java web picture upload and file upload example details
- 2020-05-17 05:28:58
- OfStack
java web picture upload and file upload
Picture upload and file upload are essentially the same, the image itself is a file. File upload is to upload pictures to the server, although there are many ways, but the underlying implementation is the file read and write operations.
Matters needing attention
1.form form 1 must have the property enctype="multipart/ form-data"
2. In order to ensure that the file can be uploaded successfully, the name property value of the file control should correspond to the control layer variable name 1 you submitted.
So, for example, the space name is file and you define it in the background
private File file; / / file control name
private String fileContentType; // picture type
private String fileFileName; / / file name
1. jsp page
<%@ 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> File upload </title>
</head>
<body>
<form method="post" action="" enctype="multipart/form-data">
<input type="file" name="file" value="file">
<input type="submit" value=" determine ">
</form>
</body>
</html>
1. Controller for page data to be submitted
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 The control of
private String fileContentType;// Image type
private String fileFileName; // The file name
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");// The server path to upload the image to
String names[]=fileFileName.split("\\.");
String fileName="";
if(names.length>=1){
fileName=getRandomString(20)+"."+names[names.length-1];
}
String picPath="upload/"+fileName;// The path to save the image to the database
File file1=new File(root);
try {
FileUtils.copyFile(file, new File(file1,fileName));
}
} catch (IOException e) {
e.printStackTrace();
}
return SUCCESS;
}
/* To obtain 1 Random string */
public String getRandomString(int length) { //length Represents the length of the generated string
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();
}
}
This is uploading files by copying and there are other ways
Method 2
@Controller("contractAction")
public class ContractAction extends ActionSupport {
private final static String UPLOADDIR = "/files";// File upload path in webContent Set up under the
private File file; //input The control of 1 As the file
// Upload file name collection
private String fileFileName;
// Upload a collection of file content types
private String fileContentType;
private String filename;
public String upload() throws FileNotFoundException, IOException{
String path=uploadFile();// The file saves the path to the database
return SUCCESS;
}
// Perform upload function
@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);
// You can also manually create the target upload directory in the application root directory
if(!fileLocation.exists()){
boolean isCreated = fileLocation.mkdir();
if(!isCreated) {
// Target upload directory creation failed , Can do other processing , Such as throwing custom exceptions ,1 This should not be the case.
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();
}
}
In addition to single picture upload and multiple picture upload, the principle is a kind of
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;
/**
* Multiple file upload
*/
public class FilesUploadAction extends ActionSupport {
// Upload file storage path
private final static String UPLOADDIR = "/upload";
// Upload file collection
private List<File> file;
// Upload file name collection
private List<String> fileFileName;
// Upload a collection of file content types
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;// Upload path
for (int i = 0; i < file.size(); i++) {
// Upload each file in a loop
uploadFile(i);
webpath="upload/"+this.getFileFileName().get(i);
}
return "SUCCESS";
}
// Perform upload function
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);
// You can also manually create the target upload directory in the application root directory
if(!fileLocation.exists()){
boolean isCreated = fileLocation.mkdir();
if(!isCreated) {
// Target upload directory creation failed , Can do other processing , Such as throwing custom exceptions ,1 This should not be the case.
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;
}
}
}
Thank you for reading, I hope to help you, thank you for your support of this site!