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法律研究如何使用 Java 读取目录中所有文件的数据？
名为 File 的 java.io 包中的类表示系统中的文件或目录（路径名）。此类提供各种方法来对文件/目录执行各种操作。
要获取目录中所有现有文件的列表，此类提供了五种不同的方法来获取特定文件夹中所有文件的详细信息：
- String[] list()
- File[] listFiles()
- String[] list(FilenameFilter filter)
- File[] listFiles(FilenameFilter filter)
- File[] listFiles(FileFilter filter)
listFiles() 方法
此方法返回一个数组，其中包含当前（File）对象表示的路径中所有文件（和目录）的对象（抽象路径）。
以下 Java 程序打印路径 D:\ExampleDirectory 中所有文件的名称、路径和大小。
示例
import java.io.File;
import java.io.IOException;
public class ListOfFiles {
public static void main(String args[]) throws IOException {
//Creating a File object for directory
File directoryPath = new File("D:\ExampleDirectory");
//List of all files and directories
File filesList[] = directoryPath.listFiles();
System.out.println("List of files and directories in the specified directory:");
for(File file : filesList) {
System.out.println("File name: "+file.getName());
System.out.println("File path: "+file.getAbsolutePath());
System.out.println("Size :"+file.getTotalSpace());
System.out.println(" ");
}
}
}输出
List of files and directories in the specified directory: File name: SampleDirectory1 File path: D:\ExampleDirectory\SampleDirectory1 Size :262538260480 File name: SampleDirectory2 File path: D:\ExampleDirectory\SampleDirectory2 Size :262538260480 File name: SampleFile1.txt File path: D:\ExampleDirectory\SampleFile1.txt Size :262538260480 File name: SampleFile2.txt File path: D:\ExampleDirectory\SampleFile2.txt Size :262538260480 File name: SapmleFile3.txt File path: D:\ExampleDirectory\SapmleFile3.txt Size :262538260480
读取目录中所有文件的内容
要读取特定目录中所有文件的内容，请使用上述方法将所有文件的文件对象作为数组获取，然后使用 Scanner 类及其方法读取数组中每个文件对象的内容。
示例
import java.io.File;
import java.io.IOException;
import java.util.Scanner;
public class ListOfFiles {
public static void main(String args[]) throws IOException {
//Creating a File object for directory
File directoryPath = new File("D:\Demo");
//List of all files and directories
File filesList[] = directoryPath.listFiles();
System.out.println("List of files and directories in the specified directory:");
Scanner sc = null;
for(File file : filesList) {
System.out.println("File name: "+file.getName());
System.out.println("File path: "+file.getAbsolutePath());
System.out.println("Size :"+file.getTotalSpace());
//Instantiating the Scanner class
sc= new Scanner(file);
String input;
StringBuffer sb = new StringBuffer();
while (sc.hasNextLine()) {
input = sc.nextLine();
sb.append(input+" ");
}
System.out.println("Contents of the file: "+sb.toString());
System.out.println(" ");
}
}
}输出
List of files and directories in the specified directory: File name: samplefile1.txt File path: D:\Demo\samplefile1.txt Size :262538260480 Contents of the file: Contents of the sample file 1 File name: samplefile2.txt File path: D:\Demo\samplefile2.txt Size :262538260480 Contents of the file: Contents of the sample file 2 File name: samplefile3.txt File path: D:\Demo\samplefile3.txt Size :262538260480 Contents of the file: Contents of the sample file 3 File name: samplefile4.txt File path: D:\Demo\samplefile4.txt Size :262538260480 Contents of the file: Contents of the sample file 4 File name: samplefile5.txt File path: D:\Demo\samplefile5.txt Size :262538260480 Contents of the file: Contents of the sample file 5
更新于: 2019年9月11日
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