ResultSet

冷不防 2023-05-31 03:23 15阅读 0赞

写一个方法，查询用户表中的所有用户信息，返回一个用户列表：

public static <T> List<T> show(String sql, Class<T> c1) {
        	List<T> listmap = new ArrayList<>();
        	DBConnection db = new DBConnection();
        	ResultSet rs = null;
        	try {
    		    Statement stmt = (Statement) db.conn.createStatement();
    		    rs = (ResultSet) stmt.executeQuery(sql);
    		    while(rs.next()){
    		    	T t = c1.newInstance();
    		    	Field[] fields = c1.getDeclaredFields();
    		    	AccessibleObject.setAccessible(fields, true);
    		    	for (Field field : fields) {
    					Object obj = rs.getObject(field.getName());
    					field.set(t, obj);
    				}
    		    	listmap.add(t);
    		    }
        	}catch (SQLException e) {
        		e.printStackTrace();
    		} catch (IllegalAccessException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (InstantiationException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
            rs.close();
            db.close();
        	return listmap; 
        }

方法调用：

public static void main(String[] args) {
    		List<UserInfo> list = MysqlUtil.show("select * from userinfo", UserInfo.class);
    		System.out.println(list);
    	}

输出：

>  \[UserInfo \[id=1, userName=王柏川, phone=18833280565, otherInfo=请问企鹅号是多少？\], UserInfo \[id=2, userName=樊胜美, phone=15935652885, otherInfo=欧克\], UserInfo \[id=3, userName=安迪, phone=15968544265, otherInfo=pop\], UserInfo \[id=4, userName=小包总, phone=13325659887, otherInfo=poll\], UserInfo \[id=6, userName=John, phone=15232253965, otherInfo=个人信息789\]\]

参考：[ResultSet结果集的使用][ResultSet]

[ResultSet]: https://blog.csdn.net/above_my_point/article/details/78934163