SpringBoot使用druid数据源整合mybatis(注解版)并实现增删改查（源码）（一个简单的例子）(没有使用逆向工程)

第一步：

导入依赖：

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

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.8</version>
        </dependency>

第二步：

编写application.yml文件;

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    url: jdbc:mysql://xxx.xxx.xxx.xxx:3306/xxx?characterEncoding=utf-8&serverTimezone=UTC
    username: xxx
    password: xxx
    driver-class-name: com.mysql.cj.jdbc.Driver

    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

    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
    initialization-mode: always

第三步：编写一个druid配置类实现监控

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

@Configuration
public class DruidCoofig {

    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druid(){
        return new DruidDataSource();
    }

    //配置一个管理后台的servlet
    @Bean
    public ServletRegistrationBean statViewServlet(){
        ServletRegistrationBean bean=new ServletRegistrationBean(new StatViewServlet(),"/druid/*");
        Map<String,String> initParams=new HashMap<>();
        initParams.put("loginUsername","admin");
        initParams.put("loginPassword","123456");
        initParams.put("allow","");
        bean.setInitParameters(initParams);
        return bean;
    }

    //配置一个web监控的filter
    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean bean=new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());
        Map<String,String> initParams=new HashMap<>();
        initParams.put("exclusions","*.js,*.css,/druid/*");
        bean.setUrlPatterns(Arrays.asList("/*"));
        bean.setInitParameters(initParams);
        return bean;
    }
}

这一步实现之后就可以使用浏览器测试成功没有，启动SpringBoot项目。然后在浏览器地址栏输入：
在这里插入图片描述

第四步：

编写一个与数据库里面的表对应的一个实体类，也就是包含数据库里面的字段（就像下图红色矩形框）。
在这里插入图片描述

第五步：编写mapper接口：并将sql语句直接用注解的方式写在方法名上面。

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

public interface EmpMapper {

    //根据eid查询一个Emp对象
    @Select("select * from emp where eid=#{eid}")
    Emp getEmpById(int eid);

    //增删改都可以设置为void，或者boolean类型的方法
    //int 表示执行之后受影响的行数，boolean代表执行成功与否

    //增加一个Emp记录,
    @Insert("insert into emp values(#{eid},#{ename})")
    int insertEmp(Emp emp);

    //删除一个Emp记录
    @Delete("delete from emp where eid=#{eid}")
    int deleteEmp(int eid);

    //更改一个Emp记录
    @Update("update emp set ename=#{ename} where eid=#{eid}")
    int updateEmp(Emp emp);


}

同时在SpringBoot启动类的上面写入@mapperscan：这里的value填入你mapper接口的全包名
在这里插入图片描述

也可以单独在mapper接口类上面写入@mapper注解即可，这两个添加mapper注解的方法二选一
在这里插入图片描述

第六步：编写controller进行测试

import com.haihai.selfwriting02.mapper.EmpMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyController {

    @Autowired
    EmpMapper empMapper;

    @RequestMapping("/select/{eid}")
    public Emp select(@PathVariable("eid") int eid){
        return empMapper.getEmpById(eid);
    }

    @RequestMapping("/insert")
    public int insert(){
        Emp emp=new Emp(1899,"1899");
        return empMapper.insertEmp(emp);
    }

    @RequestMapping("/delete/{eid}")
    public int delete(@PathVariable("eid") int eid){
        return empMapper.deleteEmp(eid);

    }

    @RequestMapping("/update")
    public int update(){
        Emp emp=new Emp(155,"155");
        return empMapper.updateEmp(emp);
    }

}