mybatis分页的

1，前端和后端之间约定的信息应该是PageSize、PageNum。
2，后端在分页之前先查询一把数据总数。
3，基于数据总数、PageSize以及PageNum就可以计算出MySQL中需要的Limit和OffSet值。

代码示例：
一，查询基类
package com.freedom.dal.common;

/**

• 分页查询的基类
• */

1. class QueryBase {

      //数据总量

   private Integer totalSize;
   //每页大小
   private Integer pageSize;
   //当前页数
   private Integer currentPage;

   // for paging
   private int startRow;
   private int endRow;

   protected Integer getDefaultPageSize() {

      return defaultPageSize;

   }

   public boolean isFirstPage() {

      return this.getCurrentPage().intValue() == 1;

   }

   public int getPreviousPage() {

      int back = this.getCurrentPage().intValue() - 1;
   
      if (back <= 0) {
          back = 1;
      }
   
      return back;

   }

   public boolean isLastPage() {

      return this.getTotalPage() == this.getCurrentPage().intValue();

   }

   public int getNextPage() {

      int back = this.getCurrentPage().intValue() + 1;
   
      if (back > this.getTotalPage()) {
          back = this.getTotalPage();
      }
   
      return back;

   }

   public Integer getCurrentPage() {

      if (currentPage == null) {
          return defaultFristPage;
      }
   
      return currentPage;

   }

   public void setCurrentPageString(String pageString) {

      if (isBlankString(pageString)) {
          this.setCurrentPage(defaultFristPage);
      }
   
      try {
          Integer integer = new Integer(pageString);
   
          this.setCurrentPage(integer);
      } catch (NumberFormatException ignore) {
          this.setCurrentPage(defaultFristPage);
      }

   }

   public void setCurrentPage(Integer cPage) {

      if ((cPage == null) || (cPage.intValue() <= 0)) {
          this.currentPage = null;
      } else {
          this.currentPage = cPage;
      }
      setStartEndRow();

   }

   private void setStartEndRow() {

      this.startRow = this.getPageSize().intValue() * (this.getCurrentPage().intValue() - 1) + 1;
      this.endRow = this.startRow + this.getPageSize().intValue() - 1;

   }

   public Integer getPageSize() {

      if (pageSize == null) {
          return getDefaultPageSize();
      }
   
      return pageSize;

   }

   public boolean hasSetPageSize() {

      return pageSize != null;

   }

   public void setPageSizeString(String pageSizeString) {

      if (isBlankString(pageSizeString)) {
          return;
      }
   
      try {
          Integer integer = new Integer(pageSizeString);
   
          this.setPageSize(integer);
      } catch (NumberFormatException ignore) {
      }

   }

   private boolean isBlankString(String pageSizeString) {

      if (pageSizeString == null) {
          return true;
      }
   
      if (pageSizeString.trim().length() == 0) {
          return true;
      }
   
      return false;

   }

   public void setPageSize(Integer pSize) {

      if ((pSize == null) || (pSize.intValue() <= 0)) {
          this.pageSize = null;
      } else {
          this.pageSize = pSize;
      }
      setStartEndRow();

   }

   public Integer getTotalItem() {

      if (totalSize == null) {
          return defaultTotleItem;
      }
   
      return totalSize;

   }

   public void setTotalItem(Integer tItem) {

      if (tItem == null) {
          throw new IllegalArgumentException("TotalItem can't be null.");
      }
   
      this.totalSize = tItem;
   
      int current  = this.getCurrentPage().intValue();
      int lastPage = this.getTotalPage();
   
      if (current > lastPage) {
          this.setCurrentPage(new Integer(lastPage));
      }

   }

   public int getTotalPage() {

      int pgSize = this.getPageSize().intValue();
      int total  = this.getTotalItem().intValue();
      int result = total / pgSize;
   
      if ((total == 0) || ((total % pgSize) != 0)) {
          result++;
      }
   
      return result;

   }

   public int getPageFristItem() {

      int cPage = this.getCurrentPage().intValue();
   
      if (cPage == 1) {
          return 1;
      }
   
      cPage--;
   
      int pgSize = this.getPageSize().intValue();
   
      return (pgSize * cPage) + 1;

   }

   public int getPageLastItem() {

      int cPage      = this.getCurrentPage().intValue();
      int pgSize     = this.getPageSize().intValue();
      int assumeLast = pgSize * cPage;
      int totalItem  = getTotalItem().intValue();
   
      if (assumeLast > totalItem) {
          return totalItem;
      } else {
          return assumeLast;
      }

   }

   public int getEndRow() {

      return endRow;

   }

   public void setEndRow(int endRow) {

      this.endRow = endRow;

   }

   public int getStartRow() {

      return startRow;

   }

   public void setStartRow(int startRow) {

      this.startRow = startRow;

   }

   protected String getSQLBlurValue(String value) {

      if (value == null) {
          return null;
      }
   
      return value + '%';

   }

   public boolean nextPage() {

       if(this.currentPage != null && this.currentPage.intValue() >= this.getTotalPage()) return false;
       if(this.currentPage == null) {
           this.setCurrentPage(defaultFristPage);
       } else {
           this.setCurrentPage(getNextPage());
       }
       return true;
   }
   

   public int getStart() {

      int startRow = getStartRow() - 1;
      return startRow > 0 ? startRow : 0;

   }
   }

二，DAO中基本逻辑
1，生成查询基类，并将前端传递过来的pageSize和pageNum设置给查询基类。
2，查询数据总量，将数据总量设置到查询基类中。
3，查询。

三，xml配置
SELECT

        <include refid="ConfigDOColums"></include>
    FROM
        CONFIGS
    WHERE
        <include refid="configQueryConditions"></include>
    LIMIT #{start}, #{pageSize}

创建一个分页类pageBean，所有的类可以继承它，在你的Action或者Controller里面，全部将实体类参数全部封装到Map，mybatis的参数全部采用Map传递比较好，然后写一个通用的sql头和sql尾，把你的业务逻辑sql都写在头和尾之间，就可以了。这也是一个笨方法，看你怎么写了