Mybatis利用拦截器做统一分页-白红宇的个人博客

发布日期：2021-05-09 05:38:19 浏览次数：22 分类：博客文章

本文共 6014 字，大约阅读时间需要 20 分钟。

mybatis利用拦截器做统一分页

查询传递Page参数，或者传递继承Page的对象参数。拦截器查询记录之后，通过改造查询sql获取总记录数。赋值Page对象，返回。

示例项目：

拦截器：

package com.xxx;import com.xxx.Page;import org.apache.ibatis.executor.Executor;import org.apache.ibatis.mapping.BoundSql;import org.apache.ibatis.mapping.MappedStatement;import org.apache.ibatis.mapping.ParameterMapping;import org.apache.ibatis.plugin.*;import org.apache.ibatis.scripting.defaults.DefaultParameterHandler;import org.apache.ibatis.session.ResultHandler;import org.apache.ibatis.session.RowBounds;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.Properties;/** */@Intercepts({//拦截query查询    @Signature(type=Executor.class,method="query",args={MappedStatement.class,Object.class,RowBounds.class,ResultHandler.class})})public class PageIntercept implements Interceptor {    public static final Logger logger = LoggerFactory.getLogger(PageIntercept.class);    @Override    public Object intercept(Invocation invocation) throws Throwable {        Object parameter = invocation.getArgs()[1];        Object args = invocation.getArgs()[1];		Object returnValue = invocation.proceed();        if(args instanceof Page && ((Page) args).isCount()){            MappedStatement mappedStatement=(MappedStatement)invocation.getArgs()[0];            BoundSql boundSql = mappedStatement.getBoundSql(parameter);            String originalSql = boundSql.getSql().trim();            Object parameterObject = boundSql.getParameterObject();            if(parameterObject instanceof Page){                ((Page) parameterObject).setOffset(0);                ((Page) parameterObject).setLimit(Integer.MAX_VALUE/((Page) parameterObject).getPage());            }            String countSql = "SELECT COUNT(*) FROM (" + originalSql + ") aliasForPage";            Connection connection=mappedStatement.getConfiguration().getEnvironment().getDataSource().getConnection();            BoundSql countBS = copyFromBoundSql(mappedStatement, boundSql, countSql);            DefaultParameterHandler parameterHandler = new DefaultParameterHandler(mappedStatement, parameterObject, countBS);            PreparedStatement countStmt = connection.prepareStatement(countSql);            parameterHandler.setParameters(countStmt);            ResultSet rs = countStmt.executeQuery();            int total =0;            if (rs.next()) {                total = rs.getInt(1);            }            rs.close();            countStmt.close();            connection.close();            //分页计算            ((Page) args).setTotal(total);        }	return returnValue;    }    private BoundSql copyFromBoundSql(MappedStatement ms, BoundSql boundSql, String sql) {        BoundSql newBoundSql = new BoundSql(ms.getConfiguration(),sql, boundSql.getParameterMappings(), boundSql.getParameterObject());        for (ParameterMapping mapping : boundSql.getParameterMappings()) {            String prop = mapping.getProperty();            if (boundSql.hasAdditionalParameter(prop)) {                newBoundSql.setAdditionalParameter(prop, boundSql.getAdditionalParameter(prop));                }            }        return newBoundSql;    }    @Override	public Object plugin(Object target) {		 return Plugin.wrap(target, this);	}	@Override	public void setProperties(Properties properties) {	}}

数据库配置：

package com.xxx.config;import javax.sql.DataSource;import com.xxx.PageIntercept;import org.apache.ibatis.plugin.Interceptor;import org.apache.ibatis.session.SqlSessionFactory;import org.mybatis.spring.SqlSessionFactoryBean;import org.mybatis.spring.annotation.MapperScan;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Primary;import org.springframework.jdbc.datasource.DataSourceTransactionManager;/*** @description */@Configuration@MapperScan(basePackages = "com.xxx.dao", sqlSessionFactoryRef = "sqlSessionFactory")public class DBConfig {	private final static Logger logger = LoggerFactory.getLogger(DBConfig.class);		@Bean(name = "dataSource")    @ConfigurationProperties(prefix = "datasource.planes")	@Primary    public DataSource dataSource() {        return DataSourceBuilder.create().build();    }		@Bean(name = "sqlSessionFactory")	@Primary    public SqlSessionFactory sqlSessionFactory() throws Exception {        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();        bean.setDataSource(dataSource());        bean.setPlugins(new Interceptor[]{new PageIntercept()});        return bean.getObject();    }		@Bean(name = "transactionManager")	@Primary    public DataSourceTransactionManager transactionManager() {        return new DataSourceTransactionManager(dataSource());    }	}

Page对象：

package com.xxx;import com.xxx.Constants;/** * Created by Administrator on 2018/1/5. */public class Page {    private int offset = 0;    private int limit = Constants.DEAFULT_PAGE_LIMIT;    private int total = 0;    private int page = 1;    private boolean count = true;    public boolean isCount() {        return count;    }    public void setCount(boolean count) {        this.count = count;    }    public Page(){}    public Page(int offset, int limit){        this. offset = offset;        this.limit = limit;    }    public int getPage() {        return page;    }    public void setPage(int page) {        this.page = page < 1?1:page;    }    public int getOffset() {        return (page - 1) * limit;    }    public void setOffset(int offset) {        this.offset = offset;    }    public int getLimit() {        return limit;    }    public void setLimit(int limit) {        this.limit = limit;    }    public int getTotal() {        return total;    }    public void setTotal(int total) {        this.total = total;    }}

上一篇：chrome json 格式化插件 JSON-Handle

下一篇：flume-kafka-storm-hdfs-hadoop-hbase

发表评论

关于作者

喝酒易醉，品茶养心，人生如梦，品茶悟道，何以解忧？唯有杜康！

-- 愿君每日到此一游！

发表评论

最新留言

关于作者

推荐文章