对List集合进行分页

1 简要说明

　　有时候，我们有一个list集合，需要对它进行分页处理

　　下面的根据类MyPageUtilVo就可以做到

　　它自带泛型，适合各种集合

　　可以设置每页的大小(默认为10)

　　根据页码(从1开始)就可以获取分页后的集合了

2 工具类

public class MyPageUtilVo<E>
{
    /**
     * 每页显示的记录数
     */
    private int pageRecords = 10;
</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 总记录数
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> totalRecord;

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 分页切割的启始点
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> startIndex;

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 分页切割的结束点
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> endIndex;

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 总页数
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> totalPage;

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 当前页数
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">int</span> currentPage = <span style="color: #800080;">1</span><span style="color: #000000;">;

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 总记录集合
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> List&lt;E&gt;<span style="color: #000000;"> totalList;

</span><span style="color: #0000ff;">public</span> MyPageUtilVo(List&lt;E&gt;<span style="color: #000000;"> totalList)
{
    super();

    </span><span style="color: #0000ff;">this</span>.totalList =<span style="color: #000000;"> totalList;

    innit();
}

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 初始化该分页对象
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">private</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> innit()
{
    </span><span style="color: #0000ff;">if</span> (<span style="color: #0000ff;">null</span> !=<span style="color: #000000;"> totalList)
    {
        totalRecord </span>=<span style="color: #000000;"> totalList.size();

        </span><span style="color: #0000ff;">if</span> (totalRecord % <span style="color: #0000ff;">this</span>.pageRecords == <span style="color: #800080;">0</span><span style="color: #000000;">)
        {
            </span><span style="color: #0000ff;">this</span>.totalPage = totalRecord / <span style="color: #0000ff;">this</span><span style="color: #000000;">.pageRecords;
        }
        </span><span style="color: #0000ff;">else</span><span style="color: #000000;">
        {
            </span><span style="color: #0000ff;">this</span>.totalPage = totalRecord / <span style="color: #0000ff;">this</span>.pageRecords + <span style="color: #800080;">1</span><span style="color: #000000;">;
        }
    }
}

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 得到分页后的数据
 *
 * @return 分页数据
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">public</span> List&lt;E&gt; getPage(<span style="color: #0000ff;">int</span><span style="color: #000000;"> currentPage)
{
    </span><span style="color: #0000ff;">this</span>.currentPage =<span style="color: #000000;"> currentPage;

    </span><span style="color: #0000ff;">if</span> (currentPage &lt;= <span style="color: #800080;">0</span><span style="color: #000000;">)
    {
        </span><span style="color: #0000ff;">this</span>.currentPage = <span style="color: #800080;">1</span><span style="color: #000000;">;
    }
    </span><span style="color: #0000ff;">if</span> (currentPage &gt;= <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalPage)
    {
        </span><span style="color: #0000ff;">this</span>.currentPage = <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalPage;
    }

    List</span>&lt;E&gt; subList = <span style="color: #0000ff;">new</span> ArrayList&lt;E&gt;<span style="color: #000000;">();

    </span><span style="color: #0000ff;">if</span> (<span style="color: #0000ff;">null</span> != <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalList)
    {
        subList.addAll(</span><span style="color: #0000ff;">this</span><span style="color: #000000;">.totalList.subList(getStartIndex(), getEndIndex()));
    }

    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> subList;
}

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 设置每页显示的记录条数,如果不设置则默认为每页显示10条记录
 *
 * @param pageRecords
 *            每页显示的记录条数(值必需介于10~100之间)
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">public</span> <span style="color: #0000ff;">void</span> setPageRecords(<span style="color: #0000ff;">int</span><span style="color: #000000;"> pageRecords)
{
    </span><span style="color: #0000ff;">if</span> (pageRecords &gt;= <span style="color: #800080;">10</span> &amp;&amp; pageRecords &lt;= <span style="color: #800080;">100</span><span style="color: #000000;">)
    {
        </span><span style="color: #0000ff;">this</span>.pageRecords =<span style="color: #000000;"> pageRecords;

        innit();
    }
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> getStartIndex()
{
    </span><span style="color: #0000ff;">if</span> (<span style="color: #0000ff;">null</span> == <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalList)
    {
        </span><span style="color: #0000ff;">return</span> <span style="color: #800080;">0</span><span style="color: #000000;">;
    }

    </span><span style="color: #0000ff;">this</span>.startIndex = (getCurrentPage() - <span style="color: #800080;">1</span>) * <span style="color: #0000ff;">this</span><span style="color: #000000;">.pageRecords;

    </span><span style="color: #0000ff;">if</span> (startIndex &gt;<span style="color: #000000;"> totalRecord)
    {
        startIndex </span>=<span style="color: #000000;"> totalRecord;
    }

    </span><span style="color: #0000ff;">if</span> (startIndex &lt; <span style="color: #800080;">0</span><span style="color: #000000;">)
    {
        startIndex </span>= <span style="color: #800080;">0</span><span style="color: #000000;">;
    }

    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> startIndex;
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> getEndIndex()
{
    </span><span style="color: #0000ff;">if</span> (<span style="color: #0000ff;">null</span> == <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalList)
    {
        </span><span style="color: #0000ff;">return</span> <span style="color: #800080;">0</span><span style="color: #000000;">;
    }

    endIndex </span>= getStartIndex() + <span style="color: #0000ff;">this</span><span style="color: #000000;">.pageRecords;

    </span><span style="color: #0000ff;">if</span> (endIndex &lt; <span style="color: #800080;">0</span><span style="color: #000000;">)
    {
        endIndex </span>= <span style="color: #800080;">0</span><span style="color: #000000;">;
    }

    </span><span style="color: #0000ff;">if</span> (endIndex &lt;<span style="color: #000000;"> getStartIndex())
    {
        endIndex </span>=<span style="color: #000000;"> getStartIndex();
    }

    </span><span style="color: #0000ff;">if</span> (endIndex &gt; <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalRecord)
    {
        endIndex </span>= <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalRecord;
    }

    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> endIndex;
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> getTotalPage()
{
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> totalPage;
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> getTotalRecord()
{
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> totalRecord;
}

</span><span style="color: #0000ff;">public</span><span style="color: #000000;"> boolean isEndPage()
{
    </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">this</span>.currentPage == <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalPage;
}

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 获取下一页的页数
 *
 * @return 下一页的页数
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> getNextPage()
{
    </span><span style="color: #0000ff;">int</span> nextPage = <span style="color: #0000ff;">this</span>.currentPage + <span style="color: #800080;">1</span><span style="color: #000000;">;

    </span><span style="color: #0000ff;">if</span> (nextPage &gt; <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalPage)
    {
        nextPage </span>= <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalPage;
    }
    </span><span style="color: #0000ff;">if</span> (nextPage &lt;= <span style="color: #800080;">0</span><span style="color: #000000;">)
    {
        nextPage </span>= <span style="color: #800080;">1</span><span style="color: #000000;">;
    }

    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> nextPage;
}

</span><span style="color: #008000;">/*</span><span style="color: #008000;">*
 * 获取上一页的页数
 *
 * @return 上一页的页数
 </span><span style="color: #008000;">*/</span>
<span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> getPrivyPage()
{
    </span><span style="color: #0000ff;">int</span> privyPage = <span style="color: #0000ff;">this</span>.currentPage - <span style="color: #800080;">1</span><span style="color: #000000;">;

    </span><span style="color: #0000ff;">if</span> (privyPage &gt; <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalPage)
    {
        privyPage </span>= <span style="color: #0000ff;">this</span><span style="color: #000000;">.totalPage;
    }

    </span><span style="color: #0000ff;">if</span> (privyPage &lt;= <span style="color: #800080;">0</span><span style="color: #000000;">)
    {
        privyPage </span>= <span style="color: #800080;">1</span><span style="color: #000000;">;
    }

    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> privyPage;
}

</span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> getCurrentPage()
{
    </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> currentPage;
}

}

3 示例

　　　　 
　　　　　//对一个List<Map<String,String>>进行分页
　　　　 int size = list.size();
        MyPageUtilVo<Map<String,String>> pa = new MyPageUtilVo(list);
        pa.setPageRecords(15); //设置每页数量
        List<Map<String, String>> page = pa.getPage(1);
        return getDataTable(page,size);