[Java知识库]SSM三大框架整合，从建数据库起，超详细版

1、我的环境

• jdk8
• maven3.6.1
• mysql8.0
• tomcat9.0.48

2、创建一个数据库为testdb

在testdb中创建一个students表并插入几条数据

create table students(
	stuId int primary key,
	stuName varchar(10),
	stuMajor varchar(10)
);

insert into students values
(1800500926,'谭熙','信息管理与信息系统'),
(1800500924,'施彦宏','信息管理与信息系统'),
(1800501501,'冯雪儿','工业工程');

3、创建maven工程

项目名为springmvc-all
不使用模板创建，就创建一个普通的mavenx项目即可。

4、导入我们需要的依赖

<!--单元测试-->
<dependency>
     <groupId>junit</groupId>
     <artifactId>junit</artifactId>
     <version>4.12</version>
 </dependency>

 <!--mysql驱动-->
 <dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
     <version>8.0.25</version>
 </dependency>

 <!--servlet,jsp,jstl-->
 <dependency>
     <groupId>javax.servlet</groupId>
     <artifactId>javax.servlet-api</artifactId>
     <version>4.0.1</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>

 <!--springMVC-->
 <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>spring-webmvc</artifactId>
     <version>5.3.8</version>
 </dependency>

 <!--mybatis-->
 <dependency>
     <groupId>org.mybatis</groupId>
     <artifactId>mybatis</artifactId>
     <version>3.5.7</version>
 </dependency>

 <!--mybatis-spring整合包-->
 <dependency>
     <groupId>org.mybatis</groupId>
     <artifactId>mybatis-spring</artifactId>
     <version>2.0.6</version>
 </dependency>

 <!--spring的jdbc-->
 <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>spring-jdbc</artifactId>
     <version>5.3.8</version>
 </dependency>

 <!--c3p0数据源-->
 <dependency>
     <groupId>com.mchange</groupId>
     <artifactId>c3p0</artifactId>
     <version>0.9.5.5</version>
 </dependency>
 <dependency>
     <groupId>com.fasterxml.jackson.core</groupId>
     <artifactId>jackson-databind</artifactId>
     <version>2.11.3</version>
 </dependency>

5、设置资源过滤

确保我们的mapper.xml可以导出出来，不然最后运行打包的时候可能会异常

在pom.xml 与dependencies同级插入以下代码（固定格式的）

<!--资源过滤-->
<build>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.xml</include>
                <include>**/*.properties</include>
                <!-- 如果有其他的继续加就行-->
            </includes>
            <filtering>true</filtering>
        </resource>

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

6、创建包结构 cn.butcher（可以自己写）

7、添加web框架支持

• 右键我们的项目名
• 添加框架支持

这样我们的web结构也出来了。

8、创建spring配置文件

在resources下创建两个配置文件

• db.properties
  这里写上连接数据库的配置 数据库的配置

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/testdb?useUnicode=true&characterEncoding=UTF8&userSSL=true&serverTimezone=GMT
jdbc.username=root
jdbc.password=tx123

注意注意，前面要有jdbc. 这是规范，不然会报错的。。。

• spring-dao.xml
  如果报错，就把中文注释去掉，下同！

<?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">

    <!--关联数据库配置文件-->
    <context:property-placeholder location="classpath:db.properties"/>

    <!--数据库连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!--数据源连接配置-->
        <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连接池私有属性-->
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <!--关闭连接后不自动提交-->
        <property name="autoCommitOnClose" value="false"/>
        <!--连接超时时间-->
        <property name="checkoutTimeout" value="10000"/>
        <!--失败后重试次数-->
        <property name="acquireRetryAttempts" value="2"/>
    </bean>

    <!--配置SqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--自动扫描pojo下的实体类，设置别名-->
        <property name="typeAliasesPackage" value="cn.butcher.pojo"/>
    </bean>

	
    
    
	<!--spring自动扫描我们的mapper接口，bean的id就是接口名（第一个字母小写）--> 
    <bean id="mapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
        <property name="mapperInterface" value="cn.butcher.mapper.UserMapper"/>
    </bean>

</beans>

可以为每个接口配置一份实例交给spring接管，但是这样接口多了，就不好玩了

<!--配置mapper-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <!--绑定sqlSessionFactory-->
    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
     <!--自动扫描mapper下的映射文件，前提是隐射文件的名字要和接口一样-->
    <property name="basePackage" value="cn.butcher.mapper"/>
</bean>

除了上面的两种方式我比较推荐的，其他还有两种方式在spring中使用mybatis，都是实现接口的方式，要再建一个接口实现类，感觉多了一步，不喜欢！
参考大佬文章

• application-context.xml
  再总的spring配置文件中引入spring-dao.xml的配置文件

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

    <import resource="spring-dao.xml"/>

</beans>

9、好了，编写我们的dao层（也就是，mapper）

whatever，按官方的规范是这样，但你怎么命名无所谓

• 创建Student实体类

package cn.butcher.pojo;

public class Student {
    private int stuId;
    private String stuName;
    private String stuMajor;

    public Student() {
    }

    public Student(int stuId, String stuName, String stuMajor) {
        this.stuId = stuId;
        this.stuName = stuName;
        this.stuMajor = stuMajor;
    }

    public int getStuId() {
        return stuId;
    }

    public void setStuId(int stuId) {
        this.stuId = stuId;
    }

    public String getStuName() {
        return stuName;
    }

    public void setStuName(String stuName) {
        this.stuName = stuName;
    }

    public String getStuMajor() {
        return stuMajor;
    }

    public void setStuMajor(String stuMajor) {
        this.stuMajor = stuMajor;
    }

    @Override
    public String toString() {
        return "Student{" +
                "stuId=" + stuId +
                ", stuName='" + stuName + '\'' +
                ", stuMajor='" + stuMajor + '\'' +
                '}';
    }
}

• 编写接口

package cn.butcher.mapper;

import cn.butcher.pojo.Student;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface StudentMapper {
    /**
     * 查询所有学生
     * @return 学生列表
     */
    List<Student> selectStudents();

    /**
     * 删除一个学生
     * @param id 学号
     * @return 状态
     */
    int deleteStudentById(@Param("stuId") int id);

    /**
     * 更新一个学生的信息
     * @param student 学生
     * @return 状态
     */
    int updateStudent(Student student);

    /**
     * 添加一个学生
     * @param student 学生
     * @return 状态
     */
    int addStudent(Student student);
}

• 编写mapper映射文件

<?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="cn.butcher.mapper.StudentMapper">
    <!--我们已经在配置文件中扫描了所有实体类，所以在这我们直接使用别名即可-->
    <select id="selectStudents" resultType="student">
        select * from students
    </select>

    <delete id="deleteStudentById">
        delete from students where stuId = #{stuId}
    </delete>
	<!--动态sql多看看官方的帮助文档就好了-->
    <update id="updateStudent" parameterType="student">
        update students
        <set>
            <if test="stuName!=null">
               stuName=#{stuName},
            </if>
            <if test="stuMajor!=null">
                 stuMajor=#{stuMajor},
            </if>
        </set>
        where stuId = #{stuId}
    </update>

    <insert id="addStudent" parameterType="student">
        insert into students(stuId, stuName, stuMajor) values (#{stuId}, #{stuName}, #{stuMajor})
    </insert>


</mapper>

• 单元测试

package cn.butcher;

import cn.butcher.mapper.StudentMapper;
import cn.butcher.pojo.Student;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

public class MyTest {

    ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");
    StudentMapper studentMapper = context.getBean("studentMapper", StudentMapper.class);

    @Test
    public void test01()  {

        List<Student> students = studentMapper.selectStudents();
        for (Student student : students) {
            System.out.println(student.toString());
        }
    }

    @Test
    public void test02()  {
        int res = studentMapper.deleteStudentById(1800500926);
        System.out.println(res);
    }

    @Test
    public void test03()  {

        Student student = new Student(1800500926, "谭熙", "信管-信息管理");
        int res = studentMapper.updateStudent(student);
        System.out.println(res);
    }


    @Test
    public void test04()  {
        Student student = new Student(1800500926, "谭熙", "信管");
        int res = studentMapper.addStudent(student);
        System.out.println(res);
    }
    
}

以上测试都是成功的，你可以在你那里跑一下。如果出问题，记得把中文注释去掉！

10、整合service层

• 创建StudentService接口

package cn.butcher.service;

import cn.butcher.pojo.Student;

import java.util.List;

public interface StudentService {
    /**
     * 查询所有学生
     * @return 学生列表
     */
    List<Student> selectStudents();

    /**
     * 删除一个学生
     * @param id 学号
     * @return 状态
     */
    int deleteStudentById(int id);

    /**
     * 更新一个学生的信息
     * @param student 学生
     * @return 状态
     */
    int updateStudent(Student student);

    /**
     * 添加一个学生
     * @param student 学生
     * @return 状态
     */
    int addStudent(Student student);
}

• 创建StudentServiceImpl是实现类

package cn.butcher.service;

import cn.butcher.mapper.StudentMapper;
import cn.butcher.pojo.Student;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class StudentServiceImpl implements StudentService {

    private StudentMapper studentMapper;

    public void setStudentMapper(StudentMapper studentMapper) {
        this.studentMapper = studentMapper;
    }

    /**
     * 查询所有学生
     *
     * @return 学生列表
     */
    public List<Student> selectStudents() {
        return studentMapper.selectStudents();
    }

    /**
     * 删除一个学生
     *
     * @param id 学号
     * @return 状态
     */
    public int deleteStudentById(int id) {
        return studentMapper.deleteStudentById(id);
    }

    /**
     * 更新一个学生的信息
     *
     * @param student 学生
     * @return 状态
     */
    public int updateStudent(Student student) {
        return studentMapper.updateStudent(student);
    }

    /**
     * 添加一个学生
     *
     * @param student 学生
     * @return 状态
     */
    public int addStudent(Student student) {
        return studentMapper.addStudent(student);
    }
}

• 在resources里创建spring-service.xml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: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">
    <!--自动扫描service包-->
    <context:component-scan base-package="cn.butcher.service"/>

    <!--显式定义StudentServiceImpl-->
    <bean id="studentServiceImpl" class="cn.butcher.service.StudentServiceImpl">
        <property name="studentMapper" ref="studentMapper"/>
    </bean>

    <!--配置事务管理器-->
    <bean id="dataSourceTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

测试没有问题

package cn.butcher;

import cn.butcher.pojo.Student;
import cn.butcher.service.StudentServiceImpl;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

public class MyTest2 {
    ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");
    StudentServiceImpl studentServiceImpl = context.getBean("studentServiceImpl", StudentServiceImpl.class);

    @Test
    public void test01()  {

        List<Student> students = studentServiceImpl.selectStudents();
        for (Student student : students) {
            System.out.println(student.toString());
        }
    }

    @Test
    public void test02()  {
        int res = studentServiceImpl.deleteStudentById(1800500926);
        System.out.println(res);
    }

    @Test
    public void test03()  {

        Student student = new Student(1800500926, "谭熙", "信管-信息管理");
        int res = studentServiceImpl.updateStudent(student);
        System.out.println(res);
    }


    @Test
    public void test04()  {
        Student student = new Student(1800500926, "谭熙", "信管");
        int res = studentServiceImpl.addStudent(student);
        System.out.println(res);
    }
}

11、开始我们的web

• 配置dispatcherServlet
  在web.xml中

<?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">

    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!--注意这里是总的配置文件-->
            <param-value>classpath:application-context.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>
	<!--解决编码问题-->
    <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>
    
    <!--会话超时时间-->
    <session-config>
        <session-timeout>15</session-timeout>
    </session-config>
</web-app>

• 创建是spring-mvc.xml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:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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 http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
	<!--扫描controller包-->
    <context:component-scan base-package="cn.butcher.controller"/>
	<!--开启注解支持-->
    <mvc:annotation-driven/>
	<!--静态资源默认设置-->
    <mvc:default-servlet-handler/>
</beans>

• 编写StudentController

package cn.butcher.controller;

import cn.butcher.pojo.Student;
import cn.butcher.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class StudentController {

    @Autowired
    @Qualifier("studentServiceImpl")
    StudentService studentService;

    @GetMapping("/list")
    public List<Student> selectStudents(){
        return studentService.selectStudents();
    }

    @GetMapping("/delete/{id}")
    public String deleteStudent(@PathVariable int id){
        int res = studentService.deleteStudentById(id);
        if (res>=1)return id+"删除成功！";
        return id+"删除失败了！";
    }

    @GetMapping("/update")
    public String updateStudent(Student student){
        int res = studentService.updateStudent(student);
        if (res>=1)return student.getStuName()+"更新成功！";
        return student.getStuName()+"更新失败了！";
    }

    @GetMapping("/add")
    public String addStudent(Student student){
        int res = studentService.addStudent(student);
        if (res>=1)return student.getStuName()+"添加成功！";
        return student.getStuName()+"添加失败了！";
    }

}

• 启动tomcat前
  检查lib目录中是否添加了jar包，如果没有，创建一个lib目录
  如果没有，创建一个lib目录
  

应用即可

• 启动tomcat
  在地址栏输入：http://localhost:8080/list
  
• 删除一个学生
  在地址栏输入：http://localhost:8080/delete/1800500926
  
  删除成功了，但是中文出现了乱码，排查一下：
  它在返回数据的时候就乱码了

是我们的过滤器没起作用，可以暂时这样解决

@GetMapping(value = "/update" ,produces = "application/json;charset=UTF-8")

或者在spring-mvc.xml中修改配置（参考自：响应数据中文乱码）

<mvc:annotation-driven>
    <mvc:message-converters>
        <!-- 解决@ResponseBody返回中文乱码 -->
        <bean class="org.springframework.http.converter.StringHttpMessageConverter">
            <property name="supportedMediaTypes">
                <list>
                    <value>text/html;charset=UTF-8</value>
                    <value>application/json;charset=UTF-8</value>
                    <value>*/*;charset=UTF-8</value>
                </list>
            </property>
            <!-- 用于避免响应头过大 -->
            <property name="writeAcceptCharset" value="false" />
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

• 更新一个学生

• 添加一个学生
  在地址栏输入：
  

12、总结

呼呼呼，终于结束了！
总结一下：征途漫漫，唯有奋斗！