SpringBoot 整合 Mybatis：提升你的Java项目开发效率

第一章：数据自动管理

1. 引入 JDBC 的依赖和 SpringBoot 的应用场景：

   <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-jdbc</artifactId>
   </dependency>
   <dependency>
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-dbcp2</artifactId>
   </dependency>
   
   <dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
       <scope>runtime</scope>
   </dependency>

2. 创建 application.yaml 进行配置：

   spring:
     datasource:
       username: root
       password: root
       url: jdbc:mysql://localhost:3306/boot_demo
       driver-class-name: com.mysql.jdbc.Driver
       type: com.zaxxer.hikari.HikariDataSource

   1. 在默认情况下，数据链接可以使用 DataSource 池进行自动配置
   2. Hikari 可用，SpringBoot 将使用它
   3. Commons DBCP2 可用，我们将使用它 
   4. 也可以指定数据源配置，通过 type 来选取使用哪种数据源

      spring:
        datasource:
          username: root
          password: root
          url: jdbc:mysql://localhost:3306/boot_demo
          driver-class-name: com.mysql.jdbc.Driver
          type: com.zaxxer.hikari.HikariDataSource
          # type: org.apache.commons.dbcp2.BasicDataSource

3. 设置 druid 数据源：

   <dependency>
       <groupId>com.alibaba</groupId>
       <artifactId>druid</artifactId>
       <version>1.0.9</version>
   </dependency>
   <dependency>
       <groupId>log4j</groupId>
       <artifactId>log4j</artifactId>
       <version>1.2.15</version>
   </dependency>

   1. 修改 application.yaml 文件中：

      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

   2. 在 application.yaml 文件中加入：

      spring:
        datasource:
          username: root
          password: root
          url: jdbc:mysql://localhost:3306/boot_demo
          driver-class-name: com.mysql.jdbc.Driver
          type: com.alibaba.druid.pool.DruidDataSource
          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

   3. 创建数据源注册类：

      @Configuration
      public class DruidConfig {
          @ConstructorProperties(prefix="spring.datasource")
          @Bean
          public DataSource dataSource(){
              return new DruidDataSource;
          }
      }

   4. 配置 druid 运行期监控

      @Configuration
      public class DruidConfig {
          @ConstructorProperties(prefix="spring.datasource")
          @Bean
          public DataSource dataSource(){
              return new DruidDataSource;
          }
      
          @Bean
          public ServletRegistrationBean statViewServlet(){
              ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(),
                      "/druid/*");
              Map<String,String> initParams = new HashMap<>();
              initParams.put("loginUsername","root");
              initParams.put("loginPassword","root");
              initParams.put("allow","");//默认就是允许所有访问
              initParams.put("deny","192.168.15.21");
              bean.setInitParameters(initParams);
              return bean;
          }
      
          //2、配置一个web监控的filter
          @Bean
          public FilterRegistrationBean webStatFilter(){
              FilterRegistrationBean bean;
              bean = new FilterRegistrationBean();
              bean.setFilter(new WebStatFilter());
              Map<String,String> initParams = new HashMap<>();
              initParams.put("exclusions","*.js,*.css,/druid/*");
              bean.setInitParameters(initParams);
              bean.setUrlPatterns(Arrays.asList("/*"));
              return bean;
          }
      }

   5. 打开监控页面：http://localhost:8080/druid

第二章：SpringBoot 整合 JDBCTemplate

1. 创建表：

   
   SET FOREIGN_KEY_CHECKS=0;
   
   -- ----------------------------
   -- Table structure for tx_user
   -- ----------------------------
   DROP TABLE IF EXISTS `tx_user`;
   CREATE TABLE `tx_user` (
     `username` varchar(10) DEFAULT NULL,
     `userId` int(10) NOT NULL,
     `password` varchar(10) DEFAULT NULL,
     PRIMARY KEY (`userId`)
   ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. 创建 Controller：

   public class TestController {
   
       @Autowired
       JdbcTemplate jdbcTemplate;
   
       @ResponseBody
       @RequestMapping("/query")
       public List<Map<String, Object>> query(){
           List<Map<String, Object>> maps = jdbcTemplate.queryForList("SELECT * FROM tx_user");
           return maps;
       }

3. 启动 SpringBoot 访问：http://localhost:8080/query
4. SpringBoot 中提供了 jdbcTemplateAutoConfiguration 的自动配置

   org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration

5. jdbcTemplateAutoConfiguration 源码：