过来的文件流输入写法：
File f=new File("/Users/buxuesong/Documents/svn_code/demo/test.txt");//OutputStreamOutputStream output = new FileOutputStream(f);byte byteVal = 100;output.write(byteVal);byte[] byteBuff = {0,63,127};output.write(byteBuff);output.flush();output.close();//WriterWriter writer = new FileWriter(f,true);char charVal = 'a';writer.write(charVal);char[] charBuff = {'a','b','c'};writer.write(charBuff);过来文件流输出写法：
File f=new File("/Users/buxuesong/Documents/svn_code/demo/test.txt");//InputStreamInputStream input = new FileInputStream(f);int intVal;while((intVal = input.read())>=0){ byte byteVla = (byte) intVal; System.out.println(byteVla);}input = new FileInputStream(f);int length;byte[] byteBuff = {1,2,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4};while((length = input.read(byteBuff))>=0){ for(int i = 0;i<length;i++){ byte byteVal = byteBuff[i]; System.out.println(byteVal); }}//ReaderReader reader = new FileReader(f);while ((intVal = reader.read())>=0){ char charVal = (char) intVal; System.out.println(charVal);}reader = new FileReader(f);char[] charBuff = {'a','b','c'};while((length = reader.read(charBuff))>=0){ for(int i=0;i<length;i++){ char charVal = charBuff[i]; System.out.println("==="+charVal); }}try with resource写法
try(BufferedReader br = new BufferedReader(new FileReader("/Users/buxuesong/Documents/svn_code/demo/test.txt"))){ while ((intVal = br.read())>=0){ char charVal = (char) intVal; System.out.println("BufferedReader"+charVal); }}try(BufferedReader br = new BufferedReader(new FileReader("/Users/buxuesong/Documents/svn_code/demo/testBufferedWriter.txt"))){ String inValue; while((inValue = br.readLine())!=null){ System.out.println("inValue"+inValue); }}新的输入输出写法：
try(BufferedReader br = Files.newBufferedReader(Paths.get("/Users/buxuesong/Documents/svn_code/demo/testBufferedWriter.txt"))){ String inValue; while((inValue = br.readLine())!=null){ System.out.println("Files.newBufferedReader="+inValue); }}List<String> lines = Files.readAllLines(Paths.get("/Users/buxuesong/Documents/svn_code/demo/testBufferedWriter.txt"));for(String line:lines)System.out.println("Files.readAllLines=="+line);try(BufferedWriter bw = Files.newBufferedWriter(Paths.get("/Users/buxuesong/Documents/svn_code/demo/testNewBufferedWriter.txt"))){ for(String d:data){ bw.write(d); bw.newLine(); }}Zip压缩文件写法：
public class ZipFileTest { public static void main(String args[]){ String[] data ={ "Line 1", "Line 2 2", "Line 3 3 3", "Line 4 4 4 4", "Line 5 5 5 5 5" }; try(FileSystem zipFs = openZip(Paths.get("/Users/buxuesong/Documents/svn_code/demo/myData.zip"))){ copyToZip(zipFs); writeToFileInZip1(zipFs,data); writeToFileInZip2(zipFs,data); }catch (Exception e){ System.out.println(e.getClass().getSimpleName()+"-"+e.getMessage()); } } private static FileSystem openZip(Path zipPath) throws IOException,URISyntaxException { Map<String,String> providerProps = new HashMap<>(); providerProps.put("create","true"); URI zipUri = new URI("jar:file",zipPath.toUri().getPath(),null); FileSystem zipFs = FileSystems.newFileSystem(zipUri, providerProps); return zipFs; } private static void copyToZip(FileSystem zipFs) throws IOException{ Path sourceFile = Paths.get("/Users/buxuesong/Documents/svn_code/demo/test.txt");// Path sourceFile = .getDefault().getPath("/Users/buxuesong/Documents/svn_code/demo/test.txt"); Path destFile = zipFs.getPath("/file1Copied.txt"); Files.copy(sourceFile,destFile, StandardCopyOption.REPLACE_EXISTING); } private static void writeToFileInZip1(FileSystem zipFs, String[] data) throws IOException{ try(BufferedWriter bw = Files.newBufferedWriter(zipFs.getPath("/newFile1.txt"))){ for(String d:data){ bw.write(d); bw.newLine(); } } } private static void writeToFileInZip2(FileSystem zipFs, String[] data) throws IOException{ Files.write(zipFs.getPath("/newFile2.txt"), Arrays.asList(data), Charset.defaultCharset(), StandardOpenOption.CREATE); }}Writer
output类型
Disk:FileWrite
In-Memory:CharArrayWriter
StringWriter, 写入StringBuffer
行为类型：
BufferedWriter
PrintWriter
StandardOpenOption类型
WRITE，APPEND写入
CREATE，CREATE_NEW，创立，创立新的
DELETE_ON_CLOSE，实现后删除（临时文件）
try(BufferedWriter bw = Files.newBufferedWriter( Paths.get("/Users/buxuesong/Documents/svn_code/test.txt") ,StandardOpenOption.CREATE,StandardOpenOption.WRITE)){ PrintWriter pw = new PrintWriter(bw); pw.write("Hello World!\n"); pw.printf("W:%4d X:%4d\n",5,235); Calendar cl = Calendar.getInstance(); cl.set(1987,11,23); pw.printf(Locale.US,"I birthed on %1$tB %1$tA %1$tY",cl);}catch (IOException e){}//输入文件Hello World!W: 5 X: 235I birthed on December Wednesday 1987Reader办法
//敞开流并开释与其关联的所有系统资源。abstract void close() //标记流中的以后地位。void mark(int readAheadLimit) //判断此流是否反对mark（）操作。boolean markSupported() //返回不读取任何字符的新 Reader 。static Reader nullReader() //读一个字符。int read() //将字符读入数组。int read(char[] cbuf) //将字符读入数组的一部分。abstract int read(char[] cbuf, int off, int len) //尝试将字符读入指定的字符缓冲区。int read(CharBuffer target) //判断此流是否能够读取。boolean ready() //重置流。void reset() //跳过字符。long skip(long n) //读取此阅读器中的所有字符，并依照读取的程序将字符写入给定的编写器。long transferTo(Writer out) DataOutputSteam & DataInputStream
public static void main(String[] args) { try(OutputStream out = Files.newOutputStream(Paths.get("C:\\Users\\Xuesong.Bu\\Desktop\\a.txt"))){ DataOutputStream dos = new DataOutputStream(out); dos.writeInt(1); dos.writeLong(2222L); dos.writeDouble(1.23); dos.writeChar('H'); dos.writeUTF("hha"); }catch (Exception e){ e.printStackTrace(); } try(InputStream in = Files.newInputStream(Paths.get("C:\\Users\\Xuesong.Bu\\Desktop\\a.txt"))){ DataInputStream dis = new DataInputStream(in); int a = dis.readInt(); System.out.println(a); Long b = dis.readLong(); System.out.println(b); Double c = dis.readDouble(); System.out.println(c); char d = dis.readChar(); System.out.println(d); String e = dis.readUTF(); System.out.println(e); }catch (Exception e){ e.printStackTrace(); }}//输入122221.23HhhaFiles循环读取文件夹下子目录及文件
Path path = Paths.get("/Users/buxuesong/Documents");FileVisitor<Path> fileVisitor = new FileVisitor<Path>(){ @Override public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException { return FileVisitResult.CONTINUE; } @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { fileCount ++; 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 { return FileVisitResult.CONTINUE; }};Files.walkFileTree(path, fileVisitor);System.out.println(fileCount);//另外几种循环读取所有文件个数Path path = Paths.get("/Users/buxuesong/Documents/python-learn/ch01");Stream<Path> stream = Files.walk(path);System.out.println(Files.walk(path) .filter(Files::isDirectory) .count());System.out.println(Files.walk(path) .filter(Files::isRegularFile) .count());System.out.println(stream.count());