SSM框架——整合ssm

SSM整合

1.准备工作

新建一个普通的Maven项目

建好所有需要的架构层

向pom.xml中导入所有的依赖

<!--MyBatis相关-->
<dependency>
   <groupId>com.mchange</groupId>
   <artifactId>c3p0</artifactId>
   <version>0.9.5.2</version>
</dependency>
<dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>5.1.47</version>
</dependency>
<dependency>
   <groupId>org.mybatis</groupId>
   <artifactId>mybatis</artifactId>
   <version>3.5.2</version>
</dependency>
<dependency>
   <groupId>org.mybatis</groupId>
   <artifactId>mybatis-spring</artifactId>
   <version>2.0.2</version>
</dependency>
<!--Spring相关-->
<dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-webmvc</artifactId>
   <version>5.1.9.RELEASE</version>
</dependency>
<dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-jdbc</artifactId>
   <version>5.1.9.RELEASE</version>
</dependency>
<!--Web相关-->
<dependency>
   <groupId>javax.servlet</groupId>
   <artifactId>servlet-api</artifactId>
   <version>2.5</version>
</dependency>
<dependency>
   <groupId>javax.servlet.jsp</groupId>
   <artifactId>jsp-api</artifactId>
   <version>2.2</version>
</dependency>
<dependency>
   <groupId>javax.servlet</groupId>
   <artifactId>jstl</artifactId>
   <version>1.2</version>
</dependency>
<!--插件-->
<dependency>
   <groupId>junit</groupId>
   <artifactId>junit</artifactId>
   <version>4.13.2</version>
</dependency>
<dependency>
   <groupId>org.projectlombok</groupId>
   <artifactId>lombok</artifactId>
   <version>1.18.12</version>
   <scope>provided</scope>
</dependency>

尝试在idea内连接数据库

2.配置MyBatis层

• 编写ORM实体类

package mycode.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @classname
 * @Author 姬如千泷
 * @Date 2021/7/25  23:01
 * @Version 1.0
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Book {
    private int bookID;
    private String bookName;
    private int bookCounts;
    private String detail;
}

• 编写dao层业务接口（为简便，以一个举例）

package mycode.dao;

import mycode.pojo.Book;

import java.util.List;

/**
 * @classname
 * @Author 姬如千泷
 * @Date 2021/7/25  23:03
 * @Version 1.0
 */
public interface BookMapper {
    //获取全部书籍信息
    List<Book> getBooks();
}

• 编写Mapper.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="mycode.dao.BookMapper">
    <select id="getBooks" resultType="mycode.pojo.Book">
        SELECT * from ssmbuild.books
    </select>
</mapper>

• 编写登录.properties文件

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/ssmbuild?useUnicode=true&characterEncoding=utf8&useSSL=false&severTimezone=GMT%2B8&allowPublicKeyRetrieval=true
username=root
password=123456

• 编写Mybatis-config.xml

<?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>
    <mappers>
        <mapper resource="mycode/dao/BookMapper.xml"/>
    </mappers>
</configuration>

3. 配置Spring层

• 编写业务抽象接口，只是为了给代理类提供接口

package mycode.service;

import mycode.pojo.Book;

import java.util.List;

/**
 * @classname
 * @Author 姬如千泷
 * @Date 2021/7/25  23:35
 * @Version 1.0
 */
public interface BookService {
    List<Book> getBooks();
}

• 编写服务代理类

package mycode.service;

import mycode.dao.BookMapper;
import mycode.pojo.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @classname
 * @Author 姬如千泷
 * @Date 2021/7/25  23:36
 * @Version 1.0
 */
@Service
public class BookImpl implements BookService{
    private BookMapper mapper;

    public void setBookMapper(BookMapper bookMapper) {
        this.mapper = bookMapper;
    }

    @Override
    public List<Book> getBooks() {
        return mapper.getBooks();
    }
}

• 编写spring-dao.xml,用spring对接数据库连接

<?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
       https://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 配置整合mybatis -->
    <!-- 1.关联数据库文件 -->
    <context:property-placeholder location="classpath:resources/database.properties"/>

    <!-- 2.数据库连接池 -->
    <!--数据库连接池
        dbcp 半自动化操作 不能自动连接
        c3p0 自动化操作（自动的加载配置文件 并且设置到对象里面）
    -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 配置连接池属性 -->
        <property name="driverClass" value="${driver}"/>
        <property name="jdbcUrl" value="${url}"/>
        <property name="user" value="${username}"/>
        <property name="password" value="${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:resources/mybatis-config.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 -->
    <!--解释 ：https://www.cnblogs.com/jpfss/p/7799806.html-->
    <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="mycode.dao"/>
    </bean>

</beans>

• 编写spring-service.xml,用spring对接dao层服务和事务

<?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">

    <!-- 扫描service相关的bean -->
    <context:component-scan base-package="mycode.service" />

    <!--BookServiceImpl注入到IOC容器中-->
    <bean id="BookImpl" class="mycode.service.BookImpl">
        <property name="bookMapper" ref="bookMapper"/>
    </bean>

    <!-- 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>

</beans>

4.配置Spring-MVC层（注解实现）

• 将maven项目升级为web项目

• 编写spring-mvc.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"
       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
   https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 配置SpringMVC -->
    <!-- 1.开启SpringMVC注解驱动 -->
    <mvc:annotation-driven />
    <!-- 2.静态资源默认servlet配置-->
    <mvc:default-servlet-handler/>

    <!-- 3.配置jsp 显示ViewResolver视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/WEB-INF/" />
        <property name="suffix" value=".jsp" />
    </bean>

    <!-- 4.扫描web相关的bean -->
    <context:component-scan base-package="mycode.controller" />

</beans>

• 编写applicationContext.xml整合xml配置

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

• 配置web.xml

<?xml version="1.0" encoding="UTF-8"?>
<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_4_0.xsd"
         version="4.0">

    <!--配置DispatcherServlet-->
    <servlet>
        <servlet-name>DispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!--加载总的配置文件-->
            <param-value>classpath:resources/applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <!--mvc过滤器-->
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>
            org.springframework.web.filter.CharacterEncodingFilter
        </filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!--Session过期时间-->
    <session-config>
        <session-timeout>15</session-timeout>
    </session-config>

</web-app>

到这里基本配置就已经完成了，只需要再对接一下前端就可以了

5. 一个业务实例（取自狂神说java）

• 首页jsp页面

<%--
  Created by IntelliJ IDEA.
  User: 姬如千泷
  Date: 2021/7/26
  Time: 0:24
  To change this template use File | Settings | File Templates.
--%>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE HTML>
<html>
<head>
  <title>首页</title>
  <style type="text/css">
    a {
      text-decoration: none;
      color: black;
      font-size: 18px;
    }
    h3 {
      width: 180px;
      height: 38px;
      margin: 100px auto;
      text-align: center;
      line-height: 38px;
      background: deepskyblue;
      border-radius: 4px;
    }
  </style>
</head>
<body>

<h3>
  <a href="${pageContext.request.contextPath}/allBook">点击进入列表页</a>
</h3>
</body>
</html>

• 跳转jsp页面

<%--
  Created by IntelliJ IDEA.
  User: 姬如千泷
  Date: 2021/7/26
  Time: 0:33
  To change this template use File | Settings | File Templates.
--%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>书籍列表</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- 引入 Bootstrap -->
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>

<div class="container">

    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    <small>书籍列表 —— 显示所有书籍</small>
                </h1>
            </div>
        </div>
    </div>

    <div class="row">
        <div class="col-md-4 column">
        </div>
    </div>

    <div class="row clearfix">
        <div class="col-md-12 column">
            <table class="table table-hover table-striped">
                <thead>
                <tr>
                    <th>书籍编号</th>
                    <th>书籍名字</th>
                    <th>书籍数量</th>
                    <th>书籍详情</th>
                    <th>操作</th>
                </tr>
                </thead>

                <tbody>
                <c:forEach var="book" items="${requestScope.get('list')}">
                    <tr>
                        <td>${book.getBookID()}</td>
                        <td>${book.getBookName()}</td>
                        <td>${book.getBookCounts()}</td>
                        <td>${book.getDetail()}</td>

                    </tr>
                </c:forEach>
                </tbody>
            </table>
        </div>
    </div>
</div>

• 编写控制类

package mycode.controller;

import mycode.pojo.Book;
import mycode.service.BookService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

/**
 * @classname
 * @Author 姬如千泷
 * @Date 2021/7/26  0:29
 * @Version 1.0
 */
@Controller
public class BookController {
    @Autowired
    @Qualifier("BookImpl")
    private BookService bookService;

    @RequestMapping("/allBook")//代表入口url
    public String list(Model model) {
        List<Book> list = bookService.getBooks();
        model.addAttribute("list", list);

        return "allBook";
    }
}

• 配置tomcat启动项目

6. 可能出现的问题

6.1 java代码变成.java不可执行文件

这说明项目的资源路径配置是存在问题的，我在开发过程中这种问题出现了不下3次，一般如果不及时处理，会报出io错误找不到xml配置文件

解决办法是重新配置资源路径

删除掉原有的资源路径配置

在新建一个即可，一般idea会重新智能匹配资源类型，如果没有自动匹配的话，重新为每一个文件选择对应类型即可

6.2 无法启动tomcat

可能是war包缺失导致，tomcat的war包是项目输出的主要包，必须提前配置好

用idea的Fix自动修复war包

或者自己新建一个war包

加入war包后，依然无法启动的话，检测out输出项目中是否含有lib目录，如果没有，则加入

将依赖全都导入进去

6.3 无法连接数据库问题（即错误中出现jdbc关键字的大部分错）

可能是由于.properties文件的编码问题导致，可以明显在错误中看到root用户名乱码

Access denied for user '姬如�泷'@'local......

解决方案一是直接不使用properties导入，明文，但这样安全系数低一些

<property name="driverClass" value="com.mysql.jdbc.Driver"/>
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/ssmbuild?useUnicode=true&amp;characterEncoding=utf8&amp;useSSL=false&amp;severTimezone=GMT%2B8&amp;allowPublicKeyRetrieval=true"/>
<property name="user" value="root"/>
<property name="password" value="123456"/>

解决方案二是在idea中设置Properties的编码方式，设置为和idea编码格式一致，一般是utf-8

6.4 如果报错文件指向mapper.xml，那么一般是sql语句出了错误，这时候一般会检查返回类型（如果是返回集合的话，返回值类型要设置为集合元素的类型）、参数类型（多个参数要加@Param注解等）

6.5 如果报一些资源未找到问题

先检测输出文件中有没有对应资源，如xml文件、Properties文件等，如果项目中有，而实际输出文件中没有的话，极有可能是文件被过滤了，这时候需要在pom.xml中设置文件过滤器跳过哪些文件

<build>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.xml</include>
                <include>**/*.properties</include>
            </includes>
            <filtering>false</filtering>
        </resource>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.xml</include>
                <include>**/*.properties</include>
            </includes>
            <filtering>false</filtering>
        </resource>
    </resources>
</build>