3、File
1、创建file对象：需要指明路径
方法一：
File file = new File("E:\kingsware\run\run_app_model1");
File file1 = new File("E:\\kingsware\\run");
File file2 = new File(file1,"run_app_model1");
//获取文件大小
long size = file3.length();
System.out.println(size);
//获取路径下文件数量
File[] files = file1.listFiles();
int number = files.length;
System.out.println(size);
boolean file3IsFile = file3.isFile();
System.out.println(file3IsFile);//run_testFile.txt是文件 ---》true
boolean file3directory = file3.isDirectory();
System.out.println(file3directory);//run_testFile.txt是文件 ---》false
boolean file3IsExists = file3.exists();
boolean exists = file1.exists();
System.out.println(exists);
System.out.println(file3IsExists);
5、创建、删除文件
删除文件：file.delete();
File file = new File("E:\\kingsware\\run\\a.text");
if(!file.exists()){
file.createNewFile();
//file.mkdir();
}
file.delete();
6、file过滤器
File file2 = new File("E:\\kingsware\\run");
File[] files1 = file2.listFiles(new FileFilter() {
@Override
public boolean accept(File pathname) {
return pathname.getName().endsWith(".txt") || pathname.isDirectory();
}
});
for (File f : files1) {
System.out.println(f.getName());
}
7、递归删除文件
//删除文件的方法
public static void recursiveDelete(File file) {
//to end the recursive loop
if (!file.exists())
return;
//if directory, go inside and call recursively
if (file.isDirectory()) {
for (File f : file.listFiles()) {
//call recursively
recursiveDelete(f);
}
}
//call delete to delete files and empty directory
file.delete();
//System.out.println("Deleted file/folder: "+file.getAbsolutePath());
}
public static boolean deleteFiles(File file){
boolean result = false;
if(file.isDirectory()){
File[] files = file.listFiles();
for (File childrenFile : files) {
deleteFiles(childrenFile);
if(!result){
return result;
}
}
}
result = file.delete();
return result;
}
8、递归获取文件
public static void main(String[] args){
//表示一个文件路径
String path = "E:\\Java\\serverDel\\";
getFiles(path);
}
/**
* 递归获取某路径下的所有文件，文件夹，并输出
*/
public static void getFiles(String clientBase) {
File file = new File(clientBase);
// 如果这个路径是文件夹
if (file.isDirectory()) {
// 获取路径下的所有文件
File[] files = file.listFiles();
for (int i = 0; i < files.length; i++) {
// 如果还是文件夹 递归获取里面的文件 文件夹
if (files[i].isDirectory()) {
System.out.println("目录：" + files[i].getPath());
//继续读取文件夹里面的所有文件
getFiles(files[i].getPath());
} else {
System.out.println("文件：" + files[i].getPath());
}
}
} else {
System.out.println("文件：" + file.getPath());
}
}
9、获取文件或文件夹的创建或修改时间：File.lastModified(),格式化输出
String s = "F:\\ideaxm\\app2022\\08io\\src\\main\\java\\cn\\wzt\\File3.java";
File f = new File(s);
Date date = new Date(f.lastModified());
System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date));
10、spring boot 下载单个文件与文件夹打包为zip下载
@GetMapping("/download")
public void download(HttpServletResponse response, @RequestParam("path") String path) throws Exception {
// 转为path
Path folderPath = Paths.get(path);
// 响应为二进制数据流
response.setContentType("application/octet-stream");
if (!Files.isDirectory(folderPath)) { // 文件下载
File file = new File(path);
if (!file.exists()) {
LOGGER.error("file not exists: " + path);
throw new IOException("file not exists: " + path);
}
try (InputStream input = new FileInputStream(file);
OutputStream output = response.getOutputStream()) {
// 写入数据
int len;
// 设置10kb缓冲区
byte[] buffer = new byte[1024 * 10];
// 文件设置，附件的形式打开
response.setHeader("content-disposition", "attachment; filename=" + file.getName());
while ((len = input.read(buffer)) > 0) {
output.write(buffer, 0, len);
}
output.flush();
} catch (IOException e) {
LOGGER.error(e.getMessage(), e);
throw new RuntimeException(e);
}
} else { // 文件夹下载
// 文件设置，附件形式打开
response.setHeader("content-disposition", "attachment; filename=" + new String((folderPath.getFileName().toString() + ".zip").getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1));
try (ZipOutputStream zipOutputStream = new ZipOutputStream(response.getOutputStream())) {
// 文件路径/ID
LinkedList<String> filePath = new LinkedList<>();
Files.walkFileTree(folderPath, new FileVisitor<Path>() {
@Override
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
// 开始遍历目录
if (!dir.equals(folderPath)) {
filePath.addLast(dir.getFileName().toString());
// 写入目录
ZipEntry zipEntry = new ZipEntry(filePath.stream().collect(Collectors.joining("/", "", "/")));
try {
zipOutputStream.putNextEntry(zipEntry);
zipOutputStream.flush();
} catch (IOException e) {
LOGGER.error(e.getMessage(), e);
throw new RuntimeException(e);
}
}
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
// 开始遍历文件
try (InputStream inputStream = Files.newInputStream(file)) {
// 创建一个压缩项，指定名称
String fileName = filePath.size() > 0
? filePath.stream().collect(Collectors.joining("/", "", "")) + "/" + file.getFileName().toString()
: file.getFileName().toString();
ZipEntry zipEntry = new ZipEntry(fileName);
// 添加到压缩流
zipOutputStream.putNextEntry(zipEntry);
// 写入数据
int len;
// 设置10kb缓冲区
byte[] buffer = new byte[1024 * 10];
while ((len = inputStream.read(buffer)) > 0) {
zipOutputStream.write(buffer, 0, len);
}
zipOutputStream.flush();
} catch (IOException e) {
LOGGER.error(e.getMessage(), e);
throw new RuntimeException(e);
}
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {
return FileVisitResult.CONTINUE;
}
@Override
public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
// 结束遍历目录
if (!filePath.isEmpty()) {
filePath.removeLast();
}
return FileVisitResult.CONTINUE;
}
});
zipOutputStream.closeEntry();
} catch (IOException e) {
LOGGER.error(e.getMessage(), e);
}
}
}
11、文件的上传
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