spring+mybatis 物理分页

新项目用的spring mvc 和 mybatis 分页。研究了一下，集众家之长然后形成现在的项目。我把分页部分剥离出来与大家分享。如有不妥的地方欢迎交流拍砖。

单独做了一个小项目，放到了下载区，如果有用到的朋友可以去下载。

本项目采用了拦截器，就是mybaits自带的plus功能。将每次select操作都进行拦截。

项目架构如下：

1：首先从cotroller层出发，啥也不说，上代码。这个最实惠

package com.flydreamer.controller;import java.util.HashMap;import java.util.Map;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.servlet.ModelAndView;import com.flydreamer.logic.UserService;import com.flydreamer.page.Page;import com.flydreamer.page.PageContext;import com.flydreamer.util.web.HandlerResult;@Controller@RequestMapping("/user.do")public class UserController {@Autowiredprivate UserService userService;@RequestMapping(params = ("method=list"))public ModelAndView listAll(HttpServletRequest request,HttpServletResponse response) {//可以将分页参数获取封装，已达到更好的复用效果。//page=2&pageSize=10&totalPages=19&totalRows=188String pagec = request.getParameter("page"); String pageSize = request.getParameter("pageSize"); String totalPages = request.getParameter("totalPages"); String totalRows = request.getParameter("totalRows"); //方法1：将分页参数直接放到mapper接口函数参数中，也可在对象中定义名字为page的属性，反射一样可以得到//后台连接直接获取//Page page = new Page();//方法2：不用进行map传参，用ThreadLocal进行传参,方便没有侵入性PageContext page = PageContext.getContext();//请自行验证if(null == pagec){page.setCurrentPage(1);page.setPageSize(10);}else{page.setCurrentPage(Integer.parseInt(pagec));page.setPageSize(Integer.parseInt(pageSize));page.setTotalPages(Integer.parseInt(totalPages));page.setTotalRows(Integer.parseInt(totalRows));}page.setPagination(true);//方法1用//Map map = new HashMap();//map.put("page", page);//HandlerResult rs = userService.list(map);//方法2用HandlerResult rs = userService.list();ModelAndView mv = new ModelAndView("/views/show.jsp");mv.addObject("userList", rs.getResultObj());mv.addObject("page",page);return mv;}}

简要说明：本文采用两种方式将page对象传入到拦截器中。第一种方式是采用参数传值，不管是用map还是在统一参数对象中名称为page的属性都可以在分页拦截器中得到page的值。第二种方式是用ThreadLocal，对service层没有侵入性。比较方便。

2：Service层代码。没啥可说的上代码

package com.flydreamer.logic;import java.util.Map;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import com.flydreamer.orm.mapper.UsersMapper;import com.flydreamer.util.web.HandlerResult;@Servicepublic class UserService {@Autowiredprivate UsersMapper usersMappser;/** * 统一Service出口，方便管理 * @param map * @return */public HandlerResult list(Map map){HandlerResult rs = new HandlerResult();rs.setResultObj(usersMappser.list(map));return rs;}/** * 采用本地线程的方式分页 * @return */public HandlerResult list(){HandlerResult rs = new HandlerResult();rs.setResultObj(usersMappser.list2());return rs;}public UsersMapper getUsersMappser() {return usersMappser;}public void setUsersMappser(UsersMapper usersMappser) {this.usersMappser = usersMappser;}}

3：mybatis接口

package com.flydreamer.orm.mapper;import java.util.List;import java.util.Map;import com.flydreamer.orm.SqlMapper;public interface UsersMapper extends SqlMapper{public List list(Map para);public List list2();}

4：page的拦截器

package com.flydreamer.interceptor;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.List;import java.util.Properties;import org.apache.ibatis.builder.xml.dynamic.ForEachSqlNode;import org.apache.ibatis.executor.ErrorContext;import org.apache.ibatis.executor.Executor;import org.apache.ibatis.executor.ExecutorException;import org.apache.ibatis.logging.Log;import org.apache.ibatis.logging.LogFactory;import org.apache.ibatis.mapping.BoundSql;import org.apache.ibatis.mapping.MappedStatement;import org.apache.ibatis.mapping.ParameterMapping;import org.apache.ibatis.mapping.ParameterMode;import org.apache.ibatis.mapping.SqlSource;import org.apache.ibatis.mapping.MappedStatement.Builder;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.MetaObject;import org.apache.ibatis.reflection.property.PropertyTokenizer;import org.apache.ibatis.session.Configuration;import org.apache.ibatis.session.ResultHandler;import org.apache.ibatis.session.RowBounds;import org.apache.ibatis.type.TypeHandler;import org.apache.ibatis.type.TypeHandlerRegistry;import com.flydreamer.page.Dialect;import com.flydreamer.page.MySql5Dialect;import com.flydreamer.page.OracleDialect;import com.flydreamer.page.Page;import com.flydreamer.page.PageContext;import com.flydreamer.page.ReflectHelper;//只拦截select部分@Intercepts({@Signature(type=Executor.class,method="query",args={ MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class })})public class PaginationInterceptor implements Interceptor{private final static Log log = LogFactory.getLog(PaginationInterceptor.class);   Dialect dialect = new MySql5Dialect(); public Object intercept(Invocation invocation) throws Throwable {MappedStatement mappedStatement=(MappedStatement)invocation.getArgs()[0];Object parameter = invocation.getArgs()[1]; BoundSql boundSql = mappedStatement.getBoundSql(parameter); String originalSql = boundSql.getSql().trim();   RowBounds rowBounds = (RowBounds)invocation.getArgs()[2];Object parameterObject = boundSql.getParameterObject();if(boundSql==null || boundSql.getSql()==null || "".equals(boundSql.getSql()))return null;//分页参数--上下文传参Page page = null;PageContext context=PageContext.getContext();//map传参每次都将currentPage重置,先判读map再判断contextif(parameterObject!=null)page = (Page)ReflectHelper.isPage(parameterObject,"page");//分页参数--context参数里的Page传参if(page==null && context.isPagination()==true){page = context;}//后面用到了context的东东if(page!=null && page.isPagination()==true) {  int totpage=page.getTotalRows();  //得到总记录数  if (totpage==0){StringBuffer countSql  = new StringBuffer(originalSql.length()+100 );countSql.append("select count(1) from (").append(originalSql).append(") t"); Connection connection=mappedStatement.getConfiguration().getEnvironment().getDataSource().getConnection()  ;                           PreparedStatement countStmt = connection.prepareStatement(countSql.toString());                   BoundSql countBS = new BoundSql(mappedStatement.getConfiguration(),countSql.toString(),boundSql.getParameterMappings(),parameterObject);                   setParameters(countStmt,mappedStatement,countBS,parameterObject);                   ResultSet rs = countStmt.executeQuery();                   if (rs.next()) {                   totpage = rs.getInt(1);                   }                   rs.close();                   countStmt.close();                   connection.close();}      //分页计算        page.init(totpage,page.getPageSize(),page.getCurrentPage());  if(rowBounds == null || rowBounds == RowBounds.DEFAULT){rowBounds= new RowBounds(page.getPageSize()*(page.getCurrentPage()-1),page.getPageSize());}//分页查询 本地化对象 修改数据库注意修改实现    String pagesql=dialect.getLimitString(originalSql, rowBounds.getOffset(), rowBounds.getLimit());    invocation.getArgs()[2] = new RowBounds(RowBounds.NO_ROW_OFFSET, RowBounds.NO_ROW_LIMIT);       BoundSql newBoundSql = new BoundSql(mappedStatement.getConfiguration(), pagesql,boundSql.getParameterMappings(),boundSql.getParameterObject());       MappedStatement newMs = copyFromMappedStatement(mappedStatement,new BoundSqlSqlSource(newBoundSql));         invocation.getArgs()[0]= newMs;  }   return invocation.proceed();}public static class BoundSqlSqlSource implements SqlSource {          BoundSql boundSql;            public BoundSqlSqlSource(BoundSql boundSql) {              this.boundSql = boundSql;          }            public BoundSql getBoundSql(Object parameterObject) {              return boundSql;          }      }  public Object plugin(Object arg0) { return Plugin.wrap(arg0, this);}public void setProperties(Properties arg0) {        }        /**      * 对SQL参数(?)设值,参考org.apache.ibatis.executor.parameter.DefaultParameterHandler      * @param ps      * @param mappedStatement      * @param boundSql      * @param parameterObject      * @throws SQLException      */      private void setParameters(PreparedStatement ps,MappedStatement mappedStatement,BoundSql boundSql,Object parameterObject) throws SQLException {          ErrorContext.instance().activity("setting parameters").object(mappedStatement.getParameterMap().getId());          List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();          if (parameterMappings != null) {              Configuration configuration = mappedStatement.getConfiguration();              TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();              MetaObject metaObject = parameterObject == null ? null: configuration.newMetaObject(parameterObject);              for (int i = 0; i < parameterMappings.size(); i++) {                  ParameterMapping parameterMapping = parameterMappings.get(i);                  if (parameterMapping.getMode() != ParameterMode.OUT) {                      Object value;                      String propertyName = parameterMapping.getProperty();                      PropertyTokenizer prop = new PropertyTokenizer(propertyName);                      if (parameterObject == null) {                          value = null;                      } else if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {                          value = parameterObject;                      } else if (boundSql.hasAdditionalParameter(propertyName)) {                          value = boundSql.getAdditionalParameter(propertyName);                      } else if (propertyName.startsWith(ForEachSqlNode.ITEM_PREFIX)&& boundSql.hasAdditionalParameter(prop.getName())) {                          value = boundSql.getAdditionalParameter(prop.getName());                          if (value != null) {                              value = configuration.newMetaObject(value).getValue(propertyName.substring(prop.getName().length()));                          }                      } else {                          value = metaObject == null ? null : metaObject.getValue(propertyName);                      }                      TypeHandler typeHandler = parameterMapping.getTypeHandler();                      if (typeHandler == null) {                          throw new ExecutorException("There was no TypeHandler found for parameter "+ propertyName + " of statement "+ mappedStatement.getId());                      }                      typeHandler.setParameter(ps, i + 1, value, parameterMapping.getJdbcType());                  }              }          }      }          private MappedStatement copyFromMappedStatement(MappedStatement ms,        SqlSource newSqlSource) {       Builder builder = new MappedStatement.Builder(ms.getConfiguration(),       ms.getId(), newSqlSource, ms.getSqlCommandType());       builder.resource(ms.getResource());       builder.fetchSize(ms.getFetchSize());       builder.statementType(ms.getStatementType());       builder.keyGenerator(ms.getKeyGenerator());       builder.keyProperty(ms.getKeyProperty());       builder.timeout(ms.getTimeout());        builder.parameterMap(ms.getParameterMap());       builder.resultMaps(ms.getResultMaps());       builder.cache(ms.getCache());       MappedStatement newMs = builder.build();       return newMs;       }        }

简要说明：刚刚忘记了，有一些查询操作是不需要分页的。可以自行修改拦截器中代码部分，加个判断啥的。

5：spring 配置

<bean id="paginationInterceptor" class="com.flydreamer.interceptor.PaginationInterceptor"></bean>  

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">      <property name="dataSource" ref="dataSource" />          <property name="plugins">    <ref bean="paginationInterceptor"/>    </property>    </bean>  

大致就是这样了。完整的可运行项目已放到这里。最近CSDN没有分了，收1分，各位童鞋见谅了~