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1.创建DynamicDataSource并继承AbstractRoutingDataSource，实现determineCurrentLookupKey方法
public final class DynamicDataSource extends AbstractRoutingDataSource implements ApplicationContextAware {
? ? private static final String DATA_SOURCES_NAME = "targetDataSources";
? ? private ApplicationContext applicationContext;
? ? @Override
? ? protected Object determineCurrentLookupKey() {
? ? ? ? DataSourceBeanBuilder dataSourceBeanBuilder = DataSourceHolder.getDataSource();
? ? ? ? if (dataSourceBeanBuilder == null) {
? ? ? ? ? ? return null;
? ? ? ? }
? ? ? ? DataSourceBean dataSourceBean = new DataSourceBean(dataSourceBeanBuilder);
? ? ? ? try {
? ? ? ? ? ? Map<Object, Object> map = null;
? ? ? ? ? ? map = getTargetDataSources();
? ? ? ? ? ? synchronized (map) {
? ? ? ? ? ? ? ? if (!map.containsKey(dataSourceBean.getBeanName())) {
? ? ? ? ? ? ? ? ? ? map.put(dataSourceBean.getBeanName(), createDataSource(dataSourceBean));
? ? ? ? ? ? ? ? ? ? super.afterPropertiesSet();//通知spring有bean更新
? ? ? ? ? ? ? ? }
? ? ? ? ? ? }
? ? ? ? } catch (NoSuchFieldException e) {
? ? ? ? ? ? logger.info("failed:" + e);
? ? ? ? } catch (IllegalAccessException e) {
? ? ? ? ? ? logger.info("failed:" + e);
? ? ? ? }
? ? ? ? return dataSourceBean.getBeanName();
? ? }
? ? private Object createDataSource(DataSourceBean dataSourceBean) throws IllegalAccessException {
? ? ? ? //在spring容器中创建并且声明bean
? ? ? ? ConfigurableApplicationContext context = (ConfigurableApplicationContext) applicationContext;
? ? ? ? DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) context.getBeanFactory();
? ? ? ? BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(DruidDataSource.class);
? ? ? ? //将dataSourceBean中的属性值赋给目标bean
? ? ? ? Map<String, Object> properties = getPropertyKeyValues(DataSourceBean.class, dataSourceBean);
? ? ? ? for (Map.Entry<String, Object> entry : properties.entrySet()) {
? ? ? ? ? ? beanDefinitionBuilder.addPropertyValue((String) entry.getKey(), entry.getValue());
? ? ? ? }
? ? ? ? beanFactory.registerBeanDefinition(dataSourceBean.getBeanName(), beanDefinitionBuilder.getBeanDefinition());
? ? ? ? return applicationContext.getBean(dataSourceBean.getBeanName());
? ? }
? ? private Map<Object, Object> getTargetDataSources() throws NoSuchFieldException, IllegalAccessException {
? ? ? ? Field field = AbstractRoutingDataSource.class.getDeclaredField(DATA_SOURCES_NAME);
? ? ? ? field.setAccessible(true);
? ? ? ? return (Map<Object, Object>) field.get(this);
? ? }
? ? private <T> Map<String, Object> getPropertyKeyValues(Class<T> clazz, Object object) throws IllegalAccessException {
? ? ? ? Field[] fields = clazz.getDeclaredFields();
? ? ? ? Map<String, Object> result = new HashMap<String, Object>();
? ? ? ? for (Field field : fields) {
? ? ? ? ? ? field.setAccessible(true);
? ? ? ? ? ? result.put(field.getName(), field.get(object));
? ? ? ? }
? ? ? ? result.remove("beanName");
? ? ? ? return result;
? ? }
? ? @Override
? ? public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
? ? ? ? this.applicationContext=applicationContext;
? ? }
}
2.threadLocal保存数据库连接信息表，保证线程安全
public final class DataSourceHolder {
? ? private static ThreadLocal<DataSourceBeanBuilder> threadLocal=new ThreadLocal<DataSourceBeanBuilder>(){
? ? ? ? @Override
? ? ? ? protected DataSourceBeanBuilder initialValue() {
? ? ? ? ? ? return null;
? ? ? ? }
? ? };
? ? static DataSourceBeanBuilder getDataSource(){
? ? ? ? return threadLocal.get();
? ? }
? ? public static void setDataSource(DataSourceBeanBuilder dataSourceBeanBuilder){
? ? ? ? threadLocal.set(dataSourceBeanBuilder);
? ? }
? ? public static void clearDataSource(){
? ? ? ? threadLocal.remove();
? ? }
}
3.设置数据源上下文环境工具类
public class DataSourceContext {
? ? public static void setDataSource(DataSourceBeanBuilder dataSourceBeanBuilder) {
? ? ? ? DataSourceHolder.setDataSource(dataSourceBeanBuilder);
? ? }
? ? public static void clearDataSource() {
? ? ? ? DataSourceHolder.clearDataSource();
? ? }
}
4.测试
public List<Object> exectQuery4LimitQuery(DataSourceBeanBuilder dataSourceBeanBuilder, String resourceSql, long limitCount, long offset, String queryConditions, String path) {
? ? ? ? List<Object> queryResults = new ArrayList<>();
? ? ? ? DataSourceContext.setDataSource(dataSourceBeanBuilder);
? ? ? ? try {
? ? ? ? ? ? //region 查询数据
? ? ? ? ? ?
? ? ? ? ? ? //endregion 时间格式字段处理完毕
? ? ? ? } catch (Exception e) {
? ? ? ? ? ? logger.error(String.format("url %s query sql error for %s", resourceSql, e));
? ? ? ? ? ? throw new RuntimeException("querying database error");
? ? ? ? } finally {
? ? ? ? ? ? DataSourceContext.clearDataSource();
? ? ? ? }
? ? ? ? return queryResults;
? ? }
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