Flask接口签名sign原理与实例代码浅析
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2023-07-03
精致小巧的java相册制作方法
本文实例为大家分享了java相册制作方法,供大家参考,具体内容如下
注:
1)html上的图片是静态指定的。当更新了新的图片时必须手工更新。所以使用Servlet读取本地images中的所有图片,动态显示给用户。
2)如果存在中文名的图片,由于get方式无法直接传递中文,会导致出错。
主页面–index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
页面显示:
上传图片功能:
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
照片:
说明:
package cn.hncu.servlet;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
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;
import org.apache.commons.io.FileUtils;
import cn.hncu.dao.PhotoDaoImpl;
import cn.hncu.domain.PhotoModel;
import cn.hncu.utils.MyUtils;
public class UploadServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
out.print("错误信息:提交方式错误...不支持Get方式上传照片");
out.println(" ");
out.println("");
out.flush();
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
//从上传表单提取信息:一,封装成photo值对象,调用dao层存储到后台
// 二,把上传的照片存储到服务器硬盘
//数据库:存储照片的存储情况的信息,,,真正的文件存储到硬盘
DiskFileItemFactory dfi=new DiskFileItemFactory();
File file=new File("d:/a");
if(file.exists()){
file.mkdirs();
}
dfi.setRepository(file);
ServletFileUpload upload=new ServletFileUpload(dfi);
upload.setSizeMax(1024*1024*8);
upload.setHeaderEncoding("utf-8");//==>request.setCharacterEncoding("utf-8");
try {
List
PhotoModel pm=new PhotoModel();
InputStream in=null;
for(FileItem fI:list){
if(fI.isFormField()){//这个不会有临时文件
String desc=fI.getString("utf-8");
pm.setDesc(desc);
}else{
in=fI.getInputStream();
// String filename=fI.getFieldName();
// System.out.println("getFieldName:"+filename);
String fileName=fI.getName();
// System.out.println("getName:"+fileName);//测试:C:\Users\adl1\Pictures\Saved Pictures\111.jpg?
//卫条件
if(fileName==null||fileName.trim().equals("")){
out.println("没有选择文件,,,请必须选择一个文件...
");
String strPath2=request.getContextPath()+"/jsps/upload.jsp";
out.println("返回上传页面");
return;
}
pm.setDt(MyUtils.getCurrentDataime());
String realName=fileName.substring(fileName.lastIndexOf("\\"));//"\112.jpg"
System.out.println(realName.substring(1, realName.length()));
pm.setRealName(realName.substring(1, realName.length()));//把realName的"\"去掉
//ext扩展名
String ext=fileName.substring(fileName.lastIndexOf("."));
pm.setExt(ext);
String id=MyUtils.getUUID();
pm.setId(id);
pm.setIp(request.getRemoteAddr());
pm.setDir(MyUtils.getDir(id));
}
}
//完成photo值对象的封装,调用dao进行存储
boolean boo=new PhotoDaoImpl().sava(pm);
if(boo){
//完成数据库的存储,接下来是服务器硬盘的存储
//把照片存储到项目根目录下的photos文件夹中存储(以打散方式存储)
String path="photos/"+pm.getDir();
// System.out.println("path:"+path);//测试:photos/9/0
String filePath=getServletContext().getRealPath(path);
// System.out.println("filePath:"+filePath);//测试:D:\apache-tomcat-7.0.30\webapps\photosWeb\photos\9\0
File dir=new File(filePath);
if(!dir.exists()){
dir.mkdirs();
}
FileUtils.copyInputStreamToFile(in, new File(filePath+"/"+pm.getId()+pm.getExt()));
// //如果硬盘保存成功就跳转到主页面--转发
//// RequestDispatcher rd=request.getRequestDispatcher(getServletContext().getContextPath()+"/index.jsp");//"/photosWeb/photosWeb/index.jsp"
// RequestDispatcher rd=request.getRequestDispatcher("/index.jsp");//"/photosWeb/index.jsp"g
// //java代码块和web.xml中url的开始"/"代表项目根目录
// rd.forward(request, response);
//这里不能使用转发,具体重定向和转发区别:http://blog.csdn.net/xanlv/article/details/52701085
//重定向
response.sendRedirect(getServletContext().getContextPath()+"/index.jsp");
}else{
//数据库保存失败--留在上传页面
RequestDispatcher rd=request.getRequestDispatcher("/jsps/upload..jsp");//"/photosWeb/index.jsp"
rd.forward(request, response);
}
} catch (FileUploadException e) {
throw new RuntimeException("上传失败", e);
}finally{//清临时文件
File f=new File("d:/a");
File fs[]=f.listFiles();
for(File ff:fs){
ff.delete();
}
}
out.println(" ");
out.println("");
out.flush();
out.close();
}
}
页面显示效果:
浏览图片功能:
package cn.hncu.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.hncu.dao.PhotoDaoImpl;
import cn.hncu.domain.PhotoModel;
public class ShowAllImgServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
String strPath=request.getContextPath()+"/jsps/upload.jsp";
out.println("返回上传页面");
//String table="
String table="
"
out.println(table);
//从dao层把所有的照片信息读取出来发送到前端页面
List
for(PhotoModel pm:list){
out.println("
out.println("
out.println("
out.println("
out.println("
String path=request.getContextPath()+"/photos/"+pm.getDir()+"/"+pm.getId()+pm.getExt();
//System.out.println(path);//"/photosWeb/photos/d/7/e78e18352b42410f85dbd8df834bd718.jpg"
//点击图片可以查看大图
out.println("
out.println("
out.println("
out.println("
out.println("
//out.println("下载图片
out.println("
下载图片");
out.println("
}
out.println("
out.println(" ");
out.println("");
out.flush();
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
out.print("不支持Post方式。。。");
out.println(" ");
out.println("");
out.flush();
out.close();
}
}
页面显示效果:
删除功能:
package cn.hncu.servlet;
import java.io.File;
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;
import cn.hncu.dao.PhotoDaoImpl;
import cn.hncu.domain.PhotoModel;
public class DelPhotoServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
String id=request.getParameter("id");
String ip=request.getRemoteAddr();
PhotoDaoImpl dao=new PhotoDaoImpl();
PhotoModel pm=dao.getSingleById(id);
if(pm!=null){
if(!pm.getIp().equals(ip)){
out.println("您没有该图片的权限去删除...");
String strPath=request.getContextPath()+"/servlet/showAllImg";
out.println("
返回继续浏览");
return ;
}
//删除包含两部分工作:清除数据库中的信息 和 删除服务器硬盘中的图片文件
//1清除数据库中的信息
boolean boo = dao.del(id);
//2删除服务器硬盘中的图片文件
if(boo){
String path="photos/"+pm.getDir()+"/"+pm.getId()+pm.getExt();
String filePath=getServletContext().getRealPath(path);
File f=new File(filePath);
if(f.exists()){
f.delete();
}
String strPath=request.getContextPath()+"/servlet/showAllImg";
// System.out.println(strPath);///photosWeb/servlet/showPhotos
out.println("删除成功...
返回浏览");
}else{
out.println("删除数据库信息失败");
}
}else{
out.println("文件不存在...");
String strPath=request.getContextPath()+"/servlet/showAllImg";
out.println("
返回继续浏览");
}
out.println(" ");
out.println("");
out.flush();
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
out.print("不支持POST方式...");
out.println(" ");
out.println("");
out.flush();
out.close();
}
}
页面显示:
下载功能:
1.在HTML页面上使用超连接指向要下载的文件(不安全容易被盗链)。
问题:
如何确定本地资源?
ServletContext – 代表一个web项目。一个web项目只有一个ServletContext对像。
getRealPath(“/”); //d:/prm/tom/web/
需求分析:
在实际的开发中,下载哪一个文件,都是由用户动态选择的。
如,在我们项目images目录下,存在着很多图片文件。用户在页面上显示所有图片,用户可以点下载连接下载喜欢的图片。
详细设计:
使用静态网页显示所有图片。给每一个图片一个下以下载的超连接。
在超连接后面传递要下载的图片id。
在serivice中动态接收图片名。完成下载 。
package cn.hncu.servlet;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.URLEncoder;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.io.FileUtils;
import cn.hncu.dao.PhotoDaoImpl;
import cn.hncu.domain.PhotoModel;
public class DownServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//获取被下载图片的信息
tring id=request.getParameter("id");
PhotoModel pm=new PhotoDaoImpl().getSingleById(id);
if(pm==null){
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
response.getWriter().println("alert('该文本已不存在...')");
out.println(" ");
out.println("");
out.flush();
out.close();
//getServletContext().getContextPath()
RequestDispatcher rd=request.getRequestDispatcher("/servlet/down");//"/photosWeb/index.jsp"
//java代码块和web.xml中url的开始"/"代表项目根目录
rd.forward(request, response);
}else{
//真正下载: 把服务器硬盘的照片文件读取出来发送给客户端(设置响应头)
//获取真实的文件
String realName=pm.getRealName();
realName=URLEncoder.encode(realName, "utf-8");//如果是中文名必须转码,防止文件名中文乱码
// InputStream in=DownServlet.class.getClassLoader().getResourceAsStream(realName);
//设置显示类型为下载
response.setContentType("application/force-download");
//设置响应头
response.setHeader("content-Disposition", "attachment;filename=\""+realName+"\"");
// String path=request.getContextPath()+"/photos/"+pm.getDir()+"/"+pm.getId()+pm.getExt();
String path="photos/"+pm.getDir()+"/"+pm.getId()+pm.getExt();
String filePath=getServletContext().getRealPath(path);
FileUtils.copyInputStreamToFile(request.getInputStream(), new File(filePath));
InputStream in=new FileInputStream(filePath);
OutputStream o=response.getOutputStream();
byte b[]=new byte[1024];
int len=0;
while((len=in.read(b))!=-1){
o.write(b, 0, len);
}
o.close();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println(" ");
out.println("");
out.println("
out.println("
out.print(" 不支持");
out.println(" ");
out.println("");
out.flush();
out.close();
}
}
页面显示效果:
配置文件web.xml
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
数据库:photos.xml
值对象:PhotoModel.java
package cn.hncu.domain;
public class PhotoModel {
//photo值对象
private String id;//UUID
private String realName;//照片真实文件名
private String ext;//扩展名
private String dir;//文件打撒后存储的目录
private String dt;//上传日期时间
private String ip;//上传客户端的ip地址
private String desc;//照片说明
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getRealName() {
return realName;
}
public void setRealName(String realName) {
this.realName = realName;
}
public String getExt() {
return ext;
}
public void setExt(String ext) {
this.ext = ext;
}
public String getDir() {
return dir;
}
public void setDir(String dir) {
this.dir = dir;
}
public String getDt() {
return dt;
}
public void setDt(String dt) {
this.dt = dt;
}
public String getIp() {
return ip;
}
public void setIp(String ip) {
this.ip = ip;
}
public String Dreturn desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
}
dao层:这里简写了,只写了实现类PhotoDaoImpl.java
package cn.hncu.dao;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.Element;
import cn.hncu.domain.PhotoModel;
import cn.hncu.utils.DomFactory;
public class PhotoDaoImpl {
public boolean sava(PhotoModel pm){
Document dom=DomFactory.getDom();
Element root=dom.getRootElement();
Element e=root.addElement("photo");
e.addAttribute("id", pm.getId());
e.addAttribute("dir", pm.getDir());
e.addAttribute("dt", pm.getDt());
e.addAttribute("ext", pm.getExt());
e.addAttribute("ip", pm.getIp());
e.addAttribute("realName", pm.getRealName());
e.addElement("desc").setText(pm.getDesc());
boolean b=DomFactory.save();
if(b){
return true;
}
return false;
}
public List
List
Document dom=DomFactory.getDom();
Element e=dom.getRootElement();
Iterator
while(it.hasNext()){
Element ie=it.next();
PhotoModel pm=new PhotoModel();
pm.setId(ie.attributeValue("id"));
pm.setDir(ie.attributeValue("dir"));
pm.setDt(ie.attributeValue("dt"));
pm.setExt(ie.attributeValue("ext"));
pm.setIp(ie.attributeValue("ip"));
pm.setRealName(ie.attributeValue("realName"));
pm.setDesc(ie.elementText("desc"));
li.add(pm);
}
return li;
}
public PhotoModel getSingleById(String id){
List
PhotoModel pm=new PhotoModel();
for(PhotoModel p:li){
if(p.getId().equals(id)){
return p;
}
}
return null;
}
public boolean del(String id) {
Document dom=DomFactory.getDom();
Element e=(Element) dom.selectSingleNode("//photo[@id='"+id+"']");
return e.getParent().remove(e);
}
}
工具类:
1.
package cn.hncu.utils;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
public class MyUtils {
private MyUtils() {
}
public static String getUUID(){
return UUID.randomUUID().toString().replace("-", "");
}
private static SimpleDateFormat sdf=new SimpleDateFormat("yy-MM-dd HH:mm:ss");
public static String getCurrentDataime(){
return sdf.format(new Date());
}
public static String getDir(String uuid){
String dir1=Integer.toHexString(uuid.hashCode()&0xf);
String dir2=Integer.toHexString((uuid.hashCode()&0xf0)>>4);
return dir1+"/"+dir2;
}
}
2.
package cn.hncu.utils;
import java.io.FileOutputStream;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
public class DomFactory {
private static Document dom;
private static String fileName;
static{
try {
SAXReader r=new SAXReader();
//获取src下的资源文件
fileName=DomFactory.class.getClassLoader().getResource("photos.xml").getPath();
System.out.println("users.xml的路径:"+fileName);//"/D:/apache-tomcat-7.0.30/webapps/photosWeb/WEB-INF/classes/photos.xml"
//注意:获取tomcat中当前项目classpath下的资源方式
dom=r.read(fileName);
} catch (DocumentException e) {
e.printStackTrace();
}
}
public static Document getDom(){
return dom;
}
public static boolean save(){
XMLWriter w;
try {
w = new XMLWriter(new FileOutputStream(fileName));
w.write(dom);
w.close();
return true;
} catch (Exception e) {
return false;
}
}
}
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