Mybatis源码之Statement处理器RoutingStatementHandler（三）

我会带着你远行 2022-03-02 08:42 156阅读 0赞

RoutingStatementHandler类似路由器，在其构造函数中会根据Mapper文件中设置的StatementType来选择使用SimpleStatementHandler、PreparedStatementHandler和CallableStatementHandler，其实现的接口StatementHandler的方法也是由这三个具体实现类来实现。

源码如下：

/**
     * @author Clinton Begin
     */
    //类似于路由器
    public class RoutingStatementHandler implements StatementHandler {
     
      private final StatementHandler delegate;
     
      //选择三种Statement，SimpleStatementHandler、PreparedStatementHandler和CallableStatementHandler
      public RoutingStatementHandler(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) {
     
        switch (ms.getStatementType()) {
          case STATEMENT:
            delegate = new SimpleStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql);
            break;
          case PREPARED:
            delegate = new PreparedStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql);
            break;
          case CALLABLE:
            delegate = new CallableStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql);
            break;
          default:
            throw new ExecutorException("Unknown statement type: " + ms.getStatementType());
        }
     
      }
     
      //选中的Statement的操作
      public Statement prepare(Connection connection) throws SQLException {
        return delegate.prepare(connection);
      }
     
      public void parameterize(Statement statement) throws SQLException {
        delegate.parameterize(statement);
      }
     
      public void batch(Statement statement) throws SQLException {
        delegate.batch(statement);
      }
     
      public int update(Statement statement) throws SQLException {
        return delegate.update(statement);
      }
     
      public <E> List<E> query(Statement statement, ResultHandler resultHandler) throws SQLException {
        return delegate.<E>query(statement, resultHandler);
      }
     
      public BoundSql getBoundSql() {
        return delegate.getBoundSql();
      }
     
      public ParameterHandler getParameterHandler() {
        return delegate.getParameterHandler();
      }
    }

本文原文地址：[https://blog.csdn.net/qq924862077/article/details/52653767][https_blog.csdn.net_qq924862077_article_details_52653767]

[https_blog.csdn.net_qq924862077_article_details_52653767]: https://blog.csdn.net/qq924862077/article/details/52653767