一、写字符到txt文件
字符流，只能操作文本文件，不能操作图片，视频等非文本文件。当我们单纯读或者写文本文件时 使用字符流 其他情况使用字节流。
有两种方法：一是使用字符输出流，二时使用字节输出流
1、保存内容到txt文件
1）、使用字符输出流
public void addLog(SystemLogDto systemLog) { try { long id = SnowflakeManager.nextValue(); systemLog.setId(id); systemLog.setHasFile(0); int maxLength = 4000; String inParamPrefixStr = "请求参数：\r\n"; String outParamPrefixStr = "返回数据：\r\n"; String inParam = systemLog.getInParam(); String outParam = systemLog.getOutParam(); if (inParam.length() > maxLength || outParam.length() > maxLength) { String data =""; String suffixPath = File.separator + DateUtil.toStringNoInterval(systemLog.getCreateTime(), 8); FileUtil.createDir(filePathPrefix + suffixPath); String category = getCategory(systemLog.getCategory()); String title = null == systemLog.getTitle() ? "" : systemLog.getTitle(); String date = DateUtil.toStringNoInterval(systemLog.getCreateTime(), 17); String fileName = date + "_" + category + "_" + title + "_" + systemLog.getId().toString()+".txt"; // 文件名 File file = new File(filePathPrefix + suffixPath + File.separator + fileName); if (!file.exists()) file.createNewFile(); systemLog.setHasFile(1); systemLog.setFilePath(suffixPath + File.separator + fileName); FileWriter fileWriter = new FileWriter(file, true); // 创建FileWriter对象 data = inParamPrefixStr + inParam+"\r\n"+outParamPrefixStr + outParam; // 内容 fileWriter.write(data); // 写到缓冲区 systemLog.setInParam(getText(inParam)); systemLog.setOutParam(getText(outParam)); fileWriter.flush(); // 写到文件 fileWriter.close(); // 释放资源 } SystemLog systemLog1 = dozerMapper.map(systemLog, SystemLog.class); systemLogDao.insertSelective(systemLog1); } catch (Exception e) { e.printStackTrace(); } }
注意:拼接成完整的文件地址要使用File.separator，同样，截取文件名和文件的目录也要使用File.separator，
String fileName = filePath.substring(filePath.lastIndexOf(File.separator) + 1); String path = filePath.substring(0, filePath.lastIndexOf(File.separator));
而不能使用\，如下所示：
String fileName = filePath.substring(filePath.lastIndexOf("\\") + 1); String path = filePath.substring(0, filePath.lastIndexOf("\\"));
2）、使用字节输出流
功能说明：将接口的请求头保存到本地电脑。
serviceImpl
@Service("outstoreUploadLogService") @Transactional @Slf4j public class OutstoreUploadLogServiceImpl implements OutstoreUploadLogService { @Resource private OutstoreUploadLogMapper outstoreUploadLogMapper; @Value("${system.file.tempPath}") private String tempPath; @Override public Result saveToTxt(JSONObject jsonObject) { // 将jsonObject转为字节数组输入流 byte[] bytes = jsonObject.toString().getBytes(); ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes); String suffix = ".txt"; String path = FileUtil.saveFile(inputStream, tempPath, suffix); return Result.operating("请求体保存成功", true, ResultCode.SUCCESS,path); } }
配置文件如下:
system.file.tempPath=d:/upload/cmdptcp/fileUpload
2、将字符写到txt文件并下载
功能说明：将数据库的公钥下载下来。
controller
/** * 公钥下载 * @param id * @param response * @return */ @PostMapping("/uploadPublikey") @Log("公钥下载") public void uploadPublikey (Long id,HttpServletResponse response)throws Exception { equipmentService.uploadPublikey(id,response); }
service
@Override public void uploadPublikey(Long id, HttpServletResponse response) throws Exception { Equipment equipment = equipmentDao.selectByPrimaryKey(id); String enterpriseName = enterpriseDao.getName(equipment.getEntityId()); String fileName = enterpriseName + "_" + equipment.getEquipmentNo() + ".txt"; // 文件名 String content = equipment.getProdPubKey(); // 内容 FileUtil.downloadFile2(fileName, content, response); }
downloadFile2方法
public static void downloadFile2(String fileName, String content, HttpServletResponse response) throws IOException { response = setResponse(fileName, response); OutputStream outputStream = response.getOutputStream(); // 不用创建直接获取字节输出流 BufferedOutputStream buffer = new BufferedOutputStream(outputStream); // 使用缓冲流，即给字节输出流加一个缓冲区 buffer.write(content.getBytes()); // 写到字节缓冲区 buffer.flush(); // 写到文件 buffer.close(); // 释放资源 outputStream.close(); }
二、获取指定位置的txt文件的内容
代码如下：
public class TxtAnalysisTest { public static void main(String[] args) throws IOException { String lineTxt_cr = null;//行读字符串 String encoding="GBK"; File file = new File("C:\\Users\\miracle\\Desktop\\a.txt"); if(file.isFile() && file.exists()) { //判断文件是否存在 InputStreamReader read = new InputStreamReader(new FileInputStream(file), encoding);//考虑到编码格式 BufferedReader bufferedReader = new BufferedReader(read); // 字符缓冲输入流 StringBuffer xpStr = new StringBuffer(); //文件文本字符串 while((lineTxt_cr = bufferedReader.readLine()) != null){ //处理字符串lineTxt_cr xpStr.append(lineTxt_cr); } // 释放资源 bufferedReader.close(); read.close(); System.out.println(xpStr); } } }
三、读取指定位置的文件并下载
功能说明：将本地电脑的文件下载下来。
代码如下：
@Override public void download(Long id, HttpServletResponse response) throws IOException { OutstoreUploadLog outstoreUploadLog = outstoreUploadLogMapper.selectByPrimaryKey(id); String filePath = outstoreUploadLog.getFilePath();
String fileName = filePath.substring(filePath.lastIndexOf("\\") + 1); // 得到文件名 String path = filePath.substring(0,filePath.lastIndexOf("\\") ); // 得到目录 FileUtil.downloadFile(path, fileName, response); }
注意:downloadFile第一个参数为path，第二个参数为文件名。
工具类
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.multipart.MultipartFile;
import sun.misc.BASE64Decoder;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.text.DecimalFormat;
import java.util.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
@Slf4j
public class FileUtil {
//压缩目录
public static void CompressDir(String filePath) {
try {
ZipOutputStream out = new ZipOutputStream(new FileOutputStream(filePath + ".zip"));
Zip(filePath, filePath.lastIndexOf(File.separator), out);
out.closeEntry();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void Zip(String path, int baseindex, ZipOutputStream out) throws Exception {
// 要压缩的目录或文件
File file = new File(path);
File[] files;
if (file.isDirectory()) {// 若是目录，则列出所有的子目录和文件
files = file.listFiles();
} else {// 若为文件，则files数组只含有一个文件
files = new File[1];
files[0] = file;
}
for (File f : files) {
if (f.isDirectory()) {
// 去掉压缩根目录以上的路径串，一面ZIP文件中含有压缩根目录父目录的层次结构
String pathname = f.getPath().substring(baseindex + 1);
// 空目录也要新建哟个项
out.putNextEntry(new ZipEntry(pathname + "/"));
// 递归
Zip(f.getPath(), baseindex, out);
} else {
// 去掉压缩根目录以上的路径串，一面ZIP文件中含有压缩根目录父目录的层次结构
String pathname = f.getPath().substring(baseindex + 1);
if (f.length() > 100 * 1024 * 1024) {
throw new Exception("文件大小不能大于100M");
}
// 新建项为一个文件
out.putNextEntry(new ZipEntry(pathname));
// 读文件
BufferedInputStream in = new BufferedInputStream(new FileInputStream(f));
int c;
while ((c = in.read()) != -1)
out.write(c);
in.close();
}
}
}
/**
* 删除文件夹
*
* @param sPath
* @return boolean
*/
public static boolean deleteFile(String sPath) {
boolean flag = false;
File file = new File(sPath);
// 路径为文件且不为空则进行删除
if (file.isFile() && file.exists()) {
file.delete();
File parent = file.getParentFile();
if (parent.isDirectory() && parent.listFiles().length <= 0) {
parent.delete();
File temp = parent.getParentFile();
deleteFile(temp.getAbsolutePath());
}
flag = true;
} else {
File parent = new File(sPath);
if (parent.isDirectory() && parent.listFiles().length <= 0) {
parent.delete();
File temp = parent.getParentFile();
deleteFile(temp.getAbsolutePath());
flag = true;
}
}
return flag;
}
/**
* 删除目录及目录下的所有文件不删除顶级目录
*
* @param sPath
* @return boolean
*/
public static boolean deleteDirFile(String sPath) {
boolean flag = false;
File file = new File(sPath);
// 路径为文件且不为空则进行删除
if (file.isFile() && file.exists()) {
file.delete();
File parent = file.getParentFile();
if (parent.isDirectory() && parent.listFiles().length <= 0) {
parent.delete();
File temp = parent.getParentFile();
deleteFile(temp.getAbsolutePath());
}
flag = true;
} else {
File parent = new File(sPath);
if (parent.isDirectory()) {
if (parent.listFiles().length <= 0) {
parent.delete();
} else {
File[] files = parent.listFiles();
for (File f : files) {
deleteDirFile(f.getAbsolutePath());
}
}
flag = true;
}
}
return flag;
}
/**
* MultipartFile 转 File
*
* @param file
* @throws Exception
*/
public static File multipartFileToFile(MultipartFile file, String tempPath) throws Exception {
File toFile = null;
if (!file.equals("") && file.getSize() > 0) {
InputStream ins = file.getInputStream();
File tempFile = new File(tempPath);
if (!(tempFile.exists() && tempFile.isDirectory())) {
tempFile.mkdirs();
}
toFile = new File(tempFile + File.separator + file.getOriginalFilename());
inputStreamToFile(ins, toFile);
ins.close();
}
return toFile;
}
//获取流文件
private static void inputStreamToFile(InputStream ins, File file) {
try {
OutputStream os = new FileOutputStream(file);
int bytesRead = 0;
byte[] buffer = new byte[8192];
while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
os.write(buffer, 0, bytesRead);
}
os.close();
ins.close();
} catch (Exception e) {
e.printStackTrace();
}
}
//删除转换存储的临时文件
public static void deleteMultipartFile(MultipartFile file, String tempPath) {
File tempFile = new File(tempPath + File.separator + file.getOriginalFilename());
tempFile.delete();
}
//生成目录
public static File createDir(String path) {
File file = new File(path);
if (!(file.exists() && file.isDirectory())) {
file.mkdirs();
}
return file;
}
public static Map<String, String> upload(MultipartFile file, String basePath) {
Map<String, String> map = new HashMap<>();
String dateStr = DateUtil.toStringNoInterval(new Date(), 8);
if (basePath.contains("\\")) {
basePath = basePath.replace("\\", File.separator);
}
File f = createDir(basePath + File.separator + dateStr);
//获取文件的原始名
String oldName = file.getOriginalFilename();
//获取文件的后缀名
String suffix = oldName.substring(oldName.lastIndexOf("."));
//使用uuid设置新的文件名，防止文件名重复
String newName = UUID.randomUUID() + suffix;
//文件保存
try {
file.transferTo(new File(f, newName));
map.put("fileName", newName);
map.put("uploadPath", dateStr);
} catch (IOException e) {
log.error("文件上传发生异常:", e);
e.printStackTrace();
}
return map;
}
/**
* 流转字节数组
*
* @param in
* @return
* @throws IOException
*/
public static byte[] streamToByteArray(InputStream in) throws IOException {
ByteArrayOutputStream output = new ByteArrayOutputStream();
byte[] buffer = new byte[4096];
int n;
while (-1 != (n = in.read(buffer))) {
output.write(buffer, 0, n);
}
return output.toByteArray();
}
/**
* 读取资源目录下的文件内容
*
* @param filePath
* @param clazz
* @return
* @throws IOException
*/
public static List<String> readResourceFile(String filePath, Class<?> clazz) throws IOException {
InputStream in = getResourceStream(filePath, clazz);
InputStreamReader reader = new InputStreamReader(in);
BufferedReader buffReader = new BufferedReader(reader);
String strTmp;
List<String> content = new ArrayList<>();
while ((strTmp = buffReader.readLine()) != null) {
content.add(strTmp);
}
buffReader.close();
return content;
}
public static InputStream getResourceStream(String filePath, Class<?> clazz) {
return clazz.getClassLoader().getResourceAsStream(filePath);
}
/**
* 将资源目录下的文件生成到磁盘
*
* @param sourcePath
* @param targetPath
* @param clazz
*/
public static void createToFileByResource(String sourcePath, String targetPath, Class<?> clazz) {
File file = new File(targetPath);
if (!file.exists()) {
InputStream is = clazz.getClassLoader().getResourceAsStream(sourcePath);
OutputStream os = null;
try {
os = new FileOutputStream(targetPath);
int len;
byte[] bytes = new byte[1024];
while ((len = is.read(bytes)) != -1) {//边读边写
os.write(bytes, 0, len);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {//关闭资源，防止内存泄漏
os.close();
is.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public static BufferedOutputStream createFile(String filePath, String fileName) throws IOException {
File file = createDir(filePath);
file = new File(filePath + File.separator + fileName);
BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(file.getPath()));
return stream;
}
/**
* 将文件字节转为 b/kb/mb/g的大小形式
*
* @param fileSize
* @return
*/
public static String transByte(String fileSize) {
// 格式化，保留两位小数
DecimalFormat df = new DecimalFormat("#.00");
Double d = Double.parseDouble(fileSize);
d = d / 1024;
if (d < 1024) {
return df.format(d) + "KB";
}
d = d / 1024;
if (d < 1024) {
return df.format(d) + "MB";
}
d = d / 1024;
return df.format(d) + "G";
}
public static List<String> readTxtByLine(File file, String tempPath) {
List<String> list = new ArrayList<>();
try {
list = readTxtByLine(file);
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
public static List<String> readTxtByLine(File file) {
List<String> list = new ArrayList<>();
InputStreamReader reader = null;
BufferedReader bufferedReader = null;
try {
//判断文件是否存在
if (file.isFile() && file.exists()) {
reader = new InputStreamReader(new FileInputStream(file), "UTF-8");
bufferedReader = new BufferedReader(reader);
String lineTxt;
while ((lineTxt = bufferedReader.readLine()) != null) {
list.add(lineTxt);
}
}
file.delete();
} catch (Exception e) {
e.printStackTrace();
log.error("按行读取txt文件异常：{}", e);
} finally {
try {
if (reader != null) {
reader.close();
}
if (bufferedReader != null) {
bufferedReader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return list;
}
public static String saveFile(InputStream in, String basePath, String suffix) {
String path = null;
BufferedOutputStream os = null;
try {
String dateStr = DateUtil.toStringNoInterval(new Date(), 8);
if (basePath.contains("\\")) {
basePath = basePath.replace("\\", File.separator);
}
File f = createDir(basePath + File.separator + dateStr);
f = new File(f, UUID.randomUUID() + suffix);
os = new BufferedOutputStream(new FileOutputStream(f));
int len;
byte[] bytes = new byte[1024 * 1024];
while ((len = in.read(bytes)) != -1) {//边读边写
os.write(bytes, 0, len);
}
path = f.getPath();
} catch (Exception e) {
e.printStackTrace();
} finally {
//关闭资源，防止内存泄漏
try {
if (os != null) os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return path;
}
/**
* base64转文件保存
*
* @param base64
* @param basePath
* @param suffix 文件后缀
* @param fileName 文件名
* @return
*/
public static String[] base64ToFile(String base64, String basePath, String suffix, String fileName) {
String dateStr = DateUtil.toStringNoInterval(new Date(), 8);
if (basePath.contains("\\")) {
basePath = basePath.replace("\\", File.separator);
}
File f = createDir(basePath + File.separator + dateStr);
if (null == fileName) {
//补齐后缀
suffix = suffix.trim();
if (!suffix.startsWith(".") && suffix.indexOf(".") == -1) {
suffix = "." + suffix;
}
fileName = UUID.randomUUID() + suffix;
}
try {
byte[] buffer = new BASE64Decoder().decodeBuffer(base64);
File file = new File(f, fileName);
FileOutputStream out = new FileOutputStream(file);
out.write(buffer);
out.close();
String[] path = {dateStr, fileName};
return path;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 文件转base64
*
* @param filePath
* @return
*/
public static String fileToBase64(String filePath) {
if (filePath == null) {
return null;
}
try {
byte[] b = Files.readAllBytes(Paths.get(filePath));
return Base64.getEncoder().encodeToString(b);
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
/**
* 通过流下载文件
*
* @param fileName 文件名
* @param response
* @throws IOException
*/
public static void downloadFile(String filePath, String fileName, HttpServletResponse response) throws IOException {
File file = new File(filePath + File.separator + fileName);
InputStream in = new FileInputStream(file);
response = setResponse(fileName, response);
int len = 0;
byte bytes[] = new byte[1024];
OutputStream out = response.getOutputStream();
while ((len = in.read(bytes)) > 0) {
out.write(bytes, 0, len);
}
in.close();
out.close();
}
/**
* 通过流下载文件
*
* @param fileNewName 文件名
* @param response
* @throws IOException
*/
public static void downloadFile1(String filePath, String fileNewName, HttpServletResponse response) throws IOException {
File file = new File(filePath);
InputStream in = new FileInputStream(file);
response = setResponse(fileNewName, response);
int len = 0;
byte bytes[] = new byte[1024];
OutputStream out = response.getOutputStream();
while ((len = in.read(bytes)) > 0) {
out.write(bytes, 0, len);
}
in.close();
out.close();
}
/**
* 设置响应信息
*
* @param fileName
* @param response
* @throws UnsupportedEncodingException
*/
private static HttpServletResponse setResponse(String fileName, HttpServletResponse response) throws UnsupportedEncodingException {
response.setHeader("Access-Control-Expose-Headers", "content-disposition");
response.setCharacterEncoding("UTF-8");
response.setContentType("application/octet-stream");
response.setHeader("content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
return response;
}
}
