Spring Dao异常体系

叁歲伎倆 2022-10-12 05:45 175阅读 0赞

### 目录 ###

*   *  DataAccessException
     *  TransientDataAccessException
     *  NonTransientDataAccessException

Spring 抽象了一套和底层持久化技术无关的 、 面向 DAO 层的异常体系。在内部：通过异常转换器（`SQLExceptionTranslator`）将不同持久化技术的异常（`SQLException`，`SQLException` 与具体数据库强相关）转换成 Spring 的持久层异常（`DataAccessException`），实现统一管理。

## DataAccessException ##

DataAccessExceptionTransientDataAccessExceptionNonTransientDataAccessExceptionScriptExceptionRecoverableDataAccessException

Spring-Dao层 Root根异常，由标准的 `SQLException`转化而来。

那么`SQLException`如何转化为`DataAccessException`的呢？

答：在 `org.springframework.jdbc.support` 包中定义了 `SQLExceptionTranslator` 接口。

DataAccessException translate(String task, @Nullable String sql, SQLException ex);

入参是标准的`SQLException`，返回的是转换后的`DataAccessException`。

该接口的两个实现类 `SQLErrorCodeSQLExceptionTranslator` 和 `SQLStateSQLExceptionTranslator`。

SQLExceptionTranslatorSQLErrorCodeSQLExceptionTranslatorSQLStateSQLExceptionTranslator

`SQLErrorCodeSQLExceptionTranslator`是根据`SQLException`的错误码`SQLState`进行转化，其中SQL错误码和具体异常映射关系是在：sql-error-codes.xml中声明的。如下格式

<bean id="MySQL" class="org.springframework.jdbc.support.SQLErrorCodes">
       <property name="databaseProductNames">
          <list>
             <value>MySQL</value>
             <value>MariaDB</value>
          </list>
       </property>
       <property name="badSqlGrammarCodes">
          <value>1054,1064,1146</value>
       </property>
       <property name="duplicateKeyCodes">
          <value>1062</value>
       </property>
       <property name="dataIntegrityViolationCodes">
          <value>630,839,840,893,1169,1215,1216,1217,1364,1451,1452,1557</value>
       </property>
       <property name="dataAccessResourceFailureCodes">
          <value>1</value>
       </property>
       <property name="cannotAcquireLockCodes">
          <value>1205,3572</value>
       </property>
       <property name="deadlockLoserCodes">
          <value>1213</value>
       </property>
    </bean>
    
    <bean id="Oracle" class="org.springframework.jdbc.support.SQLErrorCodes">
       <property name="badSqlGrammarCodes">
          <value>900,903,904,917,936,942,17006,6550</value>
       </property>
       <property name="invalidResultSetAccessCodes">
          <value>17003</value>
       </property>
       <property name="duplicateKeyCodes">
          <value>1</value>
       </property>
       <property name="dataIntegrityViolationCodes">
          <value>1400,1722,2291,2292</value>
       </property>
       <property name="dataAccessResourceFailureCodes">
          <value>17002,17447</value>
       </property>
       <property name="cannotAcquireLockCodes">
          <value>54,30006</value>
       </property>
       <property name="cannotSerializeTransactionCodes">
          <value>8177</value>
       </property>
       <property name="deadlockLoserCodes">
          <value>60</value>
       </property>
    </bean>

而`SQLStateSQLExceptionTranslator`是根据`SQLException`中的状态码（`SQLState`的前两位）进行转化的。

## TransientDataAccessException ##

TransientDataAccessExceptionQueryTimeoutExceptionConcurrencyFailureExceptionPessimisticLockingFailureExceptionCannotAcquireLockExceptionCannotSerializeTransactionExceptionDeadlockLoserDataAccessExceptionOptimisticLockingFailureExceptionTransientDataAccessResourceException

`TransientDataAccessException`，瞬态异常，失败的操作重试可能会成功。

比如：QueryTimeoutException、CannotAcquireLockException异常都属于瞬态异常。

<table> 
 <thead> 
  <tr> 
   <th>异常</th> 
   <th>描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>QueryTimeoutException</td> 
   <td>查询超时（Exception to be thrown on a query timeout. ）</td> 
  </tr> 
  <tr> 
   <td>ConcurrencyFailureException</td> 
   <td>并发相关的异常（Exception thrown on concurrency failure.）</td> 
  </tr> 
  <tr> 
   <td>PessimisticLockingFailureException</td> 
   <td>悲观锁，锁定引发的异常（Exception thrown on a pessimistic locking violation.）</td> 
  </tr> 
  <tr> 
   <td>OptimisticLockingFailureException</td> 
   <td>乐观锁，锁定引发的异常（Exception thrown on an optimistic locking violation.）</td> 
  </tr> 
  <tr> 
   <td>CannotAcquireLockException</td> 
   <td>获取锁失败（Exception thrown on failure to acquire a lock during an update，for example during a “select for update” statement.）</td> 
  </tr> 
  <tr> 
   <td>CannotSerializeTransactionException</td> 
   <td>在串行(serialized)的事务隔离级别中，由于update竞争失败抛出来的异常（Exception thrown on failure to complete a transaction in serializedmode due to update conflicts）</td> 
  </tr> 
  <tr> 
   <td>DeadlockLoserDataAccessException</td> 
   <td>死锁</td> 
  </tr> 
  <tr> 
   <td>TransientDataAccessResourceException</td> 
   <td>资源暂时出现故障时导致的数据访问异常，可以进行重试（Data access exception thrown when a resource fails temporarily and the operation can be retried.）</td> 
  </tr> 
 </tbody> 
</table>

## NonTransientDataAccessException ##

NonTransientDataAccessExceptionDataIntegrityViolationExceptionDuplicateKeyExceptionInvalidDataAccessResourceUsageExceptionBadSqlGrammarExceptionInvalidResultSetAccessExceptionTypeMismatchDataAccessExceptionIncorrectUpdateSemanticsDataAccessExceptionJdbcUpdateAffectedIncorrectNumberOfRowsExceptionNonTransientDataAccessResourceExceptionDataAccessResourceFailureExceptionCannotGetJdbcConnectionExceptionDataSourceLookupFailureExceptionUncategorizedDataAccessExceptionSQLWarningExceptionUncategorizedSQLExceptionDataRetrievalFailureExceptionCleanupFailureDataAccessExceptionPermissionDeniedDataAccessExceptionIncorrectResultSizeDataAccessExceptionEmptyResultDataAccessExceptionLobRetrievalFailureExceptionIncorrectResultSetColumnCountExceptionInvalidDataAccessApiUsageExceptionSqlXmlFeatureNotImplementedException

`NonTransientDataAccessException`，非瞬态异常，重试仍然会失败。比如：BadSqlGrammarException就是该异常的子类。