Struts2中的文件上传-优快云博客

本文链接：https://blog.youkuaiyun.com/java_mail_test/article/details/83525188

本文介绍如何在Struts2框架中实现文件上传功能，包括手动拦截上传文件类型及大小限制，以及使用Struts2内置的fileUpload拦截器实现相同功能的方法。

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package com.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.commons.io.IOUtils;
import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class UploadAction extends ActionSupport {

	/**
	 * 
	 */
	private static final long serialVersionUID = 8926090411591986144L;

	private String allowTypes ;
	
	private int maximumSize ;

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

	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 String getSavePath() {
		return savePath;
	}

	public void setSavePath(String savePath) {
		this.savePath = savePath;
	}
	
	public String getAllowTypes() {
		return allowTypes;
	}

	public void setAllowTypes(String allowTypes) {
		this.allowTypes = allowTypes;
	}
	
	public int getMaximumSize() {
		return maximumSize;
	}

	public void setMaximumSize(int maximumSize) {
		this.maximumSize = maximumSize;
	}

	@Override
	public String execute() throws Exception {
		String checkUploadType = checkUploadType();
		if(checkUploadType != null) {
			this.addFieldError("upload", "上传文件类型只能是:" + allowTypes);
			return checkUploadType;
		} 
		String checkSize = checkUploadSize();
		if(checkSize != null) {
			this.addFieldError("upload", "上传文件大小大于" + maximumSize);
			return checkSize;
		}
		String saveDir = ServletActionContext.getRequest().getSession().getServletContext().getRealPath(savePath);
		OutputStream out = new FileOutputStream(saveDir + "\\" + uploadFileName);
		InputStream in = new FileInputStream(upload);
		IOUtils.copy(in, out);
		return SUCCESS;
	}
	
	public String checkUploadSize() {
		long uploadLength = upload.length();
		if(uploadLength > maximumSize) {
			return INPUT;
		} else {
			return null;
		}
	}
	
	public String checkUploadType() {
		String result = INPUT;
		String[] types = allowTypes.split(",");
		for (String str : types) {
			if(str.equals(uploadContentType)) {
				return null;
			}
		}
		return result;
	}
}

<action name="uploadAction" class="com.test.UploadAction">
			<param name="allowTypes">image/bmp,image/png,image/gif,image/jpeg</param>
			<param name="maximumSize">10000</param>
			<param name="savePath">/upload</param>
			<result name="input">/upload.jsp</result>
			<result>/success.jsp</result>
		</action>

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<%@taglib prefix="s" uri="/struts-tags" %>
<!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">
<title>Insert title here</title>
</head>
<body>
	<s:form action="uploadAction.action" method="post" enctype="multipart/form-data">
		<s:file name="upload" label="选择文件"></s:file>
		<s:submit value="上传"></s:submit>
	</s:form>
</body>
</html>

上面是手动拦截的上传文件类型和上传文件大小，没有使用拦截器，下面写个例子是使用的struts2里面默认配置的拦截器fileUpload实现上传的拦截。

代码如下：需要将struts.xml进行配置

<action name="uploadAction" class="com.test.UploadAction">
			<param name="savePath">/upload</param>
			<interceptor-ref name="fileUpload">
				<param name="maximumSize">10000</param>
				<param name="allowedTypes">image/pjpeg,image/bmp,image/png,image/gif,image/jpeg,image/jpg</param>
			</interceptor-ref>
			<interceptor-ref name="defaultStack"></interceptor-ref>
			<interceptor-ref name="defaultStack"></interceptor-ref>
			<result>/success.jsp</result>
			<result name="input">/upload.jsp</result>
		</action>

其中这个allowedTypes如果不这么些，可能会出错，挺恶心的，

使用了这个拦截器后，就能限制文件上传类型和文件上传大小，但是相应的提示信息是英文的，如果想显示的是中文的出错提示，需要对两个地方进行修改。

就是在messageResource.properties文件中，修改这两个东西的值

struts.messages.error.content.type.not.allowed

struts.messages.error.file.too.large

其中第一个是文件类型，第二个是上传的文件大小。

如果不是这两个错误，而是发生了其他错误，就修改这个值

struts.message.error.uploading

做文件上传的时候最好指定这两个属性的值：

struts.multipart.saveDir的值这个是上传临时文件夹，如果不设置，使用的是javax.servlet.context.tempdir的值。也就是work/Catalina/localhost

struts.multipart.maxSize是上传的表单的请求内容的最大字节