先在pom.xml文件中引入MyBatis依赖和数据库驱动，这里我使用的是MySQL数据库 ``` <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.1.3</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.0.4</version> </dependency> ``` >不同版本的Spring Boot和MyBatis版本对应不一样，具体可查看官方文档：http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/。 配置Druid数据源 >引入时注意版本，有些版本会不兼容，选择适合的版本 ``` <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.10</version> </dependency> ``` >Druid是一个关系型数据库连接池，是阿里巴巴的一个开源项目，地址：https://github.com/alibaba/druid。Druid不但提供连接池的功能，还提供监控功能，可以实时查看数据库连接池和SQL查询的工作情况。 为了使用Druid连接池，需要在application.yml下配置，在resources下新建application.yml文件，配置如下： ``` server: context-path: /web spring: datasource: druid: # 数据库访问配置, 使用druid数据源 type: com.alibaba.druid.pool.DruidDataSource driver-class-name: org.gjt.mm.mysql.Driver url: jdbc:mysql://47.113.122.133:3306/lixj?serverTimezone=UTC&autoReconnect=true&useUnicode=true&characterEncoding=UTF-8 username: ****** password: ****** # 连接池配置 initial-size: 5 min-idle: 5 max-active: 20 # 连接等待超时时间 max-wait: 30000 # 配置检测可以关闭的空闲连接间隔时间 time-between-eviction-runs-millis: 60000 # 配置连接在池中的最小生存时间 min-evictable-idle-time-millis: 300000 validation-query: select '1' from dual test-while-idle: true test-on-borrow: false test-on-return: false # 打开PSCache，并且指定每个连接上PSCache的大小 pool-prepared-statements: true max-open-prepared-statements: 20 max-pool-prepared-statement-per-connection-size: 20 # 配置监控统计拦截的filters, 去掉后监控界面sql无法统计, 'wall'用于防火墙 filters: stat,wall # Spring监控AOP切入点，如x.y.z.service.*,配置多个英文逗号分隔 aop-patterns: com.example.lixj.* # WebStatFilter配置 web-stat-filter: enabled: true # 添加过滤规则 url-pattern: /* # 忽略过滤的格式 exclusions: '*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*' # StatViewServlet配置 stat-view-servlet: enabled: true # 访问路径为/druid时，跳转到StatViewServlet url-pattern: /druid/* # 是否能够重置数据 reset-enable: false # 需要账号密码才能访问控制台 login-username: druid login-password: druid123 # IP白名单 # allow: 127.0.0.1 #　IP黑名单（共同存在时，deny优先于allow） # deny: 192.168.1.218 # 配置StatFilter filter: stat: log-slow-sql: true ``` >数据库是我在自己服务器搭建的，查看[搭建经过](https://lixj.fun/archives/linux%E7%B3%BB%E7%BB%9F%E4%B8%8B%E5%AE%89%E8%A3%85mysql)，如何在Linux安装MySQL数据库。 访问 http://localhost:8080/druid/login.html  登录后可以看到  在数据库新建表 ``` SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; -- ---------------------------- -- Table structure for student -- ---------------------------- DROP TABLE IF EXISTS `student`; CREATE TABLE `student` ( `SNO` varchar(5) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL, `SNAME` varchar(15) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL, `SSEX` varchar(2) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL, PRIMARY KEY (`SNO`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic; -- ---------------------------- -- Records of student -- ---------------------------- INSERT INTO `student` VALUES ('1', '张三', '男'); INSERT INTO `student` VALUES ('2', '李四', '男'); INSERT INTO `student` VALUES ('3', '韩梅梅', '女'); INSERT INTO `student` VALUES ('4', '李梅', '女'); SET FOREIGN_KEY_CHECKS = 1; ``` 创建对应的实体类 ``` @Data public class Student implements Serializable { private String SNO; private String SNAME; private String SSEX; } ``` 创建一个包含基本CRUD的StudentMapper ``` public interface StudentMapper { int add(Student student); int update(Student student); int deleteByIds(String sno); Student queryStudentById(String id); } ``` 使用注解方式 ``` @Component @Mapper public interface StudentMapper { @Insert("insert into student(sno,sname,ssex) values(#{sno},#{name},#{sex})") int add(Student student); @Update("update student set sname=#{name},ssex=#{sex} where sno=#{sno}") int update(Student student); @Delete("delete from student where sno=#{sno}") int deleteBysno(String sno); @Select("SELECT * FROM STUDENT WHERE SNO=#{SNO}") @Results(id = "student",value= { @Result(property = "SNO", column = "SNO", javaType = String.class), @Result(property = "SNAME", column = "SNAME", javaType = String.class), @Result(property = "SSEX", column = "SSEX", javaType = String.class) }) Student queryStudentBySno(String sno); } ``` 然后编写服务层 ``` public interface IStudentService { int add(Student student); int update(Student student); int deleteById(String sno); Student queryById(String sno); } ``` 实现类 ``` @Service("studentService") public class StudentServiceImpl implements IStudentService { @Autowired private StudentMapper studentMapper; @Override public int add(Student student) { return this.studentMapper.add(student); } @Override public int update(Student student) { return this.studentMapper.update(student); } @Override public int deleteById(String sno) { return this.studentMapper.deleteBysno(sno); } @Override public Student queryById(String sno) { return this.studentMapper.queryStudentBySno(sno); } } ``` Controller入口类 ``` @RestController public class StudentController { @Autowired private StudentServiceImpl studentService; @RequestMapping( value = "/querystudent", method = RequestMethod.GET) public Student queryStudentBySno(String sno) { return this.studentService.queryById(sno); } } ``` 这里注意一个问题，在启动类上要加上 @MapperScan("com.example.lixj.mapper") ，否则会报错提示找不到 mapper文件 接下来可以启动项目了。 访问 http://localhost:8080/querystudent?sno=1  查看SQL监控的情况