dbutils的使用Demo

首先了解一下

　　　　Queryrunner.query    —————只可以执行select语句。

　　　　Queryrunner.update  —————只可以接收update,delte,insert语句

　　　　BeanHandler          ——————返回一个 Bean，结果封装到Bean。只查询第一行。适合根据id查询唯一的一行
　　　　BeanListHandler     ——————返回List<Bean>所有行，都封装到List，适合于查询多个结果

　　　　MapHandler           ——————与BeanHandler应，只返回第一行，封装成Map类型　－　也适合于查询一个结果集的    适合于关联查询，且没有匹配的Bean。
　　　　MapListHandler      ——————与BeanListHandler对应，返回所有，封装成List<Map>类型

　　　　ScalarHandler        ——————标量- 用于select count(1)|sum|avg|max …一些聚合函数

Demo（MyDataSource.getDataSource() —— 获取 DataSource）

插入数据

 @org.junit.Test
     public void Query1() throws Exception
     {
         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
         System.out.println(MyDataSource.getDataSource());
         //String sql="INSERT INTO users VALUES ('U002','tom','4321' )";
         //runner.update(sql);
         String sql="INSERT INTO users VALUES (?,?,? )";
         runner.update(sql,"U003","Jim","123456");
     }

插入数据

更新数据

 @org.junit.Test
     public void Query2() throws Exception
     {
         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
         //String sql=" UPDATE users SET NAME='Kim' WHERE NAME='jim' ";
         //runner.update(sql);
         String sql=" UPDATE users SET NAME=? WHERE NAME=? ";
         runner.update(sql,"lily","Kim");
     }

更新数据

删除数据

     @org.junit.Test
     public void Query3() throws Exception
     {
         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
         //String sql="DELETE FROM users WHERE NAME='lily' ";
         //runner.update(sql);
         String sql="DELETE FROM users WHERE NAME=? ";
         runner.update(sql,"tom");
     }

删除数据

查找数据

 @org.junit.Test
     public void Query4() throws Exception
     {
         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
         //String sql="SELECT * FROM users where id ='U002' ";
         //user u= runner.query(sql, new  BeanHandler<user>(user.class));

         String sql="SELECT * FROM users where id =? ";
         user u=runner.query(sql, new BeanHandler<user>(user.class),"U002");
         System.out.println(u);
     }

查找数据——BeanHandler

 @org.junit.Test
     public void Query5() throws Exception
     {
         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
         String sql="select * from users ";
         List<user> list= runner.query(sql, new BeanListHandler<user>(user.class));
         for(user u:list)
         {
             System.out.println(u);
         }
     }

查找数据——BeanListHandler

 @org.junit.Test
     public void Query6() throws Exception
     {
         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
         String sql="select Id,name,Pwd from users ";
         Map<String, Object> map= runner.query(sql, new MapHandler());
         System.out.println(map.toString());
     }

查找数据——MapHandler

     @org.junit.Test
     public void Query7() throws Exception
     {
         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
         String sql="Select * from users ";
         List<Map<String , Object>> list= runner.query(sql, new MapListHandler());
         System.out.println(list);
     }

查找数据——MapListHandler

     @org.junit.Test
     public void Query8() throws Exception
     {
         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
         String sql="select count(*) from Users ";
         Object obj=runner.query(sql, new ScalarHandler());
         int i=Integer.valueOf(obj.toString());
         System.out.println(i);
     }

查找数据——ScalarHandler

导入包包括