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  • SpringBoot09: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/2.1.2

    整合Mybatis

    1. 新建一个模块

    1. 导入依赖
    <!--Druid-->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.22</version>
    </dependency>
    
    <!--Log4j-->
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>
    
    <!--Lombok-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
    
    1. 配置数据库连接信息
    spring:
      datasource:
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
        username: root
        password: 123456
        type: com.alibaba.druid.pool.DruidDataSource # 自定义数据源
    
        #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
    
    1. 测试数据库是否连接成功!

    2. 创建实体类!

    3. 创建mapper目录以及对应的 Mapper 接口

      DepartmentMapper.java

    @Mapper
    @Repository
    public interface DepartmentMapper {
    
        // 获取所有部门信息
        List<Department> getDepartments();
    
        // 通过id获得部门
        Department getDepartment(@Param("id") Integer id);
    }
    
    1. 对应的Mapper映射文件

      DepartmentMapper.xml

      <?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.godfrey.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>
      
    2. maven配置资源过滤问题

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>
    
    1. 编写部门的 DepartmentController 进行测试!
    @RestController
    public 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!

    1. 增加一个员工类再测试下,为之后做准备

    2. 新建一个pojo类 Employee ;

    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public 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
    
    }
    
    1. 新建一个 EmployeeMapper 接口
    @Mapper
    @Repository
    public 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(@Param("id") Integer id);
    
        // 通过id删除员工
        int delete(@Param("id") Integer id);
    }
    
    1. 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.godfrey.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>
    
    1. 编写EmployeeController类进行测试
    @RestController
    public 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("qinjiang@qq.com");
            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!

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  • 原文地址:https://www.cnblogs.com/MessiXiaoMo3334/p/12981347.html
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