APP登陸註冊 步驟二：服務端編程

1、創建數據庫、表：

2、項目結構：

3、數據庫連接工具類 DBUtil :

public class DBUtil {
	// table，對應數據庫的表
	public static final String TABLE_PASSWORD = "account";
	public static final String TABLE_USERINFO = "userinfo";
 
	// connect to MySql database
	public static Connection getConnect() {
		String url = "jdbc:mysql://localhost:3306/android"; // 數據庫的Url，android代表數據庫名
		Connection connecter = null;
		try {
			Class.forName("com.mysql.jdbc.Driver"); // java反射，固定寫法
			//root 是數據庫的賬戶名稱，123456是賬戶密碼，改爲自己的
			connecter = (Connection) DriverManager.getConnection(url, "root", "123456");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			System.out.println("SQLException: " + e.getMessage());
			System.out.println("SQLState: " + e.getSQLState());
			System.out.println("VendorError: " + e.getErrorCode());
		}
		return connecter;
	}
}

4、處理註冊的 Servlet ：

@WebServlet("/RegisterServlet")
public class RegisterServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public RegisterServlet() {
        super();
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
//		response.getWriter().append("Served at: ").append(request.getContextPath());
		
		String account = request.getParameter("account"); // 從 request 中獲取名爲 account 的參數的值
		String password = request.getParameter("password"); // 從 request 中獲取名爲 password 的參數的值
		System.out.println("account:" + account + "\npassword:" + password); // 打印出來看一看
 
		String resCode = "";
		String resMsg = "";
		String userId = "";
		
		
		/* 這裏我們做一個最簡單的註冊邏輯，當然，你的實際業務可以相當複雜 */
		try {
			Connection connect = DBUtil.getConnect();
			Statement statement = (Statement) connect.createStatement(); // Statement可以理解爲數據庫操作實例，對數據庫的所有操作都通過它來實現
			ResultSet result;
			
			String sqlQuery = "select * from " + DBUtil.TABLE_PASSWORD + " where userAccount='" + account + "'";
			
			// 查詢類操作返回一個ResultSet集合，沒有查到結果時ResultSet的長度爲0
			result = statement.executeQuery(sqlQuery); // 先查詢同樣的賬號（比如手機號）是否存在
			if(result.next()){ // 已存在
				resCode = "201";
				resMsg = "該賬號已註冊，請使用此賬號直接登錄或使用其他賬號註冊";
				userId = "";
			} else { // 不存在
				String sqlInsertPass = "insert into " + DBUtil.TABLE_PASSWORD + "(userAccount,userPassword) values('"+account+"','"+password+"')";
				// 更新類操作返回一個int類型的值，代表該操作影響到的行數
				int row1 = statement.executeUpdate(sqlInsertPass); // 插入帳號密碼
				if(row1 == 1){
					String sqlQueryId = "select userId from " + DBUtil.TABLE_PASSWORD + " where userAccount='" + account + "'";
					ResultSet result2 = statement.executeQuery(sqlQueryId); // 查詢新增記錄的userId
					if(result2.next()){
						userId = result2.getInt("userId") + "";
					}
					int new_userId=Integer.valueOf(userId);
					String sqlInsertInfo = "insert into " + DBUtil.TABLE_USERINFO + "(userId) values('" + new_userId + "')";
					int row2 = statement.executeUpdate(sqlInsertInfo); // 在用戶信息表中插入剛註冊的Id
					if(row2 == 1){ // 兩個表中都插入成功，從業務角度認定爲註冊成功
						resCode = "100";
						resMsg = "註冊成功";
					}
				} else {
					resCode = "202";
					resMsg = "用戶信息表插入錯誤";
					userId = "";
				}
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		}
		
		HashMap<String, String> map = new HashMap<>();
		map.put("resCode", resCode);
		map.put("resMsg", resMsg);
		map.put("userId", userId);
		
		response.setContentType("text/html;charset=utf-8"); // 設置響應報文的編碼格式
		PrintWriter pw = response.getWriter(); // 獲取 response 的輸出流
		pw.println(map.toString()); // 通過輸出流把業務邏輯的結果輸出
		pw.flush();

	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

5、處理登陸的 Servlet ：

@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public LoginServlet() {
        super();
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		String code = "";
		String message = "";
 
		String account = request.getParameter("account");
		String password = request.getParameter("password");
		log(account + ";" + password); 
	
		Connection connect = DBUtil.getConnect();
		try {
			Statement statement = (Statement) connect.createStatement();
			String sql = "select userId from " + DBUtil.TABLE_PASSWORD + " where userAccount='" + account
					+ "' and userPassword='" + password + "'";
			log(sql);
			ResultSet result = statement.executeQuery(sql);
			if (result.next()) { // 能查到該賬號，說明已經註冊過了
				code = "200";
				message = "登陸成功";
			} else {
 
				code = "100";
				message = "登錄失敗，密碼不匹配或賬號未註冊";
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
 
		response.setContentType("text/html;charset=utf-8"); // 設置響應報文的編碼格式，避免瀏覽器中輸出亂碼問題
		response.getWriter().append("code:").append(code).append(";message:").append(message);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

6、運行測試：

瀏覽器中輸入要註冊的賬號、密碼：

通過 Navicat 查看數據庫表內容：

瀏覽器中輸入要登錄的賬號、密碼：

服務端環境搭建、編程到此結束，下面是客戶端的編程，請看下篇文章~

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