java 1.7 新io 实践 NIO2

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Files 类使用

package com.xinyu.test;import java.io.IOException;import java.nio.ByteBuffer;import java.nio.channels.FileChannel;import java.nio.charset.StandardCharsets;import java.nio.file.Files;import java.nio.file.LinkOption;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.StandardCopyOption;import java.nio.file.StandardOpenOption;import java.util.List;public class FileTest {    public static void main(String[] args) {        // TODO Auto-generated method stub        //Files创建，删除//      Path path =Paths.get("D:/jun/xinyu.txt");//      try {//          Files.createFile(path);//          Files.deleteIfExists(path);//      } catch (IOException e) {//          // TODO Auto-generated catch block//          e.printStackTrace();//      }        //Files复制，移动//      try {//          Path path = Paths.get("D:/jun/psb (4).jpg");//          Path target =Paths.get("D:/test/jun.jpg");//          Path parent = target.getParent();//          boolean exists = parent.toFile().exists();//          if(!exists){//              Files.createDirectories(parent);//          }////            Files.copy(path, target, StandardCopyOption.REPLACE_EXISTING);//          Files.move(path, target, StandardCopyOption.REPLACE_EXISTING);//          //      } catch (IOException e) {//          // TODO Auto-generated catch block//          e.printStackTrace();//      }        //查看文件属性//      Path path = Paths.get("D:/liebao/debug.log");//      try {//          System.out.println(Files.getLastModifiedTime(path));//          System.out.println(Files.size(path));//          System.out.println(Files.isDirectory(path));//          System.out.println(Files.readAttributes(path, "*"));//          System.out.println();//          System.out.println();//          System.out.println(19_12);//      } catch (IOException e) {//          // TODO Auto-generated catch block//          e.printStackTrace();//      }        //简化的文件读写//      Path path =Paths.get("D:/liebao/debug.log");//      try {//          List<String> readAllLines = Files.readAllLines(path,StandardCharsets.UTF_8);//          for (String entry : readAllLines){//              System.out.println(entry);//          }//          //          byte[] readAllBytes = Files.readAllBytes(path);//          System.out.println(new String(readAllBytes));//          //      } catch (IOException e) {//          // TODO Auto-generated catch block//          e.printStackTrace();//      }        //读取文件的最后几个字节        Path path=Paths.get("D:/liebao/test.txt");        try {            FileChannel open = FileChannel.open(path, StandardOpenOption.READ);            ByteBuffer buffer = ByteBuffer.allocate(1024);            //从第23个字节开始读//          int read = open.read(buffer,open.size()-(open.size()-23));///          open.read(buffer, 2, 10);//          System.out.println(new String(buffer.array()));//          System.out.println(open.size());            //下面的一直报错，不管了先            ByteBuffer[] dsts = new ByteBuffer[12];            System.out.println(dsts.length);            System.out.println(open == null);            open.read(dsts, 1, 3);            System.out.println(dsts[0].array());        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

Paths类的使用：

package com.xinyu.test;import java.io.File;import java.io.IOException;import java.nio.file.DirectoryStream;import java.nio.file.FileVisitResult;import java.nio.file.Files;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.SimpleFileVisitor;import java.nio.file.attribute.BasicFileAttributes;public class PathTest {    public static void main(String[] args) {        // TODO Auto-generated method stub        //Path  基本操作//      Path path = Paths.get("D:/jun");//      System.out.println(path.getFileName());//      System.out.println(path.getFileSystem());//      System.out.println(path.getNameCount());//      System.out.println(path.getParent());        //path 的合并//      Path path = Paths.get("D:/");//      Path resolve = path.resolve("jun");//      System.out.println(resolve.getFileName());//      System.out.println(resolve.getFileSystem());//      System.out.println(resolve.getNameCount());//      System.out.println(resolve.getParent());        //从path到path2的相对路径，输出：..\cebdoc//      Path path = Paths.get("D:/jun");//      Path path2 = Paths.get("D:/cebdoc");//      Path relativize = path.relativize(path2);//      System.out.println(relativize);        //path的一些其他操作，包括startWith,endWith//      Path path = Paths.get("D:/jun");//      Path path2 = Paths.get("D:/cebdoc");//      boolean startsWith = path.startsWith(path2);//      System.out.println(startsWith);        //jdk1.7之后 path 和file是可以相互转换的//      File file = new File("D:/jun");//      Path path3 = file.toPath();//      file =path3.toFile();        //path遍历目录  只输出制定的文件  列出目录下的所有txt文件//      Path path = Paths.get("D:\\jun");//      try {//          DirectoryStream<Path> stream = Files.newDirectoryStream(path,"*.txt");//          for (Path entry : stream){//              System.out.println(entry.getFileName());//          }//      } catch (IOException e) {//          // TODO Auto-generated catch block//          e.printStackTrace();//      }        //path遍历目录，以及目录下的目录  找出是所有的doc文件        class FindJavaVisitor extends SimpleFileVisitor<Path>{            @Override            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {                // TODO Auto-generated method stub                if(file.toString().endsWith(".txt")){                    System.out.println(file.getFileName());                }                return super.visitFile(file, attrs);            }        }        Path path = Paths.get("D:\\software");        try {            Files.walkFileTree(path, new FindJavaVisitor());        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

文件观察服务的使用
WatchService

package com.xinyu.test;import java.io.IOException;import java.nio.file.FileSystem;import java.nio.file.FileSystems;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.StandardWatchEventKinds;import java.nio.file.WatchEvent;import java.nio.file.WatchKey;import java.nio.file.WatchService;public class FilWatchServicesTest {    public static void main(String[] args) {        try {            WatchService watchService = FileSystems.getDefault().newWatchService();            Path path =Paths.get("D:/jun");            path.register(watchService,StandardWatchEventKinds.ENTRY_MODIFY);            while (true) {                WatchKey take = watchService.take();                for (WatchEvent<?> event : take.pollEvents()) {                    if (event.kind() == StandardWatchEventKinds.ENTRY_DELETE) {                        System.out.println("i is delete");                    }                    if (event.kind() == StandardWatchEventKinds.ENTRY_MODIFY) {                        System.out.println("i is modify");                    }                }                take.reset();            }        } catch (IOException | InterruptedException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}

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