Java文件下载之解决中文乱码

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/gyx_2110/article/details/76099178

文件上传和下载是web开发中常遇到的问题，而如果下载的文件带有中文时一般都会出现乱码现象，但是对这个问题，不同的浏浏览器所能识别的编码也不一样，而下面这段代码提供了一个通用的解决方案。

import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.io.IOUtils;
import sun.misc.BASE64Encoder;

public class DownLoadServlet extends HttpServlet {
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String fileName = "E:/深入理解Java虚拟机.pdf";
		// 设置响应头参数值
		String contentType = this.getServletContext().getMimeType(fileName);
		String contentDisposition = "attachment;fileName="
				+ fileNameEncoding(fileName.substring(3), request);
		response.setHeader("Content-Type", contentType);
		response.setHeader("Content-Disposition", contentDisposition);

		// 设置响应头
		ServletOutputStream output = response.getOutputStream();
		FileInputStream input = new FileInputStream(fileName);
		// 将输入流中的文件写入到输出流
		IOUtils.copy(input, output);
		input.close();
	}

	public String fileNameEncoding(String fileName, HttpServletRequest request)
			throws IOException {
		String agent = request.getHeader("User-Agent");
		if (agent.contains("Firefox")) {
			BASE64Encoder base64Encoder = new BASE64Encoder();
			fileName = "=?utf-8?B?"
					+ base64Encoder.encode(fileName.getBytes("utf-8")) + "?=";
		} else {
			fileName = URLEncoder.encode(fileName, "utf-8");
		}
		return fileName;
	}
}