struts2上传文件

上传文件在一个系统当中是一个很常用的功能，也是一个比较重要的功能。今天我们就一起来学习一下Struts2如何上传文件。
今天讲的上传文件的方式有三种：
1，以字节为单位传输文件；
2，Struts2封装的一种方式；
3，以字符的方式传输文件。

其实这三种方式都差不多，都是将文件先从客户端一临时文件的形式，传输到服务器的临时文件夹下，然后在将该临时文件复制到我们要上传的目录。另外，有一个需要注意，就是上传过程中产生的这些临时文件，Struts2不会自动清理，所以我们需要手动清理临时文件，这一个下面的代码中有提到。

用Action来完成我们上传的核心功能：
[java] view plaincopy在CODE上查看代码片派生到我的代码片
package com.action;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Map;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;


public class UploadAction extends ActionSupport {

private File upload;
private String uploadFileName;
private String uploadContentType;

private long maximumSize;
private String allowedTypes;


public File getUpload() {
return upload;
}
public void setUpload(File upload) {
this.upload = upload;
}
public String getUploadFileName() {
return uploadFileName;
}
public void setUploadFileName(String uploadFileName) {
this.uploadFileName = uploadFileName;
}

public String getUploadContentType() {
return uploadContentType;
}
public void setUploadContentType(String uploadContentType) {
this.uploadContentType = uploadContentType;
}
public long getMaximumSize() {
return maximumSize;
}
public void setMaximumSize(long maximumSize) {
this.maximumSize = maximumSize;
}
public String getAllowedTypes() {
return allowedTypes;
}
public void setAllowedTypes(String allowedTypes) {
this.allowedTypes = allowedTypes;
}
@Override
public String execute() throws Exception {

File uploadFile = new File(ServletActionContext.getServletContext().getRealPath("upload"));
if(!uploadFile.exists()) {
uploadFile.mkdir();
}

//验证文件大小及格式
if (maximumSize < upload.length()) {
return "error";
}

boolean flag =false;
String[] allowedTypesStr = allowedTypes.split(",");
for (int i = 0; i < allowedTypesStr.length; i++) {
if (uploadContentType.equals(allowedTypesStr[i])) {
flag = true;
}
}
if (flag == false) {
Map request = (Map) ActionContext.getContext().get("request");
request.put("errorMassage", "文件类型不合法！");

System.out.println(request.toString());
return "error";
}

//第一种上传方式
// FileInputStream input = new FileInputStream(upload);
// FileOutputStream out = new FileOutputStream(uploadFile +"//"+ uploadFileName);
// try {
// byte[] b =new byte[1024];
// int i = 0;
// while ((i=input.read(b))>0) {
// out.write(b, 0, i);
// }
// } catch (Exception e) {
// e.printStackTrace();
// } finally {
// //关闭输入、输出流
// input.close();
// out.close();
// //删除临时文件
// upload.delete();
// }

//第二种上传方式
// FileUtils.copyFile(upload, new File(uploadFile+"\\"+uploadFileName));
// //删除临时文件
// upload.delete();

//第三种上传方式
BufferedReader bReader = new BufferedReader(new InputStreamReader(new FileInputStream(upload)));
BufferedWriter bWriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(uploadFile+"\\"+ uploadFileName)));
try {
char [] c =new char[1024];
int i = 0;
while ((i = bReader.read(c)) > 0) {
bWriter.write(c, 0, i);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
bReader.close();
bWriter.close();
//删除临时文件
upload.delete();
}


return "success";
}

}