本文实例为大家分享了完整的java分页拦截类，供大家参考，具体内容如下
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package com.opms.interceptor;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.Properties;import org.apache.ibatis.executor.parameter.ParameterHandler;import org.apache.ibatis.executor.statement.StatementHandler;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.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.factory.DefaultObjectFactory;import org.apache.ibatis.reflection.factory.ObjectFactory;import org.apache.ibatis.reflection.wrapper.DefaultObjectWrapperFactory;import org.apache.ibatis.reflection.wrapper.ObjectWrapperFactory;import org.apache.ibatis.scripting.defaults.DefaultParameterHandler;import org.apache.ibatis.session.RowBounds;import com.wifi.core.page.Page;/** * 通过拦截<code>StatementHandler</code>的<code>prepare</code>方法，重写sql语句实现物理分页。 * 老规矩，签名里要拦截的类型只能是接口。 * * @author 湖畔微风 * */@Intercepts({@Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class})})public class PageInterceptor implements Interceptor { /** * 日志 */ private static final Log logger = LogFactory.getLog(PageInterceptor.class); /** * 声明对象 */ private static final ObjectFactory DEFAULT_OBJECT_FACTORY = new DefaultObjectFactory(); /** * 声明对象 */ private static final ObjectWrapperFactory DEFAULT_OBJECT_WRAPPER_FACTORY = new DefaultObjectWrapperFactory(); /** * 数据库类型(默认为mysql) */ private static String defaultDialect = "mysql"; /** * 需要拦截的ID(正则匹配) */ private static String defaultPageSqlId = ".*4Page$"; /** * 数据库类型(默认为mysql) */ private static String dialect = ""; /** * 需要拦截的ID(正则匹配) */ private static String pageSqlId = ""; /** * @param invocation 参数 * @return Object * @throws Throwable 抛出异常 */ public Object intercept(Invocation invocation) throws Throwable { StatementHandler statementHandler = (StatementHandler) invocation.getTarget(); MetaObject metaStatementHandler = MetaObject.forObject(statementHandler, DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY); // 分离代理对象链(由于目标类可能被多个拦截器拦截，从而形成多次代理，通过下面的两次循环可以分离出最原始的的目标类) while (metaStatementHandler.hasGetter("h")) { Object object = metaStatementHandler.getValue("h"); metaStatementHandler = MetaObject.forObject(object, DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY); } // 分离最后一个代理对象的目标类 while (metaStatementHandler.hasGetter("target")) { Object object = metaStatementHandler.getValue("target"); metaStatementHandler = MetaObject.forObject(object, DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY); } dialect=defaultDialect;pageSqlId=defaultPageSqlId; /* Configuration configuration = (Configuration) metaStatementHandler.getValue("delegate.configuration"); dialect = configuration.getVariables().getProperty("dialect"); if (null == dialect || "".equals(dialect)) { logger.warn("Property dialect is not setted,use default 'mysql' "); dialect = defaultDialect; } pageSqlId = configuration.getVariables().getProperty("pageSqlId"); if (null == pageSqlId || "".equals(pageSqlId)) { logger.warn("Property pageSqlId is not setted,use default '.*Page$' "); pageSqlId = defaultPageSqlId; }*/ MappedStatement mappedStatement = (MappedStatement) metaStatementHandler.getValue("delegate.mappedStatement"); // 只重写需要分页的sql语句。通过MappedStatement的ID匹配，默认重写以Page结尾的MappedStatement的sql if (mappedStatement.getId().matches(pageSqlId)) { BoundSql boundSql = (BoundSql) metaStatementHandler.getValue("delegate.boundSql"); Object parameterObject = boundSql.getParameterObject(); if (parameterObject == null) { throw new NullPointerException("parameterObject is null!"); } else { Object obj = metaStatementHandler .getValue("delegate.boundSql.parameterObject.page"); // 传入了page参数且需要开启分页时 if(obj!=null&&obj instanceof Page &&((Page)obj).isPagination()){ Page page = (Page) metaStatementHandler .getValue("delegate.boundSql.parameterObject.page"); String sql = boundSql.getSql(); // 重写sql String pageSql = buildPageSql(sql, page); metaStatementHandler.setValue("delegate.boundSql.sql", pageSql); // 采用物理分页后，就不需要mybatis的内存分页了，所以重置下面的两个参数 metaStatementHandler.setValue("delegate.rowBounds.offset", RowBounds.NO_ROW_OFFSET); metaStatementHandler.setValue("delegate.rowBounds.limit", RowBounds.NO_ROW_LIMIT); Connection connection = (Connection) invocation.getArgs()[0]; // 重设分页参数里的总页数等 setPageParameter(sql, connection, mappedStatement, boundSql, page); } } } // 将执行权交给下一个拦截器 return invocation.proceed(); } /** * 从数据库里查询总的记录数并计算总页数，回写进分页参数<code>PageParameter</code>,这样调用者就可用通过 分页参数 * <code>PageParameter</code>获得相关信息。 * * @param sql 参数 * @param connection 连接 * @param mappedStatement 参数 * @param boundSql 绑定sql * @param page 页 */ private void setPageParameter(String sql, Connection connection, MappedStatement mappedStatement, BoundSql boundSql, Page page) { // 记录总记录数 String countSql = "select count(0) from (" + sql + ") as total"; PreparedStatement countStmt = null; ResultSet rs = null; try { countStmt = connection.prepareStatement(countSql); BoundSql countBS = new BoundSql(mappedStatement.getConfiguration(), countSql, boundSql.getParameterMappings(), boundSql.getParameterObject()); setParameters(countStmt, mappedStatement, countBS, boundSql.getParameterObject()); rs = countStmt.executeQuery(); int totalCount = 0; if (rs.next()) { totalCount = rs.getInt(1); } page.setTotalCount(totalCount); page.init(page.getCurPage(), page.getPageSize(), totalCount); } catch (SQLException e) { logger.error("Ignore this exception", e); } finally { try { rs.close(); } catch (SQLException e) { logger.error("Ignore this exception", e); } try { countStmt.close(); } catch (SQLException e) { logger.error("Ignore this exception", e); } } } /** * 对SQL参数(?)设值 * * @param ps 参数 * @param mappedStatement 参数 * @param boundSql 绑定sql * @param parameterObject 参数对象 * @throws SQLException 抛出sql异常 */ private void setParameters(PreparedStatement ps, MappedStatement mappedStatement, BoundSql boundSql, Object parameterObject) throws SQLException { ParameterHandler parameterHandler = new DefaultParameterHandler(mappedStatement, parameterObject, boundSql); parameterHandler.setParameters(ps); } /** * 根据数据库类型，生成特定的分页sql * * @param sql 餐宿 * @param page 页 * @return String */ private String buildPageSql(String sql, Page page) { if (page != null) { StringBuilder pageSql = new StringBuilder(); if ("mysql".equals(dialect)) { pageSql = buildPageSqlForMysql(sql, page); } else if ("oracle".equals(dialect)) { pageSql = buildPageSqlForOracle(sql, page); } else { return sql; } return pageSql.toString(); } else { return sql; } } /** * mysql的分页语句 * * @param sql 参数 * @param page 页 * @return String */ public StringBuilder buildPageSqlForMysql(String sql, Page page) { StringBuilder pageSql = new StringBuilder(100); String beginrow = String.valueOf((page.getCurPage() - 1) * page.getPageSize()); pageSql.append(sql); pageSql.append(" limit " + beginrow + "," + page.getPageSize()); return pageSql; } /** * 参考hibernate的实现完成oracle的分页 * * @param sql 参数 * @param page 参数 * @return String */ public StringBuilder buildPageSqlForOracle(String sql, Page page) { StringBuilder pageSql = new StringBuilder(100); String beginrow = String.valueOf((page.getCurPage() - 1) * page.getPageSize()); String endrow = String.valueOf(page.getCurPage() * page.getPageSize()); pageSql.append("select * from ( select temp.*, rownum row_id from ( "); pageSql.append(sql); pageSql.append(" ) temp where rownum <= ").append(endrow); pageSql.append(") where row_id > ").append(beginrow); return pageSql; } /** * @param target 参数 * @return Object */ public Object plugin(Object target) { // 当目标类是StatementHandler类型时，才包装目标类，否者直接返回目标本身,减少目标被代理的次数 if (target instanceof StatementHandler) { return Plugin.wrap(target, this); } else { return target; } } /** * @param properties 参数 */ public void setProperties(Properties properties) { }} |
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