项目中如果需要由多个数据源，比如3个，一个主两个从。主库主要是写操作，两个从库做读操作。
那么在spring boot中怎么使用AOP判断程序是读还是写，并且分配到不同的数据源中呢？
本文重要是 的代码是使用 spring boot 、druid、mybatis、mybatis plus等技术做支持的。
逻辑步骤
大概的逻辑为，
1、引入durid
2、配置三个数据源，1个写，2个读，两个从库实现简单的负载功能。
3、配置mybatis
4、配置mybatis plus
5、配置aop
6、定义却点 读（select）的方法操作，使用读库的数据源，其他的 update、delete、insert等使用写库的数据源
7、给写库配置spring 的事务，出现异常的时候回滚。
引入jar
这里不累赘写 mysql 、druid等jar包的引入。
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>配置Druid
@Configuration
public class DruidConfig {
/**
* 注册DruidServlet
* http://localhost:8080/druid/datasource.html查看监控信息
* @return
*/
@Bean
public ServletRegistrationBean druidServletRegistrationBean() {
ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
servletRegistrationBean.setServlet(new StatViewServlet());
servletRegistrationBean.addUrlMappings("/druid/*");
return servletRegistrationBean;
}
/**
* 注册DruidFilter拦截
*
* @return
*/
@Bean
public FilterRegistrationBean duridFilterRegistrationBean() {
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
filterRegistrationBean.setFilter(new WebStatFilter());
Map<String, String> initParams = new HashMap<String, String>();
//设置忽略请求
initParams.put("exclusions", "*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/monitor/druid/*");
filterRegistrationBean.setInitParameters(initParams);
filterRegistrationBean.addUrlPatterns("/*");
return filterRegistrationBean;
}
}
配置yml
writedatasource:
url: jdbc:mysql://xx.x.x.x:3306/slife?useUnicode=true&characterEncoding=utf8&useSSL=false
driverClass: com.mysql.jdbc.Driver
username: xx
password: cdd
initialSize: 1
minIdle: 1
maxActive: 20
testOnBorrow: true
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnReturn: false
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat,wall,logback
#connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
useGlobalDataSourceStat: true
mybatis:
mapper-locations: classpath:mapper/*.xml
type-aliases-package: com.slife.entity
readdatasource01:
url: jdbc:mysql://xx.x.x.x:3306/slife?useUnicode=true&characterEncoding=utf8&useSSL=false
driverClass: com.mysql.jdbc.Driver
username: xx
password: cdd
initialSize: 1
minIdle: 1
maxActive: 20
testOnBorrow: true
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnReturn: false
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat,wall,logback
#connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
useGlobalDataSourceStat: true
readdatasource02:
url: jdbc:mysql://xx.x.x.x:3306/slife?useUnicode=true&characterEncoding=utf8&useSSL=false
driverClass: com.mysql.jdbc.Driver
username: xx
password: cdd
initialSize: 1
minIdle: 1
maxActive: 20
testOnBorrow: true
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnReturn: false
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat,wall,logback
#connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
useGlobalDataSourceStat: true
加载配置文件数据
/**
* 只提供了常用的属性，如果有需要，自己添加
*
*/
@Component
@ConfigurationProperties(prefix = "writedatasource")
public class WriteProperties extends DataProperties{
}
/**
* 只提供了常用的属性，如果有需要，自己添加
*
*/
@Component
@ConfigurationProperties(prefix = "readdatasource02")
public class ReadProperties2 extends DataProperties{
}
@ConfigurationProperties(prefix = "druid")
public class DruidProperties {
private String url;
private String username;
private String password;
private String driverClass;
private int maxActive;
private int minIdle;
private int initialSize;
private boolean testOnBorrow;
private String filters;
。
。
。
。
get set 省略
3、定义数据源
public enum DataSourceType {
read("read", "从库"),
write("write", "主库");
private String type;
private String name;
DataSourceType(String type, String name) {
this.type = type;
this.name = name;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}简单的负载均衡配置
public class BlifeAbstractRoutingDataSource extends AbstractRoutingDataSource {
private int dataSourceNumber;
private AtomicInteger count = new AtomicInteger(0);
public BlifeAbstractRoutingDataSource(int dataSourceNumber) {
this.dataSourceNumber = dataSourceNumber;
}
@Override
protected Object determineCurrentLookupKey() {
String typeKey = DataSourceContextHolder.getJdbcType();
if (DataSourceType.write.getType().equals(typeKey)){
return DataSourceType.write.getType();
}
// 读 简单负载均衡
int number = count.getAndAdd(1);
int lookupKey = number % dataSourceNumber;
return new Integer(lookupKey);
}
}把数据源加ThreadLocal中
public class DataSourceContextHolder {
private static final ThreadLocal<String> LOCAL = new ThreadLocal<String>();
private static Logger logger = LoggerFactory.getLogger(DataSourceContextHolder.class);
public static ThreadLocal<String> getLocal() {
return LOCAL;
}
/**
* 读可能是多个库
*/
public static void read() {
LOCAL.set(DataSourceType.read.getType());
}
/**
* 写只有一个库
*/
public static void write() {
logger.debug("writewritewrite");
LOCAL.set(DataSourceType.write.getType());
}
public static String getJdbcType() {
return LOCAL.get();
}
}配置写库的事物
读库 一般没配置事物的需求，当然配置了只读会有更好的效果。
@Configuration
@EnableTransactionManagement
public class DataSourceTransactionManager extends DataSourceTransactionManagerAutoConfiguration {
private Logger logger= LoggerFactory.getLogger(getClass());
/**
* 自定义事务
* MyBatis自动参与到spring事务管理中，无需额外配置，
* 只要org.mybatis.spring.SqlSessionFactoryBean引用的数据源与
* DataSourceTransactionManager引用的数据源一致即可，否则事务管理会不起作用。
* @return
*/
@Resource(name = "writeDataSource1")
private DataSource dataSource;
@Bean(name = "transactionManager")
public org.springframework.jdbc.datasource.DataSourceTransactionManager transactionManagers() {
logger.info("-------------------- transactionManager init ---------------------");
return new org.springframework.jdbc.datasource.DataSourceTransactionManager(dataSource);
}
}约定方法，读写动态切换
@Aspect
@Component
@Order(-100)// 保证该AOP在@Transactional之前执行
public class DataSourceAop {
private Logger logger = LoggerFactory.getLogger(getClass());
@Before("execution(* com.slife.dao..*.select*(..)) || execution(* com.slife.dao..*.get*(..))")
public void setReadDataSourceType() {
DataSourceContextHolder.read();
logger.info("dataSource切换到：Read");
}
@Before("execution(* com.slife.dao..*.*insert*(..)) || execution(* com.slife.dao..*.*update*(..))")
public void setWriteDataSourceType() {
DataSourceContextHolder.write();
logger.info("dataSource切换到：write");
}
}运行项目，执行结果
点击获取阿里云优惠券
我的官网
我的官网http://guan2ye.com
我的CSDN地址http://blog.csdn.net/chenjianandiyi
我的简书地址http://www.jianshu.com/u/9b5d1921ce34
我的githubhttps://github.com/javanan
我的码云地址https://gitee.com/jamen/
阿里云优惠券https://promotion.aliyun.com/ntms/act/ambassador/sharetouser.html?userCode=vf2b5zld&utm_source=vf2b5zld
时间： 2024-08-01 16:14:45