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SpringBoot学习(3)

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:

 1 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 2     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 3     <modelVersion>4.0.0</modelVersion>
 4 
 5     <groupId>com.study.springboot</groupId>
 6     <artifactId>spring-boot-jdbc</artifactId>
 7     <version>1.0.0</version>
 8     <packaging>jar</packaging>
 9 
10     <name>springboot</name>
11     <url>http://maven.apache.org</url>
12 
13     <properties>
14         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
15     </properties>
16 
17     <dependencyManagement>
18         <dependencies>
19             <dependency>
20                 <groupId>org.springframework.boot</groupId>
21                 <artifactId>spring-boot-dependencies</artifactId>
22                 <version>1.5.3.RELEASE</version>
23                 <scope>import</scope>
24                 <type>pom</type>
25             </dependency>
26         </dependencies>
27     </dependencyManagement>
28 
29     <dependencies>
30         <dependency>
31             <groupId>org.springframework.boot</groupId>
32             <artifactId>spring-boot-starter-jdbc</artifactId>
33         </dependency>
34         <dependency>
35             <groupId>mysql</groupId>
36             <artifactId>mysql-connector-java</artifactId>
37         </dependency>
38         <dependency>
39             <groupId>junit</groupId>
40             <artifactId>junit</artifactId>
41             <scope>test</scope>
42         </dependency>
43     </dependencies>
44 </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:

1 spring.datasource.driverClassName=com.mysql.jdbc.Driver
2 spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot
3 spring.datasource.username=root
4 spring.datasource.password=adminroot

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

 1 package com.study.spring_boot_jdbc.dao;
 2 
 3 
 4 import org.springframework.beans.factory.annotation.Autowired;
 5 import org.springframework.jdbc.core.JdbcTemplate;
 6 import org.springframework.stereotype.Repository;
 7 
 8 @Repository
 9 public class ProductDao {
10 
11     @Autowired
12     private JdbcTemplate jdbcTemplate;
13     
14     public void addProduct(String name){
15         String sql = "insert into product (pname) values ('" + name + "')";
16         jdbcTemplate.execute(sql);
17     }
18     
19 }

 1 @SpringBootApplication 3 public class App {
 4 
 5     public static void main(String[] args) throws Exception {
 6         ConfigurableApplicationContext context = SpringApplication.run(App.class,args);
 7         DataSource ds = context.getBean(DataSource.class);
 8         Connection conn = ds.getConnection();
 9         System.out.println(conn.getCatalog());
10         System.out.println(context.getBean(JdbcTemplate.class));
11         conn.close();
12         System.out.println(ds.getClass());
13         context.close();
14     }
15 
16 }

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

1 <dependency>
2         <groupId>com.zaxxer</groupId>
3         <artifactId>HikariCP</artifactId>
4 </dependency>

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:

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

b)排除Tomcat的数据源

pom.xml:

 1         <dependency>
 2             <groupId>org.springframework.boot</groupId>
 3             <artifactId>spring-boot-starter-jdbc</artifactId>
 4             <exclusions>
 5                 <exclusion>
 6                     <groupId>org.apache.tomcat</groupId>
 7                     <artifactId>tomcat-jdbc</artifactId>
 8                 </exclusion>
 9             </exclusions>
10         </dependency>

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

1         <dependency>
2             <groupId>com.alibaba</groupId>
3             <artifactId>druid</artifactId>
4             <version>1.0.31</version>
5         </dependency>

 1 @SpringBootConfiguration
 2 public class DBConfiguration {
 3     @Autowired
 4     private Environment env;
 5     @Bean
 6     public DataSource createDataSource(){
 7         DruidDataSource ds = new DruidDataSource();
 8         ds.setUrl(env.getProperty("spring.datasource.url"));
 9         ds.setUsername(env.getProperty("spring.datasource.username"));
10         ds.setPassword(env.getProperty("spring.datasource.password"));
11         ds.setDriverClassName(env.getProperty("spring.datasource.driverClassName"));
12         return ds;
13     }
14 
15 }

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：

 1 @SpringBootApplication
 2 @EnableTransactionManagement
 3 public class App {
 4 
 5     public static void main(String[] args) throws Exception {
 6         ConfigurableApplicationContext context = SpringApplication.run(App.class,args);
 7 
 8         context.getBean(ProductDao.class).addProductBatch("TV","MP3","MP4");
 9         
10         System.out.println(ds.getClass());
11         context.close();
12     }
13 
14 }

 1 package com.study.spring_boot_jdbc.dao;
 2 
 3 import java.io.FileNotFoundException;
 4 
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.jdbc.core.JdbcTemplate;
 7 import org.springframework.stereotype.Repository;
 8 import org.springframework.transaction.annotation.Transactional;
 9 
10 @Repository
11 public class ProductDao {
12 
13     @Autowired
14     private JdbcTemplate jdbcTemplate;
15     
16     public void addProduct(String name){
17         String sql = "insert into product (pname) values ('" + name + "')";
18         jdbcTemplate.execute(sql);
19     }
20     
21     /**
22      * rollbackFor 设置对哪些异常进行回滚，默认是运行时异常
23      * noRollbackFor 设置哪些异常不回滚
24      * @param names
25      * @throws Exception
26      */
27     @Transactional(noRollbackFor=NullPointerException.class)
28     public void addProductBatch(String ... names) throws Exception{
29         for (String name : names) {
30             String sql = "insert into product (pname) values ('" + name + "')";
31             jdbcTemplate.execute(sql);
32             if ("".equals("")) {
33                 throw new NullPointerException();
34             }
35         }
36         
37     }
38 
39     
40 }

注意，在需要使用事务的方法上加上@Transactional！！！

 1 package com.study.spring_boot_jdbc.dao;
 2 
 3 import java.io.FileNotFoundException;
 4 
 5 import org.springframework.beans.factory.annotation.Autowired;
 6 import org.springframework.jdbc.core.JdbcTemplate;
 7 import org.springframework.stereotype.Repository;
 8 import org.springframework.transaction.annotation.Transactional;
 9 
10 @Repository
11 public class ProductDao {
12 
13     @Autowired
14     private JdbcTemplate jdbcTemplate;
15     
16     public void addProduct(String name){
17         String sql = "insert into product (pname) values ('" + name + "')";
18         jdbcTemplate.execute(sql);
19     }
20     
21     @Transactional
22     public void addProductBatch(String ... names) throws Exception{
23         add(names);
24         
25     }
26     
27     @Transactional
28     public void add(String ... names) throws Exception{
29         for (String name : names) {
30             String sql = "insert into product (pname) values ('" + name + "')";
31             jdbcTemplate.execute(sql);
32             if ("".equals("")) {
33                 throw new NullPointerException();
34             }
35         }
36     }
37     
38 }

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。

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原文地址：https://www.cnblogs.com/ivy-xu/p/6904711.html