016-Spring Boot JDBC

一、数据源装配

通过查看代码可知，默认已装配了数据源和JdbcTemplate

System.out.println(context.getBean(DataSource.class));
System.out.println(context.getBean(JdbcTemplate.class));

1.1、环境搭建

主要是pom引用：spring-boot-starter-jdbc、增加数据库驱动

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.lhx.spring</groupId><artifactId>springboot-web</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>springboot-web</name><url>http://maven.apache.org</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.target>1.8</maven.compiler.target><maven.compiler.source>1.8</maven.compiler.source></properties><dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>1.5.9.RELEASE</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency></dependencies>
</project>

查看spring-boot-autoconfigure-1.5.9.RELEASE.jar包下的org.springframework.boot.autoconfigure.jdbc下的DataSourceProperties其实所有的都是类似的配置

@ConfigurationProperties(prefix = "spring.datasource")
public class DataSourcePropertiesimplements BeanClassLoaderAware, EnvironmentAware, InitializingBean {

可以看到默认读取spring.datasource开头的配置。

1.2、配置

spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot
spring.datasource.username=root
spring.datasource.password=root

1.3、使用

    public static void main(String[] args) throws SQLException {ConfigurableApplicationContext context = SpringApplication.run(App.class, args);dataSource = context.getBean(DataSource.class);Connection connection = dataSource.getConnection();System.out.println(connection.getCatalog());}

二、JdbcTemplate

在配置好基本配置后，JdbcTemplate就可以使用了

@Repository
public class ProductDao {@Autowiredprivate JdbcTemplate jdbcTemplate;public void addProdcut(String value) {String sql = "insert into product(pname) values('" + value + "')";jdbcTemplate.execute(sql);}
}

调用

public class App {public static void main(String[] args) throws SQLException {ConfigurableApplicationContext context = SpringApplication.run(App.class, args);context.getBean(ProductDao.class).addProdcut("mp3");connection.close();}
}

三、切换数据源

System.out.println(context.getBean(DataSource.class));

查看到使用的是默认提供的：org.apache.tomcat.jdbc.pool.DataSource数据源

方式一、排除添加切换

1》排除掉tomcat-jdbc

        <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId><exclusions><exclusion><groupId>org.apache.tomcat</groupId><artifactId>tomcat-jdbc</artifactId></exclusion></exclusions></dependency>

2》添加新的数据源

        <dependency><groupId>com.zaxxer</groupId><artifactId>HikariCP</artifactId></dependency>

方式二、type配置数据源切换

3.2.1、原理查看

查看spring-boot-autoconfigure-1.5.9.RELEASE.jar包下的org.springframework.boot.autoconfigure.jdbc下的DataSourceProperties的配置

使用type指定【private Class<? extends DataSource> type;】在application.properties中

spring.datasource.type=com.zaxxer.hikari.HikariDataSource

默认支持以下几种数据源类型，查看spring-boot-autoconfigure-1.5.9.RELEASE.jar包下的org.springframework.boot.autoconfigure.jdbc下的DataSourceAutoConfiguration

DataSourceConfiguration.Tomcat.class
DataSourceConfiguration.Hikari.class
DataSourceConfiguration.Dbcp.class
DataSourceConfiguration.Dbcp2.class
DataSourceConfiguration.Generic.class

3.2.2、具体步骤

1》添加对应数据源pom

        <dependency><groupId>com.zaxxer</groupId><artifactId>HikariCP</artifactId></dependency>

2》使用配置

spring.datasource.type=com.zaxxer.hikari.HikariDataSource

3.3、配置自定义数据源

1》添加POM依赖

        <dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.1.6</version></dependency>

2》、增加DBConfiguration配置类

package com.lhx.spring.springboot_web;import javax.sql.DataSource;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;import com.alibaba.druid.pool.DruidDataSource;@SpringBootConfiguration
public class DBConfiguration {@Autowiredprivate Environment env;@Beanpublic DataSource createDataSource() {DruidDataSource source = new DruidDataSource();source.setUrl(env.getProperty("spring.datasource.url"));source.setUsername(env.getProperty("spring.datasource.username"));source.setPassword(env.getProperty("spring.datasource.password"));source.setDriverClassName(env.getProperty("spring.datasource.driverClassName"));return source;}
}

四、事务

4.1、配置开启

1、在入口app增加注解

@EnableTransactionManagement

2、在需要事务的公有方法上添加注解

@Transactional

示例

    @Transactionalpublic void addProdcutBatch(String... names) throws Exception {for (String name : names) {String sql = "insert into product(pname) values('" + name + "')";jdbcTemplate.execute(sql);if ("".equals("")) {throw new NullPointerException();}}}

注意：spring事务，默认支持运行时异常，即RunTimeException，非运行时异常不会回滚

4.2、设置针对哪些异常使用事务

默认是运行时

设置所有异常

@Transactional(rollbackFor=Exception.class)

设置哪些异常不回滚

@Transactional(noRollbackFor=NullPointerException.class)

 

注意点：

1、要想使用事务生效，被调用的方法必须有Transactional 注解，对于内部调用方法有无注解无影响

2、需要数据库支持事务。