();
        list.add(books);
        model.addAttribute("list", list);
        return "allBook";
    }

9. 测试，查询功能OK！

10. 无聊优化！我们发现查询的东西不存在的时候，查出来的页面是空的，我们可以提高一下用户的体 验性！

　　1. 在前端添加一个展示全部书籍的按钮

 　　2. 并在后台增加一些判断性的代码！

  @RequestMapping("/queryBook")
    public String queryBook(String queryBookName,Model model){
        System.out.println("要查询的书籍:"+queryBookName);
//如果查询的数据存在空格，则优化
        Books books =
                bookService.queryBookByName(queryBookName.trim());
        List list = new ArrayList();
        list.add(books);
//如果没有查出来书籍，则返回全部书籍列表
        if (books==null){
            list = bookService.queryAllBook();
            model.addAttribute("error", "没有找到本书！");
        }
        model.addAttribute("list", list);
        return "allBook";
    }

　　3. 将错误信息展示在前台页面！完整的查询栏代码

<div class="row">
<div class="col-md-4 column">
    <a class="btn btn-primary"
       href="${pageContext.request.contextPath}/book/toAddBook">新增a>
    <a class="btn btn-primary"
       href="${pageContext.request.contextPath}/book/allBook">显示全部书籍
    a>
div>
<div class="col-md-8 column">
    <form class="form-inline" action="/book/queryBook"
          method="post" style="float: right">
        <span style="color:red;font-weight: bold">${error}
        span>
        <input type="text" name="queryBookName" class="formcontrol" placeholder="输入查询书名" required>
        <input type="submit" value="查询" class="btn btnprimary">
    form>
div>
div>