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; } } }以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持武林网。