SpringBoot学习(3) - jdbc

数据库使用MySQL 5.7.18版本。

装配DataSource的步骤：
1.加入数据库驱动

pom.xml:

 <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.study.springboot</groupId>
     <artifactId>spring-boot-jdbc</artifactId>
     <version>1.0.0</version>
     <packaging>jar</packaging>

     <name>springboot</name>
     <url>http://maven.apache.org</url>

     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>

     <dependencyManagement>
         <dependencies>
             <dependency>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-dependencies</artifactId>
                 <version>1.5.3.RELEASE</version>
                 <scope>import</scope>
                 <type>pom</type>
             </dependency>
         </dependencies>
     </dependencyManagement>

     <dependencies>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-jdbc</artifactId>
         </dependency>
         <dependency>
             <groupId>mysql</groupId>
             <artifactId>mysql-connector-java</artifactId>
         </dependency>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <scope>test</scope>
         </dependency>
     </dependencies>
 </project>

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=adminroot

application.properties:

 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=adminroot

以上操作，springboot会自动装配好DataSource和JdbcTemplate，可以直接使用

 package com.study.spring_boot_jdbc.dao;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Repository;

 @Repository
 public class ProductDao {

     @Autowired
     private JdbcTemplate jdbcTemplate;

     public void addProduct(String name){
         String sql = "insert into product (pname) values ('" + name + "')";
         jdbcTemplate.execute(sql);
     }

 }

 @SpringBootApplication public class App {

     public static void main(String[] args) throws Exception {
         ConfigurableApplicationContext context = SpringApplication.run(App.class,args);
         DataSource ds = context.getBean(DataSource.class);
         Connection conn = ds.getConnection();
         System.out.println(conn.getCatalog());
         System.out.println(context.getBean(JdbcTemplate.class));
         conn.close();
         System.out.println(ds.getClass());
         context.close();
     }

 }

如果不想使用Tomcat的DataSource，可以使用两种方式配置需要的数据源，步骤：

1.pom.xml 添加相关依赖

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

2.

a)spring.datasource.type配置项，可指定具体使用哪种数据源

默认支持Tomcat,Hikari,Dbcp,Dbcp2,Generic（1.5.3.RELEASE）

application.properties:

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

b)排除Tomcat的数据源

pom.xml:

         <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>

配置自定义DataSource，只需要装配一个DataSource到spring容器中即可

         <dependency>
             <groupId>com.alibaba</groupId>
             <artifactId>druid</artifactId>
             <version>1.0.31</version>
         </dependency>

 @SpringBootConfiguration
 public class DBConfiguration {
     @Autowired
     private Environment env;
     @Bean
     public DataSource createDataSource(){
         DruidDataSource ds = new DruidDataSource();
         ds.setUrl(env.getProperty("spring.datasource.url"));
         ds.setUsername(env.getProperty("spring.datasource.username"));
         ds.setPassword(env.getProperty("spring.datasource.password"));
         ds.setDriverClassName(env.getProperty("spring.datasource.driverClassName"));
         return ds;
     }

 }

事务：
首先要使用@EnableTransactionManagement启用对事务的支持
然后，在需要使用事务的方法上加上@Transactional
注意，默认只会对运行时异常进行事务回滚，非运行时异常不会回滚事务

APP.class：

 @SpringBootApplication
 @EnableTransactionManagement
 public class App {

     public static void main(String[] args) throws Exception {
         ConfigurableApplicationContext context = SpringApplication.run(App.class,args);

         context.getBean(ProductDao.class).addProductBatch("TV","MP3","MP4");

         System.out.println(ds.getClass());
         context.close();
     }

 }

 package com.study.spring_boot_jdbc.dao;

 import java.io.FileNotFoundException;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Repository;
 import org.springframework.transaction.annotation.Transactional;

 @Repository
 public class ProductDao {

     @Autowired
     private JdbcTemplate jdbcTemplate;

     public void addProduct(String name){
         String sql = "insert into product (pname) values ('" + name + "')";
         jdbcTemplate.execute(sql);
     }

     /**
      * rollbackFor 设置对哪些异常进行回滚，默认是运行时异常
      * noRollbackFor 设置哪些异常不回滚
      * @param names
      * @throws Exception
      */
     @Transactional(noRollbackFor=NullPointerException.class)
     public void addProductBatch(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，在需要使用事务的方法上加上@Transactional！！！

 package com.study.spring_boot_jdbc.dao;

 import java.io.FileNotFoundException;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.stereotype.Repository;
 import org.springframework.transaction.annotation.Transactional;

 @Repository
 public class ProductDao {

     @Autowired
     private JdbcTemplate jdbcTemplate;

     public void addProduct(String name){
         String sql = "insert into product (pname) values ('" + name + "')";
         jdbcTemplate.execute(sql);
     }

     @Transactional
     public void addProductBatch(String ... names) throws Exception{
         add(names);

     }

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

 }

若addProductBatch方法没有@Transactional，执行addProductBatch，事务不起作用。若是执行add，事务起作用。