mybatis分页插件的简单实现

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mybatis分页插件的简单实现

mybatis使用的版本是3.3.0，spring-mybatis使用的是1.1.0，使用的数据库是mySQL。
自定义拦截器（）

package com.xinrui.micromessage.action.interceptor;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.Map;import java.util.Properties;import org.apache.ibatis.executor.parameter.ParameterHandler;import org.apache.ibatis.executor.statement.StatementHandler;import org.apache.ibatis.mapping.BoundSql;import org.apache.ibatis.mapping.MappedStatement;import org.apache.ibatis.plugin.Interceptor;import org.apache.ibatis.plugin.Intercepts;import org.apache.ibatis.plugin.Invocation;import org.apache.ibatis.plugin.Plugin;import org.apache.ibatis.plugin.Signature;import org.apache.ibatis.reflection.DefaultReflectorFactory;import org.apache.ibatis.reflection.MetaObject;import org.apache.ibatis.reflection.SystemMetaObject;import com.xinrui.micromessage.bean.Page;/** *  * @ClassName: PageIntercetor * @Description: 分页拦截器 * @author 梁志成 * @date 2016年3月19日 上午11:52:02 * */@Intercepts({ @Signature(type = StatementHandler.class, method = "prepare", args = { Connection.class }) })public class PageIntercetor implements Interceptor {    @Override    public Object intercept(Invocation invocation) throws Throwable {        StatementHandler statementHandler = (StatementHandler) invocation                .getTarget();        MetaObject metaObject = MetaObject.forObject(statementHandler,                SystemMetaObject.DEFAULT_OBJECT_FACTORY,                SystemMetaObject.DEFAULT_OBJECT_WRAPPER_FACTORY,                new DefaultReflectorFactory());        MappedStatement mappedStatement = (MappedStatement) metaObject                .getValue("delegate.mappedStatement");        // 配置文件中SQL语句的ID        String id = mappedStatement.getId();        // 拦截原始sql语句中以ByPage结尾的语句        if (id.matches(".+ByPage$")) {            BoundSql boundSql = statementHandler.getBoundSql();            // 原始的SQL语句            String sql = boundSql.getSql();            // 查询总条数的SQL语句            String countSql = "select count(*) from (" + sql + ")a";            Connection connection = (Connection) invocation.getArgs()[0];            PreparedStatement countStatement = connection                    .prepareStatement(countSql);            ParameterHandler parameterHandler = (ParameterHandler) metaObject                    .getValue("delegate.parameterHandler");            parameterHandler.setParameters(countStatement);            ResultSet rs = countStatement.executeQuery();            Map<?, ?> parameter = (Map<?, ?>) boundSql.getParameterObject();            Page page = (Page) parameter.get("page");            if (rs.next()) {                page.setTotalNumber(rs.getInt(1));            }            // 改造后带分页查询的SQL语句            String pageSql = sql + " limit " + page.getDbIndex() + ","                    + page.getDbNumber();            metaObject.setValue("delegate.boundSql.sql", pageSql);        }        return invocation.proceed();    }    @Override    public Object plugin(Object target) {        return Plugin.wrap(target, this);    }    @Override    public void setProperties(Properties arg0) {    }}

3.分页实体类

package com.xinrui.micromessage.bean;/** * 分页对应的实体类 */public class Page {    /**     * 总条数     */    private int totalNumber;    /**     * 当前第几页     */    private int currentPage;    /**     * 总页数     */    private int totalPage;    /**     * 每页显示条数     */    private int pageNumber = 5;    /**     * 数据库中limit的参数，从第几条开始取     */    private int dbIndex;    /**     * 数据库中limit的参数，一共取多少条     */    private int dbNumber;    /**     * 根据当前对象中属性值计算并设置相关属性值     */    public void count() {        // 计算总页数        int totalPageTemp = this.totalNumber / this.pageNumber;        int plus = (this.totalNumber % this.pageNumber) == 0 ? 0 : 1;        totalPageTemp = totalPageTemp + plus;        if(totalPageTemp <= 0) {            totalPageTemp = 1;        }        this.totalPage = totalPageTemp;        // 设置当前页数        // 总页数小于当前页数，应将当前页数设置为总页数        if(this.totalPage < this.currentPage) {            this.currentPage = this.totalPage;        }        // 当前页数小于1设置为1        if(this.currentPage < 1) {            this.currentPage = 1;        }        // 设置limit的参数        this.dbIndex = (this.currentPage - 1) * this.pageNumber;        this.dbNumber = this.pageNumber;    }    public int getTotalNumber() {        return totalNumber;    }    public void setTotalNumber(int totalNumber) {        this.totalNumber = totalNumber;        this.count();    }    public int getCurrentPage() {        return currentPage;    }    public void setCurrentPage(int currentPage) {        this.currentPage = currentPage;    }    public int getTotalPage() {        return totalPage;    }    public void setTotalPage(int totalPage) {        this.totalPage = totalPage;    }    public int getPageNumber() {        return pageNumber;    }    public void setPageNumber(int pageNumber) {        this.pageNumber = pageNumber;        this.count();    }    public int getDbIndex() {        return dbIndex;    }    public void setDbIndex(int dbIndex) {        this.dbIndex = dbIndex;    }    public int getDbNumber() {        return dbNumber;    }    public void setDbNumber(int dbNumber) {        this.dbNumber = dbNumber;    }}

4.在mybatis-config.xml中注册该插件（拦截器）

<configuration>    <plugins><!-- 为拦截器注册 -->        <plugin interceptor="com.xinrui.micromessage.action.interceptor.PageIntercetor"></plugin>    </plugins></configuration>

5.controller 层

package com.xinrui.micromessage.action;import java.util.List;import java.util.regex.Pattern;import javax.annotation.Resource;import org.apache.commons.lang.StringUtils;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.servlet.ModelAndView;import com.xinrui.micromessage.bean.Message;import com.xinrui.micromessage.bean.Page;import com.xinrui.micromessage.service.impl.PageTwoServiceImpl;/** *  * @ClassName: PageTwoController * @Description: 使用拦截器实现分页控制 * @author 梁志成 * @date 2016年3月19日 下午4:33:20 * */@Controllerpublic class PageTwoController {    @Resource    private PageTwoServiceImpl pageTwoService;    @RequestMapping(value = "pagetwo", method = RequestMethod.GET)    public ModelAndView pagetwo(String command, String description,            String currentPage) {        // 进入主框架        ModelAndView mav = new ModelAndView("back/list");        // 创建分页对象        Page page = new Page();        // 页数由数字组成,不能超过9位        Pattern pattern = Pattern.compile("[0-9]{1,9}");        // 页数不符合规则,设置为第一页        if (StringUtils.isEmpty(currentPage)                || !pattern.matcher(currentPage).matches()) {            page.setCurrentPage(1);        } else {            page.setCurrentPage(Integer.valueOf(currentPage));        }        List<Message> messageList = pageTwoService.queryMessageListByPage(command, description, page);        // 向页面输出内容        mav.addObject("command", command);        mav.addObject("description", description);        mav.addObject("page", page);        mav.addObject("messageList", messageList);        return mav;    }}

6.service层

package com.xinrui.micromessage.service.impl;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.annotation.Resource;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;import com.xinrui.micromessage.bean.Message;import com.xinrui.micromessage.bean.Page;import com.xinrui.micromessage.dao.PageTwoDao;/** *  * @ClassName: PageTwoServiceImpl * @Description: 使用拦截器实现分页拦截实现类 * @author 梁志成 * @date 2016年3月19日 下午4:26:48 * */@Servicepublic class PageTwoServiceImpl {    @Resource    private PageTwoDao pageTwoDao;    /**     *      * @Title: queryMessageListByPage     * @Description: 使用拦截器实现分页拦截服务     * @param @param command     * @param @param description     * @param @param page     * @param @return     * @return List<Message>     * @throws     */    @Transactional    public List<Message> queryMessageListByPage(String command,            String description, Page page) {        Map<String, Object> parameter = new HashMap<String, Object>();        // 组织消息对象        Message message = new Message();        message.setCommand(command);        message.setDescription(description);        parameter.put("message", message);        parameter.put("page", page);        return this.pageTwoDao.queryMessageListByPage(parameter);    }}

7.dao层

package com.xinrui.micromessage.dao;import java.util.List;import java.util.Map;import org.springframework.stereotype.Repository;import com.xinrui.micromessage.bean.Message;/** *  * @ClassName: PageTwoDao * @Description: 分页查询与数据库交互部分 * @author 梁志成 * @date 2016年3月19日 下午4:24:11 * */@Repositorypublic class PageTwoDao extends BaseDao {    /**     *      * @Title: queryMessageListByPage     * @Description: 分页查询消息表     * @param @param parameter     * @param @return     * @return List<Message>     * @throws     */    public List<Message> queryMessageListByPage(Map<String, Object> parameter) {        return this.getSqlSession().selectList(                "com.xinrui.micromessage.bean.Message.queryMessageListByPage",                parameter);    }}

8.mybatis mapper

<select id="queryMessageListByPage" parameterType="java.util.Map"        resultType="com.xinrui.micromessage.bean.Message">        select        id,command,description,content        from message        <where>            <if                test="message.command != null and !&quot;&quot;.equals(message.command.trim())">                and command=#{message.command}            </if>            <if                test="message.description != null and !&quot;&quot;.equals(message.description.trim())">                and description like '%' #{message.description} '%'            </if>        </where>        order by id    </select>

9.jsp页面呈现

                        <div class='page fix'>                            共 <b>${page.totalNumber }</b> 条                            <c:if test="${page.currentPage != 1 }">                                <a href="javascript:changeCurrentPage(1)" class='first'>首页</a>                                <a href="javascript:changeCurrentPage(${page.currentPage-1 })" class='pre'>上一页</a>                            </c:if>                            当前第<span>${page.currentPage }/${page.totalPage }</span>页                            <c:if test="${page.currentPage != page.totalPage }">                                <a href="javascript:changeCurrentPage(${page.currentPage+1 })" class='next'>下一页</a>                                <a href="javascript:changeCurrentPage(${page.totalPage })" class='last'>末页</a>                            </c:if>                            跳至&nbsp;<input  id="currentPageText" type='text' value="${page.currentPage}" class='allInput w28' />&nbsp;页&nbsp;                            <a href="javascript:changeCurrentPage($('#currentPageText').val())" class='go'>GO</a>                        </div>

10.js脚本

function changeCurrentPage(currentPage){    $("#currentPage").val(currentPage);    $("#mainForm").submit();}

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