2024年11月14日
Java 中的 StandardCopyOption (Java SE 22 & JDK 22) 及其示例。
您将找到大多数 StandardCopyOption 方法的代码示例。
注解 :
- 本文可能使用了翻译软件以方便阅读。 另请查看英文原文。
简介
定义标准复印选项。 (机器翻译)
Annotation :
- Most of the code examples in this page are run on Windows.
final var source = Path.of("R:", "java-work", "src.txt");
System.out.println(source); // R:\java-work\src.txt
final var target = Path.of("R:", "java-work", "dst.txt");
System.out.println(target); // R:\java-work\dst.txt
Files.writeString(source, "abc");
Files.writeString(target, "XYZ");
System.out.println(Files.readString(source)); // abc
System.out.println(Files.readString(target)); // XYZ
try {
System.out.println("-- copy --");
Files.copy(source, target);
} catch (FileAlreadyExistsException e) {
System.out.println("FileAlreadyExistsException! : " + e.getMessage());
}
// Result
// ↓
//-- copy --
//FileAlreadyExistsException! : R:\java-work\dst.txt
System.out.println(Files.readString(source)); // abc
System.out.println(Files.readString(target)); // XYZ
Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);
System.out.println(Files.readString(source)); // abc
System.out.println(Files.readString(target)); // abc
Enum Constants
ATOMIC_MOVE
将文件移动作为原子文件系统操作。 (机器翻译)
final var source = Path.of("D:", "java-work", "src.txt");
System.out.println(source); // D:\java-work\src.txt
final var target = Path.of("R:", "java-work", "dst.txt");
System.out.println(target); // R:\java-work\dst.txt
Files.writeString(source, "abc");
System.out.println(Files.readString(source)); // abc
System.out.println(Files.exists(target)); // false
try {
System.out.println("-- move --");
Files.move(source, target, StandardCopyOption.ATOMIC_MOVE);
} catch (AtomicMoveNotSupportedException e) {
System.out.println("AtomicMoveNotSupportedException!");
}
// Result
// ↓
//-- move --
//AtomicMoveNotSupportedException!
System.out.println(Files.readString(source)); // abc
System.out.println(Files.exists(target)); // false
Files.move(source, target);
System.out.println(Files.exists(source)); // false
System.out.println(Files.readString(target)); // abc
COPY_ATTRIBUTES
将属性复制到新文件。 (机器翻译)
// The following code runs on Linux.
System.out.println(System.getProperty("os.name")); // Linux
final var source = Path.of("src.txt");
System.out.println(source); // src.txt
Files.createFile(source);
Files.setLastModifiedTime(source, FileTime.fromMillis(0));
System.out.println(Files.getLastModifiedTime(source)); // 1970-01-01T00:00:00Z
final var target1 = Path.of("dst1.txt");
System.out.println(target1); // dst1.txt
final var target2 = Path.of("dst2.txt");
System.out.println(target2); // dst2.txt
Files.copy(source, target1);
Files.copy(source, target2, StandardCopyOption.COPY_ATTRIBUTES);
System.out.println(Files.getLastModifiedTime(target1)); // 2024-11-06T06:28:38.017333603Z
System.out.println(Files.getLastModifiedTime(target2)); // 1970-01-01T00:00:00Z
REPLACE_EXISTING
如果存在则替换现有文件。 (机器翻译)
final var source = Path.of("R:", "java-work", "src.txt");
System.out.println(source); // R:\java-work\src.txt
final var target = Path.of("R:", "java-work", "dst.txt");
System.out.println(target); // R:\java-work\dst.txt
Files.writeString(source, "abc");
Files.writeString(target, "XYZ");
System.out.println(Files.readString(source)); // abc
System.out.println(Files.readString(target)); // XYZ
try {
System.out.println("-- copy --");
Files.copy(source, target);
} catch (FileAlreadyExistsException e) {
System.out.println("FileAlreadyExistsException! : " + e.getMessage());
}
// Result
// ↓
//-- copy --
//FileAlreadyExistsException! : R:\java-work\dst.txt
System.out.println(Files.readString(source)); // abc
System.out.println(Files.readString(target)); // XYZ
Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);
System.out.println(Files.readString(source)); // abc
System.out.println(Files.readString(target)); // abc
Methods
static StandardCopyOption valueOf (String name)
返回具有指定名称的此类的枚举常量。 (机器翻译)
final var ret1 = StandardCopyOption.valueOf("REPLACE_EXISTING");
System.out.println(ret1); // REPLACE_EXISTING
final var ret2 = StandardCopyOption.valueOf("COPY_ATTRIBUTES");
System.out.println(ret2); // COPY_ATTRIBUTES
static StandardCopyOption[] values ()
返回一个包含此枚举类常量的数组，按照声明的顺序排列。 (机器翻译)
for (final var value : StandardCopyOption.values()) {
System.out.println(value);
}
// Result
// ↓
//REPLACE_EXISTING
//COPY_ATTRIBUTES
//ATOMIC_MOVE
Methods declared in Enum
clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf
请参阅下面的链接。