本例介绍SpringBoot与数据源的使用
JDBC
1、新建一个项目SpringBoot Web项目，引入JDBC相关jar包。SpringBoot版本是：2.1.8.RELEASE，pom文件如下：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> 5 <modelVersion>4.0.0</modelVersion> 6 7 <groupId>com.test</groupId> 8 <artifactId>test-springboot-jdbc</artifactId> 9 <version>1.0-SNAPSHOT</version> 10 11 <parent> 12 <groupId>org.springframework.boot</groupId> 13 <artifactId>spring-boot-starter-parent</artifactId> 14 <version>2.1.8.RELEASE</version> 15 </parent> 16 17 <properties> 18 19 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 20 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> 21 <java.version>1.8</java.version> 22 </properties> 23 24 <dependencies> 25 26 <dependency> 27 <groupId>org.springframework.boot</groupId> 28 <artifactId>spring-boot-starter-web</artifactId> 29 </dependency> 30 31 <!-- mysql --> 32 <dependency> 33 <groupId>org.springframework.boot</groupId> 34 <artifactId>spring-boot-starter-jdbc</artifactId> 35 </dependency> 36 37 <!-- mysql --> 38 <dependency> 39 <groupId>mysql</groupId> 40 <artifactId>mysql-connector-java</artifactId> 41 <version>8.0.12</version> 42 </dependency> 43 44 <dependency> 45 <groupId>org.springframework.boot</groupId> 46 <artifactId>spring-boot-starter-test</artifactId> 47 <scope>test</scope> 48 </dependency> 49 50 </dependencies> 51 52 53 <!-- SpringBoot打包插件，可以将代码打包成一个可执行的jar包 --> 54 <build> 55 <plugins> 56 <plugin> 57 <groupId>org.springframework.boot</groupId> 58 <artifactId>spring-boot-maven-plugin</artifactId> 59 </plugin> 60 </plugins> 61 </build> 62 </project>
2、配置数据源
1 spring: 2 datasource: 3 username: admin 4 password: 123456 5 url: jdbc:mysql://127.0.0.1:3306/test 6 driver-class-name: com.mysql.jdbc.Driver
3、编辑测试JDBC代码，如下：
1 package com.test.springboot; 2 3 import com.mysql.jdbc.Driver; 4 import org.junit.Test; 5 import org.junit.runner.RunWith; 6 import org.springframework.beans.factory.annotation.Autowired; 7 import org.springframework.boot.test.context.SpringBootTest; 8 import org.springframework.jdbc.core.JdbcTemplate; 9 import org.springframework.test.context.junit4.SpringRunner; 10 11 import javax.sql.DataSource; 12 import java.sql.Connection; 13 import java.sql.PreparedStatement; 14 import java.sql.ResultSet; 15 import java.sql.SQLException; 16 import java.util.List; 17 import java.util.Map; 18 19 @RunWith(SpringRunner.class) 20 @SpringBootTest 21 public class TestApplication { 22 23 @Autowired 24 private DataSource dataSource; 25 26 @Autowired 27 private JdbcTemplate jdbcTemplate; 28 29 @Test 30 public void context() throws SQLException { 31 System.out.println("========"); 32 System.out.println("dataSource ====" + dataSource); 33 34 Connection connection = dataSource.getConnection(); 35 System.out.println("connecttion ====" + connection); 36 37 List<Map<String, Object>> maps = jdbcTemplate.queryForList("select * from user"); 38 System.out.println(maps); 39 } 40 41 }
4、测试：
效果: 默认是用com.zaxxer.hikari.HikariDataSource作为数据源; 数据源的相关配置都在DataSourceProperties里面;
数据自动配置原理
通过参考org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration类，可以看到自动配置内容
1、参考DataSourceConfiguration，根据配置创建数据源，默认使用HikariDataSource连接池;可以使用 spring.datasource.type指定自定义的数据源类型;
2、SpringBoot默认可以支持：
org.apache.tomcat.jdbc.pool.DataSource、HikariDataSource、BasicDataSource
3、自定义数据源类型
1 /** 2 * Generic DataSource configuration. 3 */ 4 @Configuration 5 @ConditionalOnMissingBean(DataSource.class) 6 @ConditionalOnProperty(name = "spring.datasource.type") 7 static class Generic { 8 9 @Bean 10 public DataSource dataSource(DataSourceProperties properties) { 11 12 //使用DataSourceBuilder创建数据源，利用反射创建响应type的数据源，并且绑定相关属性 13 return properties.initializeDataSourceBuilder().build(); 14 } 15 16 }
4、操作数据库:自动配置了JdbcTemplate操作数据库
整合Druid数据源
1、引入druid数据源依赖
<!--引入druid数据源-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.8</version>
</dependency>
2、编辑Druid数据源配置类
1 package com.test.springboot.config; 2 3 import com.alibaba.druid.pool.DruidDataSource; 4 import com.alibaba.druid.support.http.StatViewServlet; 5 import com.alibaba.druid.support.http.WebStatFilter; 6 import org.springframework.boot.context.properties.ConfigurationProperties; 7 import org.springframework.boot.web.servlet.FilterRegistrationBean; 8 import org.springframework.boot.web.servlet.ServletRegistrationBean; 9 import org.springframework.context.annotation.Bean; 10 import org.springframework.context.annotation.Configuration; 11 12 import javax.sql.DataSource; 13 import java.util.Arrays; 14 import java.util.HashMap; 15 import java.util.Map; 16 17 @Configuration 18 public class DruidConfig { 19 20 @ConfigurationProperties(prefix = "spring.datasource") 21 @Bean 22 public DataSource druid(){ 23 return new DruidDataSource(); 24 } 25 26 //配置Druid的监控 27 //1、配置一个管理后台的Servlet 28 @Bean 29 public ServletRegistrationBean statViewServlet(){ 30 ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*"); 31 Map<String,String> initParams = new HashMap<>(); 32 33 // 后台用户名 34 initParams.put("loginUsername","admin"); 35 // 后台密码 36 initParams.put("loginPassword","123456"); 37 //默认就是允许所有访问 38 initParams.put("allow",""); 39 // 拒接访问 40 initParams.put("deny","192.168.1.3"); 41 42 bean.setInitParameters(initParams); 43 return bean; 44 } 45 46 47 //2、配置一个web监控的filter 48 @Bean 49 public FilterRegistrationBean webStatFilter(){ 50 FilterRegistrationBean bean = new FilterRegistrationBean(); 51 bean.setFilter(new WebStatFilter()); 52 53 Map<String,String> initParams = new HashMap<>(); 54 initParams.put("exclusions","*.js,*.css,*.png,*.jpg,/druid/*"); 55 56 bean.setInitParameters(initParams); 57 58 bean.setUrlPatterns(Arrays.asList("/*")); 59 60 return bean; 61 } 62 }
3、启动web项目。浏览器输入地址：http://localhost:8080/druid/，进行访问
