javaweb增删改查实例_JavaWeb图像可视化管理系统之后台搭建（二）用户管理与增删改查（内含代码）...

上一篇文章中，我们介绍了环境配置与后台设计，对于不了解的同学，可以看这个链接

CharlesDDDD：JavaWeb图像可视化管理系统之后台搭建（一）环境配置与后台设计zhuanlan.zhihu.com

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 blocke.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jpgif(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 exceptionreturn 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 settingsprivate 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 fieldsString 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 requestPart filePart = request.getPart("sat_address");if (filePart != null) {// prints out some information for debuggingSystem.out.println(filePart.getName());System.out.println(filePart.getSize());System.out.println(filePart.getContentType());// obtains input stream of the upload fileinputStream = filePart.getInputStream();}Connection conn = null; // connection to the databaseString message = null;  // message will be sent back to clienttry {// connects to the databaseDriverManager.registerDriver(new com.mysql.jdbc.Driver());conn = DriverManager.getConnection(dbURL, dbUser, dbPass);// constructs SQL statementString 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 columnstatement.setBlob(6, inputStream);}// sends the statement to the database serverint 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 connectiontry {conn.close();} catch (SQLException ex) {ex.printStackTrace();}}// sets the message in request scoperequest.setAttribute("Message", message);// forwards to the message pagegetServletContext().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，完整代码push在github上面了，稍后会放一个链接。

作者的联系方式是QQ:296830921,如果对这个项目有什么疑问与技术问题，欢迎探讨。

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