数据库连接池之_DButils

Posted 2020-10-04 烟雨蒙尘

  1 // 这个是在添加数据
  2     @Test
  3     public void demo1() {
  4         QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
  5         String sql = "insert into Book values(?,?)";
  6         try {
  7             int num = qr.update(sql, 26, "明朝那些事");
  8             if (num > 0) {
  9                 System.out.println("添加成功");
 10             } else {
 11                 System.out.println("添加失败");
 12             }
 13         } catch (SQLException e) {
 14             // TODO Auto-generated catch block
 15             e.printStackTrace();
 16         }
 17     }
 18 
 19     // 修改数据
 20     @Test
 21     public void demo2() {
 22         QueryRunner queryRunner = new QueryRunner(JDBCUtils.getDataSource());
 23         try {
 24             String sql = "update Book set bname=? where id=?";
 25             int num = queryRunner.update(sql, "史记", 29);
 26             if (num > 0) {
 27                 System.out.println("添加成功");
 28             } else {
 29                 System.out.println("添加失败");
 30             }
 31         } catch (Exception e) {
 32             e.printStackTrace();
 33         }
 34     }
 35 
 36     // 下面的是查询语句
 37     // 将数据表中的第一条数据封装成object
 38     @Test
 39     public void demo3() {
 40         QueryRunner queryRunner = new QueryRunner(JDBCUtils.getDataSource());
 41         try {
 42             String sql = "select * from Book";
 43             Object[] objects = queryRunner.query(sql, new ArrayHandler());
 44 
 45             System.out.println(Arrays.toString(objects));
 46         } catch (Exception e) {
 47             e.printStackTrace();
 48         }
 49     }
 50     
 51     //将数据表中的每一条数据封装成object    new ArrayListHandler()
 52     @Test
 53     public void demo4(){
 54         QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
 55         try {
 56             String sql="select * from Book";
 57             List<Object[]> list=queryRunner.query(sql,new ArrayListHandler());
 58             
 59             for(Object[] objects:list){
 60                 System.out.println(Arrays.toString(objects));
 61             }
 62             
 63         } catch (Exception e) {
 64             e.printStackTrace();
 65         }
 66     }
 67 
 68 
 69     //把数据表中的第一条数据封装成JavaBean实体类对象   BeanHandler
 70     @Test
 71     public void demo5(){
 72         QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
 73         try {
 74             String sql="select * from Book";
 75             Book list=queryRunner.query(sql,new BeanHandler<>(Book.class));
 76             
 77             System.out.println(list.toString());
 78         } catch (Exception e) {
 79             e.printStackTrace();
 80         }
 81     }
 82 
 83     
 84     //把数据表中的每一条数据封装成JavaBean实体类对象   BeanListHandler
 85         @Test
 86     public void demo6(){
 87             QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
 88             try {
 89                 String sql="select * from Book";
 90                 List<Book> list=queryRunner.query(sql,new BeanListHandler<>(Book.class));
 91                 
 92                 for(Book book:list)
 93                     System.out.println(book.toString());
 94             } catch (Exception e) {
 95                 e.printStackTrace();
 96             }
 97         }
 98 
 99     //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()
100     @Test
101     public void demo7(){
102         QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
103         try {
104             String sql="select * from Book";
105             Map<String,Object > map=queryRunner.query(sql,new MapHandler());
106         
107             System.out.println(map);
108         } catch (Exception e) {
109             e.printStackTrace();
110         }
111     }    
112     
113     //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()
114         @Test
115         public void demo8(){
116             QueryRunner queryRunner=new QueryRunner(JDBCUtils.getDataSource());
117             try {
118                 String sql="select * from Book";
119                 List<Map<String,Object >>list=queryRunner.query(sql,new MapListHandler());
120                for(Map<String,Object>map:list)
121                 System.out.println(map);
122             } catch (Exception e) {
123                 e.printStackTrace();
124             }
125         }    
126         
127         // 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.
128         @Test
129         public void demo9() {
130             // 1. 获取可以执行SQL语句的对象: QueryRunner
131             QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
132             // 2. 编写需要执行的SQL语句
133             String sql = "select * from Book;";
134             // 3. 执行SQL语句, 获取结果集
135             try {
136                 List<Object> list = qr.query(sql, new ColumnListHandler("bname"));
137                 System.out.println(list);
138             } catch (SQLException e) {
139                 e.printStackTrace();
140             }
141         }
142         
143         // 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.
144         @Test
145         public void demo10() {
146             // 1. 获取可以执行SQL语句的对象: QueryRunner
147             QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
148             // 2. 编写需要执行的SQL语句
149             String sql = "select count(*) from Book;";
150             // 3. 执行SQL语句, 获取结果集
151             try {
152                 Object obj = qr.query(sql, new ScalarHandler());
153                 System.out.println(obj);
154             } catch (SQLException e) {
155                 e.printStackTrace();
156             }
157         }
158         
159         // 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.
160         @Test
161         public void demo11() {
162             // 1. 获取可以执行SQL语句的对象: QueryRunner
163             QueryRunner qr = new QueryRunner(JDBCUtils.getDataSource());
164             // 2. 编写需要执行的SQL语句
165             String sql = "select * from Book;";
166             // 3. 执行SQL语句, 获取结果集
167             try {
168                 Map<Object, Map<String, Object>> map = qr.query(sql, new KeyedHandler("bname"));
169                 for (Object key : map.keySet()) {
170                     System.out.println(key + "..." + map.get(key));
171                 }
172                 
173             } catch (SQLException e) {
174                 e.printStackTrace();
175             }
176         }