java 批量下载文件

经常遇到选择多个文件进行批量下载的情况，可以先将选择的所有的文件生成一个zip文件，然后再下载，该zip文件，即可实现批量下载，但是在打包过程中，常常也会出现下载过来的zip文件中里面有乱码的文件名，通过使用ant.jar中的org.apache.tools.zip里的ZipOutPutStream为实现编码的设置。
代码如下：
ant包引用

<dependency>
  <groupId>antgroupId>
  <artifactId>antartifactId>
  <version>1.6.5version>
dependency>

		
		  ant
		  ant
		  1.6.5
			

压缩下载的action代码

package demo.action;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;

import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;
import org.apache.struts2.ServletActionContext;
import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipOutputStream;

import com.opensymphony.xwork2.ActionSupport;

/**
 * 批量下载文件：
 *   使用ant.jar包中的org.apache.tools.zip.*完成压缩，
 * java原生也有java.util.zip.*但是测试了下无法搞定压缩
 * 文件内文件名的中文问题
 * @author yangcong
 *
 */
public class BatchDownloadAction extends ActionSupport {

    private Logger Log = Logger.getLogger(BatchDownloadAction.class);
    private static final String FilePath = "D:\\";

    private static final long serialVersionUID = -8694640030455344419L;

    public String execute() {
        //生成的ZIP文件名为Demo.zip
        String tmpFileName = "Demo.zip";
        byte[] buffer = new byte[1024];
        String strZipPath = FilePath + tmpFileName;
        try {
            ZipOutputStream out = new ZipOutputStream(new FileOutputStream(
                    strZipPath));
            // 需要同时下载的两个文件result.txt ，source.txt
            File[] file1 = { new File(FilePath+"test1.txt"),
                    new File(FilePath+"测试2.docx") };
            for (int i = 0; i < file1.length; i++) {
                FileInputStream fis = new FileInputStream(file1[i]);
                out.putNextEntry(new ZipEntry(file1[i].getName()));
                //设置压缩文件内的字符编码，不然会变成乱码
                out.setEncoding("GBK");
                int len;
                // 读入需要下载的文件的内容，打包到zip文件
                while ((len = fis.read(buffer)) > 0) {
                    out.write(buffer, 0, len);
                }
                out.closeEntry();
                fis.close();
            }
            out.close();
            this.downFile(getResponse(), tmpFileName);
        } catch (Exception e) {
            Log.error("文件下载出错", e);
        }
        return null;
    }

    /**
     * 获取Response
     * @return
     */
    private HttpServletResponse getResponse() {
        return ServletActionContext.getResponse();
    }

    /**
     * 文件下载
     * @param response
     * @param str
     */
    private void downFile(HttpServletResponse response, String str) {
        try {
            String path = FilePath + str;
            File file = new File(path);
            if (file.exists()) {
                InputStream ins = new FileInputStream(path);
                BufferedInputStream bins = new BufferedInputStream(ins);// 放到缓冲流里面
                OutputStream outs = response.getOutputStream();// 获取文件输出IO流
                BufferedOutputStream bouts = new BufferedOutputStream(outs);
                response.setContentType("application/x-download");// 设置response内容的类型
                response.setHeader(
                        "Content-disposition",
                        "attachment;filename="
                                + URLEncoder.encode(str, "UTF-8"));// 设置头部信息
                int bytesRead = 0;
                byte[] buffer = new byte[8192];
                // 开始向网络传输文件流
                while ((bytesRead = bins.read(buffer, 0, 8192)) != -1) {
                    bouts.write(buffer, 0, bytesRead);
                }
                bouts.flush();// 这里一定要调用flush()方法
                ins.close();
                bins.close();
                outs.close();
                bouts.close();
            } else {
                response.sendRedirect("../error.jsp");
            }
        } catch (IOException e) {
            Log.error("文件下载出错", e);
        }
    }
}