java - 如何使用 JDBCTemplate 使线程尝试重新连接到数据库 x 次

Question

我有一个线程尝试使用 JDBCTemplate 连接到数据库，如下所示:

JDBCTemplate jdbcTemplate =  new JdbcTemplate(dataSource); 

try{
    jdbcTemplate.execute(new CallableStatementCreator() {
        @Override
        public CallableStatement createCallableStatement(Connection con)
        throws SQLException {
            return con.prepareCall(query);
        }
    }, new CallableStatementCallback() {
        @Override
        public Object doInCallableStatement(CallableStatement cs)
        throws SQLException {
            cs.setString(1, subscriberID);
            cs.execute();
            return null;
        }
    });
 } catch (DataAccessException dae) {
     throw new CougarFrameworkException(
             "Problem removing subscriber from events queue: "
             + subscriberID, dae);
 }

我想确保如果上面的代码抛出 DataAccessException 或 SQLException，线程会等待几秒钟并尝试重新连接，再说 5 次然后放弃。我怎样才能做到这一点？此外，如果在执行期间数据库出现故障并再次出现，我如何确保我的程序从中恢复并继续运行而不是抛出异常并退出？

提前致谢。

Answer 1

试试这个。我的考虑是:运行一个循环，直到语句执行成功。如果失败，容忍失败5次，每次等待2秒，等待下一次执行。

JDBCTemplate jdbcTemplate =  new JdbcTemplate(dataSource); 
boolean successfullyExecuted = false;
int failCount = 0;
while (!successfullyExecuted){
 try{
    jdbcTemplate.execute(new CallableStatementCreator() {
        @Override
        public CallableStatement createCallableStatement(Connection con)
        throws SQLException {
            return con.prepareCall(query);
        }
    }, new CallableStatementCallback() {
        @Override
        public Object doInCallableStatement(CallableStatement cs)
        throws SQLException {
            cs.setString(1, subscriberID);
            cs.execute();
            return null;
        }
    });
    successfullyExecuted = true;
 } catch (DataAccessException dae) {
     if (failedCount < 5){
        failedCount ++;
        try{java.lang.Thread.sleep(2 * 1000L); // Wait for 2 seconds
        }catch(java.lang.Exception e){}
     }else{
     throw new CougarFrameworkException(
             "Problem removing subscriber from events queue: "
             + subscriberID, dae);
     }
 } catch (java.sql.SQLException sqle){
     if (failedCount < 5){
        failedCount ++;
     }else{
     try{java.lang.Thread.sleep(2 * 1000L); // Wait for 2 seconds
     }catch(java.lang.Exception e){}
     throw new CougarFrameworkException(
             "Problem removing subscriber from events queue: "
             + subscriberID, dae);
     }
 }
}