java架构师之路（持续更新中）

public static List<Map<String,Object>> queryForList(){  
    Connection connection = null;  
    ResultSet rs = null;  
    PreparedStatement stmt = null;  
    List<Map<String,Object>> resultList = new ArrayList<Map<String,Object>>();  
          
    try {  
        // 加载JDBC驱动  
        Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();  
        String url = "jdbc:oracle:thin:@localhost:1521:ORACLEDB";  
              
        String user = "trainer";   
        String password = "trainer";   
              
        // 获取数据库连接  
        connection = DriverManager.getConnection(url,user,password);   
              
        String sql = "select * from userinfo where user_id = ? ";  
        // 创建Statement对象（每一个Statement为一次数据库执行请求）  
        stmt = connection.prepareStatement(sql);  
              
        // 设置传入参数  
        stmt.setString(1, "zhangsan");  
              
        // 执行SQL语句  
        rs = stmt.executeQuery();  
              
        // 处理查询结果（将查询结果转换成List<Map>格式）  
        ResultSetMetaData rsmd = rs.getMetaData();  
        int num = rsmd.getColumnCount();  
              
        while(rs.next()){  
            Map map = new HashMap();  
            for(int i = 0;i < num;i++){  
                String columnName = rsmd.getColumnName(i+1);  
                map.put(columnName,rs.getString(columnName));  
            }  
            resultList.add(map);  
        }  
              
    } catch (Exception e) {  
        e.printStackTrace();  
    } finally {  
        try {  
            // 关闭结果集  
            if (rs != null) {  
                rs.close();  
                rs = null;  
            }  
            // 关闭执行  
            if (stmt != null) {  
                stmt.close();  
                stmt = null;  
            }  
            if (connection != null) {  
                connection.close();  
                connection = null;  
            }  
        } catch (SQLException e) {  
            e.printStackTrace();  
        }  
    }        
    return resultList;  
}