sis-background/gyee-sample-impala/src/main/java/com/gyee/impala/common/util/FileUtil.java

package com.gyee.impala.common.util;

import com.gyee.impala.common.exception.CustomException;
import com.gyee.impala.common.result.ResultCode;
import lombok.extern.slf4j.Slf4j;
import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.MalformedURLException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.nio.file.Path;
import java.util.List;

@Slf4j
public class FileUtil {

    /**
     * 写入文件
     *
     * @param fileName
     * @param content
     */
    public static void writeFile(String fileName, String content) {
        BufferedWriter bw = null;

        try {
            File file = new File(fileName);
            if (!file.exists())
                file.createNewFile();

            bw = new BufferedWriter(new FileWriter(file, true));

            String[] list = content.split("\n");
            for(int i = 0; i < list.length; i++){
                bw.write(list[i]);
                bw.write("\n");
                if (i % 500 == 0)
                    bw.flush();
            }
            bw.flush();
        } catch (Exception e) {
            log.error(e.getMessage());
        } finally {
            try {
                bw.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 写入文件
     *
     * @param path
     * @param fileName
     * @param inputStream
     */
    public static void writeFile(String path, String fileName, InputStream inputStream) {
        OutputStream os = null;
        try {
            byte[] bs = new byte[1024];
            int len;

            File file = new File(path);
            if (!file.exists()) {
                file.mkdirs();
            }
            os = new FileOutputStream(file.getPath() + File.separator + fileName);
            // 开始读取
            while ((len = inputStream.read(bs)) != -1) {
                os.write(bs, 0, len);
            }

        } catch (IOException e) {
            e.printStackTrace();
            log.error(e.getMessage());
        } catch (Exception e) {
            e.printStackTrace();
            log.error(e.getMessage());
        } finally {
            // 完毕，关闭所有链接
            try {
                os.close();
                inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
                log.error(e.getMessage());
            }
        }
    }


    // String -> InputStream
    public static InputStream convertStringToInputStream(String content) {

        InputStream result = new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8));
        return result;

    }


    /**
     * 加载文件
     *
     * @param fileName
     * @return
     */
    public static void download(String fileName, HttpServletResponse response) {
        FileInputStream fis = null;
        BufferedInputStream bis = null;
        try {
            // 获取文件
            File file = new File(fileName);
            // 清空缓冲区，状态码和响应头(headers)
            response.reset();
            // 设置ContentType，响应内容为二进制数据流，编码为utf-8，此处设定的编码是文件内容的编码
            response.setContentType("application/octet-stream;charset=utf-8");
            // 以（Content-Disposition: attachment; filename="filename.jpg"）格式设定默认文件名，设定utf编码，此处的编码是文件名的编码，使能正确显示中文文件名
            response.setHeader("Content-Disposition", "attachment;fileName=" + file.getName() + ";filename*=utf-8''" + URLEncoder.encode(file.getName(), "utf-8"));

            // 实现文件下载
            byte[] buffer = new byte[1024];
            fis = new FileInputStream(file);
            bis = new BufferedInputStream(fis);
            // 获取字节流
            OutputStream os = response.getOutputStream();
            int i = bis.read(buffer);
            while (i != -1) {
                os.write(buffer, 0, i);
                i = bis.read(buffer);
            }
        } catch (FileNotFoundException e) {
            throw new CustomException(ResultCode.ERROR_FILE_NO);
        } catch (Exception e) {
            throw new CustomException(ResultCode.ERROR);
        } finally {
            if (bis != null) {
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}