注:本文的多数据源配置及切换的实现方法是,在框架中封装,具体项目中配置及使用,也适用于多模块项目
配置文件数据源读取
通过springboot的Envioment和Binder对象进行读取,无需手动声明DataSource的Bean
yml数据源配置格式如下:
spring:
datasource:
master:
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/main?
useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai
username: root
password: 11111
cluster:
- key: db1
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/haopanframetest_db1?
useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai
username: root
password: 11111
- key: db2
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/haopanframetest_db2?
useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&serverTimezone=Asia/Shanghai
username: root
password: 11111
master为主数据库必须配置,cluster下的为从库,选择性配置
获取配置文件信息代码如下
@Autowired
private Environment env;
@Autowired
private ApplicationContext applicationContext;
private Binder binder;
binder = Binder.get(env);
List<Map> configs = binder.bind("spring.datasource.cluster", Bindable.listOf(Map.class)).get();
for (int i = 0; i < configs.size(); i++) {
config = configs.get(i);
String key = ConvertOp.convert2String(config.get("key"));
String type = ConvertOp.convert2String(config.get("type"));
String driverClassName = ConvertOp.convert2String(config.get("driverClassName"));
String url = ConvertOp.convert2String(config.get("url"));
String username = ConvertOp.convert2String(config.get("username"));
String password = ConvertOp.convert2String(config.get("password"));
}
动态加入数据源
定义获取数据源的Service,具体项目中进行实现
public interface ExtraDataSourceService {
List<DataSourceModel> getExtraDataSourc();
}
获取对应Service的所有实现类进行调用
private List<DataSourceModel> getExtraDataSource(){
List<DataSourceModel> dataSourceModelList = new ArrayList<>();
Map<String, ExtraDataSourceService> res =
applicationContext.getBeansOfType(ExtraDataSourceService.class);
for (Map.Entry en :res.entrySet()) {
ExtraDataSourceService service = (ExtraDataSourceService)en.getValue();
dataSourceModelList.addAll(service.getExtraDataSourc());
}
return dataSourceModelList;
}
通过代码进行数据源注册
主要是用过继承类AbstractRoutingDataSource,重写setTargetDataSources/setDefaultTargetDataSource方法
// 创建数据源
public boolean createDataSource(String key, String driveClass, String url, String username, String password, String databasetype) {
try {
try { // 排除连接不上的错误
Class.forName(driveClass);
DriverManager.getConnection(url, username, password);// 相当于连接数据库
} catch (Exception e) {
return false;
}
@SuppressWarnings("resource")
DruidDataSource druidDataSource = new DruidDataSource();
druidDataSource.setName(key);
druidDataSource.setDriverClassName(driveClass);
druidDataSource.setUrl(url);
druidDataSource.setUsername(username);
druidDataSource.setPassword(password);
druidDataSource.setInitialSize(1); //初始化时建立物理连接的个数。初始化发生在显示调用init方法,或者第一次getConnection时
druidDataSource.setMaxActive(20); //最大连接池数量
druidDataSource.setMaxWait(60000); //获取连接时最大等待时间,单位毫秒。当链接数已经达到了最大链接数的时候,应用如果还要获取链接就会出现等待的现象,等待链接释放并回到链接池,如果等待的时间过长就应该踢掉这个等待,不然应用很可能出现雪崩现象
druidDataSource.setMinIdle(5); //最小连接池数量
String validationQuery = "select 1 from dual";
druidDataSource.setTestOnBorrow(true); //申请连接时执行validationQuery检测连接是否有效,这里建议配置为TRUE,防止取到的连接不可用
druidDataSource.setTestWhileIdle(true);//建议配置为true,不影响性能,并且保证安全性。申请连接的时候检测,如果空闲时间大于timeBetweenEvictionRunsMillis,执行validationQuery检测连接是否有效。
druidDataSource.setValidationQuery(validationQuery); //用来检测连接是否有效的sql,要求是一个查询语句。如果validationQuery为null,testOnBorrow、testOnReturn、testWhileIdle都不会起作用。
druidDataSource.setFilters("stat");//属性类型是字符串,通过别名的方式配置扩展插件,常用的插件有:监控统计用的filter:stat日志用的filter:log4j防御sql注入的filter:wall
druidDataSource.setTimeBetweenEvictionRunsMillis(60000); //配置间隔多久才进行一次检测,检测需要关闭的空闲连接,单位是毫秒
druidDataSource.setMinEvictableIdleTimeMillis(180000); //配置一个连接在池中最小生存的时间,单位是毫秒,这里配置为3分钟180000
druidDataSource.setKeepAlive(true); //打开druid.keepAlive之后,当连接池空闲时,池中的minIdle数量以内的连接,空闲时间超过minEvictableIdleTimeMillis,则会执行keepAlive操作,即执行druid.validationQuery指定的查询SQL,一般为select * from dual,只要minEvictableIdleTimeMillis设置的小于防火墙切断连接时间,就可以保证当连接空闲时自动做保活检测,不会被防火墙切断
druidDataSource.setRemoveAbandoned(true); //是否移除泄露的连接/超过时间限制是否回收。
druidDataSource.setRemoveAbandonedTimeout(3600); //泄露连接的定义时间(要超过最大事务的处理时间);单位为秒。这里配置为1小时
druidDataSource.setLogAbandoned(true); //移除泄露连接发生是是否记录日志
druidDataSource.init();
this.dynamicTargetDataSources.put(key, druidDataSource);
setTargetDataSources(this.dynamicTargetDataSources);// 将map赋值给父类的TargetDataSources
super.afterPropertiesSet();// 将TargetDataSources中的连接信息放入resolvedDataSources管理
log.info(key+"数据源初始化成功");
//log.info(key+"数据源的概况:"+druidDataSource.dump());
return true;
} catch (Exception e) {
log.error(e + "");
return false;
}
}
通过切面注解统一切换
定义注解
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE, ElementType.PARAMETER})
@Documented
public @interface TargetDataSource {
String value() default "master"; //该值即key值
}
定义基于线程的切换类
public class DBContextHolder {
private static Logger log = LoggerFactory.getLogger(DBContextHolder.class);
// 对当前线程的操作-线程安全的
private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
// 调用此方法,切换数据源
public static void setDataSource(String dataSource) {
contextHolder.set(dataSource);
log.info("已切换到数据源:{}",dataSource);
}
// 获取数据源
public static String getDataSource() {
return contextHolder.get();
}
// 删除数据源
public static void clearDataSource() {
contextHolder.remove();
log.info("已切换到主数据源");
}
}
定义切面
方法的注解优先级高于类注解,一般用于Service的实现类
@Aspect
@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class DruidDBAspect {
private static Logger logger = LoggerFactory.getLogger(DruidDBAspect.class);
@Autowired
private DynamicDataSource dynamicDataSource;
/**
* 切面点 指定注解
* */
@Pointcut("@annotation(com.haopan.frame.common.annotation.TargetDataSource) " +
"|| @within(com.haopan.frame.common.annotation.TargetDataSource)")
public void dataSourcePointCut() {
}
/**
* 拦截方法指定为 dataSourcePointCut
* */
@Around("dataSourcePointCut()")
public Object around(ProceedingJoinPoint point) throws Throwable {
MethodSignature signature = (MethodSignature) point.getSignature();
Class targetClass = point.getTarget().getClass();
Method method = signature.getMethod();
TargetDataSource targetDataSource = (TargetDataSource)targetClass.getAnnotation(TargetDataSource.class);
TargetDataSource methodDataSource = method.getAnnotation(TargetDataSource.class);
if(targetDataSource != null || methodDataSource != null){
String value;
if(methodDataSource != null){
value = methodDataSource.value();
}else {
value = targetDataSource.value();
}
DBContextHolder.setDataSource(value);
logger.info("DB切换成功,切换至{}",value);
}
try {
return point.proceed();
} finally {
logger.info("清除DB切换");
DBContextHolder.clearDataSource();
}
}
}
分库切换
开发过程中某个库的某个表做了拆分操作,相同的某一次数据库操作可能对应到不同的库,需要对方法级别进行精确拦截,可以定义一个业务层面的切面,规定每个方法必须第一个参数为dbName,根据具体业务找到对应的库传参
@Around("dataSourcePointCut()")
public Object around(ProceedingJoinPoint point) throws Throwable {
MethodSignature signature = (MethodSignature) point.getSignature();
Class targetClass = point.getTarget().getClass();
Method method = signature.getMethod();
ProjectDataSource targetDataSource =
(ProjectDataSource)targetClass.getAnnotation(ProjectDataSource.class);
ProjectDataSource methodDataSource = method.getAnnotation(ProjectDataSource.class);
String value = "";
if(targetDataSource != null || methodDataSource != null){
//获取方法定义参数
DefaultParameterNameDiscoverer discover = new DefaultParameterNameDiscoverer();
String[] parameterNames = discover.getParameterNames(method);
//获取传入目标方法的参数
Object[] args = point.getArgs();
for (int i=0;i<parameterNames.length;i++){
String pName = parameterNames[i];
if(pName.toLowerCase().equals("dbname")){
value = ConvertOp.convert2String(args[i]);
}
}
if(!StringUtil.isEmpty(value)){
DBContextHolder.setDataSource(value);
logger.info("DB切换成功,切换至{}",value);
}
}
try {
return point.proceed();
} finally {
if(!StringUtil.isEmpty(value)){
logger.info("清除DB切换");
DBContextHolder.clearDataSource();
}
}
}