Spring框架学习[JdbcTemplate封装Jdbc] - JAVA

ert.notNull(action, "Callback object must not be null"); if (logger.isDebugEnabled()) { String sql = getSql(psc); logger.debug("Executing prepared SQL statement" + (sql != null " [" + sql + "]" : "")); } //获取数据库连接 Connection con = DataSourceUtils.getConnection(getDataSource()); PreparedStatement ps = null; try { Connection conToUse = con; //如果JdbcTemplate指定了jdbc本地提取器，则将获取到的数据库连接转换 //为本地数据库连接 if (this.nativeJdbcExtractor != null && this.nativeJdbcExtractor.isNativeConnectionNecessaryForNativePreparedStatements()) { conToUse = this.nativeJdbcExtractor.getNativeConnection(con); } //根据数据库连接和sql语句创建PreparedStatement ps = psc.createPreparedStatement(conToUse); applyStatementSettings(ps); PreparedStatement psToUse = ps; //如果JdbcTemplate指定了jdbc本地提取器，则将PreparedStatement转换 //为本地PreparedStatement if (this.nativeJdbcExtractor != null) { psToUse = this.nativeJdbcExtractor.getNativePreparedStatement(ps); } //调用回调处理器，执行相应操作 T result = action.doInPreparedStatement(psToUse); handleWarnings(ps); return result; } catch (SQLException ex) { //关闭资源，释放连接 if (psc instanceof ParameterDisposer) { ((ParameterDisposer) psc).cleanupParameters(); } String sql = getSql(psc); psc = null; JdbcUtils.closeStatement(ps); ps = null; DataSourceUtils.releaseConnection(con, getDataSource()); con = null; //将jdbc相关异常封装转换为Spring异常向调用者抛出 throw getExceptionTranslator().translate("PreparedStatementCallback", sql, ex); } finally { //清除PreparedStatement的参数 if (psc instanceof ParameterDisposer) { ((ParameterDisposer) psc).cleanupParameters(); } //关闭PreparedStatement JdbcUtils.closeStatement(ps); //释放数据库连接 DataSourceUtils.releaseConnection(con, getDataSource()); } }

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</div>//PreparedStatement处理sql语句的execute方法public <T> T execute(String sql, PreparedStatementCallback<T> action) throws DataAccessException {//将sql语句封装成为SimplePreparedStatementCreator，调用处理//PreparedStatement的方法		return execute(new SimplePreparedStatementCreator(sql), action);	}//处理PreparedStatementpublic <T> T execute(PreparedStatementCreator psc, PreparedStatementCallback<T> action)			throws DataAccessException {		Assert.notNull(psc, "PreparedStatementCreator must not be null");		Assert.notNull(action, "Callback object must not be null");		if (logger.isDebugEnabled()) {			String sql = getSql(psc);			logger.debug("Executing prepared SQL statement" + (sql != null   " [" + sql + "]" : ""));		}		//获取数据库连接		Connection con = DataSourceUtils.getConnection(getDataSource());		PreparedStatement ps = null;		try {			Connection conToUse = con;	    //如果JdbcTemplate指定了jdbc本地提取器，则将获取到的数据库连接转换//为本地数据库连接			if (this.nativeJdbcExtractor != null &&	this.nativeJdbcExtractor.isNativeConnectionNecessaryForNativePreparedStatements()) {				conToUse = this.nativeJdbcExtractor.getNativeConnection(con);			}			//根据数据库连接和sql语句创建PreparedStatement			ps = psc.createPreparedStatement(conToUse);			applyStatementSettings(ps);			PreparedStatement psToUse = ps;			//如果JdbcTemplate指定了jdbc本地提取器，则将PreparedStatement转换//为本地PreparedStatement			if (this.nativeJdbcExtractor != null) {				psToUse = this.nativeJdbcExtractor.getNativePreparedStatement(ps);			}			//调用回调处理器，执行相应操作			T result = action.doInPreparedStatement(psToUse);			handleWarnings(ps);			return result;		}		catch (SQLException ex) {			//关闭资源，释放连接			if (psc instanc</span>
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