Spring jdbcTemplate + EasyUI 物理分页

    前文说到，新项目中，用到的是SpringMVC + jdbcTemplate，前台是EasyUI，发现同事以前封装分页是逻辑分页，于是，自己动手封装了下物理分页。

    这个是核心分页实体：

import java.io.Serializable;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang.StringUtils;
import org.springframework.jdbc.core.JdbcTemplate;


/**
 * 分页实体
 * @author lyh
 * @version 2013-10-10
 * @see Pagination
 * @since
 */
public class Pagination implements Serializable
{
    /**
     * 序列号<br>
     */
    private static final long serialVersionUID = -2554565760258955645L;

    /**
     * 每页显示的记录数
     */
    private int numPerPage;

    /**
     * 记录总数 （命名必须为total 对应easyui分页）
     */
    private int total;

    /**
     * 总页数
     */
    private int totalPages;

    /**
     * 当前页码
     */
    private int currentPage;

    /**
     * 记录起始行数
     */
    private int startIndex;

    /**
     * 记录结束行数
     */
    private int lastIndex;

    /**
     * 结果集存放List （命名必须为rows 对应easyui分页）
     */
    private List<Map<String,Object>> rows;


    /**
     * 构造函数
     * @param sql sql语句
     * @param currentPage 当前页码
     * @param numPerPage 每页显示记录数
     * @param jdbcTemplate JdbcTemplate实例
     */
    public Pagination(String sql, int currentPage, int numPerPage, JdbcTemplate jdbcTemplate)
    {
        if (jdbcTemplate == null)
        {
            throw new IllegalArgumentException(
                "jdbcTemplate is null , pls initialize ... ");
        }
        else if (StringUtils.isBlank(sql))
        {
            throw new IllegalArgumentException("sql is blank , pls initialize ... ");
        }
        //设置每页显示记录数
        setNumPerPage(numPerPage);

        //设置当前页数
        setCurrentPage(currentPage);

        //计算总记录数SQL
        StringBuffer totalSQL = new StringBuffer(" select count(1) from ( ");
        totalSQL.append(sql);
        totalSQL.append(" ) ");

        //总记录数
        setTotal(jdbcTemplate.queryForInt(totalSQL.toString()));

        //计算总页数
        setTotalPages();

        //计算起始行数
        setStartIndex();

        //计算结束行数
        setLastIndex();

        //拼装oracle的分页语句 （其他DB修改此处的分页关键词即可）
        StringBuffer paginationSQL = new StringBuffer(" select * from ( ");
        paginationSQL.append(" select row_limit.*,rownum rownum_ from ( ");
        paginationSQL.append(sql);
        paginationSQL.append("　) row_limit where rownum <= " + lastIndex);
        paginationSQL.append(" ) where　rownum_ > " + startIndex);

        //装入结果集（key转为小写）
        setRows(ConvertMapkey.listKeyToLower(jdbcTemplate.queryForList(
            paginationSQL.toString())));
    }

    /**
     * 根据总记录数和每页显示记录数 计算总页数
     *    
     * @see
     */
    private void setTotalPages()
    {
        if (total % numPerPage == 0)
        {
            this.totalPages = total / numPerPage;
        }
        else
        {
            this.totalPages = (total / numPerPage) + 1;
        }
    }

    /**
     * 根据当前页和每页显示记录条数 计算记录开始行数
     *    
     * @see
     */
    private void setStartIndex()
    {
        this.startIndex = (currentPage - 1) * numPerPage;
    }

    /**
     * 计算记录结束行数
     *    
     * @see
     */
    private void setLastIndex()
    {
        if (total < numPerPage)
        {
            this.lastIndex = total;
        }
        else if ((total % numPerPage == 0)
                 || (total % numPerPage != 0 && currentPage < totalPages))
        {
            this.lastIndex = currentPage * numPerPage;
        }
        else if (total % numPerPage != 0 && currentPage == totalPages)
        {
            this.lastIndex = total;
        }
    }

    //setter and getter
    public int getCurrentPage()
    {
        return currentPage;
    }

    public void setCurrentPage(int currentPage)
    {
        this.currentPage = currentPage;
    }

    public int getNumPerPage()
    {
        return numPerPage;
    }

    public void setNumPerPage(int numPerPage)
    {
        this.numPerPage = numPerPage;
    }

    public List<Map<String,Object>> getRows()
    {
        return rows;
    }

    public void setRows(List<Map<String,Object>> rows)
    {
        this.rows = rows;
    }

    public int getTotalPages()
    {
        return totalPages;
    }

    public int getTotal()
    {
        return total;
    }

    public void setTotal(int total)
    {
        this.total = total;
    }

    public int getStartIndex()
    {
        return startIndex;
    }

    public int getLastIndex()
    {
        return lastIndex;
    }

}

Map转化工具类：

public class ConvertMapkey {

	/**
	 * 把map对象的key全部转为小写形式
	 * @param map
	 * @return
	 */
	public static Map<String, Object> keyToLower(Map<String, Object> map) {
		Map<String, Object> r = new HashMap<String, Object>();
		if (map == null || map.size() == 0)
			return r;
		for (Map.Entry<String, Object> entry : map.entrySet()) {
			r.put(entry.getKey().toLowerCase(), entry.getValue());
        }
		return r;
	}
	
	/**
	 * 把list map中map对象的key全部转为小写形式
	 * @param listmap
	 * @return
	 */
	public static List<Map<String, Object>> listKeyToLower(List<Map<String, Object>> listmap) {
		List<Map<String, Object>> r = new ArrayList<Map<String, Object>>();
		if (listmap == null || listmap.size() == 0)
			return r;
		for (Map<String, Object> map : listmap) {
			r.add(keyToLower(map));
		}
		return r;
	}
}

DAO层 Service层：

return new Pagination(sqlFetchRows, page, rows, jdbcTemplate);

Controller层：

  @RequestMapping(value = "/list_school")
	@ResponseBody
	public Pagination listSchool(HttpServletRequest request) {
	    
	    Pagination p = null;
		try {
			
			int page = Integer.parseInt(request.getParameter("page"));
			int rows = Integer.parseInt(request.getParameter("rows"));
			
			String school_code = request.getParameter("s_school_code");
			String school_name = request.getParameter("s_school_name");
			
			//page：当前页   rows：每页显示记录条数  区别结果集存放List-rows
			p  = schoolService.pageData(page, rows, school_id, school_code, school_name);			
			
		} catch (Exception e) {
			logger.error(e);
		}
		return p;
	}

注意：Controller返回的 Pagination实体在会转为JSON（故实体中一定不能含有jdbcTemplate字段，jdbcTemplate只能通过方法形式注入），然后在EasyUi中展示。

通过FireFox 可以发现上述返回的分页实体的JSON。

JS部分：

      // 查询
	$('#btn_02010100').click(function() {
		$('#basedg').datagrid('load');
	});

	$('#basedg').datagrid({
        animate: true,        //是否动画展开折叠
        checkbox: true, //全选复选框
        checkOnSelect: true, //选中复选框的同时选中行
        selectOnCheck: true, //选中行的同时选中复选框
        singleSelect: false, //是否单选
        collapsible: true,    //是否可折叠
        height: 'auto',  //自动高度
        iconCls: 'icon-save',  //样式图标
        idField: 'school_id',   //主索引，唯一标识字段
        loadMsg: '数据载入中，请稍候......',
        maximizable: true,
        nowrap: true,  //截断内文
        pagination: true, //分页
        pageList: [10,15,20,25,30],
        rownumbers: true,   //是否显示列数,
	    url: basePath + '/school/list_school',
	    frozenColumns: [[
   	        {field:'ck',checkbox:true},
   	        {field:'school_id',title:'唯一id',hidden:true},
   	        {field:'school_code',title:'学校代码',80},
   	        {field:'school_name',title:'学校名称',200}
   	    ]],
	    columns: [[
	        {field:'schooling_length',title:'学制',100},
	        {field:'telephone',title:'联系电话',120},
	        {field:'school_address',title:'学校地址',300},
	        {field:'establishment_date',title:'建校年月',80,
			    formatter:function (value) {
			        return value == null ? '' : (new Date(value).format('yyyy-MM-dd'));
			    }
			}
	    ]],
	    onBeforeLoad: function (param) {
	    	param.s_school_code = $('#s_school_code').searchbox('getValue');
	    	param.s_school_name = $('#s_school_name').searchbox('getValue');
        }
	});
}

JSP页面：

<table id="basedg" toolbar="#toolbar" pagination="true"></table>
<div id="toolbar">
	    <div id="searchbar">
	    	<table cellspacing="0" cellpadding="0">
				<tr>
					<td>查询条件：</td>
					<td>
						<input id="s_school_code" class="easyui-searchbox" data-options="prompt:'学校代码'"></input>
					</td>
					<td>
						<input id="s_school_name" class="easyui-searchbox" data-options="prompt:'学校名称'"></input>
					</td>
				</tr>
		</table>
	    </div>
	    <a href="javascript:void(0)" id="btn_02010100" class="easyui-linkbutton" iconCls="icon-search" plain="true">查询</a>
</div>

最终效果：

每次查询时的触发SQL如下：

log Begining method: com.ruhuiyun.studentmanager.service.SchoolService.pageData
2013-10-11 10:40:18,345 [qtp14565508-22] DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing SQL query [ select count(1) from ( SELECT school_id, school_code, school_name, schooling_length, school_address, telephone, establishment_date FROM T_SCHOOL WHERE 1 = 1 AND instr(school_name, '无锡') > 0 ) ]
2013-10-11 10:40:18,349 [qtp14565508-22] DEBUG [org.springframework.jdbc.core.JdbcTemplate] - Executing SQL query [ select * from (  select row_limit.*,rownum rownum_ from ( SELECT school_id, school_code, school_name, schooling_length, school_address, telephone, establishment_date FROM T_SCHOOL WHERE 1 = 1 AND instr(school_name, '无锡') > 0　) row_limit where rownum <= 2 ) where　rownum_ > 0]
2013-10-11 10:40:18,353 [qtp14565508-22] INFO  [com.ruhuiyun.studentmanager.aop.LogAdvice] - log Ending method: com.ruhuiyun.studentmanager.service.SchoolService.pageData

一曲终了~~