public class DataSourceSelector {

     /**

     * 线程threadlocal

     */

    private static ThreadLocal<String> dbLookCxt = new ThreadLocal<>();

    public static final String _DEFAULT_DB = MultiDruidDataSources.PREFIX+".default";

    public static String getDataSourceKey() {

        String db = dbLookCxt.get();

        if (db == null) {

            db = _DEFAULT_DB;

        }

        return db;

    }

    public static void select(String dbKey) {

        dbLookCxt.set(dbKey);

    }

    public static void remove() {

        dbLookCxt.remove();

    }

}

public class TransactionContextHolder {

    public static final String TRACE_ID = "traceId";

    private static ThreadLocal<HashMap<String, String>> locals = new ThreadLocal<>();

    public static void set(HashMap<String, String> data){

        HashMap<String, String> map = locals.get();

        if (map == null) {

            locals.set(data);

        } else {

            map.putAll(data);

        }

        if (data.containsKey(TRACE_ID)) {

            String traceIdValue = data.get(TRACE_ID);

            MDC.put("traceId", traceIdValue);

        }

    }

    public static String get(String key) {

        return get().get(key);

    }

    public static void set(String key, String value){

        if (value != null && key != null){

            get().put(key, value);

            if (TRACE_ID.equals(key)) {

                MDC.put("traceId", value);

            }

        }

    }

    public static HashMap<String, String> get() {

        HashMap<String, String> map = locals.get();

        if (map == null) {

            map = new HashMap<>();

            set(map);

        }

        return map;

    }

    public static void remove(){

        locals.remove();

        MDC.remove("traceId");

    }

    public static void remove(String key) {

        get().remove(key);

    }

    public static void copy(Map<String, String> parentContext) {

        if (parentContext != null && parentContext.size() > 0) {

            get().putAll(parentContext);

        }

    }

}