java web图片上传和文件上传实例详解
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2024-03-09 18:05:59
java web图片上传和文件上传
图片上传和文件上传本质上是一样的，图片本身也是文件。文件上传就是将图片上传到服务器，方式虽然有很多，但底层的实现都是文件的读写操作。...
java web图片上传和文件上传
图片上传和文件上传本质上是一样的，图片本身也是文件。文件上传就是将图片上传到服务器，方式虽然有很多，但底层的实现都是文件的读写操作。
注意事项
1.form表单一定要写属性enctype="multipart/form-data"
2.为了能保证文件能上传成功file控件的name属性值要和你提交的控制层变量名一致，
例如空间名是file那么你要在后台这样定义
private file file; //file控件名
private string filecontenttype;//图片类型
private string filefilename; //文件名
1.jsp页面
<%@ page language="java" contenttype="text/html; charset=utf-8" pageencoding="utf-8"%> <!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> <meta http-equiv="pragma" content="no-cache" /> <base target="_self"> <title>文件上传</title> </head> <body> <form method="post" action="" enctype="multipart/form-data"> <input type="file" name="file" value="file"> <input type="submit" value="确定"> </form> </body> </html>
1.页面数据需要提交的controller
package com.cpsec.tang.chemical.action;
import java.io.file;
import java.io.ioexception;
import java.util.random;
import javax.annotation.resource;
import javax.servlet.http.httpservletrequest;
import org.apache.commons.io.fileutils;
import org.apache.struts2.servletactioncontext;
import org.springframework.stereotype.controller;
import com.cpsec.tang.chemical.biz.lunbobiz;
import com.cpsec.tang.chemical.entity.image;
import com.opensymphony.xwork2.actionsupport;
@controller("lunboaction")
public class lunboaction extends actionsupport {
/**
*
*/
private static final long serialversionuid = 1l;
@resource(name="lunbobiz")
private lunbobiz lunbobiz;
private image image;
private file file; //file控件名
private string filecontenttype;//图片类型
private string filefilename; //文件名
private integer number;
public string findimage(){
image=lunbobiz.findimage();
return success;
}
public string alterimage(){
image=lunbobiz.findimage();
return success;
}
public string alterimage1(){
httpservletrequest request = servletactioncontext.getrequest();
string root = request.getrealpath("/upload");//图片要上传到的服务器路径
string names[]=filefilename.split("\\.");
string filename="";
if(names.length>=1){
filename=getrandomstring(20)+"."+names[names.length-1];
}
string picpath="upload/"+filename;//图片保存到数据库的路径
file file1=new file(root);
try {
fileutils.copyfile(file, new file(file1,filename));
}
} catch (ioexception e) {
e.printstacktrace();
}
return success;
}
/*获取一条随机字符串*/
public string getrandomstring(int length) { //length表示生成字符串的长度
string base = "abcdefghijklmnopqrstuvwxyz0123456789";
random random = new random();
stringbuffer sb = new stringbuffer();
for (int i = 0; i < length; i++) {
int number = random.nextint(base.length());
sb.append(base.charat(number));
}
return sb.tostring();
}
}
这是通过复制的方式上传文件，还有其他方式
方法二
@controller("contractaction")
public class contractaction extends actionsupport {
private final static string uploaddir = "/files";//文件上传的路径，在webcontent下建立
private file file; //input控件名一定为file
//上传文件名集合
private string filefilename;
//上传文件内容类型集合
private string filecontenttype;
private string filename;
public string upload() throws filenotfoundexception, ioexception{
string path=uploadfile();//文件保存数据库的路径
return success;
}
//执行上传功能
@suppresswarnings("deprecation")
public string uploadfile() throws filenotfoundexception, ioexception {
try {
inputstream in = new fileinputstream(file);
string dir = servletactioncontext.getrequest().getrealpath(uploaddir);
file filelocation = new file(dir);
//此处也可以在应用根目录手动建立目标上传目录
if(!filelocation.exists()){
boolean iscreated = filelocation.mkdir();
if(!iscreated) {
//目标上传目录创建失败,可做其他处理,例如抛出自定义异常等,一般应该不会出现这种情况。
return null;
}
}
// this.setfilefilename(getrandomstring(20));
string[] name=this.getfilefilename().split("\\.");
string filename=getrandomstring(20)+"."+name[name.length-1];
this.setfilefilename(filename);
system.out.println(filename);
file uploadfile = new file(dir, filename);
outputstream out = new fileoutputstream(uploadfile);
byte[] buffer = new byte[1024 * 1024];
int length;
while ((length = in.read(buffer)) > 0) {
out.write(buffer, 0, length);
}
in.close();
out.close();
return uploaddir.substring(1)+"\\"+filefilename;
} catch (filenotfoundexception ex) {
return null;
} catch (ioexception ex) {
return null;
}
}
public static string getrandomstring(int length){
string str="abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789";
random random=new random();
stringbuffer sb=new stringbuffer();
for(int i=0;i<length;i++){
int number=random.nextint(62);
sb.append(str.charat(number));
}
return sb.tostring();
}
}
除了单图上传还有多图上传，原理都是一样的
package com.cpsec.tang.chemical.action;
import java.io.file;
import java.io.fileinputstream;
import java.io.filenotfoundexception;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.inputstream;
import java.io.outputstream;
import java.util.list;
import javax.servlet.http.httpservletrequest;
import org.apache.struts2.servletactioncontext;
import com.opensymphony.xwork2.actionsupport;
/**
* 多文件上传
*/
public class filesuploadaction extends actionsupport {
//上传文件存放路径
private final static string uploaddir = "/upload";
//上传文件集合
private list<file> file;
//上传文件名集合
private list<string> filefilename;
//上传文件内容类型集合
private list<string> filecontenttype;
public list<file> getfile() {
return file;
}
public void setfile(list<file> file) {
this.file = file;
}
public list<string> getfilefilename() {
return filefilename;
}
public void setfilefilename(list<string> filefilename) {
this.filefilename = filefilename;
}
public list<string> getfilecontenttype() {
return filecontenttype;
}
public void setfilecontenttype(list<string> filecontenttype) {
this.filecontenttype = filecontenttype;
}
public string uploadform() throws exception {
httpservletrequest request = servletactioncontext.getrequest();
string webpath=null;//上传路径
for (int i = 0; i < file.size(); i++) {
//循环上传每个文件
uploadfile(i);
webpath="upload/"+this.getfilefilename().get(i);
}
return "success";
}
//执行上传功能
private string uploadfile(int i) throws filenotfoundexception, ioexception {
try {
inputstream in = new fileinputstream(file.get(i));
string dir = servletactioncontext.getrequest().getrealpath(uploaddir);
file filelocation = new file(dir);
//此处也可以在应用根目录手动建立目标上传目录
if(!filelocation.exists()){
boolean iscreated = filelocation.mkdir();
if(!iscreated) {
//目标上传目录创建失败,可做其他处理,例如抛出自定义异常等,一般应该不会出现这种情况。
return null;
}
}
string filename=this.getfilefilename().get(i);
file uploadfile = new file(dir, filename);
outputstream out = new fileoutputstream(uploadfile);
byte[] buffer = new byte[1024 * 1024];
int length;
while ((length = in.read(buffer)) > 0) {
out.write(buffer, 0, length);
}
in.close();
out.close();
return uploadfile.tostring();
} catch (filenotfoundexception ex) {
return null;
} catch (ioexception ex) {
return null;
}
}
}
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