Mybatis源码之Statement处理器CallableStatementHandler（六）

布满荆棘的人生 2022-03-01 07:57 236阅读 0赞

CallableStatementHandler实际就是使用CallableStatement来执行SQL语句，当然它执行的是存储过程。

源码如下：

/**
     * @author Clinton Begin
     */
    /***/
    public class CallableStatementHandler extends BaseStatementHandler {
     
      public CallableStatementHandler(Executor executor, MappedStatement mappedStatement, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) {
        super(executor, mappedStatement, parameter, rowBounds, resultHandler, boundSql);
      }
     
      public int update(Statement statement)
          throws SQLException {
    	//用来调用存储过程,它提供了对输出和输入/输出参数的支持
        CallableStatement cs = (CallableStatement) statement;
        cs.execute();
        int rows = cs.getUpdateCount();
        Object parameterObject = boundSql.getParameterObject();
        KeyGenerator keyGenerator = mappedStatement.getKeyGenerator();
        keyGenerator.processAfter(executor, mappedStatement, cs, parameterObject);
    	
        resultSetHandler.handleOutputParameters(cs);
        return rows;
      }
     
      public void batch(Statement statement)
          throws SQLException {
        CallableStatement cs = (CallableStatement) statement;
        cs.addBatch();
      }
     
      public <E> List<E> query(Statement statement, ResultHandler resultHandler)
          throws SQLException {
        CallableStatement cs = (CallableStatement) statement;
        cs.execute();
        List<E> resultList = resultSetHandler.<E>handleResultSets(cs);
        resultSetHandler.handleOutputParameters(cs);
        return resultList;
      }
     
      protected Statement instantiateStatement(Connection connection) throws SQLException {
        String sql = boundSql.getSql();
        if (mappedStatement.getResultSetType() != null) {
          return connection.prepareCall(sql, mappedStatement.getResultSetType().getValue(), ResultSet.CONCUR_READ_ONLY);
        } else {
          return connection.prepareCall(sql);
        }
      }
     
      public void parameterize(Statement statement) throws SQLException {
    	 //注册out参数
        registerOutputParameters((CallableStatement) statement);
        parameterHandler.setParameters((CallableStatement) statement);
      }
     
      private void registerOutputParameters(CallableStatement cs) throws SQLException {
        List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
        for (int i = 0, n = parameterMappings.size(); i < n; i++) {
          ParameterMapping parameterMapping = parameterMappings.get(i);
    	  //处理存储过程的INOUT和OUT
          if (parameterMapping.getMode() == ParameterMode.OUT || parameterMapping.getMode() == ParameterMode.INOUT) {
            if (null == parameterMapping.getJdbcType()) {
              throw new ExecutorException("The JDBC Type must be specified for output parameter.  Parameter: " + parameterMapping.getProperty());
            } else {
              if (parameterMapping.getNumericScale() != null && (parameterMapping.getJdbcType() == JdbcType.NUMERIC || parameterMapping.getJdbcType() == JdbcType.DECIMAL)) {
                cs.registerOutParameter(i + 1, parameterMapping.getJdbcType().TYPE_CODE, parameterMapping.getNumericScale());
              } else {
                if (parameterMapping.getJdbcTypeName() == null) {
                  cs.registerOutParameter(i + 1, parameterMapping.getJdbcType().TYPE_CODE);
                } else {
                  cs.registerOutParameter(i + 1, parameterMapping.getJdbcType().TYPE_CODE, parameterMapping.getJdbcTypeName());
                }
              }
            }
          }
        }
      }
     
    }

本文原文地址：[https://blog.csdn.net/qq924862077/article/details/52654228][https_blog.csdn.net_qq924862077_article_details_52654228]

[https_blog.csdn.net_qq924862077_article_details_52654228]: https://blog.csdn.net/qq924862077/article/details/52654228