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();
             }
         }