Java Web 应用：使用 Servlet 和数据库操作机器人信息

这段代码展示了一个简单的 Java Web 应用，使用 Servlet 和数据库来管理机器人信息。

@WebServlet({"/welcome"})
public class Robot extends HttpServlet {
protected void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
String action = req.getParameter("action");

	if ("addRobot".equals(action)) {  
		
		RobotInfo robot = new RobotInfo();  
		robot.setNAME(req.getParameter('robotname'));  
		robot.setweight(req.getParameter('robotweight'));  
		robot.setsize(req.getParameter('robotsize'));  
		PreparedStatement pstmt = null;   
		DBConnected dbc = null;  
		String sql = "INSERT INTO `javawebdb`.`robot` (`ID`, `NAME`, `WEIGHT`, `SIZE`, `IMAGE`) VALUES (NULL,?,?,?,NULL)";  
		try {   
			
			dbc = new DBConnected();   
			pstmt = dbc.getConnection().prepareStatement(sql);  
			pstmt.setString(1, robot.getNAME());  
			pstmt.setString(2, robot.getweight());  
			pstmt.setString(3, robot.getsize());  
			  
			int rs = pstmt.executeUpdate();  
			  
			pstmt.close();  
			res.sendRedirect("./welcome.jsp");  
		} catch (SQLException e) {   
			System.out.println(e.getMessage());   
		} finally {   
			
			dbc.close();   
		}  
	} else if ("deleteRobot".equals(action)) {  
		  
		RobotInfo robot = new RobotInfo();  
		String ID = req.getParameter('robotID');  
		PreparedStatement pstmt = null;   
		DBConnected dbc = null;  
		String sql = "DELETE FROM Robot WHERE id = ?";  
		;  
		try {   
			  
			dbc = new DBConnected();   
			pstmt = dbc.getConnection().prepareStatement(sql);  
			pstmt.setString(1, ID);  
			  
			int rs = pstmt.executeUpdate();  
			  
			pstmt.close();  
			res.sendRedirect("./welcome.jsp");  
		} catch (SQLException e) {   
			System.out.println(e.getMessage());   
		} finally {   
			  
			dbc.close();   
		}  
	} else if ("changeRobot".equals(action)) {  
		RobotInfo robot = new RobotInfo();  
		String ID = req.getParameter('robotID1');  
		robot.setNAME(req.getParameter('robotname1'));  
		robot.setweight(req.getParameter('robotweight1'));  
		robot.setsize(req.getParameter('robotsize1'));  
		PreparedStatement pstmt = null;   
		DBConnected dbc = null;  
		String sql = "UPDATE Robot SET NAME = ?, WEIGHT = ?, SIZE=? WHERE id =?";  
		;  
		try {   
			  
			dbc = new DBConnected();   
			pstmt = dbc.getConnection().prepareStatement(sql);  
			pstmt.setString(1, robot.getNAME());  
			pstmt.setString(2, robot.getweight());  
			pstmt.setString(3, robot.getsize());  
			pstmt.setString(4, ID);  
			  
			int rs = pstmt.executeUpdate();  
			pstmt.close();  
			res.sendRedirect("./welcome.jsp");  
		} catch (SQLException e) {   
			System.out.println(e.getMessage());   
		} finally {   
			
			dbc.close();  
			  
		}  
		}  
}  

}

这段代码中的增加操作是如何通过req.getParameter获取机器人参数的内容：在增加机器人操作中，通过req.getParameter方法来获取机器人的参数。具体代码如下：

RobotInfo robot = new RobotInfo();  
robot.setNAME(req.getParameter('robotname'));  
robot.setweight(req.getParameter('robotweight'));  
robot.setsize(req.getParameter('robotsize'));  

这里使用req.getParameter方法来获取表单中对应的参数值，然后通过setXXX方法将参数值设置到RobotInfo对象中。其中XXX表示RobotInfo对象的属性名，如setNAME表示设置机器人名称。