Java生成文件以流响应出去

àì夳堔傛蜴生んèń 2022-12-23 11:10 90阅读 0赞

package com.supwisdom.portal.utils;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.*;
    
    /**
     * Created by jyl on 2020/5/8.
     **/
    
    public class CreateFileUtil {
    
        public static boolean createJsonFile(String jsonString, String fileName, HttpServletResponse response, HttpServletRequest request) throws UnsupportedEncodingException {
            // 标记文件生成是否成功
            boolean flag = true;
    
            String filePath = System.getProperty("user.dir") + "/data/tmp";
            // 拼接文件完整路径
            String fullPath = filePath + File.separator + fileName + ".json";
            System.out.println(fullPath);
    
            // 生成json格式文件
            try {
                // 保证创建一个新文件
                File file = new File(fullPath);
                if (!file.exists()) { // 如果父目录不存在，创建父目录
                    file.getParentFile().mkdirs();
                }
    
                if (file.exists()) { // 如果已存在,删除旧文件
                    file.delete();
                }
    
                file.createNewFile();
    
                // 格式化json字符串
    //            jsonString = JsonFormatTool.formatJson(jsonString);
    
                // 将格式化后的字符串写入文件
                Writer write = new OutputStreamWriter(new FileOutputStream(file), "UTF-8");
                write.write(jsonString);
                write.flush();
                write.close();
    
                //读取文件
                BufferedInputStream br = new BufferedInputStream(new FileInputStream(file));
    
                response.reset();
    
                response.setHeader("Access-Control-Expose-Headers", "Content-Type,Content-Disposition");
                response.setContentType("application/octet-stream;charset=UTF-8;");
    //            response.setHeader("Content-Disposition","attachment;filename="+filename+ ".json");
                response.setHeader( "Content-Disposition", "attachment;filename=" + new String( fileName.getBytes("gb2312"), "ISO8859-1" ) +".json");
    
                // 将要下载的文件内容通过输出流写到浏览器
                OutputStream out = response.getOutputStream();
                byte[] buf = new byte[1024];
                int len = 0;
                while ((len = br.read(buf))>0)out.write(buf,0,len);
                br.close();
                out.close();
            } catch (Exception e) {
                flag = false;
                e.printStackTrace();
            }
    
            // 返回是否成功的标记
            return flag;
        }
    }