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问一个Mybatis分页问题，Page和PageInfo的区别

10 你使用了selectOne方法，这个方法返回一条数据原因在这句异常： org.apache: Expected one result (or null) to be returned by selectOne(), but found.ibatis.exceptions.TooManyResultsException

MyBatis怎样实现MySQL动态分页

针对上述思路，首先在 demo.mybatis.model下面新建一个名为PagenateArgs的分页参数实体类与一个名为SortDirectionEnum的枚举 类，里面包含当前页面索引pageIndex, 当前页展示业务记录数pageSize， pageStart属性表示从第几条开始，（pageStart=pageIndex*pageSize）因为limit关键词用法是表示【limit 起始条数（不包含），取几条】，orderFieldStr排序字段，orderDirectionStr 排序方向，所以具体创建如下：
package david.mybatis.model;/* * 分页参数实体类 */public class PagenateArgs { private int pageIndex; private int pageSize; private int pageStart; private String orderFieldStr; private String orderDirectionStr; public PagenateArgs() { // TODO Auto-generated constructor stub } public PagenateArgs(int pageIndex, int pageSize, String orderFieldStr, String orderDirectionStr) { this.pageIndex = pageIndex; this.pageSize = pageSize; this.orderFieldStr = orderFieldStr; this.orderDirectionStr = orderDirectionStr; pageStart = pageIndex * pageSize; } public int getPageIndex() { return pageIndex; } public int getPageStart() { return pageStart; } public int getPageSize() { return pageSize; } public String orderFieldStr() { return orderFieldStr; } public String getOrderDirectionStr() { return orderDirectionStr; }}

package david.mybatis.model;/* * 排序枚举 */public enum SortDirectionEnum { /* * 升序 */ ASC, /* * 降序 */ DESC}
完成上面的步骤以后在IVisitorOperation接口类中继续添加一个方法public List getListByPagenate(PagenateArgs args)，这次的分页其实也就是在这个的基础上稍加改动即可，IVisitorOperation接口类 改动后如下所示：
package david.mybatis.demo;import java.util.List;import david.mybatis.model.PagenateArgs;import david.mybatis.model.Visitor;import david.mybatis.model.VisitorWithRn;public interface IVisitorOperation { /* * 基础查询 */ public Visitor basicQuery(int id); /* * 添加访问者 */ public int add(Visitor visitor); /* * 删除访问者 */ public int delete(int id); /* * 更新访问者 */ public int update(Visitor visitor); /* * 查询访问者 */ public Visitor query(int id); /* * 查询List */ public List getList(); /* * 分页查询List */ public List getListByPagenate(PagenateArgs args); }
接下来改动VisitorMapper.xml配置文件了，新增一个节点id与参数类型参照前几章的方式配置好，如下此处新增的id就为getListByPagenate，配置好以后如下
insert into Visitor (Name, Email, Status, CreateTime) values (#{name}, #{email}, #{status}, #{createTime}) delete from Visitor where status>0 and id = #{id} update Visitor set Name = #{name}, Email=#{email}, Status=#{status} where id=#{id} and Status>0; select Id, Name, Email, Status, CreateTime from visitor where id=#{id} and Status>0 order by Id select * from visitor where id=#{id} and Status>0 order by Id select * from Visitor where status>0 select * from ( ) t -1 and pageSize>-1"> limit #{pageStart}, #{pageSize} order by ${orderFieldStr} ${orderDirectionStr}
这里面的字段属性都是针对PagenateArgs参数类中的属性名，保持一致。
-1 and pageSize>-1"> limit #{pageStart}, #{pageSize}
在DemoRun类中创建测试方法：
/* * 分页参数 */public static void queryVisitorListWithPagenate(int pageIndex, int pageSize, String orderField, String orderDire) { PagenateArgs args = new PagenateArgs(pageIndex, pageSize, orderField, orderDire); SqlSession session = MybatisUtils.getSqlSession(); IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class); List visitors = vOperation.getListByPagenate(args); for (Visitor visitor : visitors) { System.out.println(visitor); } MybatisUtils.closeSession(session); MybatisUtils.showMessages(CRUD_Enum.List, visitors.size());}
DemoRun.queryVisitorListWithPagenate(0, 100, "id", SortDirectionEnum.DESC.toString());
运行后下测试结果，先按Id倒序排列，查的Visitor表一共有14条记录，



假设取在第2页取5条，执行下面也就是6-10条数据，这样传参数就行了
DemoRun.queryVisitorListWithPagenate(1, 5, "id", SortDirectionEnum.DESC.toString());

springmvc mybatis怎么实现分页查询

1.封装分页Page类　　package com.framework.common.page.impl;　　　　import java.io.Serializable;　　　　import com.framework.common.page.IPage;　　/**　　*　　*　　*　　*/　　public abstract class BasePage implements IPage, Serializable {　　　　/**　　*　　*/　　private static final long serialVersionUID = -3623448612757790359L;　　　　public static int DEFAULT_PAGE_SIZE = 20;　　private int pageSize = DEFAULT_PAGE_SIZE;　　private int currentResult;　　private int totalPage;　　private int currentPage = 1;　　private int totalCount = -1;　　　　public BasePage(int currentPage, int pageSize, int totalCount) {　　this.currentPage = currentPage;　　this.pageSize = pageSize;　　this.totalCount = totalCount;　　}　　　　public int getTotalCount() {　　return this.totalCount;　　}　　　　public void setTotalCount(int totalCount) {　　if (totalCount = getTotalPage();　　}　　　　public int getNextPage() {　　if (isLastPage()) {　　return this.currentPage;　　}　　return this.currentPage + 1;　　}　　　　public int getCurrentResult() {　　this.currentResult = ((getPageNo() - 1) * getPageSize());　　if (this.currentResult data;　　　　public Page() {　　}　　　　public Page(int currentPage, int pageSize, int totalCount) {　　super(currentPage, pageSize, totalCount);　　}　　　　public Page(int currentPage, int pageSize, int totalCount, List data) {　　super(currentPage, pageSize, totalCount);　　this.data = data;　　}　　　　public List getData() {　　return data;　　}　　　　public void setData(List data) {　　this.data = data;　　}　　　　　　}　　　　2.封装分页插件　　package com.framework.common.page.plugin;　　　　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 javax.xml.bind.PropertyException;　　　　import org.apache.commons.lang3.StringUtils;　　import org.apache.ibatis.executor.ErrorContext;　　import org.apache.ibatis.executor.ExecutorException;　　import org.apache.ibatis.executor.statement.BaseStatementHandler;　　import org.apache.ibatis.executor.statement.RoutingStatementHandler;　　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.plugin.Interceptor;　　import org.apache.ibatis.plugin.Intercepts;　　import org.apache.ibatis.plugin.Invocation;　　import org.apache.ibatis.plugin.Plugin;　　import org.apache.ibatis.reflection.MetaObject;　　import org.apache.ibatis.reflection.property.PropertyTokenizer;　　import org.apache.ibatis.scripting.xmltags.ForEachSqlNode;　　import org.apache.ibatis.session.Configuration;　　import org.apache.ibatis.type.TypeHandler;　　import org.apache.ibatis.type.TypeHandlerRegistry;　　　　import com.framework.common.page.impl.Page;　　import com.framework.common.utils.ReflectUtil;　　/**　　*　　*　　*　　*/　　@Intercepts({ @org.apache.ibatis.plugin.Signature(type = org.apache.ibatis.executor.statement.StatementHandler.class, method = "prepare", args = { Connection.class }) })　　public class PagePlugin implements Interceptor {　　　　private String dialect = "";　　private String pageSqlId = "";　　　　@Override　　public Object intercept(Invocation invocation) throws Throwable {　　if (invocation.getTarget() instanceof RoutingStatementHandler) {　　BaseStatementHandler delegate = (BaseStatementHandler) ReflectUtil　　.getValueByFieldName(　　(RoutingStatementHandler) invocation.getTarget(),　　"delegate");　　MappedStatement mappedStatement = (MappedStatement) ReflectUtil　　.getValueByFieldName(delegate,　　"mappedStatement");　　　　Page page = Page.threadLocal.get();　　if (page == null) {　　page = new Page();　　Page.threadLocal.set(page);　　}　　　　if (mappedStatement.getId().matches(".*(" + this.pageSqlId + ")$") && page.getPageSize() > 0) {　　BoundSql boundSql = delegate.getBoundSql();　　Object parameterObject = boundSql.getParameterObject();　　　　String sql = boundSql.getSql();　　String countSqlId = mappedStatement.getId().replaceAll(pageSqlId, "Count");　　MappedStatement countMappedStatement = null;　　if (mappedStatement.getConfiguration().hasStatement(countSqlId)) {　　countMappedStatement = mappedStatement.getConfiguration().getMappedStatement(countSqlId);　　}　　String countSql = null;　　if (countMappedStatement != null) {　　countSql = countMappedStatement.getBoundSql(parameterObject).getSql();　　} else {　　countSql = "SELECT COUNT(1) FROM (" + sql + ") T_COUNT";　　}　　　　int totalCount = 0;　　PreparedStatement countStmt = null;　　ResultSet resultSet = null;　　try {　　Connection connection = (Connection) invocation.getArgs()[0];　　countStmt = connection.prepareStatement(countSql);　　BoundSql countBoundSql = new BoundSql(mappedStatement.getConfiguration(), countSql, boundSql.getParameterMappings(), parameterObject);　　　　setParameters(countStmt, mappedStatement, countBoundSql, parameterObject);　　　　resultSet = countStmt.executeQuery();　　if(resultSet.next()) {　　totalCount = resultSet.getInt(1);　　}　　} catch (Exception e) {　　throw e;　　} finally {　　try {　　if (resultSet != null) {　　resultSet.close();　　}　　} finally {　　if (countStmt != null) {　　countStmt.close();　　}　　}　　}　　　　page.setTotalCount(totalCount);　　　　ReflectUtil.setValueByFieldName(boundSql, "sql", generatePageSql(sql,page));　　}　　}　　　　return invocation.proceed();　　}　　　　　　/**　　* 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 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 ");　　pageSql.append(page.getCurrentResult());　　}　　return pageSql.toString();　　}else{　　return sql;　　}　　}　　　　@Override　　public Object plugin(Object target) {　　return Plugin.wrap(target, this);　　}　　　　@Override　　public void setProperties(Properties properties) {　　try {　　if (StringUtils.isEmpty(this.dialect = properties　　.getProperty("dialect"))) {　　throw new PropertyException("dialect property is not found!");　　}　　if (StringUtils.isEmpty(this.pageSqlId = properties　　.getProperty("pageSqlId"))) {　　throw new PropertyException("pageSqlId property is not found!");　　}　　} catch (PropertyException e) {　　e.printStackTrace();　　}　　}　　　　}附上出处链接：71829.htmspringmvc mybatis怎么实现分页查询

如何访问一个链接地址跳转到另一个链接，如访问www.ipage.com自动跳转到www.ipage.com/me?的链接

使用一些安全狗等软件都可以

mybatisplus selectById 查不到结果

MyBatis 每次创建结果对象的新实例时，它都会使用一个对象工厂（ObjectFactory）实例来完成。 默认的对象工厂需要做的仅仅是实例化目标类，要么通过默认构造方法，要么在参数映射存在的时候通过参数构造方法来实例化。