UserManager

刚刚学习servlet,打算学做一个小项目把前边学到的知识做一个总结.

由于只是实现了一些简单的功能,所以美工就凑合着看吧(美工其实也不太会).

首先项目整体架构如图

项目准备工作:

要用到mysql数据库,所以要导入

直接复制在webroot/web-inf/lib下

然后创建Users库,user表

CREATE DATABASE Users;
USE Users;
CREATE TABLE USER(
	id INT PRIMARY KEY AUTO_INCREMENT,//主键
	username VARCHAR(32) NOT NULL,//用户名
	email VARCHAR(64) NOT NULL,//邮箱
	grade INT DEFAULT 1,//级别
	PASSWORD VARCHAR(32) NOT NULL//密码

);

　　事先插入一些用户

INSERT INTO USER(username,email,PASSWORD) VALUES ("mahui","1130804967@sohu.com","123"),
("aaaa","1130804967@sina.com","123"),
("bbbb","1130804967@baidu.com","123"),
("cccc","1130804967@google.com","123"),
("dddd","1130804967@163.com","123");

1.LoginServlet.java

package com.mh.view;

import java.io.IOException;
import java.io.PrintWriter;

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

public class LoginServlet extends HttpServlet {

    

    private static final long serialVersionUID = 1L;


    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset =UTF-8");
        request.setCharacterEncoding("UTF-8");
        PrintWriter out = response.getWriter();
        
        out.println("<h1>登录界面<h1>");
        
        out.println("<form action  = '/UsersManager/LoginClServlet' method = 'post'>");//form表单提交到LoginClServlet.java
        out.println("I D:<input type = 'text' name = 'id'/><br/>");
        out.println("密　码:<input type = 'password' name = 'password'/><br/>");
        out.println("<input type = 'submit' value = 'Submit'/>");
        out.println("</form>");
        String errInfo =(String)request.getAttribute("err");//第一次该属性为null,什么都不显示
        if(errInfo != null){
            out.println("<font color = 'red'>"+errInfo+"<font>");//如果errinfo不为空,则输出错误信息
        }
        
    }

    
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

    
    }

    
    
}

2.LoginClServlet.java(该servlet用于简易的处理用户登录信息)

package com.mh.controller;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

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

public class LoginClServlet extends HttpServlet {


    private static final long serialVersionUID = 1L;
    
    public final static String URL = "jdbc:mysql://localhost:3306/Users";//建立连接
    
    public final static String USER = "root";//用户
    
    public final static String PASSWORD = "334400";//密码


    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        
        String id = request.getParameter("id");//获取id
        String pass = request.getParameter("password");//获取密码
        
        
        Connection conn = null;
        PreparedStatement prep = null;
        ResultSet set = null;
        try{
            Class.forName("com.mysql.jdbc.Driver");//加载驱动
            
            conn = DriverManager.getConnection(URL,USER,PASSWORD);//获得与数据库的连接对象conn
            
            prep = conn.prepareStatement("select * from User where id = ? and password = ?");//预处理语句
            
            prep.setString(1,id);//第一个?赋值
            prep.setString(2,pass);//第二个?赋值
            
            set = prep.executeQuery();//执行查询
            
            if(set.next()){//如果结果集合存在用户
                request.getRequestDispatcher("/MainFrame").forward(request,response);//转发到/MainFrame主页面
            }else{
                request.setAttribute("err", "用户ID或密码有误!");//如果不存在该用户,则设置err属性的信息
                request.getRequestDispatcher("/LoginServlet").forward(request, response);//转发到登录界面
            }
            
            
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            //以下为关闭资源
            if(set != null){
                try {
                    set.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(prep != null){
                try {
                    prep.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        
    }

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

}

3.MainFrame.java

package com.mh.view;

import java.io.IOException;
import java.io.PrintWriter;

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

public class MainFrame extends HttpServlet {


	private static final long serialVersionUID = 1L;


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=UTF-8");
		request.setCharacterEncoding("utf-8");
		PrintWriter out = response.getWriter();
		//这里没什么好讲的,都是一些链接
		out.println("<h1>登陆成功<h1>");
		out.println("<h3>请选择一下操作<h3>");
		out.println("<a href = '/UsersManager/ManageUsers'>管理用户</a>");//跳转到管理界面
		out.println("<a href = '/UsersManager/AddUserMain'>添加用户</a>");//添加用户
		out.println("<a href = '/UsersManager/SelectUsers'>查询用户</a>");//查询
		out.println("<a href = '/UsersManager/LoginServlet'>安全退出</a>");//退出
	
	}

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

	}

}

　　4.跳转到管理用户页面,这里边是逻辑比较复杂的一个页面,因为页面和逻辑没有实现分离,还有里边使用了分页,mysql的分页是依靠limit来实现

package com.mh.view;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

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

public class ManageUsers extends HttpServlet {

    
    
    private static final long serialVersionUID = 1L;
    
    public final static String URL = "jdbc:mysql://localhost:3306/Users";
    
    public final static String USER = "root";
    
    public final static String PASSWORD = "334400";



    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        //以下四行代码实现了跳转功能,document.getElementById('pageNow')首先获得你要跳转的页面,然后在本页面(_self参数控制)打开一个新的页面,并把page当成参数传给本页面
        out.print("<script type = 'text/javascript' language = 'javascript'>");
        out.print("function go(){var page = document.getElementById('pageNow');"
                + "window.open('/UsersManager/ManageUsers?page='+page.value,'_self');}");
        out.print("</script>");
        
        
        
        out.println("<h1>用户管理</h1><a href = '/UsersManager/MainFrame'>主页面</a><hr/>");
        
        out.println("<table border = 1 width = 500px>");
        
        out.println("<tr><th>ID</th><th>用户名</th><th>Email</th><th>级别</th></tr>");
        
        Connection conn = null;
        PreparedStatement prep = null;
        ResultSet set = null;
        try{
            Class.forName("com.mysql.jdbc.Driver");
            
            conn = DriverManager.getConnection(URL,USER,PASSWORD);
            
            prep = conn.prepareStatement("select count(id) from User ");//获得总共有多少条记录,为分页做准备
            
            set = prep.executeQuery();
            
            set.next();//这里要注意,因为光标是指向集合第一条记录的前面,所以要执行next()方法
            int rowCount = set.getInt(1);//把总数赋值给rowcount
            
            int pageSize = 3;//每页显示几条记录
            
            int pageCount = (rowCount-1)/pageSize + 1;//总共有几页(这里用到了一个小算法)
            
            int pageCurr = 1;//当前页
            
            String curr_Page = (String) request.getParameter("page");//这里是为了获取用户点击下边的第i页跳转到本页面提交的page参数
            
            
            if(curr_Page != null){
                pageCurr = Integer.parseInt(curr_Page);//第一次该参数为null,以后根据用户点击的页数而定
            }
            
            prep.close();//先关闭
            set.close();
            
            String sql = "select * from User limit "+(pageCurr-1)*pageSize+ ","+pageSize;//这里分页用到了limit,使用limit (第几页-1)*每页显示的记录,每页显示记录数
            prep = conn.prepareStatement(sql);//再次预处理新的sql
            
            set = prep.executeQuery();//执行
            
        while(set.next()){//这里得到的set结果集是一个集合,所以使用while循环
            out.println("<tr><td>"+set.getInt(1)+"</td><td>"
        +set.getString(2)+"</td><td>"+set.getString(3)
        +"</td><td>"+set.getString(4)+"</td></tr>");
        }
            out.println("</table><br/>");
            if(pageCurr != 1){
                out.print("<a href = '/UsersManager/ManageUsers?page="+(pageCurr-1)+"'>上一页 </a>");
            }
            //这里是表格的下边把总页数以for循环的方式创建超链接
            for(int i = 1; i <= pageCount; i++){////如果不等于第一页,则显示,否则隐藏
                out.print("<a href = '/UsersManager/ManageUsers?page="+i+"'><"+i+"></a>");
            }
            if(pageCurr != pageCount){//如果不等于最后一页,则显示,否则隐藏
                out.print("<a href = '/UsersManager/ManageUsers?page="+(pageCurr+1)+"'>下一页 </a>");
            }
            
            out.print("当前页"+pageCurr+"/总页数"+pageCount);
            //下边是一个跳转功能,要用到javascript,给按钮增加一个点击事件,一点击该按钮,则调用go()方法,该方法在代码的头部
            out.print("<br/>跳转到");
            out.print("<input type = 'text' size = '20px' id = 'pageNow'/>");
            out.print("&nbsp;&nbsp;<input type = 'button' value = 'GO' onclick = 'go()'/>");
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            //关闭资源
            if(set != null){
                try {
                    set.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(prep != null){
                try {
                    prep.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }

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

}

5.AddUserMain.java 没什么好说的

package com.mh.view;

import java.io.IOException;
import java.io.PrintWriter;

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

public class AddUserMain extends HttpServlet {

    private static final long serialVersionUID = 1L;

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        
        out.print("<h1>添加用户</h1><br/><hr/>");
        out.print("<form action = '/UsersManager/AddUserHandle' method = 'post'>Name:<input type = 'text' name = 'name'/><br/>");
        out.print("Email:<input type = 'text' name = 'email'/><br/>");
        out.print("PassWord:<input type = 'password' name = 'password'/><br/>");
        out.print("<input type = 'submit' value = 'Submit'/>");
        
        out.print("</form>");
        
        
    }
        
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doGet(request,response);
    }

}

6.AddUserHandle.java

package com.mh.controller;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

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

public class AddUserHandle extends HttpServlet {


    private static final long serialVersionUID = 1L;
    
    public final static String URL = "jdbc:mysql://localhost:3306/Users";
    
    public final static String USER = "root";
    
    public final static String PASSWORD = "334400";

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        
        String username = new String(request.getParameter("name").getBytes("ISO-8859-1"),"UTF-8") ;//获取用户名,这样写是为了用户输入的中文乱码
        String email = request.getParameter("email");//获取邮箱
        String password = request.getParameter("password");//获取密码
        
        int row = 0;
        Connection conn = null;
        PreparedStatement prep = null;
        ResultSet set = null;
        try{
            Class.forName("com.mysql.jdbc.Driver");
            
            conn = DriverManager.getConnection(URL,USER,PASSWORD);
            
            prep = conn.prepareStatement("insert into User (username,email,password)values(?,?,?)");//预处理
            
            prep.setString(1,username);//赋值
            prep.setString(2,email);
            prep.setString(3, password);
            
            row = prep.executeUpdate();//执行更新,返回一个整数
            
            if(row != 0){//插入成功返回到ManageUsers.java
                request.getRequestDispatcher("/ManageUsers").forward(request,response);
            }else{
                //录入失败返回本界面
                request.getRequestDispatcher("/AddUserMain").forward(request, response);
            }
            
            
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            //关闭资源
            if(set != null){
                try {
                    set.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(prep != null){
                try {
                    prep.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        
    
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doGet(request,response);
    }

}

7.SelectUsers.java

package com.mh.view;

import java.io.IOException;
import java.io.PrintWriter;

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

public class SelectUsers extends HttpServlet {

    private static final long serialVersionUID = 1L;


    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        out.print("<h1>查找用户</h1><br/><hr/>");
        out.print("&nbsp;&nbsp;&nbsp;&nbsp;<a href = '/UsersManager/MainFrame'>主页面</a>");
        out.print("<form action = '/UsersManager/SelectHandle' method = 'post'>");//跳转到SelectHandle.java
        out.print("请输入关键字&nbsp;&nbsp;<input type = 'text' size =  '10px' name = 'key'/>");
        out.print("&nbsp;&nbsp;<input type = 'submit' value = '查找'/>");
        out.print("</form>");
    }

    
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doGet(request,response);
    }

}

8.SelectHandle.java

package com.mh.controller;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

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

public class SelectHandle extends HttpServlet {

    private static final long serialVersionUID = 1L;
    
    public final static String URL = "jdbc:mysql://localhost:3306/Users";
    
    public final static String USER = "root";
    
    public final static String PASSWORD = "334400";

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html;charset=utf-8");
        
        PrintWriter out = response.getWriter();
        
        String key = new String(request.getParameter("key").getBytes("ISO-8859-1"),"UTF-8") ;
        
        Connection conn = null;
        PreparedStatement prep = null;
        ResultSet set = null;
        try{
            Class.forName("com.mysql.jdbc.Driver");
            
            conn = DriverManager.getConnection(URL,USER,PASSWORD);
            
            prep = conn.prepareStatement("select * from User where username like ?");//模糊查询username
            
            prep.setString(1,"%"+key+"%");//模糊查询格式
            set = prep.executeQuery();
            out.print("<h1>查询结果</h1><br/><hr/>");
            out.print("&nbsp;&nbsp;&nbsp;&nbsp;<a href = '/UsersManager/SelectUsers'>返回</a>");
            out.println("<table border = 1 width = 500px>");
            
            out.println("<tr><th>ID</th><th>用户名</th><th>Email</th><th>级别</th></tr>");
            
            while(set.next()){//返回集合,遍历
                out.println("<tr><td>"+set.getInt(1)+"</td><td>"
                        +set.getString(2)+"</td><td>"+set.getString(3)
                        +"</td><td>"+set.getString(4)+"</td></tr>");
            }
            out.println("</table><br/>");
            
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            if(set != null){
                try {
                    set.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(prep != null){
                try {
                    prep.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(conn != null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
        
    }

    
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doGet(request,response);
    }

}