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  • 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

     1 @org.junit.Test
     2     public void Query1() throws Exception
     3     {
     4         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
     5         System.out.println(MyDataSource.getDataSource());
     6         //String sql="INSERT INTO users VALUES ('U002','tom','4321' )";
     7         //runner.update(sql);
     8         String sql="INSERT INTO users VALUES (?,?,? )";
     9         runner.update(sql,"U003","Jim","123456");
    10     }
    插入数据

    更新数据

    1 @org.junit.Test
    2     public void Query2() throws Exception
    3     {
    4         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
    5         //String sql=" UPDATE users SET NAME='Kim' WHERE NAME='jim' ";
    6         //runner.update(sql);
    7         String sql=" UPDATE users SET NAME=? WHERE NAME=? ";
    8         runner.update(sql,"lily","Kim");
    9     }
    更新数据

    删除数据

    1     @org.junit.Test
    2     public void Query3() throws Exception
    3     {
    4         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
    5         //String sql="DELETE FROM users WHERE NAME='lily' ";
    6         //runner.update(sql);
    7         String sql="DELETE FROM users WHERE NAME=? ";
    8         runner.update(sql,"tom");
    9     }
    删除数据

    查找数据

     1 @org.junit.Test
     2     public void Query4() throws Exception
     3     {
     4         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
     5         //String sql="SELECT * FROM users where id ='U002' ";
     6         //user u= runner.query(sql, new  BeanHandler<user>(user.class));
     7         
     8         String sql="SELECT * FROM users where id =? ";
     9         user u=runner.query(sql, new BeanHandler<user>(user.class),"U002");
    10         System.out.println(u);
    11     }
    查找数据——BeanHandler
     1 @org.junit.Test
     2     public void Query5() throws Exception
     3     {
     4         QueryRunner runner=new QueryRunner(MyDataSource.getDataSource());
     5         String sql="select * from users ";
     6         List<user> list= runner.query(sql, new BeanListHandler<user>(user.class));
     7         for(user u:list)
     8         {
     9             System.out.println(u);
    10         }
    11     }
    查找数据——BeanListHandler
    1 @org.junit.Test
    2     public void Query6() throws Exception
    3     {
    4         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
    5         String sql="select Id,name,Pwd from users ";
    6         Map<String, Object> map= runner.query(sql, new MapHandler());
    7         System.out.println(map.toString());
    8     }
    查找数据——MapHandler
    1     @org.junit.Test
    2     public void Query7() throws Exception
    3     {
    4         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
    5         String sql="Select * from users ";
    6         List<Map<String , Object>> list= runner.query(sql, new MapListHandler());
    7         System.out.println(list);
    8     }
    查找数据——MapListHandler
    1     @org.junit.Test
    2     public void Query8() throws Exception
    3     {
    4         QueryRunner runner =new QueryRunner(MyDataSource.getDataSource());
    5         String sql="select count(*) from Users ";
    6         Object obj=runner.query(sql, new ScalarHandler());
    7         int i=Integer.valueOf(obj.toString());
    8         System.out.println(i);
    9     }
    查找数据——ScalarHandler

    导入包包括

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  • 原文地址:https://www.cnblogs.com/liuwt365/p/4111584.html
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