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ibatis 两次查询的问题

发布时间 2023-06-01 17:12:49作者: zno2

10年前的项目框架中发现分页检索都是两次查询，执行的线程是相同的

一开始怀疑是 DAO 和 DAO2 中有重名的方法导致

后来经过反复调查，原来是在DAO中使用 queryForPaginatedList 导致的

com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl

  /**
   * Execute a query and return a paginated list
   *
   * @param sessionScope     - the session scope
   * @param id          - the statement ID
   * @param paramObject - the parameter object
   * @param pageSize    - the page size
   * @return - the data list
   * @throws SQLException - if the query fails
   * @deprecated All paginated list features have been deprecated
   */
  public PaginatedList queryForPaginatedList(SessionScope sessionScope, String id, Object paramObject, int pageSize) throws SQLException {
    return new PaginatedDataList(sessionScope.getSqlMapExecutor(), id, paramObject, pageSize);
  }

上面这个执行一次查询，紧接着gotoPage 会执行第二次查询

  /**
   * Moves to a specified page.  If the specified
   * page is beyond the last page, wrap to the first page.
   * If the specified page is before the first page, wrap
   * to the last page.
   *
   * @param pageNumber The page to go to
   */
  public void gotoPage(int pageNumber);

 

 

上面这个已经不推荐适用了，修改为即可。 

 /**
   * Execute a query for a list
   *
   * @param sessionScope     - the session scope
   * @param id          - the statement ID
   * @param paramObject - the parameter object
   * @param skip        - the number of rows to skip
   * @param max         - the maximum number of rows to return
   * @return - the data list
   * @throws SQLException - if the query fails
   */
  public List queryForList(SessionScope sessionScope, String id, Object paramObject, int skip, int max) throws SQLException {
    List list = null;

    MappedStatement ms = getMappedStatement(id);
    Transaction trans = getTransaction(sessionScope);
    boolean autoStart = trans == null;

    try {
      trans = autoStartTransaction(sessionScope, autoStart, trans);

      StatementScope statementScope = beginStatementScope(sessionScope, ms);
      try {
        list = ms.executeQueryForList(statementScope, trans, paramObject, skip, max);
      } finally {
        endStatementScope(statementScope);
      }

      autoCommitTransaction(sessionScope, autoStart);
    } finally {
      autoEndTransaction(sessionScope, autoStart);
    }

    return list;
  }