数据库连接池之_DButils

// 这个是在添加数据
    @Test
    public void demo1() {
        QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
        String sql = "insert into Book values(?,?)";
        try {
            int num = qr.update(sql, 26, "明朝那些事");
            if (num > 0) {
                System.out.println("添加成功");
            } else {
                System.out.println("添加失败");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    // 修改数据
    @Test
    public void demo2() {
        QueryRunner queryRunner = new QueryRunner(JDBCUtils.getDataSource());
        try {
            String sql = "update Book set bname=? where id=?";
            int num = queryRunner.update(sql, "史记", 29);
            if (num > 0) {
                System.out.println("添加成功");
            } else {
                System.out.println("添加失败");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 下面的是查询语句
    // 将数据表中的第一条数据封装成object
    @Test
    public void demo3() {
        QueryRunner queryRunner = new QueryRunner(JDBCUtils.getDataSource());
        try {
            String sql = "select * from Book";
            Object[] objects = queryRunner.query(sql, new ArrayHandler());

            System.out.println(Arrays.toString(objects));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    //将数据表中的每一条数据封装成object    new ArrayListHandler()
    @Test
    public void demo4(){
        QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
        try {
            String sql="select * from Book";
            List<Object[]> list=queryRunner.query(sql,new ArrayListHandler());
            
            for(Object[] objects:list){
                System.out.println(Arrays.toString(objects));
            }
            
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    //把数据表中的第一条数据封装成JavaBean实体类对象   BeanHandler
    @Test
    public void demo5(){
        QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
        try {
            String sql="select * from Book";
            Book list=queryRunner.query(sql,new BeanHandler<>(Book.class));
            
            System.out.println(list.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    
    //把数据表中的每一条数据封装成JavaBean实体类对象   BeanListHandler
        @Test
    public void demo6(){
            QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
            try {
                String sql="select * from Book";
                List<Book> list=queryRunner.query(sql,new BeanListHandler<>(Book.class));
                
                for(Book book:list)
                    System.out.println(book.toString());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    //把数据表中的第一条数据封装成Map集合 ,键:列名  值:该列的值 new MapHandler()
    @Test
    public void demo7(){
        QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
        try {
            String sql="select * from Book";
            Map<String,Object > map=queryRunner.query(sql,new MapHandler());
        
            System.out.println(map);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }    
    
    //把数据表中的每一条数据封装成Map集合 ,键:列名  值:该列的值 new MapListHandler()
        @Test
        public void demo8(){
            QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
            try {
                String sql="select * from Book";
                List<Map<String,Object >>list=queryRunner.query(sql,new MapListHandler());
               for(Map<String,Object>map:list)
                System.out.println(map);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }    
        
        // ColunmListHandler: 把数据表中的没一条数据封装成 Map集合, 键:列名      值:该列的值 , 然后把每一行的Map集合装入到一个List集合中.
        @Test
        public void demo9() {
            // 1. 获取可以执行SQL语句的对象: QueryRunner
            QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
            // 2. 编写需要执行的SQL语句
            String sql = "select * from Book;";
            // 3. 执行SQL语句, 获取结果集
            try {
                List<Object> list = qr.query(sql, new ColumnListHandler("bname"));
                System.out.println(list);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        // ScalarHandler: 把数据表中的没一条数据封装成 Map集合, 键:列名      值:该列的值 , 然后把每一行的Map集合装入到一个List集合中.
        @Test
        public void demo10() {
            // 1. 获取可以执行SQL语句的对象: QueryRunner
            QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
            // 2. 编写需要执行的SQL语句
            String sql = "select count(*) from Book;";
            // 3. 执行SQL语句, 获取结果集
            try {
                Object obj = qr.query(sql, new ScalarHandler());
                System.out.println(obj);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        // KeyedHandler: 把数据表中的没一条数据封装成 Map集合, 键:列名      值:该列的值 , 然后把每一行的Map集合装入到一个List集合中.
        @Test
        public void demo11() {
            // 1. 获取可以执行SQL语句的对象: QueryRunner
            QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
            // 2. 编写需要执行的SQL语句
            String sql = "select * from Book;";
            // 3. 执行SQL语句, 获取结果集
            try {
                Map<Object, Map<String, Object>> map = qr.query(sql, new KeyedHandler("bname"));
                for (Object key : map.keySet()) {
                    System.out.println(key + "..." + map.get(key));
                }
                
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }