search

Home >Java >javaTutorial >java web image upload and file upload

java web image upload and file upload

高洛峰
高洛峰Original
2016-11-21 13:46:141632browse

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

 

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>

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;   
             }   
         }
     }


Statement：
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Previous article：Java basics (infinite loop exit option)Next article：Java basics (infinite loop exit option)

Related articles

See more