写点什么

手把手整合 SSM 框架

用户头像
JavaPub
关注
发布于: 2020 年 07 月 12 日
手把手整合SSM框架

前言


如果看过前几篇文章,对 SpringMyBatis 有了一定了解,一定想上手试试。这篇文章从 0 到 1,手把手整合 SSM (Spring、Spring MVC、MyBatis)。


本篇是代码篇,在 PC 端浏览更佳,源码在文末


[toc]


搭建整合 SSM 之 HelloWorld


开发环境


  • idea

  • MySql5.x

  • jdk8

  • maven


对应的技术入门在 公众号 历史文章 都可以找到


目录



目录包括 main、resources、mapper、webapp,不一一介绍,不熟悉查看前面文章。


环境搭建


新建项目


这里使用的是 IDEA 编辑器,新建一个 Maven 工程,选择 web 项目。



导入依赖


使用 Maven 管理项目 jar ,只需要在 pom.xml 加如相关依赖即可。


<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0"         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>
<groupId>javapub.rodert.github</groupId> <artifactId>ssm_helloword_web</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <url></url><!-- 源码:https://github.com/Rodert/JavaPub-->
<properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <spring.version>4.3.6.RELEASE</spring.version> </properties>
<dependencies> <!-- 单元测试 --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> </dependency>
<!-- 1.日志 --> <!-- 实现slf4j接口并整合 --> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.1.1</version> </dependency>
<!-- 2.数据库 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.37</version> <scope>runtime</scope> </dependency> <dependency> <groupId>c3p0</groupId> <artifactId>c3p0</artifactId> <version>0.9.1.2</version> </dependency>
<!-- DAO: MyBatis --> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.3.0</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>1.2.3</version> </dependency>
<!-- 3.Servlet web --> <dependency> <groupId>taglibs</groupId> <artifactId>standard</artifactId> <version>1.1.2</version> </dependency> <dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.5.4</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> </dependency>
<!-- 4.Spring --> <!-- 1)Spring核心 --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <!-- 2)Spring DAO层 --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${spring.version}</version> </dependency> <!-- 3)Spring web --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <!-- 4)Spring test --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency>
<!-- redis客户端:Jedis --> <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>2.7.3</version> </dependency> <dependency> <groupId>com.dyuproject.protostuff</groupId> <artifactId>protostuff-core</artifactId> <version>1.0.8</version> </dependency> <dependency> <groupId>com.dyuproject.protostuff</groupId> <artifactId>protostuff-runtime</artifactId> <version>1.0.8</version> </dependency>
<!-- Map工具类 --> <dependency> <groupId>commons-collections</groupId> <artifactId>commons-collections</artifactId> <version>3.2</version> </dependency>
<!--注解--> <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok --> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.12</version> <scope>provided</scope> </dependency> </dependencies>

<build> <finalName>ssm_helloword_web</finalName> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>7</source> <target>7</target> </configuration> </plugin> </plugins> </build>
</project><!-- 源码:https://github.com/Rodert/JavaPub-->
复制代码


编码


配置文件

spring-dao.xml


  • 先在 spring 文件夹里新建 spring-dao.xml 文件,我们这里分三层,分别是 dao service web。


  1. 加载数据库配置

  2. 配置数据库连接池

  3. 配置 SqlSessionFactory 对象(MyBatis)

  4. 配置扫描 dao 层接口,动态代理实现 Dao 实现类,执行 sql 写在 xml


<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"       xsi:schemaLocation="http://www.springframework.org/schema/beans	http://www.springframework.org/schema/beans/spring-beans.xsd	http://www.springframework.org/schema/context	http://www.springframework.org/schema/context/spring-context.xsd">    <!-- 配置整合mybatis过程 -->    <!-- 1.配置数据库相关参数properties的属性:${url} -->
<context:property-placeholder location="classpath:jdbc.properties" />
<!-- 2.数据库连接池 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <!-- 配置连接池属性 --> <property name="driverClass" value="${jdbc.driver}" /> <property name="jdbcUrl" value="${jdbc.url}" /> <property name="user" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" />
<!-- c3p0连接池的私有属性 --> <property name="maxPoolSize" value="30" /> <property name="minPoolSize" value="10" /> <!-- 关闭连接后不自动commit --> <property name="autoCommitOnClose" value="false" /> <!-- 获取连接超时时间 --> <property name="checkoutTimeout" value="10000" /> <!-- 当获取连接失败重试次数 --> <property name="acquireRetryAttempts" value="2" /> </bean>
<!-- 3.配置SqlSessionFactory对象 --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <!-- 注入数据库连接池 --> <property name="dataSource" ref="dataSource" /> <!-- 配置MyBaties全局配置文件:mybatis-config.xml --> <property name="configLocation" value="classpath:Mybatis-config.xml" /> <!-- 扫描entity包 使用别名 --> <property name="typeAliasesPackage" value="javapub.rodert.github.entity" /> <!-- 扫描sql配置文件:mapper需要的xml文件 --> <property name="mapperLocations" value="classpath:mapper/*.xml" /> </bean>
<!-- 4.配置扫描Dao接口包,动态实现Dao接口,注入到spring容器中 --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <!-- 注入sqlSessionFactory --> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" /> <!-- 给出需要扫描Dao接口包 --> <property name="basePackage" value="javapub.rodert.github.dao" /> </bean></beans>
复制代码


jdbc.properties


数据库配置,在 resources 文件夹里新建一个 jdbc.properties 文件,注意自己的密码。


jdbc.driver=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://localhost:3306/ssm1?useUnicode=true&characterEncoding=utf8jdbc.username=rootjdbc.password=
复制代码


mybatis-config.xml


MyBatis 核心文件,在 recources 文件夹里新建 mybatis-config.xml 文件。


  1. 使用自增主键

  2. 使用列别名

  3. 开启驼峰命名转换 create_time -> createTime


<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE configuration        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration>    <!-- 配置全局属性 -->    <settings>        <!-- 使用jdbc的getGeneratedKeys获取数据库自增主键值 -->        <setting name="useGeneratedKeys" value="true" />
<!-- 使用列别名替换列名 默认:true --> <setting name="useColumnLabel" value="true" />
<!-- 开启驼峰命名转换:Table{create_time} -> Entity{createTime} --> <setting name="mapUnderscoreToCamelCase" value="true" /> </settings></configuration>
复制代码


spring-service.xml


在 spring 文件夹里新建 spring-service.xml 文件。


  1. 扫描 service 包所有注解 @Service

  2. 配置事务管理器,把事务管理交由 spring 来完成

  3. 基于注解的 声明式事务,可以直接在方法上 @Transaction


<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:context="http://www.springframework.org/schema/context"       xmlns:tx="http://www.springframework.org/schema/tx"       xsi:schemaLocation="http://www.springframework.org/schema/beans	http://www.springframework.org/schema/beans/spring-beans.xsd	http://www.springframework.org/schema/context	http://www.springframework.org/schema/context/spring-context.xsd	http://www.springframework.org/schema/tx	http://www.springframework.org/schema/tx/spring-tx.xsd">    <!-- 扫描service包下所有使用注解的类型 -->    <context:component-scan base-package="javapub.rodert.github.service" />
<!-- 配置事务管理器 --> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <!-- 注入数据库连接池 --> <property name="dataSource" ref="dataSource" /> </bean>
<!-- 配置基于注解的声明式事务 --> <tx:annotation-driven transaction-manager="transactionManager" /></beans>
复制代码


spring-web.xml


web 层,在 spring 文件夹里新建 spring-web.xml 文件。


  1. 开启 SpringMVC 注解模式,可以使用 @RequestMapping,@PathVariable,@ResponseBody 等

  2. 对静态资源处理,如 js,css,jpg 等

  3. 配置 jsp 显示 ViewResolver,及渲染后的 JSP

  4. 扫描 web 层 @Controller


<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:context="http://www.springframework.org/schema/context"       xmlns:mvc="http://www.springframework.org/schema/mvc"       xsi:schemaLocation="http://www.springframework.org/schema/beans	http://www.springframework.org/schema/beans/spring-beans.xsd	http://www.springframework.org/schema/context	http://www.springframework.org/schema/context/spring-context.xsd	http://www.springframework.org/schema/mvc	http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">    <!-- 配置SpringMVC -->    <!-- 1.开启SpringMVC注解模式 -->    <!-- 简化配置:        (1)自动注册DefaultAnootationHandlerMapping,AnotationMethodHandlerAdapter        (2)提供一些列:数据绑定,数字和日期的format @NumberFormat, @DateTimeFormat, xml,json默认读写支持    -->    <mvc:annotation-driven />
<!-- 2.静态资源默认servlet配置 (1)加入对静态资源的处理:js,gif,png (2)允许使用"/"做整体映射 --> <mvc:default-servlet-handler/>
<!-- 3.配置jsp 显示ViewResolver --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /><!-- <property name="contentType" value="text/html"/>--> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> </bean>
<!-- 4.扫描web相关的bean --> <context:component-scan base-package="javapub.rodert.github.web" /></beans>
复制代码


web.xml


修改 web.xml 文件了,它在 webapp 的 WEB-INF 下。也可以在这里配置过滤器、监听器等。


<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee                      http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"         version="3.1" metadata-complete="true">  <!-- 如果是用mvn命令生成的xml,需要修改servlet版本为3.1 -->  <!-- 配置DispatcherServlet -->  <servlet>    <servlet-name>dispatcherServlet</servlet-name>    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>    <!-- 配置springMVC需要加载的配置文件        spring-dao.xml,spring-service.xml,spring-web.xml        Mybatis - > spring -> springmvc     -->    <init-param>      <param-name>contextConfigLocation</param-name>      <param-value>classpath:spring/spring-*.xml</param-value>    </init-param>    <load-on-startup>1</load-on-startup>  </servlet>  <servlet-mapping>    <servlet-name>dispatcherServlet</servlet-name>    <!-- 默认匹配所有的请求 -->    <url-pattern>/</url-pattern>  </servlet-mapping>
<welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list></web-app>
复制代码


日志


配置一些简单的日志,使用 logback ,在 resources 文件夹里新建logback.xml 文件。


<?xml version="1.0" encoding="UTF-8"?><configuration debug="true">    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">        <!-- encoders are by default assigned the type ch.qos.logback.classic.encoder.PatternLayoutEncoder -->        <encoder>            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>        </encoder>    </appender>
<root level="debug"> <appender-ref ref="STDOUT" /> </root></configuration>
复制代码


配置说明


以上配置是整合 SSM 的基础配置,目录结构如图所示:





SSM 实例-图书管理系统


sql


以上部分整个 SSM 框架就已经搭建好了,下面是一个 Demo ,供参考。


新建俩张表,图书表 book 和 预约图书表 appointment,并初始化数据。


/*Navicat MySQL Data Transfer
Source Server : localhostSource Server Version : 50716Source Host : localhost:3306Source Database : ssm1
Target Server Type : MYSQLTarget Server Version : 50716File Encoding : 65001
Date: 2020-07-12 16:50:43*/
SET FOREIGN_KEY_CHECKS=0;
-- ------------------------------ Table structure for appointment-- ----------------------------DROP TABLE IF EXISTS `appointment`;CREATE TABLE `appointment` ( `book_id` bigint(20) NOT NULL COMMENT '图书ID', `student_id` bigint(20) NOT NULL COMMENT '学号', `appoint_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '预约时间', PRIMARY KEY (`book_id`,`student_id`), KEY `idx_appoint_time` (`appoint_time`)) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='预约图书表';
-- ------------------------------ Records of appointment-- ----------------------------
-- ------------------------------ Table structure for book-- ----------------------------DROP TABLE IF EXISTS `book`;CREATE TABLE `book` ( `book_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '图书ID', `name` varchar(100) NOT NULL COMMENT '图书名称', `number` int(11) NOT NULL COMMENT '馆藏数量', PRIMARY KEY (`book_id`)) ENGINE=InnoDB AUTO_INCREMENT=1004 DEFAULT CHARSET=utf8 COMMENT='图书表';
-- ------------------------------ Records of book-- ----------------------------INSERT INTO `book` VALUES ('2000', 'Java程序设计', '20');INSERT INTO `book` VALUES ('2001', '数据结构', '7');INSERT INTO `book` VALUES ('2002', '设计模式', '20');INSERT INTO `book` VALUES ('2003', '编译原理', '20');
复制代码


实体


entity 包下新建实体 BookAppointment


  • Book.java


package javapub.rodert.github.entity;
import lombok.Getter;import lombok.Setter;import lombok.ToString;
/** * @author wangshiyu rodert * @date 2020/7/6 20:58 * @description * * @Data 注解,简化代码,自动添加get set toSting 方法 * @Getter * @Setter * @ToString */@Getter@Setter@ToStringpublic class Book {
private long bookId;// 图书ID
private String name;// 图书名称
private int number;// 馆藏数量
// 省略构造方法,getter和setter方法,toString方法
}
复制代码


  • Appointment.java


package javapub.rodert.github.entity;
/** * @author wangshiyu rodert * @date 2020/7/6 20:58 * @description */
import lombok.Data;import lombok.Getter;import lombok.Setter;import lombok.ToString;
import java.util.Date;
/** * 预约图书实体 * @Data 注解,简化代码,自动添加get set toSting 方法 */@Datapublic class Appointment {
private long bookId;// 图书ID
private long studentId;// 学号
private Date appointTime;// 预约时间
// 多对一的复合属性 private Book book;// 图书实体
// 省略构造方法,getter和setter方法,toString方法
}
复制代码


dao 接口


dao包新建接口 BookDao.javaAppointment.java


  • BookDao.java


package javapub.rodert.github.dao;
/** * @author wangshiyu rodert * @date 2020/7/6 21:01 * @description */
import javapub.rodert.github.entity.Book;import org.apache.ibatis.annotations.Param;
import java.util.List;
public interface BookDao {
/** * 通过ID查询单本图书 * * @param id * @return */ Book queryById(long id);
/** * 查询所有图书 * * @param offset 查询起始位置 * @param limit 查询条数 * @return */ List<Book> queryAll(@Param("offset") int offset, @Param("limit") int limit);
/** * 减少馆藏数量 * * @param bookId * @return 如果影响行数等于>1,表示更新的记录行数 */ int reduceNumber(long bookId);}
复制代码


  • AppointmentDao.java


package javapub.rodert.github.dao;
/** * @author wangshiyu rodert * @date 2020/7/6 21:01 * @description */
import javapub.rodert.github.entity.Appointment;import org.apache.ibatis.annotations.Param;
public interface AppointmentDao {
/** * 插入预约图书记录 * * @param bookId * @param studentId * @return 插入的行数 */ int insertAppointment(@Param("bookId") long bookId, @Param("studentId") long studentId);
/** * 通过主键查询预约图书记录,并且携带图书实体 * * @param bookId * @param studentId * @return */ Appointment queryByKeyWithBook(@Param("bookId") long bookId, @Param("studentId") long studentId);
}
复制代码


提示:这里为什么要给方法的参数添加 @Param注解呢?是因为该方法有两个或以上的参数,一定要加,不然 mybatis 识别不了。上面的 BookDao 接口的 queryById 方法和 reduceNumber 方法只有一个参数 book_id ,所以可以不用加 @Param 注解。




dao 接口 xml


这里不需要写 dao接口 的实现类,mybatis 会帮我们动态实现,上面我们已经在 spring-dao.xml 配置了动态扫描。现在需要编写相应的 mapper

mapper 目录里新建两个文件 BookDao.xmlAppointmentDao.xml ,分别对应上面两个 dao 接口。


  • BookDao.xml


<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="javapub.rodert.github.dao.BookDao">    <!-- 目的:为dao接口方法提供sql语句配置 -->    <select id="queryById" resultType="Book" parameterType="long">        <!-- 具体的sql -->        SELECT        book_id,        name,        number        FROM        book        WHERE        book_id = #{bookId}    </select>
<select id="queryAll" resultType="Book"> SELECT book_id, name, number FROM book ORDER BY book_id LIMIT #{offset}, #{limit} </select>
<update id="reduceNumber"> UPDATE book SET number = number - 1 WHERE book_id = #{bookId} AND number > 0 </update></mapper>
复制代码


  • AppointmentDao.xml


<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapper        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="javapub.rodert.github.dao.AppointmentDao">    <insert id="insertAppointment">        <!-- ignore 主键冲突,报错 -->        INSERT ignore INTO appointment (book_id, student_id)        VALUES (#{bookId}, #{studentId})    </insert>
<select id="queryByKeyWithBook" resultType="Appointment"> <!-- 如何告诉MyBatis把结果映射到Appointment同时映射book属性 --> <!-- 可以自由控制SQL --> SELECT a.book_id, a.student_id, a.appoint_time, b.book_id "book.book_id", b.`name` "book.name", b.number "book.number" FROM appointment a INNER JOIN book b ON a.book_id = b.book_id WHERE a.book_id = #{bookId} AND a.student_id = #{studentId} </select></mapper>
复制代码


mapper 说明namespace 是 xml 对应的接口全名,selectupdate 中的 id 对应方法名(唯一),resultType 是返回值类型,parameterType 是参数类型(这个其实可选),#{...} 中填写的是方法的参数




dao 接口测试


现在的写法是从数据库层向前(web)写,现在测试一下 dao 接口,编写测试类。


因为每次测试都要加载配置文件,所有抽离一个类(BaseTest),每次测试方法都继承它。


  • BaseTest.java


package javapub.rodert.github;
/** * @author wangshiyu rodert * @date 2020/7/6 21:07 * @description */
import org.junit.runner.RunWith;import org.springframework.test.context.ContextConfiguration;import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
/** * 配置spring和junit整合,junit启动时加载springIOC容器 spring-test,junit */@RunWith(SpringJUnit4ClassRunner.class)// 告诉junit spring配置文件@ContextConfiguration({ "classpath:spring/spring-dao.xml", "classpath:spring/spring-service.xml" })public class BaseTest {
}
复制代码


新建 BookDaoTest.javaAppointmentDaoTest.java 两个 dao 测试文件。


  • BookDao.java


package javapub.rodert.github.dao;
/** * @author wangshiyu rodert * @date 2020/7/6 21:08 * @description */

import javapub.rodert.github.BaseTest;import javapub.rodert.github.entity.Book;import org.junit.Test;import org.springframework.beans.factory.annotation.Autowired;
import java.util.List;
public class BookDaoTest extends BaseTest {
@Autowired private BookDao bookDao;
@Test public void testQueryById() throws Exception { long bookId = 1000; Book book = bookDao.queryById(bookId); System.out.println(book); }
@Test public void testQueryAll() throws Exception { List<Book> books = bookDao.queryAll(0, 4); for (Book book : books) { System.out.println(book); } }
@Test public void testReduceNumber() throws Exception { long bookId = 1000; int update = bookDao.reduceNumber(bookId); System.out.println("update=" + update); }
}
复制代码


  • AppointmentDaoTest.java


package javapub.rodert.github.dao;
/** * @author wangshiyu rodert * @date 2020/7/6 21:18 * @description */

import javapub.rodert.github.BaseTest;import javapub.rodert.github.entity.Appointment;import org.junit.Test;import org.springframework.beans.factory.annotation.Autowired;
public class AppointmentDaoTest extends BaseTest {
@Autowired private AppointmentDao appointmentDao;
@Test public void testInsertAppointment() throws Exception { long bookId = 1000; long studentId = 12345678910L; int insert = appointmentDao.insertAppointment(bookId, studentId); System.out.println("insert=" + insert); }
@Test public void testQueryByKeyWithBook() throws Exception { long bookId = 1000; long studentId = 12345678910L; Appointment appointment = appointmentDao.queryByKeyWithBook(bookId, studentId); System.out.println(appointment); System.out.println(appointment.getBook()); }
}
复制代码


  • BookDaoTest.java -- > testQueryById()



测试方法都验证过,没有问题,不一一测试了




业务层-结果集封装


到这里,我们的 dao 层,及数据库接口操作都没有问题,下面开始业务层编写。


如果你有实战项目经验,那一定会发现,对于后端接口,我们都会定义一个统一的返回格式,及定义一个返回标准方便前端解析,如下:


{	"code":200,	"message":"成功",	"result":{},	"isSuccess":true}
复制代码


开始写我们的代码,新建枚举类,用来定义预约业务的数据字典。如果不太明白,先看代码,后面在 JavaPub 微信公众号文章索引中查找对应文章。


新建一个包叫 enums,在里面新建一个枚举类 AppointStateEnum.java


  • AppointStateEnum.java


package javapub.rodert.github.enums;
/** * @author wangshiyu rodert * @date 2020/7/6 21:20 * @description */

/** * 使用枚举表述常量数据字典 */public enum AppointStateEnum {
SUCCESS(1, "预约成功"), NO_NUMBER(0, "库存不足"), REPEAT_APPOINT(-1, "重复预约"), INNER_ERROR(-2, "系统异常");
private int state;
private String stateInfo;
private AppointStateEnum(int state, String stateInfo) { this.state = state; this.stateInfo = stateInfo; }
public int getState() { return state; }
public String getStateInfo() { return stateInfo; }
public static AppointStateEnum stateOf(int index) { for (AppointStateEnum state : values()) { if (state.getState() == index) { return state; } } return null; }
}
复制代码


dto 包下新建 AppointExecution.java 用来存储我们执行预约操作的返回结果。


  • AppointExecution.java


package javapub.rodert.github.dto;
/** * @author wangshiyu rodert * @date 2020/7/7 16:26 * @description */

import javapub.rodert.github.entity.Appointment;import javapub.rodert.github.enums.AppointStateEnum;import lombok.Data;
/** * 封装预约执行后结果 */@Datapublic class AppointExecution {
// 图书ID private long bookId;
// 秒杀预约结果状态 private int state;
// 状态标识 private String stateInfo;
// 预约成功对象 private Appointment appointment;
public AppointExecution() { }
// 预约失败的构造器 public AppointExecution(long bookId, AppointStateEnum stateEnum) { this.bookId = bookId; this.state = stateEnum.getState(); this.stateInfo = stateEnum.getStateInfo(); }
// 预约成功的构造器 public AppointExecution(long bookId, AppointStateEnum stateEnum, Appointment appointment) { this.bookId = bookId; this.state = stateEnum.getState(); this.stateInfo = stateEnum.getStateInfo(); this.appointment = appointment; }
// 省略getter和setter方法,toString方法
}
复制代码


exception 包下新建三个文件


NoNumberException.java

RepeatAppointException.java

AppointException.java


预约业务异常类(都需要继承 RuntimeException ---运行时异常类),分别是无库存异常、重复预约异常、预约未知错误异常,用于业务层非成功情况下的返回(即成功返回结果,失败抛出异常)。为事务做准备。


  • AppointException.java


package javapub.rodert.github.exception;
/** * @author wangshiyu rodert * @date 2020/7/7 16:31 * @description */
/** * 预约业务异常 */public class AppointException extends RuntimeException {
public AppointException(String message) { super(message); }
public AppointException(String message, Throwable cause) { super(message, cause); }
}
复制代码


  • NoNumberException.java


/** * @author wangshiyu rodert * @date 2020/7/7 16:30 * @description */package javapub.rodert.github.exception;
/** * 库存不足异常 */public class NoNumberException extends RuntimeException {
public NoNumberException(String message) { super(message); }
public NoNumberException(String message, Throwable cause) { super(message, cause); }
}
复制代码


  • RepeatAppointException.java



/** * @author wangshiyu rodert * @date 2020/7/7 16:31 * @description */package javapub.rodert.github.exception;
/** * 重复预约异常 */public class RepeatAppointException extends RuntimeException {
public RepeatAppointException(String message) { super(message); }
public RepeatAppointException(String message, Throwable cause) { super(message, cause); }
}
复制代码


Service 业务接口代码


在 service 包下新建 BookService.java 图书业务接口。


  • BookService.java



/** * @author wangshiyu rodert * @date 2020/7/7 16:32 * @description */package javapub.rodert.github.service;

import javapub.rodert.github.dto.AppointExecution;import javapub.rodert.github.entity.Book;
import java.util.List;
/** * 业务接口:站在"使用者"角度设计接口 三个方面:方法定义粒度,参数,返回类型(return 类型/异常) */public interface BookService {
/** * 查询一本图书 * * @param bookId * @return */ Book getById(long bookId);
/** * 查询所有图书 * * @return */ List<Book> getList();
/** * 预约图书 * * @param bookId * @param studentId * @return */ AppointExecution appoint(long bookId, long studentId);
}
复制代码


service.impl 包下新建 BookServiceImpl.java 使用 BookService 接口,并实现里面的方法。


  • BookServiceImpl.java




/** * @author wangshiyu rodert * @date 2020/7/7 16:39 * @description */package javapub.rodert.github.service.impl;

import javapub.rodert.github.dao.AppointmentDao;import javapub.rodert.github.dao.BookDao;import javapub.rodert.github.dto.AppointExecution;import javapub.rodert.github.entity.Appointment;import javapub.rodert.github.entity.Book;import javapub.rodert.github.enums.AppointStateEnum;import javapub.rodert.github.exception.AppointException;import javapub.rodert.github.exception.NoNumberException;import javapub.rodert.github.exception.RepeatAppointException;import javapub.rodert.github.service.BookService;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;
import java.util.List;
@Servicepublic class BookServiceImpl implements BookService {
private Logger logger = LoggerFactory.getLogger(this.getClass());
// 注入Service依赖 @Autowired private BookDao bookDao;
@Autowired private AppointmentDao appointmentDao;

@Override public Book getById(long bookId) { return bookDao.queryById(bookId); }
@Override public List<Book> getList() { return bookDao.queryAll(0, 1000); }
@Override @Transactional /** * 使用注解控制事务方法的优点: * 1.开发团队达成一致约定,明确标注事务方法的编程风格 * 2.保证事务方法的执行时间尽可能短,不要穿插其他网络操作,RPC/HTTP请求或者剥离到事务方法外部 * 3.不是所有的方法都需要事务,如只有一条修改操作,只读操作不需要事务控制 */ public AppointExecution appoint(long bookId, long studentId) { try { // 减库存 int update = bookDao.reduceNumber(bookId); if (update <= 0) {// 库存不足 //return new AppointExecution(bookId, AppointStateEnum.NO_NUMBER);//错误写法 throw new NoNumberException("no number");// 抛出异常,保证触发事务执行 } else { // 执行预约操作 int insert = appointmentDao.insertAppointment(bookId, studentId); if (insert <= 0) {// 重复预约 //return new AppointExecution(bookId, AppointStateEnum.REPEAT_APPOINT);//错误写法 throw new RepeatAppointException("repeat appoint"); } else {// 预约成功 Appointment appointment = appointmentDao.queryByKeyWithBook(bookId, studentId); return new AppointExecution(bookId, AppointStateEnum.SUCCESS, appointment); } } // 要先于catch Exception异常前先catch住再抛出,不然自定义的异常也会被转换为AppointException,导致控制层无法具体识别是哪个异常 } catch (NoNumberException | RepeatAppointException e1) { throw e1; } catch (Exception e) { logger.error(e.getMessage(), e); // 所有编译期异常转换为运行期异常 //return new AppointExecution(bookId, AppointStateEnum.INNER_ERROR);//错误写法 throw new AppointException("appoint inner error:" + e.getMessage()); } }
}
复制代码


实现类使用了我们上边定义的异常方法 RepeatAppointException ,用于业务层非成功情况下的返回(即成功返回结果,失败抛出异常)。触发事务。




测试一下业务层代码,这里演示预约图书业务。


  • BookServiceImplTest.java



/** * @author wangshiyu rodert * @date 2020/7/7 16:40 * @description */package javapub.rodert.github.service.impl;

import javapub.rodert.github.BaseTest;import javapub.rodert.github.dto.AppointExecution;import javapub.rodert.github.service.BookService;import org.junit.Test;import org.springframework.beans.factory.annotation.Autowired;
public class BookServiceImplTest extends BaseTest {
@Autowired private BookService bookService;
@Test public void testAppoint() throws Exception { long bookId = 1001; long studentId = 12345678910L; AppointExecution execution = bookService.appoint(bookId, studentId); System.out.println(execution); }
}
复制代码


测试结果:



首次执行是“预约成功”,如果再次执行的话,应该会出现“重复预约”,至此,我们所有的后台代码都通过单元测试啦~~ 是不是很开心~




咱们还需要在 dto 包里新建一个封装 json 返回结果的类 Result.java,设计成泛型。


  • Result.java


package javapub.rodert.github.dto;
/** * @author wangshiyu rodert * @date 2020/7/7 21:00 * @description */
import lombok.Data;
/** * 封装json对象,所有返回结果都使用它 */@Datapublic class Result<T> {
private boolean success;// 是否成功标志
private T data;// 成功时返回的数据
private String error;// 错误信息
public Result() { }
// 成功时的构造器 public Result(boolean success, T data) { this.success = success; this.data = data; }
// 错误时的构造器 public Result(boolean success, String error) { this.success = success; this.error = error; }
// 省略getter和setter方法 使用注解代替}
复制代码


web 层


web 层,也就是 controller 层,我们在 web 包下新建 BookController.java 文件。


  • BookController.java


package javapub.rodert.github.web;
/** * @author wangshiyu rodert * @date 2020/7/7 21:05 * @description */

import javapub.rodert.github.dto.AppointExecution;import javapub.rodert.github.dto.Result;import javapub.rodert.github.entity.Book;import javapub.rodert.github.enums.AppointStateEnum;import javapub.rodert.github.exception.NoNumberException;import javapub.rodert.github.exception.RepeatAppointException;import javapub.rodert.github.service.BookService;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.*;import org.springframework.web.servlet.ModelAndView;
import java.util.List;
@RestController@RequestMapping("/book") // url:/模块/资源/{id}/细分 /seckill/listpublic class BookController {
private Logger logger = LoggerFactory.getLogger(this.getClass());
@Autowired private BookService bookService;
@RequestMapping(value = "/test") public ModelAndView test(){ ModelAndView modelAndView = new ModelAndView(); modelAndView.setViewName("book/test"); modelAndView.addObject("key","welcome javaPub"); return modelAndView; }
@RequestMapping(value = "/list", method = RequestMethod.GET) private String list(Model model) { List<Book> list = bookService.getList(); model.addAttribute("list", list); // list.jsp + model = ModelAndView return "list";// WEB-INF/jsp/"list".jsp }
@RequestMapping(value = "/{bookId}/detail", method = RequestMethod.GET) private String detail(@PathVariable("bookId") Long bookId, Model model) { if (bookId == null) { return "redirect:/book/list"; } Book book = bookService.getById(bookId); if (book == null) { return "forward:/book/list"; } model.addAttribute("book", book); return "detail"; }
//ajax json //method = RequestMethod.POST, @RequestMapping(value = "/{bookId}/appoint", produces = { "application/json; charset=utf-8" }) @ResponseBody private Result<AppointExecution> appoint(@PathVariable("bookId") Long bookId, @RequestParam("studentId") Long studentId) { if (studentId == null || studentId.equals("")) { return new Result<>(false, "学号不能为空"); } //AppointExecution execution = bookService.appoint(bookId, studentId);//错误写法,不能统一返回,要处理异常(失败)情况 AppointExecution execution = null; try { execution = bookService.appoint(bookId, studentId); } catch (NoNumberException e1) { execution = new AppointExecution(bookId, AppointStateEnum.NO_NUMBER); } catch (RepeatAppointException e2) { execution = new AppointExecution(bookId, AppointStateEnum.REPEAT_APPOINT); } catch (Exception e) { execution = new AppointExecution(bookId, AppointStateEnum.INNER_ERROR); } return new Result<AppointExecution>(true, execution); }
}
复制代码


目前大多项目都是前后端分离,我们作为服务端,一般和前端通过接口数据交互(json),像接口方法 appoint ,应该添加 @ResponseBody 注解。

测试 controller --> appoint 方法可以通过 curl ,如:


curl -H “Accept: application/json; charset=utf-8” -d “studentId=1234567890” localhost:8080/book/1003/appoint


运行项目


现在整个项目全部完成,配置 tomcat,通过左上角引入 tomcat ,选择我们的项目 ssm。



启动成功后:



这里对前端代码只写较少部分,具体可参考 BookController --> book/test 接口,有需要帮助请留言。


  • BookController.java --> book/test


    @RequestMapping(value = "/test")    public ModelAndView test(){        ModelAndView modelAndView = new ModelAndView();        modelAndView.setViewName("book/test");        modelAndView.addObject("key","welcome javaPub");        return modelAndView;    }
复制代码


  • test.jsp


<%@ page language="java" contentType="text/html; charset=UTF-8"         pageEncoding="UTF-8"%>
<!DOCTYPE HTML><html><head> <%@ page isELIgnored="false"%> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0,maximum-scale=1.0,user-scalable=no"/> <title>news detail</title>
</head><body class="fn-pd24"><h1>大家好 ${key}</h1>
<a href="https://mp.weixin.qq.com/s/kfyRAPnRDp8LLktjgd658Q">JavaPub知识清单</a></body></html>
复制代码


通过 ModelAndView 将我们需要渲染的数据存储传输到对应视图,由 Sping MVC 定义好的视图解析器对该对象解析,最后将结果数据显示到指定页面。



完整代码地址:https://github.com/Rodert/JavaPub/code/ssmhelloworldweb/


最后:知识点总结


文章底部都有对应原创 PDF,持续更新中,

教程纯手打,致力于最实用教程,微信搜:JavaPub ,无套路领取免费原创 PDF 、学习路线图,后台回复【666】。



觉得文章内容不错,记得点赞或在看都行,这是对我最大的鼓励!


发布于: 2020 年 07 月 12 日阅读数: 189
用户头像

JavaPub

关注

原创技术公众号:JavaPub 2018.12.02 加入

原创技术公众号:JavaPub | 限时免费领取原创PDF

评论

发布
暂无评论
手把手整合SSM框架