Java7中文件IO發(fā)生了很大的變化，專門引入了很多新的類：
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，主要通過File構(gòu)造一個文件，然后將File作為入?yún)?，獲取輸入流等操作。Api的操作不是很流暢。在新的文件IO中，用Path取代了File，用Files作為一個操作類，并且封裝了很多非常實用的Api,看完下面的示例，就會有一個新的理解。
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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 [email protected] */public class PathTest { private static String separator = File.separator; /** * 構(gòu)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(); } /** * 創(chuàng)建一個空文件/文件夾 * @throws IOException */ @Test public void create() throws IOException { //文件夾 Path path = Paths.get("/Users/kingboy/Desktop/hello"); if(!Files.exists(path)){ Files.createDirectory(path); //創(chuàng)建多個目錄 //Files.createDirectories(path); } //文件 Path path1 = Paths.get("/Users/kingboy/Desktop/helloFile"); if(Files.exists(path1)){ Files.createFile(path1); } } /** * 文件屬性 */ @Test public void getFileProperties() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); System.out.println(Files.getLastModifiedTime(path));//最后修改時間 System.out.println(Files.getOwner(path));//擁有者 System.out.println(Files.getPosixFilePermissions(path));//權(quán)限 System.out.println(Files.size(path));//文件大小 } /** * 讀取一個文本文件 */ @Test public void readText() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); //通過bufferedReader讀取 BufferedReader bufferedReader = Files.newBufferedReader(path, StandardCharsets.UTF_8);//文件編碼 StringBuilder sb = new StringBuilder(); String tempString = null; while ((tempString = bufferedReader.readLine())!=null){ sb = sb.append(tempString); } System.out.println(sb); //通過Files方法readAllLines List<String> strings = Files.readAllLines(path); strings.forEach(s -> System.out.print(s)); //輸出結(jié)果 //adsfasdfasdfadsfasdfgsdfsdffsdfsdf //adsfasdfasdfadsfasdfgsdfsdffsdfsdf } /** * 拿到文件輸入流 * @throws IOException */ @Test public void getInputStream() throws IOException { Path path = Paths.get("/Users/kingboy/Desktop/text.txt"); InputStream inputStream = Files.newInputStream(path); } /** * 文件寫操作 */ @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(); } /** * 遍歷一個文件夾 */ @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()); }); } /** * 遍歷文件樹 */ @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());//根目錄 System.out.println(path1.getFileName());//文件名// System.out.println(path1.getParent());//上級目錄// System.out.println(path1.getFileSystem());//文件系統(tǒng) }); //還有種方式Files.walkFileTree() } /** * 文件復(fù)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); } /** * 讀取權(quán)限見上面示例，設(shè)置權(quán)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); } //還有很多其他操作Api,自己查看方法名，很容易就能分辨出功能。 } |
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