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  • jdbc ---- DBUTilDao 类

    1, 列用工具包  阿里的

    DbUtils: JDBC Utility Component Examples

     再次封装成通用的 update, query

    package com.ljs.dao;
    
    import java.sql.Connection;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.apache.commons.dbutils.QueryRunner;
    import org.apache.commons.dbutils.handlers.BeanHandler;
    import org.apache.commons.dbutils.handlers.BeanListHandler;
    import org.apache.commons.dbutils.handlers.ScalarHandler;
    
    import com.ljs.util.JDBCUtil;
    
    public class DBUtilDao{
        
        QueryRunner qRunner = new QueryRunner();
        Connection connection = null;
        /*
         *  查询多条结果。
         */
        public<T> List<T> queryMutil(Class<T> clazz, String sql, Object...object){
            List<T> list = new ArrayList<>();
            try {
                connection = JDBCUtil.getConn();
                list = qRunner.query(connection, sql,new BeanListHandler<T>(clazz),object);
            }catch (Exception e) {
                
                e.printStackTrace();
            }finally {
                JDBCUtil.close(null, null, connection);
            }
        
            return list;
        }
        
        /*
         *  查询一条结果。
         */
        public<T> T queryOne(Class<T> clazz, String sql, Object...objects){
            
            try {
                connection = JDBCUtil.getConn();
                T t = clazz.newInstance();
                t = qRunner.query(connection, sql, new BeanHandler<T>(clazz), objects);
                
                return t; 
            } catch (Exception e) {
                
                e.printStackTrace();
            }
            return null;
        }
        /*
         * 更新表
         */
        public<T> void update(String sql, Object...objects){
            
            try {
                connection = JDBCUtil.getConn();
                qRunner.update(connection, sql, objects);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        /*
         * 查询某个数scalar
         */
        public String scalar(String sql, Object...objects){
            
            try {
                connection = JDBCUtil.getConn();
                return qRunner.query(connection, sql,new ScalarHandler<>(), objects).toString();
            } catch (Exception e) {
                
                e.printStackTrace();
            }
        
            return null;
        }
    
    }
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  • 原文地址:https://www.cnblogs.com/lijins/p/10122617.html
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