Apache—DBUtils框架

一、什么是dbutils

commons-dbutils 是 Apache 组织提供的一个开源 JDBC工具类库，它是对JDBC的简单封装，学习成本极低，并且使用dbutils能极大简化jdbc编码的工作量，同时也不会影响程序的性能。因此dbutils成为很多不喜欢hibernate的公司的首选。

 

二、dbutils核心API

1、QueryRunner类

 

使用QueryRunner实现增删改查

package com.dbutils;

import java.sql.SQLException;
import java.util.Date;
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.junit.Test;

import com.domain.User;
import com.utils.JdbcUtils;

/**
 * 
 * 使用dbutils完成数据库的增删改查
 * 
 */
public class Demo1 {
    // 插入
    @Test
    public void insert() throws SQLException {
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "insert into users(id,name,password,email,birthday) values(?,?,?,?,?)";
        Object params[] = { 1, "aa", "123", "aaa@sina.com", new Date() };
        runner.update(sql, params);
    }

    // 删除
    @Test
    public void delete() throws SQLException {
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "delete from users where id=?";
        runner.update(sql, 2);
    }

    // 修改
    @Test
    public void update() throws SQLException {
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "update users set email=? where id=?";
        Object params[] = { "ffd@sina.com", 2 };
        runner.update(sql, params);
    }

    // 查找单条记录
    @Test
    public void find() throws SQLException {
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "select * from users where id=?";
        User user = (User) runner.query(sql, 1, new BeanHandler(User.class));
        System.out.println(user.getEmail());
    }

    // 查找所有记录
    @Test
    public void getAll() throws SQLException {
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "select * from users";
        List<User> list = (List) runner.query(sql, new BeanListHandler(
                User.class));
        for (User user : list) {
            System.out.println(user.getEmail());
        }
    }
    
    // 批处理
        @Test
        public void batch() throws SQLException {
            QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
            String sql = "insert into users(id,name,password,email,birthday) values(?,?,?,?,?)";
            
            //三条sql，五个参数
            Object params[][] = new Object[3][5];
            
            for(int i=0;i<params.length;i++){
                params[i] = new Object[]{i+1,"aaa"+i,"123","sina.com",new Date()};
            }
            
            runner.batch(sql, params);
        }
            
}

public class JdbcUtils {
    private static DataSource ds;
    static{
        try {
            Properties prop = new Properties();
            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("dbcpconfig.properties");
            prop.load(in);
            
            //创建数据源
            BasicDataSourceFactory factory = new BasicDataSourceFactory();
            ds = factory.createDataSource(prop);
        } catch (Exception e) {
            throw new ExceptionInInitializerError(e);
        }
    }
    
    //提供数据源
    public static DataSource getDataSource(){
        return ds;
    }
    
    //获取连接
    public static Connection  getConnection() throws SQLException{
        return ds.getConnection();
    }
}

2、ResultSetHandler接口的实现类

ArrayHandler：把结果集中的第一行数据转成对象数组。

ArrayListHandler：把结果集中的每一行数据都转成一个数组，再存放到List中。

BeanHandler：将结果集中的第一行数据封装到一个对应的JavaBean实例中。

BeanListHandler：将结果集中的每一行数据都封装到一个对应的JavaBean实例中，存放到List里。

ColumnListHandler：将结果集中某一列的数据存放到List中。

KeyedHandler(name)：将结果集中的每一行数据都封装到一个Map里，再把这些map再存到一个map里，其key为指定的key。

MapHandler：将结果集中的第一行数据封装到一个Map里，key是列名，value就是对应的值。

MapListHandler：将结果集中的每一行数据都封装到一个Map里，然后再存放到List

package com.dbutils;
import java.sql.SQLException;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import javax.swing.JButton;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.ArrayHandler;
import org.apache.commons.dbutils.handlers.ArrayListHandler;
import org.apache.commons.dbutils.handlers.ColumnListHandler;
import org.apache.commons.dbutils.handlers.KeyedHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import org.junit.Test;

import com.utils.JdbcUtils;

/**
 * 
 * dbutils结果集
 *
 */
public class Demo2 {
    @Test
    //把结果的第一行数据封装到数组中
    public void test1() throws SQLException{
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "select * from users";
        //强转的时候要加[]
        Object result[] = (Object[]) runner.query(sql, new ArrayHandler());
        System.out.println(result[0]);
        System.out.println(result[1]);
    }
    
    @Test
    //把结果的每行数据封装到数组中，在把数据存放在list集合中
    public void test2() throws SQLException{
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "select * from users";
        List<Object[]> list = (List) runner.query(sql, new ArrayListHandler());
        System.out.println(list);
        for(Object[] objects : list){
            System.out.println(Arrays.toString(objects));
        }
    }
    
    @Test
    //把结果集的某一列封装到一个list集合中
    public void test3() throws SQLException{
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "select * from users";
        
        List list1 = (List) runner.query(sql, new ColumnListHandler());
        for(Object object : list1){
            System.out.println(object);
        }
        
        List list2 = (List) runner.query(sql,new ColumnListHandler("name"));
        for(Object object : list2){
            System.out.println(object);
        }
        
        List list3 = (List) runner.query(sql,new ColumnListHandler(4));
        for(Object object : list3){
            System.out.println(object);
        }
    }
    
    //KeyedHandler(name)：将结果集中的每一行数据都封装到一个Map里，再把这些map再存到一个map里，其key为指定的key
    @Test
 71     public void test4() throws SQLException{
 72         QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
 73         String sql = "select * from users";
 74         Map<Integer,Map<String,Object>> map = (Map) runner.query(sql, new KeyedHandler("id"));
 75         for(Map.Entry<Integer, Map<String, Object>> me : map.entrySet()){
 76             int key = me.getKey();
 77             
 78             //拿到封装每条记录的map
 79             for(Map.Entry<String, Object> entry:me.getValue().entrySet()){
 80                 System.out.println(entry.getKey()+"="+entry.getValue());
 81             }
 82         }
 83     }
 84     
    
    @Test
    //获取记录总数
    public void test5() throws SQLException{
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        String sql = "select count(*) from users";
        //Object result[] = (Object[]) runner.query(sql, new ArrayHandler());
        /*long totalrecord = (Long)result[0];
        int num = (int)totalrecord;
        System.out.println(num);
        int totalrecord = ((Long)result[0]).intValue();
        */
        int totalrecord = ((Long)runner.query(sql, new ScalarHandler(1))).intValue();
        System.out.println(totalrecord);
    }
    
    
}