9、java SpringBoot 整合MyBatis

整合MyBatis

官方文档：http://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/

Maven仓库地址：https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter/2.1.1

整合测试

1、导入 MyBatis 所需要的依赖

<dependency>    <groupId>org.mybatis.spring.boot</groupId>    <artifactId>mybatis-spring-boot-starter</artifactId>    <version>2.1.1</version></dependency>

2、配置数据库连接信息（不变）

spring:  datasource:    username: root    password: 123456    #?serverTimezone=UTC解决时区的报错    url: jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8    driver-class-name: com.mysql.cj.jdbc.Driver    type: com.alibaba.druid.pool.DruidDataSource    #Spring Boot 默认是不注入这些属性值的，需要自己绑定    #druid 数据源专有配置    initialSize: 5    minIdle: 5    maxActive: 20    maxWait: 60000    timeBetweenEvictionRunsMillis: 60000    minEvictableIdleTimeMillis: 300000    validationQuery: SELECT 1 FROM DUAL    testWhileIdle: true    testOnBorrow: false    testOnReturn: false    poolPreparedStatements: true    #配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入    #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority    #则导入 log4j 依赖即可，Maven 地址：https://mvnrepository.com/artifact/log4j/log4j    filters: stat,wall,log4j    maxPoolPreparedStatementPerConnectionSize: 20    useGlobalDataSourceStat: true    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

3、测试数据库是否连接成功！

4、创建实体类，导入 Lombok！

Department.java

package com.kuang.pojo;import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;@Data@NoArgsConstructor@AllArgsConstructorpublic class Department {
   
       private Integer id;    private String departmentName;}

5、创建mapper目录以及对应的 Mapper 接口

DepartmentMapper.java

//@Mapper : 表示本类是一个 MyBatis 的 Mapper@Mapper@Repositorypublic interface DepartmentMapper {
   
       // 获取所有部门信息    List<Department> getDepartments();    // 通过id获得部门    Department getDepartment(Integer id);}

6、对应的Mapper映射文件

DepartmentMapper.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="com.kuang.mapper.DepartmentMapper">    <select id="getDepartments" resultType="Department">       select * from department;    </select>    <select id="getDepartment" resultType="Department" parameterType="int">       select * from department where id = #{id};    </select></mapper>

7、maven配置资源过滤问题

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

8、编写部门的 DepartmentController 进行测试！

@RestControllerpublic class DepartmentController {
   
           @Autowired    DepartmentMapper departmentMapper;        // 查询全部部门    @GetMapping("/getDepartments")    public List<Department> getDepartments(){
   
           return departmentMapper.getDepartments();    }    // 查询全部部门    @GetMapping("/getDepartment/{id}")    public Department getDepartment(@PathVariable("id") Integer id){
   
           return departmentMapper.getDepartment(id);    }    }

启动项目访问进行测试！

我们增加一个员工类再测试下，为之后做准备

1、新建一个pojo类 Employee ；

@Data@AllArgsConstructor@NoArgsConstructorpublic class Employee {
   
       private Integer id;    private String lastName;    private String email;    //1 male, 0 female    private Integer gender;    private Integer department;    private Date birth;    private Department eDepartment; // 冗余设计}

2、新建一个 EmployeeMapper 接口

//@Mapper : 表示本类是一个 MyBatis 的 Mapper@Mapper@Repositorypublic interface EmployeeMapper {
   
       // 获取所有员工信息    List<Employee> getEmployees();    // 新增一个员工    int save(Employee employee);    // 通过id获得员工信息    Employee get(Integer id);    // 通过id删除员工    int delete(Integer id);}

3、编写 EmployeeMapper.xml 配置文件

<?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="com.kuang.mapper.EmployeeMapper">    <resultMap id="EmployeeMap" type="Employee">        <id property="id" column="eid"/>        <result property="lastName" column="last_name"/>        <result property="email" column="email"/>        <result property="gender" column="gender"/>        <result property="birth" column="birth"/>        <association property="eDepartment"  javaType="Department">            <id property="id" column="did"/>            <result property="departmentName" column="dname"/>        </association>    </resultMap>    <select id="getEmployees" resultMap="EmployeeMap">        select e.id as eid,last_name,email,gender,birth,d.id as did,d.department_name as dname        from department d,employee e        where d.id = e.department    </select>    <insert id="save" parameterType="Employee">        insert into employee (last_name,email,gender,department,birth)        values (#{lastName},#{email},#{gender},#{department},#{birth});    </insert>    <select id="get" resultType="Employee">        select * from employee where id = #{id}    </select>    <delete id="delete" parameterType="int">        delete from employee where id = #{id}    </delete></mapper>

4、编写EmployeeController类进行测试

@RestControllerpublic class EmployeeController {
   
       @Autowired    EmployeeMapper employeeMapper;    // 获取所有员工信息    @GetMapping("/getEmployees")    public List<Employee> getEmployees(){
   
           return employeeMapper.getEmployees();    }    @GetMapping("/save")    public int save(){
   
           Employee employee = new Employee();        employee.setLastName("kuangshen");        employee.setEmail("[email protected]");        employee.setGender(1);        employee.setDepartment(101);        employee.setBirth(new Date());        return employeeMapper.save(employee);    }    // 通过id获得员工信息    @GetMapping("/get/{id}")    public Employee get(@PathVariable("id") Integer id){
   
           return employeeMapper.get(id);    }    // 通过id删除员工    @GetMapping("/delete/{id}")    public int delete(@PathVariable("id") Integer id){
   
           return employeeMapper.delete(id);    }}

测试结果完成，搞定收工！