Java7中文件IO发生了很大的变化，专门引入了很多新的类：
import java.nio.file.DirectoryStream;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;
在以前的操作中，主要通过File构造一个文件，然后将File作为入参，获取输入流等操作。Api的操作不是很流畅。在新的文件IO中，用Path取代了File，用Files作为一个操作类，并且封装了很多非常实用的Api,看完下面的示例，就会有一个新的理解。
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package filespaths;import org.junit.Test;import java.io.*;import java.net.URI;import java.nio.charset.StandardCharsets;import java.nio.file.FileSystems;import java.nio.file.Files;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.attribute.PosixFilePermission;import java.util.HashSet;import java.util.List;import java.util.Set;import java.util.stream.Stream;/** * @Author kingboy * @Date 2017/4/13 11:05 * @Description Path is used to Path Sample * @email kingboyworld@163.com */public class PathTest { private static String separator = File.separator; /** * 构建Path */ @Test public void constructon(){ //1.Paths Path path = Paths.get("/Users/kingboy/Desktop/"); Path path1 = Paths.get(URI.create("/Users/kingboy/Desktop/")); //2.FileSystems Path path2 = FileSystems.getDefault().getPath("/Users/kingboy/Desktop/"); //3.File Path path3 = new File("/Users/kingboy/Desktop/").toPath(); } /** * 创建一个空文件/文件夹 * @throws IOException */ @Test public void create() throws IOException { //文件夹 Path path = Paths.get("/Users/kingboy/Desktop/hello"); if(!Files.exists(path)){ Files.createDirectory(path); //创建多个目录 //Files.createDirectories(path); } //文件 Path path1 = Paths.get("/Users/kingboy/Desktop/helloFile"); if(Files.exists(path1)){ Files.createFile(path1); } } /** * 文件属性 */ @Test public void getFileProperties() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); System.out.println(Files.getLastModifiedTime(path));//最后修改时间 System.out.println(Files.getOwner(path));//拥有者 System.out.println(Files.getPosixFilePermissions(path));//权限 System.out.println(Files.size(path));//文件大小 } /** * 读取一个文本文件 */ @Test public void readText() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); //通过bufferedReader读取 BufferedReader bufferedReader = Files.newBufferedReader(path, StandardCharsets.UTF_8);//文件编码 StringBuilder sb = new StringBuilder(); String tempString = null; while ((tempString = bufferedReader.readLine())!=null){ sb = sb.append(tempString); } System.out.println(sb); //通过Files方法readAllLines List<String> strings = Files.readAllLines(path); strings.forEach(s -> System.out.print(s)); //输出结果 //adsfasdfasdfadsfasdfgsdfsdffsdfsdf //adsfasdfasdfadsfasdfgsdfsdffsdfsdf } /** * 拿到文件输入流 * @throws IOException */ @Test public void getInputStream() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); InputStream inputStream = Files.newInputStream(path); } /** * 文件写操作 */ @Test public void writeFile() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/writeFile"); BufferedWriter bufferedWriter = Files.newBufferedWriter(path); String str = "write file test"; bufferedWriter.write(str); bufferedWriter.flush(); bufferedWriter.close(); } /** * 遍历一个文件夹 */ @Test public void traverseDirectory() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/"); Stream<Path> list = Files.list(path); list.forEach(p -> { System.out.println(p.getFileName()); }); } /** * 遍历文件树 */ @Test public void traverseTree() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/"); Stream<Path> walk = Files.walk(path); walk.forEach(path1 -> {// System.out.println(path1.getRoot());//根目录 System.out.println(path1.getFileName());//文件名// System.out.println(path1.getParent());//上级目录// System.out.println(path1.getFileSystem());//文件系统 }); //还有种方式Files.walkFileTree() } /** * 文件复制 */ @Test public void copyFile() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); Path path2 = Paths.get("/Users/kingboy/Desktop/hello.txt"); Files.copy(path,path2); } /** * 读取权限见上面示例，设置权限 */ @Test public void writePermission() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); Set<PosixFilePermission> permissionSet = new HashSet<>(); permissionSet.add(PosixFilePermission.GROUP_WRITE); permissionSet.add(PosixFilePermission.OWNER_EXECUTE); Files.setPosixFilePermissions(path,permissionSet); } //还有很多其他操作Api,自己查看方法名，很容易就能分辨出功能。 } |
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