基于javaweb的网上书城管理系统登陆、注册首页相关Servlet代码

1. 登陆相关Servlet代码：

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

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

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

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html; charset=UTF-8");
        PrintWriter out = response.getWriter();

        String username = request.getParameter("username");
        String password = request.getParameter("password");

        HttpSession session = request.getSession();

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bookstore?useSSL=false", "root", "123456");

            String sql = "select * from user where username=? and password=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, username);
            pstmt.setString(2, password);
            rs = pstmt.executeQuery();

            if (rs.next()) {
                session.setAttribute("username", username);
                response.sendRedirect("index.jsp");
            } else {
                out.println("<script>alert('用户名或密码错误！'); window.location.href='login.jsp'</script>");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) rs.close();
                if (pstmt != null) pstmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

2. 注册相关Servlet代码：

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

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

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html; charset=UTF-8");
        PrintWriter out = response.getWriter();

        String username = request.getParameter("username");
        String password = request.getParameter("password");
        String repassword = request.getParameter("repassword");
        String email = request.getParameter("email");

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bookstore?useSSL=false", "root", "123456");

            String sql = "select * from user where username=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, username);
            rs = pstmt.executeQuery();

            if (rs.next()) {
                out.println("<script>alert('用户名已存在！'); window.location.href='register.jsp'</script>");
            } else {
                sql = "insert into user(username, password, email) values(?, ?, ?)";
                pstmt = conn.prepareStatement(sql);
                pstmt.setString(1, username);
                pstmt.setString(2, password);
                pstmt.setString(3, email);
                pstmt.executeUpdate();

                out.println("<script>alert('注册成功！'); window.location.href='login.jsp'</script>");
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) rs.close();
                if (pstmt != null) pstmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

3. 首页相关Servlet代码：

import java.io.IOException;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

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

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html; charset=UTF-8");

        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bookstore?useSSL=false", "root", "123456");

            String sql = "select * from book";
            pstmt = conn.prepareStatement(sql);
            rs = pstmt.executeQuery();

            List<Book> list = new ArrayList<Book>();
            while (rs.next()) {
                Book book = new Book();
                book.setId(rs.getInt("id"));
                book.setName(rs.getString("name"));
                book.setAuthor(rs.getString("author"));
                book.setPrice(rs.getFloat("price"));
                book.setDescription(rs.getString("description"));
                book.setCategory(rs.getString("category"));
                list.add(book);
            }

            request.setAttribute("bookList", list);
            request.getRequestDispatcher("index.jsp").forward(request, response);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) rs.close();
                if (pstmt != null) pstmt.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}