今日练习：SpringBoot整合jdbc

将启动器，数据库驱动，数据源依赖添加到pom.xml文件中

<!-- jdbc启动器 -->
		
			org.springframework.boot
			spring-boot-starter-jdbc
		
<!-- 数据库驱动，根据自己的数据库版本决定-->
		
			mysql
			mysql-connector-java
			8.0.13
		

		>
			>com.alibaba>
			>druid>
			>1.1.12>
		>

第一种：

在resource目录创建jdbc.properties文件

jdbc.driverClassName=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/miduoduo?useSSL=false&serverTimezone=UTC&characterEncoding=utf-8
jdbc.username=root
jdbc.password=123456

创建一个类用于获取DataSource

@Configuration
@PropertySource("classpath:/jdbc.properties")//加载指定的properties文件
public class JDBCConfig {
     
	@Value("${jdbc.username}")
private String username;
	@Value("${jdbc.password}")
private String password;
	@Value("${jdbc.url}")
private String url;
	@Value("${jdbc.driverClassName}")
private String driverClassName;
@Bean
public DataSource getDataSource() {
     
	DruidDataSource source=new DruidDataSource();
	source.setUsername(username);
	source.setPassword(password);
	source.setUrl(url);
	source.setDriverClassName(driverClassName);
	return source;
}
}

第二种：可以通过属性，构造，入参，只要改动获取DataSource的类就行

通过属性：

直接在application配置文件中添加jdbc连接属性，注意除了前缀后面的部分必须与属性名相同
yaml格式：

jdbc: 
 driverClassName: com.mysql.cj.jdbc.Driver
 url: jdbc:mysql://localhost:3306/miduoduo?useSSL=false&serverTimezone=UTC&characterEncoding=utf-8
 username: root
 password: 123456

properties格式：

jdbc.driverClassName=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/miduoduo?useSSL=false&serverTimezone=UTC&characterEncoding=utf-8
jdbc.username=root
jdbc.password=123456

创建一个JDBC属性配置类（随便啥子名字都行）

@ConfigurationProperties(prefix = "jdbc")//springboot的注解，只能读取springboot的配置文件，prefix规定读取以什么为前缀的属性
public class JDBC {
     
private String username;
private String password;
private String url;
private String driverClassName;
public JDBC() {
     }

public JDBC(String username, String password, String url, String driverClassName) {
     
	super();
	this.username = username;
	this.password = password;
	this.url = url;
	this.driverClassName = driverClassName;
}

public String getUsername() {
     
	return username;
}
public void setUsername(String username) {
     
	this.username = username;
}
public String getPassword() {
     
	return password;
}
public void setPassword(String password) {
     
	this.password = password;
}
public String getUrl() {
     
	return url;
}
public void setUrl(String url) {
     
	this.url = url;
}
public String getDriverClassName() {
     
	return driverClassName;
}
public void setDriverClassName(String driverClassName) {
     
	this.driverClassName = driverClassName;
}

}

获取DataSource的类

@Configuration
//@PropertySource("classpath:/jdbc.properties")//加载指定的properties文件
@EnableConfigurationProperties(JDBC.class)
public class JDBCConfig {
     
@Autowired
private JDBC jdbc;
@Bean
public DataSource getDataSource() {
     
	DruidDataSource source=new DruidDataSource();
	source.setUsername(jdbc.getUsername());
	source.setPassword(jdbc.getPassword());
	source.setUrl(jdbc.getUrl());
	source.setDriverClassName(jdbc.getDriverClassName());
	return source;
}
}

通过构造
获取DataSource的类

@Configuration
//@PropertySource("classpath:/jdbc.properties")//加载指定的properties文件
@EnableConfigurationProperties(JDBC.class)
public class JDBCConfig {
     
private JDBC jdbc;
public JDBCConfig(JDBC jdbc){
     
this.jdbc=jdbc;
}
@Bean
public DataSource getDataSource() {
     
	DruidDataSource source=new DruidDataSource();
	source.setUsername(jdbc.getUsername());
	source.setPassword(jdbc.getPassword());
	source.setUrl(jdbc.getUrl());
	source.setDriverClassName(jdbc.getDriverClassName());
	return source;
}
}

通过入参
获取DataSource的类

@Configuration
//@PropertySource("classpath:/jdbc.properties")//加载指定的properties文件
@EnableConfigurationProperties(JDBC.class)
public class JDBCConfig {
     
@Bean
public DataSource getDataSource(JDBC jdbc) {
     
	DruidDataSource source=new DruidDataSource();
	source.setUsername(jdbc.getUsername());
	source.setPassword(jdbc.getPassword());
	source.setUrl(jdbc.getUrl());
	source.setDriverClassName(jdbc.getDriverClassName());
	return source;
}
}

第三种

没有JDBC配置属性类，直接在获取DataSource的类中装配DruidDataSource
直接在application配置文件中添加jdbc连接属性
yaml格式：

jdbc: 
 driverClassName: com.mysql.cj.jdbc.Driver
 url: jdbc:mysql://localhost:3306/miduoduo?useSSL=false&serverTimezone=UTC&characterEncoding=utf-8
 username: root
 password: 123456

properties格式：

jdbc.driverClassName=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/miduoduo?useSSL=false&serverTimezone=UTC&characterEncoding=utf-8
jdbc.username=root
jdbc.password=123456

获取DataSource的类

@Configuration
//@PropertySource("classpath:/jdbc.properties")//加载指定的properties文件
//@EnableConfigurationProperties(JDBC.class)
public class JDBCConfig {
     

@Bean
@ConfigurationProperties(prefix = "jdbc")//直接将注解标注在方法上，自动装配在配置文件中以jdbc为前缀的属性
public DataSource getDataSource() {
     
	DruidDataSource source=new DruidDataSource();
	return source;
}
}