Path;Paths和Files;FileVisitor

package filet;

import java.io.FileOutputStream;
import java.nio.file.FileStore;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

public class FileTest {

	public static void main(String[] args) throws Exception {

		//复制文件
		Files.copy(Paths.get("C:\\Users\\Administrator\\Desktop\\a.txt"),new FileOutputStream("C:\\Users\\Administrator\\Desktop\\test.txt"));

		//一次性得到fileTest的所有文件
		List<String> lines = Files.readAllLines(Paths.get("C:\\Users\\Administrator\\Desktop\\a.txt"));
		System.out.println(lines);

		//复制文件
				Files.copy(Paths.get("C:\\Users\\Administrator\\Desktop\\dd.png"),new FileOutputStream("C:\\Users\\Administrator\\Desktop\\ddtest.png"));

				List<String> pome = new ArrayList<>();
				pome.add("aadddd");
				pome.add("dfgfdf");
				//直接将多个字符串内容写入指定文件
				Files.write(Paths.get("C:\\Users\\Administrator\\Desktop\\a.txt"),pome);
				//使用java8新增的Stream API读取文件内容
				Files.list(Paths.get(".")).forEach(path->System.out.println(path));

				Files.lines(Paths.get("C:\\Users\\Administrator\\Desktop\\a.txt")).forEach(line->System.out.println(line));
				//判断c盘可用空间
				FileStore csStore = Files.getFileStore(Paths.get("C:"));

				System.out.println("C共有空间:"+csStore.getTotalSpace());
				System.out.println("C可用空间:"+csStore.getUsableSpace());

	}

}

　　使用FileVisitor遍历文件和目录

package filet;

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 FileVisitorTest {

    public static void main(String[] args) throws Exception {

        //遍历该盘下的所有文件和子目录
        Files.walkFileTree(Paths.get("C:\\Users\\Administrator\\Desktop"), new     SimpleFileVisitor<Path>() {

            //访问文件时触发该方法
            @Override
            public FileVisitResult visitFile(Path file,BasicFileAttributes attrs) {
                System.out.println("正在访问"+file+"文件");
                //找到了File
                if(file.endsWith("a.txt")) {
                    System.out.println("已找到目标文件");
                    return FileVisitResult.TERMINATE;
                }
                return FileVisitResult.CONTINUE;

            }

            //开始访问目标目录时触发该方法
            @Override
            public FileVisitResult preVisitDirectory(Path dir,BasicFileAttributes attrs) {

                System.out.println("正在访问:"+dir+"路径");

                return FileVisitResult.CONTINUE;

            }

        });

    }

}