SSM整合

1、环境要求以及JAR包导入

环境要求

jdk1.8
maven3.6.1
tomcat9
mysql8

jar导入

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.18</version>
    </dependency>
    <dependency>
        <groupId>com.mchange</groupId>
        <artifactId>c3p0</artifactId>
        <version>0.9.5.5</version>
    </dependency>

    <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>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.3</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
        <version>2.0.3</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.2.3.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.2.3.RELEASE</version>
    </dependency>
</dependencies>

其他设置

<!--2.资源过滤以及其他配置-->
    <build>
    <!--1,资源过滤-->
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    <!--相关插件导入 -->
        <!--设置编译器,以及字节码的版本-->
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

2、Dao层整合

步骤

在resources目录下创建连接数据库的外部配置文件db.properties

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/stx?useSSL=true&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
jdbc.username=root
jdbc.password=root

在resources目录下创建mybatis主配置文件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>
    <typeAliases>
        <package name="com.stx.pojo"/>
    </typeAliases>
    <mappers>
        <package name="com.stx.mapper"/>
    </mappers>
</configuration>

在resources目录下创建mybatis，mapper映射文件存放文件夹

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.lehu.dao.UserMapper">
    <select id="getAll" resultType="T_user">
        select * from t_user
    </select>
</mapper>

在resources目录下创建spring-dao.xml配置文件来整合dao层

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">
    <!-- 1.导入连接数据库的配置文件-->
    <context:property-placeholder location="classpath:db.properties"/>
    <!--2.创建数据库连接池对象-->
    <bean class="org.springframework.jdbc.datasource.DriverManagerDataSource"                    name="dataSource">
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
    <!--3.获取SqlSessionFactoryBean对象->
    <bean class="org.mybatis.spring.SqlSessionFactoryBean" name="sqlSessionFactory">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:/mybatis/UserMapper.xml"/>
    </bean>
    <!--4.1.方法1:配置dao/mapper接口扫描包,动态的实现Dao接口注入到spring容器中-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer" id="configurer">
        <!--注入SqlSessionFactory-->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!--扫描dao/mapper包-->
        <property name="basePackage" value="com.stx.dao"/>
    </bean>
    <!--4.2.方法2.使用SqlSessionTemplate-->
    <!--    <bean class="org.mybatis.spring.SqlSessionTemplate" name="SqlSession">-->
    <!--        <constructor-arg ref="sqlSessionFactory"/>-->
    <!--    </bean>-->
    <!--注册使用SqlSessionTemplate完成相关操作的对象-->
    <!--    <bean class="..." id="mapper">-->
    <!--        <property name="sessionTemplate" ref="SqlSession"/>-->
    <!--    </bean>-->
</beans>

在com.stx.pojo中创建对应实体类

3、Service层整合

步骤

在com.stx.service分别编写UserService接口以及对应的实现类

接口

package com.stx.service;

import com.stx.pojo.User;

import java.util.List;
@Service
public interface UserService {
    List<User> getAll();
}

实现类

package com.stx.service;

import com.stx.pojo.User;

import java.util.List;
@Service
public class UserServiceImp implements UserService {
    @Override
    public List<User> getAll() {
        return null;
    }
}

在resources目录下编写spring-service.xml文件整合service层，将Service层对象交给spring容器托管

<?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">

    <context:component-scan base-package="com.stx.service"/>
</beans>

使用注解的方式将service层接口交给容器托管，需要在service层接口/类上加上@Service注解，接口实现类使用@Autowired注解引用Dao层对象

package com.stx.service;

import com.stx.dao.UserMapper;
import com.stx.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
@Service
public class UserServiceImp implements UserService {
    @Autowired
    UserMapper userMapper;
    @Override
    public List<User> getAll() {
        return userMapper.getAll();
    }

}

注意

dao层引入对象创建失败问题

六月 17, 2020 4:56:10 下午 org.springframework.context.support.AbstractApplicationContext refresh
警告: Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userServiceImp': Unsatisfied dependency expressed through field 'userMapper'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.stx.dao.UserMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

这是因为service层对象使用@Autowired注解引用dao层对象时，无法在spring-service.xml找到dao层对象实例，只需要将spring-dao.xml和spring-service关联起来即可，在spring-service.xml中使用<import resource="spring-dao.xml"/>引入spring-dao.xml的所有配置信息。

4、Controller层整合

步骤

创建spring-mvc.xml配置文件

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

    <!--1.导入mvc独用的注解驱动,不用导入普通的<context:annotation-config/>-->
    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <!--设置使用Jackson方式来转换json格式，使用前提是必须导入Jackson这个依赖-->
<!--            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">-->
<!--                <property name="objectMapper">-->
<!--                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">-->
<!--                        <property name="failOnEmptyBeans" value="false"/>-->
<!--                    </bean>-->
<!--                </property>-->
<!--            </bean>-->
        </mvc:message-converters>
    </mvc:annotation-driven>
    <!--2.对静态的资源进行过滤-->
    <mvc:default-servlet-handler/>
    <!--3.扫描进行注解配置装配的包-->
    <context:component-scan base-package="com.stx.controller"/>
    <!--4.导入视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" >
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
        <!--配置文件类型解析器-->
    <bean id="multipartResolver"             class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxInMemorySize" value="10485760"/>
    </bean>
</beans>

将所有的spring配置文件整合到applicaitonContex.xml中

<?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>

在web.xml中配置前端控制器DispatcherServlet

<?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">
    <!--0.配置applicationContext上下文加载监听器-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <!--1.配置DisPatcherServlet分发器-->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <!--2.设置过滤器:解决乱码问题-->
    <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>
    <!--配置Session过期时间-->
    <session-config>
        <session-timeout>14</session-timeout>
    </session-config>
</web-app>

编写相关Controller实现类

package com.stx.controller;

import com.stx.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class Test01 {
    @Autowired
    UserService userService;
    @RequestMapping("/hi")
    String h1() {
        return "hello 双体系";
    }
    @RequestMapping("/getusers")
    String getUsers() {
        return userService.getAll().toString();
    }
}

配置tomcat

运行测试

注意

必须在spring-mvc.xml配置文件中加入以下内容，因为spring默认的消息转换器的默认编码标准是ISO-8859-1，该编码是西欧编码，无法对中文编码

    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

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