java 在页面上添加按钮 javaweb菜单添加界面

上一篇文章中，我们介绍了环境配置与后台设计

这篇文章，我们将直接面向功能进行分析，是这个系列文章中干货最多，最需要理解的一篇。

首先，我们要搭一个后台，需要提前做的是确定Java Resources中Package的目录结构，将不同的java类放在不同的文件夹下面。第一级目录我们一般设为com,而在本项目中，我将com下面的包划分为数据访问层(Dao层)，实体映射层(Entity层)、功能层(Util层)以及放Servlet和Filter的两个层。

PS: 建包的时候在空包下面建包会得到同级目录的包，要先在包中新建一个类再创建。

（1）用户登陆与注册

DengluServlet

package com.servlet;
 
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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

import com.dao.PhotoDaoImpl;
import com.dao.UserDao;
import com.dao.UserDaoImpl;
import com.entity.Photo;
import com.entity.User;
 
public class DengluServlet extends HttpServlet {  //需要继承HttpServlet  并重写doGet  doPost方法
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);  //将信息使用doPost方法执行   对应jsp页面中的form表单中的method
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		String name = request.getParameter("user"); //得到jsp页面传过来的参数
		String pwd = request.getParameter("pswd"); //得到jsp页面传过来的参数
		
		UserDao ud = new UserDaoImpl();
		HttpSession session = request.getSession();
		if(ud.login(name, pwd)){
			if(name.equals("root"))
			{
				UserDaoImpl userService = new UserDaoImpl();
				List<User> UserList = new ArrayList<User>();
	            UserList = userService.getUserAll();
	        request.setAttribute("UserList",UserList);				
			session.setAttribute("loginMsg","管理员登陆成功!");
			request.getRequestDispatcher("UserManagement.jsp").forward(request, response);//转发到成功页面
		     
			}else {
				    PhotoDaoImpl photoService = new PhotoDaoImpl();
				    List<Photo> PhotoList = new ArrayList<Photo>();
			        PhotoList = photoService.getAllPhotos();
			        request.setAttribute("PhotoList",PhotoList);
				session.setAttribute("loginMsg","普通用户登陆成功!");
				request.setAttribute("user", name);
				request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
			}
		}
			else{
			session.setAttribute("loginMsg","用户不存在或密码错误!");
			response.sendRedirect("login.jsp"); //重定向到首页
			}
		
	}
 
}

ZhuceServlet

package com.servlet;
 
import java.io.IOException;

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

import com.dao.UserDao;
import com.dao.UserDaoImpl;
import com.entity.User;
 
public class ZhuceServlet extends HttpServlet {
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		String name = request.getParameter("register_user"); //获取jsp页面传过来的参数
		String pwd = request.getParameter("register_pswd");
		
		User user = new User(); //实例化一个对象，组装属性
		user.setName(name);
		user.setPwd(pwd);		
		UserDao ud = new UserDaoImpl();
		
		if(ud.register(user)){
			request.setAttribute("username", name);  //向request域中放置参数
			request.getRequestDispatcher("login.jsp").forward(request, response);  //转发到登录页面
		}else{
			
			response.sendRedirect("login.jsp");//重定向到首页
		}
	}
}

UserDao(用户层接口)

package com.dao;
 
import java.util.List;

import com.entity.User;
 
public interface UserDao {
	public boolean login(String name,String pwd);//登录 
	public boolean register(User user);//注册
	public List<User> getUserAll();//返回用户信息集合
	public boolean delete(String name) ;//根据id删除用户
	public boolean update(String name, String pwd) ;//更新用户信息
}

UserDaoImpl（用户层接口实现）

package com.dao;
 
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.entity.User;
import com.util.DBconn;
 
public class UserDaoImpl implements UserDao{
	
	public boolean register(User user) {
		boolean flag = false;
		DBconn.init();
		int i =DBconn.addUpdDel("insert into userdata(user,password) " +
				"values('"+user.getName()+"','"+user.getPwd()+"')");
		if(i>0){
			flag = true;
		}
		DBconn.closeConn();
		return flag;
	}
    public boolean login(String name, String pwd) {
		boolean flag = false;
		try {
			    DBconn.init();
				ResultSet rs = DBconn.selectSql("select * from userdata where user='"+name+"' and password='"+pwd+"'");
				while(rs.next()){
					if(rs.getString("user").equals(name) && rs.getString("password").equals(pwd)){
						flag = true;
					}
				}
				DBconn.closeConn();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return flag;
	}
	public List<User> getUserAll() {
		List<User> list = new ArrayList<User>();
    	try {
		    DBconn.init();
			ResultSet rs = DBconn.selectSql("select * from userdata");
			while(rs.next()){
				User user = new User();
				user.setName(rs.getString("user"));
				user.setPwd(rs.getString("password"));
				list.add(user);
			}
			DBconn.closeConn();
			return list;
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return null;
	}
	public boolean update(String name, String pwd) {
		boolean flag = false;
		DBconn.init();
		String sql ="update user set user ='"+name
				+"' , password ='"+pwd
				+"' where user = "+name;
		int i =DBconn.addUpdDel(sql);
		if(i>0){
			flag = true;
		}
		DBconn.closeConn();
		return flag;
	}
	public boolean delete(String name) {
		boolean flag = false;
		DBconn.init();
		String sql = "delete from userdata where user='"+name+"'";
		int i =DBconn.addUpdDel(sql);
		if(i>0){
			flag = true;
		}
		DBconn.closeConn();
		return flag;
	}
    
}

User(对应数据库中一条User信息)

package com.entity;
 
public class User {
    private String name;
    private String pwd;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}   
}

(2) 图片增删改查（以卫星图片为例）

PhotoDaoImpl(方法层)

package com.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.entity.Photo;
import com.util.DBconn;

public class PhotoDaoImpl implements PhotoDao {
	public boolean add(Photo photo)  {
		DBconn.init();
		int i = 0;
		try {
		ResultSet rs = DBconn.selectSql("select * from j2ee_satellite_pic");
		while(rs.next()){
			if(rs.getString("name").equals(photo.getName()) ){
				i = 1;
			   }
		    }
		}
		catch (SQLException e) {
			e.printStackTrace();
		}
		if(i==0)
		{
		i = DBconn.addUpdDel("insert into j2ee_satellite_pic(src,country,name,resolution,latitude_longtitude,ac_time) values('"+photo.getSrc()+"','"+photo.getCountry()+"','"+photo.getName()+"','"+photo.getResolution()+"','"+photo.getLatitude_longitude()+"','"+photo.getAc_time()+"')");
		return true;
		}
		return false;
	
		
	}


	public boolean delete(String name) {
		boolean flag = false;
		DBconn.init();
		String sql = "delete from j2ee_satellite_pic where name='"+ name +"'";
		int i = DBconn.addUpdDel(sql);
		System.out.print(i);
		flag = (i>0)?true:false;
		DBconn.closeConn();
		System.out.print(flag);
		return flag;
	}

	public boolean update(String name,String country,String resolution,String lalg,String actime) {
		boolean flag = false;
		DBconn.init();
		try {
		ResultSet rs = DBconn.selectSql("select name,country,resolution,latitude_longtitude,ac_time from j2ee_satellite_pic where name ='"+name+"'");
		while(rs.next()){
			if(rs.getString("name").equals(name) ){
				if(country=="")
				{
					country = rs.getString("country");
				}
				if(resolution=="")
				{
					resolution = rs.getString("resolution");
				}
				if(lalg=="")
				{
					lalg = rs.getString("latitude_longtitude");
				}
				if(actime=="")
				{
					actime = rs.getString("ac_time");
				}
			   }
		    }
		}
		catch (SQLException e) {
			e.printStackTrace();
		}
		//对图库的值进行更新
		String sql1 ="update j2ee_satellite_pic set country ='"+ country
				+"' , resolution ='"+resolution + "', latitude_longtitude ='"
				+ lalg + "' , ac_time = '" + actime 
				+"' where name = '"+name + "'";
		System.out.print(sql1);
		int j = DBconn.addUpdDel(sql1);
		if(j>0)
			flag = true;
		else {
			flag = false;
		}
		return flag;
	}
	public List <Photo> search(String sql){
		List<Photo> photolistList = new ArrayList<Photo>();
		try {
		    DBconn.init();
			ResultSet rs = DBconn.selectSql(sql);
			while(rs.next()){
				Photo photo = new Photo();
				System.out.println(rs.getString("name"));
				photo.setSrc(rs.getString("src"));
				photo.setName(rs.getString("name"));
				photo.setCountry(rs.getString("country"));
				photo.setResolution(rs.getString("resolution"));
				photo.setLatitude_longitude(rs.getString("latitude_longtitude"));
				photo.setAc_time(rs.getString("ac_time"));
				photolistList.add(photo);
			}
			DBconn.closeConn();
	
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return photolistList;
	}
	public List <Photo> getAllPhotos(){
		List<Photo> photolistList = new ArrayList<Photo>();
		try {
		    DBconn.init();
		    String sql  = "select * from j2ee_satellite_pic";
			ResultSet rs = DBconn.selectSql(sql);
			while(rs.next()){
				Photo photo = new Photo();
				System.out.println(rs.getString("name"));
				photo.setSrc(rs.getString("src"));
				photo.setName(rs.getString("name"));
				photo.setCountry(rs.getString("country"));
				photo.setResolution(rs.getString("resolution"));
				photo.setLatitude_longitude(rs.getString("latitude_longtitude"));
				photo.setAc_time(rs.getString("ac_time"));
				photolistList.add(photo);
			}
			DBconn.closeConn();
	
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return photolistList;
	}
}

图片增加

在这个部分我将介绍两种存储图片的方式并将它们的代码放下来，第一种是将图片存到本地的服务器中，然后获得图片路径并将图片路径存到数据库中。第二种方法是将图片以二进制流的形式读入，然后直接将二进制流存在数据库中，这里我强烈选择第一种，虽然第二种方便很多，但是数据库的资源是极其有限的，直接存图片到数据库中效率是很低的。

第一种方法(推荐)：

增加图片(AddPictureServlet)

package com.servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import org.apache.commons.fileupload.FileItem;

import com.dao.LogDaoImpl;
import com.dao.PhotoDao;
import com.dao.PhotoDaoImpl;
import com.dao.p;
import com.entity.Photo;


public class AddPictureServlet extends HttpServlet {
    public AddPictureServlet() {
        super();
    }
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
 String method = request.getParameter("method");
try {
    switch (method) {
                        case "add":
        //转接给相对应的函数去处理相关数据。
        addDVDinfo(request, response);
        break;}
    
             } catch (SQLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();}
    }
/**
     * <p>
     *  这个函数实现了增加dvd的功能
     * <p>
     * @throws SQLException 
     * @throws ServletException 
     */
    private static void addDVDinfo(HttpServletRequest request, HttpServletResponse response) throws IOException, SQLException, ServletException {
        List<String> list=new ArrayList<String>();
        String filename=p.getPhotoNewName();
        ServletContext servletContext=null;
        servletContext=request.getSession().getServletContext();
        //数据库中存储格式:/webTest/imgs/***.jpg
        //第一步:获取页面上上传的图片资源
        List<FileItem> items=p.getRequsetFileItems(request,servletContext);
        String isLoadToSQL;
        
		/*
		 * Date date = new Date(); DateFormat format = new
		 * SimpleDateFormat("yyyy-MM-dd"); String currentData = format.format(date);
		 * String name = request.getParameter("name");
		 */
        Photo photo = new Photo();
        
        for(FileItem item:items) {
            if(!item.isFormField()){
                //判断后缀名是否是jpg
                if(p.isGif(item)) {
                    isLoadToSQL=p.saveFile(item,filename);
                    System.out.println(isLoadToSQL);
                }else {
                    System.out.println("后缀格式有误，保存文件失败");
                }
            }
            else { 
                /*获取表单中的非文件值
                表单中的空间name值*/
                System.out.println("name值:  "+item.getFieldName());
                /*该name值空间中的value值*/
                System.out.println(item.getString("UTF-8"));
                list.add(item.getString("UTF-8")); 
            }
        }
        String fileaddress1 = "pic/satellitepic/"+filename;
        String name = list.get(0);
        String country = list.get(1);
        String resolution = list.get(2);
        String lalg = list.get(3);
        String actime = list.get(4);
        String user = list.get(5);//记录操作者 
        photo.setSrc(fileaddress1);
        photo.setName(name);
        photo.setCountry(country);
        photo.setResolution(resolution);
        photo.setLatitude_longitude(lalg);
        photo.setAc_time(actime);
        PhotoDao ph = new PhotoDaoImpl();
        HttpSession session = request.getSession();
        Boolean x = ph.add(photo);
        if(x==true) {
        	//增加日志
        	SimpleDateFormat sdf = new SimpleDateFormat();// 格式化时间 
            sdf.applyPattern("yyyy-MM-dd HH:mm:ss a");// a为am/pm的标记  
            Date date = new Date();// 获取当前时间
            String time = sdf.format(date).toString();
        	LogDaoImpl tempDaoImpl = new LogDaoImpl();
        	tempDaoImpl.add(user,"增加", time, "卫星图片", name);
        	//得到所有图片
        	PhotoDaoImpl photoService = new PhotoDaoImpl();
		    List<Photo> PhotoList = new ArrayList<Photo>();
	        PhotoList = photoService.getAllPhotos();
	        request.setAttribute("PhotoList",PhotoList);
	        request.setAttribute("user", user);
        	session.setAttribute("operationMsg", "图片增加成功!");
        	request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
        }
        else {
        	PhotoDaoImpl photoService = new PhotoDaoImpl();
		    List<Photo> PhotoList = new ArrayList<Photo>();
	        PhotoList = photoService.getAllPhotos();
	        request.setAttribute("PhotoList",PhotoList);
	        request.setAttribute("user", user);
        	session.setAttribute("operationMsg", "图片增加失败，已存在同名图片!");
        	request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
		}
    }
    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
}

辅助增加图片的类p

package com.dao;

import java.io.File;
import java.util.Date;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class p {
    /**
    *这个函数的功能是获取前端的数据集合，将文件打包成File以便后续操作
     */
    public static List<FileItem> getRequsetFileItems(HttpServletRequest request,ServletContext servletContext){
        boolean isMultipart=ServletFileUpload.isMultipartContent(request);
        if(isMultipart) {
            DiskFileItemFactory factory = new DiskFileItemFactory();
            String str="javax.servelet.context.tempdir";
            File repository=(File) servletContext.getAttribute(str);
            factory.setRepository(repository);
            ServletFileUpload upload=new ServletFileUpload(factory);
            try {
                return upload.parseRequest(request);
            }catch (FileUploadException e) {
                // TODO: handle exception
                return null;
            }
        }else {
            return null;
        }
    }
    /**
    *这个函数的功能是将文件传到预先设置的绝对路径中，也就是项目里的imgs文件夹
     */
    public static String saveFile(FileItem item,String fileName) {        
        File savePath=new File("C:javaeclipseImageManagerWebContentpicsatellitepic");
        if(!savePath.exists()) {
            savePath.mkdirs();
        }
        File uploadFile=new File(savePath+File.separator+fileName);
        String fileaddress = "pic/satellitepic/"+fileName;
        try{
            item.write(uploadFile);
            System.out.println("保存文件成功");
            return fileaddress;
        }catch(Exception e){
            System.out.println("保存文件失败");
        }
        return "false";
    }
    /**
    *这个函数的功能是获取当前时间点与1970年的间隔秒数
     */
    public static int getSecondTimestamp(Date date){
        if (null == date) {
            return 0;
        }
        String timestamp = String.valueOf(date.getTime());
        System.out.println(timestamp);
        int length = timestamp.length();
        if (length > 3) {
            return Integer.valueOf(timestamp.substring(0,length-3));
        } else {
            return 0;
        }
    }
    
    /**
     * 
          *这个函数的功能是得到新的照片名称
     */
     public static String getPhotoNewName() {
         Date date=new Date();
         int second=getSecondTimestamp(date);
         String fileName=String.valueOf(second)+".jpg";
         return fileName;
    }
     
     /**
              *这个函数的功能是判断文件后缀是否是jpg格式
      */
     public static boolean isGif(FileItem item) {
        String fileFullName=item.getName();
         File fileInfo=new File(fileFullName);
         String suffix = fileInfo.getName().substring(fileInfo.getName().lastIndexOf(".") + 1);
         if(suffix.equals("jpg")) {
             return true;
         }
         return false;        
     }
}

第二种方法（不推荐）：

package com.servlet;
 
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
//这个方法是将路径变为二进制流存在路径中 但因为效率不高没被使用
@WebServlet("/uploadServlet")
@MultipartConfig(maxFileSize = 16177215)    // upload file's size up to 16MB
public class FileUploadDBServlet extends HttpServlet {
 
    // database connection settings
    private String dbURL = "jdbc:mysql://localhost:3306/mysql?useUnicode=true&characterEncoding=utf-8";
    private String dbUser = "root";
    private String dbPass = "WAMM0609dd";
 
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // gets values of text fields
        String name = request.getParameter("pic_name");
        String country = request.getParameter("sat_nationality");
        String resolution = request.getParameter("sat_resolution");
        String lalg = request.getParameter("sat_longtitude");
        String actime = request.getParameter("sat_actime");
        System.out.println(name);
        System.out.println(country);
        System.out.println(resolution);
        System.out.println(lalg);
        System.out.println(actime);
        InputStream inputStream = null; // input stream of the upload file
 
        // obtains the upload file part in this multipart request
        Part filePart = request.getPart("sat_address");
        if (filePart != null) {
            // prints out some information for debugging
            System.out.println(filePart.getName());
            System.out.println(filePart.getSize());
            System.out.println(filePart.getContentType());
 
            // obtains input stream of the upload file
            inputStream = filePart.getInputStream();
        }
 
        Connection conn = null; // connection to the database
        String message = null;  // message will be sent back to client
 
        try {
            // connects to the database
            DriverManager.registerDriver(new com.mysql.jdbc.Driver());
            conn = DriverManager.getConnection(dbURL, dbUser, dbPass);
 
            // constructs SQL statement
            String sql = "INSERT INTO j2ee_satellite_pic (name,country,resolution,latitude_longtitude,ac_time,src) values (?,?,?,?,?,?)";
            PreparedStatement statement = conn.prepareStatement(sql);
            statement.setString(1, name);
            statement.setString(2, country);
            statement.setString(3, resolution);
            statement.setString(4, lalg);
            statement.setString(5, actime);
 
            if (inputStream != null) {
                // fetches input stream of the upload file for the blob column
                statement.setBlob(6, inputStream);
            }
 
            // sends the statement to the database server
            int row = statement.executeUpdate();
            if (row > 0) {
                message = "File uploaded and saved into database";
            }
        } catch (SQLException ex) {
            message = "ERROR: " + ex.getMessage();
            ex.printStackTrace();
        } finally {
            if (conn != null) {
                // closes the database connection
                try {
                    conn.close();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
            // sets the message in request scope
            request.setAttribute("Message", message);
 
            // forwards to the message page
            getServletContext().getRequestDispatcher("/Message.jsp").forward(request, response);
        }
    }
}

第二种方法大家看看就好，作者自己先实现了第二种，但是发现很不好，然后连夜更换了全部后台。

图片删除

DeleteServlet

package com.servlet;
 
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import com.dao.LogDaoImpl;
import com.dao.PhotoDaoImpl;
import com.dao.UserDaoImpl;
import com.entity.Photo;
 
public class DeleteServlet extends HttpServlet {  //需要继承HttpServlet  并重写doGet  doPost方法
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);  //将信息使用doPost方法执行   对应jsp页面中的form表单中的method
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		HttpSession session = request.getSession();
		String name = request.getParameter("sat_name"); //得到jsp页面传过来的参数
		String user = request.getParameter("username");
		System.out.println(name);
		PhotoDaoImpl tempDaoImpl = new PhotoDaoImpl();
		boolean i = tempDaoImpl.delete(name);
		System.out.print(i);
		if(i==true)
		{
			//增加日志
        	SimpleDateFormat sdf = new SimpleDateFormat();// 格式化时间 
            sdf.applyPattern("yyyy-MM-dd HH:mm:ss a");// a为am/pm的标记  
            Date date = new Date();// 获取当前时间
            String time = sdf.format(date).toString();
        	LogDaoImpl logDaoImpl = new LogDaoImpl();
        	logDaoImpl.add(user,"删除", time, "卫星图片", name);
        	
			UserDaoImpl userService = new UserDaoImpl();
			PhotoDaoImpl photoService = new PhotoDaoImpl();
		    List<Photo> PhotoList = new ArrayList<Photo>();
	        PhotoList = photoService.getAllPhotos();
	        request.setAttribute("PhotoList",PhotoList);
	        request.setAttribute("user",user);
			session.setAttribute("operationMsg","删除成功!");
			request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
		}
		else {
			PhotoDaoImpl photoService = new PhotoDaoImpl();
		    List<Photo> PhotoList = new ArrayList<Photo>();
	        PhotoList = photoService.getAllPhotos();
	        request.setAttribute("PhotoList",PhotoList);
	        request.setAttribute("user", user);
			session.setAttribute("operationMsg","删除失败，请输入正确的名字!");
			request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
		}
		
	}
 
}

图片修改

这个这个地方需要注意的是假如用户在表单中不输入某个参数，数据库的这个值不应该修改而是保留不变，作者这个地方的方法比较物理，假如有比较精妙的SQL语句一定要跟作者交流！

UpdateSevlet

package com.servlet;
 
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import com.dao.LogDaoImpl;
import com.dao.PhotoDaoImpl;
import com.entity.Photo;
import com.util.DBconn;
 
public class UpdateServlet extends HttpServlet {  //需要继承HttpServlet  并重写doGet  doPost方法
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);  //将信息使用doPost方法执行   对应jsp页面中的form表单中的method
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		String name = request.getParameter("sat_name");
		String country = request.getParameter("sat_nationality");
		String resolution = request.getParameter("sat_resolution");
		String lalg = request.getParameter("sat_latitude_longtitude");
		String actime = request.getParameter("sat_actime");//得到jsp页面传过来的参数
		String user = request.getParameter("username");
		System.out.println(name);
		PhotoDaoImpl photoDaoImpl = new PhotoDaoImpl();
		boolean a = photoDaoImpl.update(name, country, resolution, lalg, actime);
		HttpSession session = request.getSession();	
		if(a==true)
		{
			//增加日志
        	SimpleDateFormat sdf = new SimpleDateFormat();// 格式化时间 
            sdf.applyPattern("yyyy-MM-dd HH:mm:ss a");// a为am/pm的标记  
            Date date = new Date();// 获取当前时间
            String time = sdf.format(date).toString();
        	LogDaoImpl logDaoImpl = new LogDaoImpl();
        	logDaoImpl.add(user,"更新", time, "卫星图片", name);
        	
			PhotoDaoImpl photoService = new PhotoDaoImpl();
		    List<Photo> PhotoList = new ArrayList<Photo>();
	        PhotoList = photoService.getAllPhotos();
	        request.setAttribute("user",user);
	        request.setAttribute("PhotoList",PhotoList);
			session.setAttribute("operationMsg","图像信息更新成功!");
			request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
			}
		else {
			PhotoDaoImpl photoService = new PhotoDaoImpl();
		    List<Photo> PhotoList = new ArrayList<Photo>();
	        PhotoList = photoService.getAllPhotos();
	        request.setAttribute("user",user);
	        request.setAttribute("PhotoList",PhotoList);
			session.setAttribute("operationMsg","图像信息更新失败，请正确输入图片名!" );
			request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
		}
		DBconn.closeConn();
		
	}
 
}

图片查找

这里实现的是模糊查找，也就是SQL语句中使用 'where parameter like %XXX%'这种结构。

SearchServlet

package com.servlet;
 
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import com.dao.LogDaoImpl;
import com.dao.PhotoDaoImpl;
import com.entity.Photo;
 
public class SearchServlet extends HttpServlet {  //需要继承HttpServlet  并重写doGet  doPost方法
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);  //将信息使用doPost方法执行   对应jsp页面中的form表单中的method
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		String name = request.getParameter("sat_name");
		String country = request.getParameter("sat_nationality");
		String resolution = request.getParameter("sat_resolution");
		String lalg = request.getParameter("sat_latitude_longtitude");
		String actime = request.getParameter("sat_actime");//得到jsp页面传过来的参数
		String user = request.getParameter("username");
		if(name==null)
			name = "";
		if(country==null)
			country = "";
		if(resolution==null)
			resolution = "";
		if(lalg==null)
			lalg = "";
		if(actime==null)
			actime = "";
		System.out.println(name);
		String sql ="select * from j2ee_satellite_pic where name like '%" + name + "%'" + " and"
				+ " country like '%" + country + "%' and"
				+ " resolution like '%" + resolution + "%' and"
				+ " latitude_longtitude like '%" + lalg + "%' and"
				+ " ac_time like '%" + actime + "%'";
		System.out.println(sql);
		List<Photo> list = new ArrayList <Photo>();
		PhotoDaoImpl photoDaoImpl = new PhotoDaoImpl();
		list = photoDaoImpl.search(sql);   	
    	
    	HttpSession session = request.getSession();
    	boolean flag = list.isEmpty();
    	System.out.println(list.isEmpty());
    	if(flag==false)
    	{
			/*
			 * for(Photo a:list) { System.out.println(a.getSrc());
			 * System.out.println(a.getName()); System.out.println(a.getCountry());
			 * System.out.println(a.getResolution());
			 * System.out.println(a.getLatitude_longitude());
			 * System.out.println(a.getAc_time()); }
			 */
    		//增加日志
        	SimpleDateFormat sdf = new SimpleDateFormat();// 格式化时间 
            sdf.applyPattern("yyyy-MM-dd HH:mm:ss a");// a为am/pm的标记  
            Date date = new Date();// 获取当前时间
            String time = sdf.format(date).toString();
        	LogDaoImpl logDaoImpl = new LogDaoImpl();
        	logDaoImpl.add(user,"查询", time, "卫星图片", name);

 	        request.setAttribute("user",user);
    		request.setAttribute("PhotoList",list);
    		session.setAttribute("operationMsg", "查询成功!");
    		request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
    	}
    	else {
 	        request.setAttribute("user",user);
    		request.setAttribute("PhotoList",list);
    		session.setAttribute("operationMsg", "没有符合条件的图片!");
    		request.getRequestDispatcher("SatellitePic.jsp").forward(request, response);
		}
		  
		 
		
	}
 
}

以上就是我的后台中最为核心的部分了。