1. 整合SSM框架

1.1 环境要求

环境：

  • IDEA
  • MySQL 5.7.19
  • Tomcat 9
  • Maven 3.6

要求：

  • 需要熟练掌握MySQL数据库，Spring，JavaWeb及MyBatis知识，简单的前端知识；

1.2 项目结构图

SSM商场小项目 - 图1

SSM商场小项目 - 图2

2. 数据库环境

创建一个存放书籍数据的数据库表

  1. CREATE DATABASE `ssmbuild`;
  3. USE `ssmbuild`;
  5. DROP TABLE IF EXISTS `books`;
  7. CREATE TABLE `books` (
  8. `bookID` INT(10) NOT NULL AUTO_INCREMENT COMMENT '书id',
  9. `bookName` VARCHAR(100) NOT NULL COMMENT '书名',
  10. `bookCounts` INT(11) NOT NULL COMMENT '数量',
  11. `detail` VARCHAR(200) NOT NULL COMMENT '描述',
  12. KEY `bookID` (`bookID`)
  13. ) ENGINE=INNODB DEFAULT CHARSET=utf8;
  15. INSERT  INTO `books`(`bookID`,`bookName`,`bookCounts`,`detail`)VALUES 
  16. (1,'Java',1,'从入门到放弃'),
  17. (2,'MySQL',10,'从删库到跑路'),
  18. (3,'Linux',5,'从进门到进牢');

3. 基本环境搭建

3.1 新建Maven项目

新建 ssmbuild

添加web的支持

3.2 导入相关的pom依赖！

  1. <dependencies>
  2.    <!--Junit-->
  3.    <dependency>
  4.        <groupId>junit</groupId>
  5.        <artifactId>junit</artifactId>
  6.        <version>4.12</version>
  7.    </dependency>
  8.    <!--数据库驱动-->
  9.    <dependency>
  10.        <groupId>mysql</groupId>
  11.        <artifactId>mysql-connector-java</artifactId>
  12.        <version>5.1.47</version>
  13.    </dependency>
  14.    <!-- 数据库连接池 -->
  15.    <dependency>
  16.        <groupId>com.mchange</groupId>
  17.        <artifactId>c3p0</artifactId>
  18.        <version>0.9.5.2</version>
  19.    </dependency>
  21.    <!--Servlet - JSP -->
  22.    <dependency>
  23.        <groupId>javax.servlet</groupId>
  24.        <artifactId>servlet-api</artifactId>
  25.        <version>2.5</version>
  26.    </dependency>
  27.    <dependency>
  28.        <groupId>javax.servlet.jsp</groupId>
  29.        <artifactId>jsp-api</artifactId>
  30.        <version>2.2</version>
  31.    </dependency>
  32.    <dependency>
  33.        <groupId>javax.servlet</groupId>
  34.        <artifactId>jstl</artifactId>
  35.        <version>1.2</version>
  36.    </dependency>
  38.    <!--Mybatis-->
  39.    <dependency>
  40.        <groupId>org.mybatis</groupId>
  41.        <artifactId>mybatis</artifactId>
  42.        <version>3.5.2</version>
  43.    </dependency>
  44.    <dependency>
  45.        <groupId>org.mybatis</groupId>
  46.        <artifactId>mybatis-spring</artifactId>
  47.        <version>2.0.2</version>
  48.    </dependency>
  50.    <!--Spring-->
  51.    <dependency>
  52.        <groupId>org.springframework</groupId>
  53.        <artifactId>spring-webmvc</artifactId>
  54.        <version>5.1.9.RELEASE</version>
  55.    </dependency>
  56.    <dependency>
  57.        <groupId>org.springframework</groupId>
  58.        <artifactId>spring-jdbc</artifactId>
  59.        <version>5.1.9.RELEASE</version>
  60.    </dependency>
  61. </dependencies>

3.3 Maven资源过滤设置

  1. <build>
  2.    <resources>
  3.        <resource>
  4.            <directory>src/main/java</directory>
  5.            <includes>
  6.                <include>**/*.properties</include>
  7.                <include>**/*.xml</include>
  8.            </includes>
  9.            <filtering>false</filtering>
  10.        </resource>
  11.        <resource>
  12.            <directory>src/main/resources</directory>
  13.            <includes>
  14.                <include>**/*.properties</include>
  15.                <include>**/*.xml</include>
  16.            </includes>
  17.            <filtering>false</filtering>
  18.        </resource>
  19.    </resources>
  20. </build>

3.4 建立基本结构和配置框架！

  • nuc.ss.pojo

  • nuc.ss.dao

  • nuc.ss.service

  • nuc.ss.controller

  • mybatis-config.xml ```xml <?xml version=”1.0” encoding=”UTF-8” ?> <!DOCTYPE configuration

    1.  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
    2.  "http://mybatis.org/dtd/mybatis-3-config.dtd">

  3. - 
  4. applicationContext.xml
  5. ```xml
  6. <?xml version="1.0" encoding="UTF-8"?>
  7. <beans xmlns="http://www.springframework.org/schema/beans"
  8.       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  9.       xsi:schemaLocation="http://www.springframework.org/schema/beans
  10.        http://www.springframework.org/schema/beans/spring-beans.xsd">
  12. </beans>

4. Mybatis层编写

4.1 数据库配置文件 database.properties

  1. jdbc.driver=com.mysql.jdbc.Driver
  2. jdbc.url=jdbc:mysql://localhost:3306/ssmbuild?useSSL=true&useUnicode=true&characterEncoding=utf8
  3. jdbc.username=root
  4. jdbc.password=admin

4.2 IDEA关联数据库

测试查询数据库是否正常

4.3 编写MyBatis的核心配置文件

  1.   <?xml version="1.0" encoding="UTF-8" ?>
  2.   <!DOCTYPE configuration
  3.          PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  4.          "http://mybatis.org/dtd/mybatis-3-config.dtd">
  5.   <configuration>
  7.      <typeAliases>
  8.          <package name="nuc.ss.pojo"/>
  9.      </typeAliases>
  10.      <mappers>
  11.          <mapper resource="nuc/ss/dao/BookMapper.xml"/>
  12.      </mappers>
  14.   </configuration>

4.4 编写数据库对应的实体类

nuc.ss.pojo.Books

（使用lombok插件！）

  1.   package nuc.ss.pojo;
  3.   import lombok.AllArgsConstructor;
  4.   import lombok.Data;
  5.   import lombok.NoArgsConstructor;
  7.   @Data
  8.   @AllArgsConstructor
  9.   @NoArgsConstructor
  10.   public class Books {
  12.      private int bookID;
  13.      private String bookName;
  14.      private int bookCounts;
  15.      private String detail;
  17.   }

4.5 编写Dao层的 Mapper接口！

  1.   package nuc.ss.dao;
  3.   import nuc.ss.pojo.Books;
  4.   import java.util.List;
  6.   public interface BookMapper {
  8.      //增加一个Book
  9.      int addBook(Books book);
  11.      //根据id删除一个Book
  12.      int deleteBookById(int id);
  14.      //更新Book
  15.      int updateBook(Books books);
  17.      //根据id查询,返回一个Book
  18.      Books queryBookById(int id);
  20.      //查询全部Book,返回list集合
  21.      List<Books> queryAllBook();
  23.   }

4.6 编写接口对应的 Mapper.xml 文件

需要导入MyBatis的包；

  1.   <?xml version="1.0" encoding="UTF-8" ?>
  2.   <!DOCTYPE mapper
  3.          PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  4.          "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  6.   <mapper namespace="nuc.ss.dao.BookMapper">
  8.      <!--增加一个Book-->
  9.      <insert id="addBook" parameterType="Books">
  10.         insert into ssmbuild.books(bookName,bookCounts,detail)
  11.         values (#{bookName}, #{bookCounts}, #{detail})
  12.      </insert>
  14.      <!--根据id删除一个Book-->
  15.      <delete id="deleteBookById" parameterType="int">
  16.         delete from ssmbuild.books where bookID=#{bookID}
  17.      </delete>
  19.      <!--更新Book-->
  20.      <update id="updateBook" parameterType="Books">
  21.         update ssmbuild.books
  22.         set bookName = #{bookName},bookCounts = #{bookCounts},detail = #{detail}
  23.         where bookID = #{bookID}
  24.      </update>
  26.      <!--根据id查询,返回一个Book-->
  27.      <select id="queryBookById" resultType="Books">
  28.         select * from ssmbuild.books
  29.         where bookID = #{bookID}
  30.      </select>
  32.      <!--查询全部Book-->
  33.      <select id="queryAllBook" resultType="Books">
  34.         SELECT * from ssmbuild.books
  35.      </select>
  37.   </mapper>

4.7 编写Service层的接口和实现类

接口：

  1.   package nuc.ss.service;
  3.   import nuc.ss.pojo.Books;
  5.   import java.util.List;
  7.   //BookService:底下需要去实现,调用dao层
  8.   public interface BookService {
  9.      //增加一个Book
  10.      int addBook(Books book);
  11.      //根据id删除一个Book
  12.      int deleteBookById(int id);
  13.      //更新Book
  14.      int updateBook(Books books);
  15.      //根据id查询,返回一个Book
  16.      Books queryBookById(int id);
  17.      //查询全部Book,返回list集合
  18.      List<Books> queryAllBook();
  19.   }

实现类：

  1.   package nuc.ss.service;
  3.   import nuc.ss.dao.BookMapper;
  4.   import nuc.ss.pojo.Books;
  5.   import java.util.List;
  7.   public class BookServiceImpl implements BookService {
  9.      //调用dao层的操作，设置一个set接口，方便Spring管理
  10.      private BookMapper bookMapper;
  12.      public void setBookMapper(BookMapper bookMapper) {
  13.          this.bookMapper = bookMapper;
  14.     }
  16.      public int addBook(Books book) {
  17.          return bookMapper.addBook(book);
  18.     }
  20.      public int deleteBookById(int id) {
  21.          return bookMapper.deleteBookById(id);
  22.     }
  24.      public int updateBook(Books books) {
  25.          return bookMapper.updateBook(books);
  26.     }
  28.      public Books queryBookById(int id) {
  29.          return bookMapper.queryBookById(id);
  30.     }
  32.      public List<Books> queryAllBook() {
  33.          return bookMapper.queryAllBook();
  34.     }
  35.   }

OK，到此，底层需求操作编写完毕！

5. Spring层

配置Spring整合MyBatis，我们这里数据源使用c3p0连接池；

5.1 配置spring-dao.xml

我们去编写Spring整合Mybatis的相关的配置文件；spring-dao.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <beans xmlns="http://www.springframework.org/schema/beans"
  3.       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.       xmlns:context="http://www.springframework.org/schema/context"
  5.       xsi:schemaLocation="http://www.springframework.org/schema/beans
  6.        http://www.springframework.org/schema/beans/spring-beans.xsd
  7.        http://www.springframework.org/schema/context
  8.        https://www.springframework.org/schema/context/spring-context.xsd">
  10.    <!-- 配置整合mybatis -->
  11.    <!-- 1.关联数据库文件 -->
  12.    <context:property-placeholder location="classpath:database.properties"/>
  14.    <!-- 2.数据库连接池 -->
  15.    <!--数据库连接池
  16.        dbcp 半自动化操作 不能自动连接
  17.        c3p0 自动化操作（自动的加载配置文件 并且设置到对象里面）
  18.    -->
  19.    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
  20.        <!-- 配置连接池属性 -->
  21.        <property name="driverClass" value="${jdbc.driver}"/>
  22.        <property name="jdbcUrl" value="${jdbc.url}"/>
  23.        <property name="user" value="${jdbc.username}"/>
  24.        <property name="password" value="${jdbc.password}"/>
  26.        <!-- c3p0连接池的私有属性 -->
  27.        <property name="maxPoolSize" value="30"/>
  28.        <property name="minPoolSize" value="10"/>
  29.        <!-- 关闭连接后不自动commit -->
  30.        <property name="autoCommitOnClose" value="false"/>
  31.        <!-- 获取连接超时时间 -->
  32.        <property name="checkoutTimeout" value="10000"/>
  33.        <!-- 当获取连接失败重试次数 -->
  34.        <property name="acquireRetryAttempts" value="2"/>
  35.    </bean>
  37.    <!-- 3.配置SqlSessionFactory对象 -->
  38.    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
  39.        <!-- 注入数据库连接池 -->
  40.        <property name="dataSource" ref="dataSource"/>
  41.        <!-- 配置MyBaties全局配置文件:mybatis-config.xml -->
  42.        <property name="configLocation" value="classpath:mybatis-config.xml"/>
  43.    </bean>
  45.    <!-- 4.配置扫描Dao接口包，动态实现Dao接口注入到spring容器中 -->
  46.    <!--解释 ：https://www.cnblogs.com/jpfss/p/7799806.html-->
  47.    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
  48.        <!-- 注入sqlSessionFactory -->
  49.        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
  50.        <!-- 给出需要扫描Dao接口包 -->
  51.        <property name="basePackage" value="nuc.ss.dao"/>
  52.    </bean>
  54. </beans>

5.2 配置spring-service.xml

Spring整合service层

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <beans xmlns="http://www.springframework.org/schema/beans"
  3.       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.       xmlns:context="http://www.springframework.org/schema/context"
  5.       xsi:schemaLocation="http://www.springframework.org/schema/beans
  6.    http://www.springframework.org/schema/beans/spring-beans.xsd
  7.    http://www.springframework.org/schema/context
  8.    http://www.springframework.org/schema/context/spring-context.xsd">
  10.    <!-- 扫描service相关的bean -->
  11.    <context:component-scan base-package="nuc.ss.service" />
  13.    <!--BookServiceImpl注入到IOC容器中-->
  14.    <bean id="BookServiceImpl" class="nuc.ss.service.BookServiceImpl">
  15.        <property name="bookMapper" ref="bookMapper"/>
  16.    </bean>
  18.    <!-- 配置事务管理器 -->
  19.    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
  20.        <!-- 注入数据库连接池 -->
  21.        <property name="dataSource" ref="dataSource" />
  22.    </bean>
  24. </beans>

6. SpringMVC层

6.1 配置web.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  3.         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
  5.         version="4.0">
  7.    <!--DispatcherServlet-->
  8.    <servlet>
  9.        <servlet-name>DispatcherServlet</servlet-name>
  10.        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  11.        <init-param>
  12.            <param-name>contextConfigLocation</param-name>
  13.            <!--一定要注意:我们这里加载的是总的配置文件，之前被这里坑了！-->  
  14.            <param-value>classpath:applicationContext.xml</param-value>
  15.        </init-param>
  16.        <load-on-startup>1</load-on-startup>
  17.    </servlet>
  18.    <servlet-mapping>
  19.        <servlet-name>DispatcherServlet</servlet-name>
  20.        <url-pattern>/</url-pattern>
  21.    </servlet-mapping>
  23.    <!--encodingFilter-->
  24.    <filter>
  25.        <filter-name>encodingFilter</filter-name>
  26.        <filter-class>
  27.           org.springframework.web.filter.CharacterEncodingFilter
  28.        </filter-class>
  29.        <init-param>
  30.            <param-name>encoding</param-name>
  31.            <param-value>utf-8</param-value>
  32.        </init-param>
  33.    </filter>
  34.    <filter-mapping>
  35.        <filter-name>encodingFilter</filter-name>
  36.        <url-pattern>/*</url-pattern>
  37.    </filter-mapping>
  39.    <!--Session过期时间-->
  40.    <session-config>
  41.        <session-timeout>15</session-timeout>
  42.    </session-config>
  44. </web-app>

6.2 配置spring-mvc.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <beans xmlns="http://www.springframework.org/schema/beans"
  3.       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.       xmlns:context="http://www.springframework.org/schema/context"
  5.       xmlns:mvc="http://www.springframework.org/schema/mvc"
  6.       xsi:schemaLocation="http://www.springframework.org/schema/beans
  7.    http://www.springframework.org/schema/beans/spring-beans.xsd
  8.    http://www.springframework.org/schema/context
  9.    http://www.springframework.org/schema/context/spring-context.xsd
  10.    http://www.springframework.org/schema/mvc
  11.    https://www.springframework.org/schema/mvc/spring-mvc.xsd">
  13.    <!-- 配置SpringMVC -->
  14.    <!-- 1.开启SpringMVC注解驱动 -->
  15.    <mvc:annotation-driven />
  16.    <!-- 2.静态资源默认servlet配置-->
  17.    <mvc:default-servlet-handler/>
  19.    <!-- 3.配置jsp 显示ViewResolver视图解析器 -->
  20.    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
  21.        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
  22.        <property name="prefix" value="/WEB-INF/jsp/" />
  23.        <property name="suffix" value=".jsp" />
  24.    </bean>
  26.    <!-- 4.扫描web相关的bean -->
  27.    <context:component-scan base-package="nuc.ss.controller" />
  29. </beans>

6.3 配置applicationContext.xml

Spring配置整合文件，applicationContext.xml

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <beans xmlns="http://www.springframework.org/schema/beans"
  3.       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.       xsi:schemaLocation="http://www.springframework.org/schema/beans
  5.        http://www.springframework.org/schema/beans/spring-beans.xsd">
  7.    <import resource="spring-dao.xml"/>
  8.    <import resource="spring-service.xml"/>
  9.    <import resource="spring-mvc.xml"/>
  11. </beans>

配置文件，暂时结束！

7. 测试Spring和Mybatis的连接

在test包中：使用Spring的bean来调用查询数据

  1.     @Test
  2.     public void test1(){
  3.         ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
  4.         BookService bookServiceImpl = (BookService) context.getBean("BookServiceImpl");
  5.         List<Books> books = bookServiceImpl.queryAllBook();
  6.         for (Books book : books) {
  7.             System.out.println(book);
  8.         }
  9.     }

报错：

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)

Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!

Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could notacquire a resource from its primary factory or source.

解决方案：

  1. 用户名密码错误，多了空格问题；
  2. 权限问题：在MySQL中使用：GRANT ALL PRIVILEGES ON *.* TO 'root'@'127.0.0.1' IDENTIFIED BY 'root';给予最大权限

1，驱动配置有误：driver=com.mysql.jdbc.Driver
2，数据库连接地址有误：url=jdbc:mysql://localhost:3306/test?3useUnicode=true&characterEncoding=utf8
3，密码或帐号有误：username=root password=root

(上面三条一般都写在配置文件中，如果是因为修改了配置文件后导致该错误，建议重写一遍配置文件，因为有时候开发工具就是很蛋疼，表面没有错误，程序运行却提示报错)

4，数据库未启动或无权访问

5，项目未引入对应的驱动jar包mysql-connector-java-5.1.6-bin.jar

6,mysql root没有远程访问的权限，需要增加权限，增加权限的步骤如下：
进入mysql数据库：
grant all privileges on *.* to 'root'@'%' identified by 'root' with grant option;
flush privileges;

7.在普通java项目中使用 mybatis+C3p0+spring时也遇见上述问题。
问题原因是：在xml配置文件中显示声明了自动装载 <beans default-autowire="byName"> 几经折腾，把自动装载设置去掉，就没有问题了，应该使用默认的byType。

参考的文章http://jyao.iteye.com/blog/1915561

8.配置tomcat导入jar包

SSM商场小项目 - 图3

9. Controller 和 视图层编写

9.1查询全部书籍

  1. BookController 类编写 ， 方法一：查询全部书籍

    1. @Controller
    2. @RequestMapping("/book")
    3. public class BookController {
    5. @Autowired
    6. @Qualifier("BookServiceImpl")
    7. private BookService bookService;
    9. @RequestMapping("/allBook")
    10. public String list(Model model) {
    11.     List<Books> list = bookService.queryAllBook();
    12.     model.addAttribute("list", list);
    13.     return "allBook";
    14. }
    15. }
  1. 编写首页 index.jsp ```jsp <%@ page language=”java” contentType=”text/html; charset=UTF-8” pageEncoding=”UTF-8” %> <!DOCTYPE HTML>

点击进入列表页 

  3. 3. 
  4. 书籍列表页面 **allbook.jsp**
  5. ```jsp
  6. <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
  7. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
  8. <html>
  9. <head>
  10.    <title>书籍列表</title>
  11.    <meta name="viewport" content="width=device-width, initial-scale=1.0">
  12.    <!-- 引入 Bootstrap -->
  13.    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
  14. </head>
  15. <body>
  17. <div class="container">
  19.    <div class="row clearfix">
  20.        <div class="col-md-12 column">
  21.            <div class="page-header">
  22.                <h1>
  23.                    <small>书籍列表 —— 显示所有书籍</small>
  24.                </h1>
  25.            </div>
  26.        </div>
  27.    </div>
  29.    <div class="row">
  30.        <div class="col-md-4 column">
  31.            <a class="btn btn-primary" href="${pageContext.request.contextPath}/book/toAddBook">新增</a>
  32.        </div>
  33.    </div>
  35.    <div class="row clearfix">
  36.        <div class="col-md-12 column">
  37.            <table class="table table-hover table-striped">
  38.                <thead>
  39.                <tr>
  40.                    <th>书籍编号</th>
  41.                    <th>书籍名字</th>
  42.                    <th>书籍数量</th>
  43.                    <th>书籍详情</th>
  44.                    <th>操作</th>
  45.                </tr>
  46.                </thead>
  48.                <tbody>
  49.                <c:forEach var="book" items="${requestScope.get('list')}">
  50.                    <tr>
  51.                        <td>${book.getBookID()}</td>
  52.                        <td>${book.getBookName()}</td>
  53.                        <td>${book.getBookCounts()}</td>
  54.                        <td>${book.getDetail()}</td>
  55.                        <td>
  56.                            <a href="${pageContext.request.contextPath}/book/toUpdateBook?id=${book.getBookID()}">更改</a> |
  57.                            <a href="${pageContext.request.contextPath}/book/del/${book.getBookID()}">删除</a>
  58.                        </td>
  59.                    </tr>
  60.                </c:forEach>
  61.                </tbody>
  62.            </table>
  63.        </div>
  64.    </div>
  65. </div>

9.2 添加书籍

  1. BookController 类编写 ， 方法二：添加书籍 ```java @RequestMapping(“/toAddBook”) public String toAddBook() { return “addBook”; }

@RequestMapping(“/addBook”) public String addBook(Books books) { System.out.println(books); bookService.addBook(books); return “redirect:/book/allBook”; // return “allBooks”; /WEB-INF/jsptest/allBooks.jsp，直接调用了allBooks.jsp页面，没有从getAllBooks方法过去，也就没有传递的book数据，会报错查不到book.bookName为空 // return “redirect:allBooks”; // 重定向到http://localhost:8080/books/allBooks，然后发起请求给对应的getAllBooks方法，最后调用allBooks.jsp页面去显示 }

  2.    2. 添加书籍页面：**addBook.jsp**
  3. ```jsp
  4. <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
  5. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
  7. <html>
  8. <head>
  9.    <title>新增书籍</title>
  10.    <meta name="viewport" content="width=device-width, initial-scale=1.0">
  11.    <!-- 引入 Bootstrap -->
  12.    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
  13. </head>
  14. <body>
  15. <div class="container">
  17.    <div class="row clearfix">
  18.        <div class="col-md-12 column">
  19.            <div class="page-header">
  20.                <h1>
  21.                    <small>新增书籍</small>
  22.                </h1>
  23.            </div>
  24.        </div>
  25.    </div>
  26.    <form action="${pageContext.request.contextPath}/book/addBook" method="post">
  27.       书籍名称：<input type="text" name="bookName"><br><br><br>
  28.       书籍数量：<input type="text" name="bookCounts"><br><br><br>
  29.       书籍详情：<input type="text" name="detail"><br><br><br>
  30.        <input type="submit" value="添加">
  31.    </form>
  33. </div>

9.3 修改书籍

  1. BookController 类编写 ， 方法三：修改书籍 ```java @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”; }

  2.    2. 修改书籍页面  **updateBook.jsp**
  3. ```jsp
  4. <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
  5. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
  6. <html>
  7. <head>
  8.    <title>修改信息</title>
  9.    <meta name="viewport" content="width=device-width, initial-scale=1.0">
  10.    <!-- 引入 Bootstrap -->
  11.    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
  12. </head>
  13. <body>
  14. <div class="container">
  16.    <div class="row clearfix">
  17.        <div class="col-md-12 column">
  18.            <div class="page-header">
  19.                <h1>
  20.                    <small>修改信息</small>
  21.                </h1>
  22.            </div>
  23.        </div>
  24.    </div>
  26.    <form action="${pageContext.request.contextPath}/book/updateBook" method="post">
  27.        <input type="hidden" name="bookID" value="${book.getBookID()}"/>
  28.       书籍名称：<input type="text" name="bookName" value="${book.getBookName()}"/>
  29.       书籍数量：<input type="text" name="bookCounts" value="${book.getBookCounts()}"/>
  30.       书籍详情：<input type="text" name="detail" value="${book.getDetail() }"/>
  31.        <input type="submit" value="提交"/>
  32.    </form>
  34. </div>

9.4 删除书籍

  1. @RequestMapping("/del/{bookId}")
  2. public String deleteBook(@PathVariable("bookId") int id) {
  3.    bookService.deleteBookById(id);
  4.    return "redirect:/book/allBook";
  5. // return "redirect:allBooks";  如果本来就在http://localhost:8080/books/allBooks页面，重定向刷新本页面应该使用绝对路径，否则http://localhost:8080/books/deleteBooks/allBooks   
  6. }
  1. 配置Tomcat，进行运行！