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Commit 6804e62

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author
jim.deng
committed
2020年12月11日14:57:40
1 parent 4682ea8 commit 6804e62

13 files changed

Lines changed: 437 additions & 37 deletions

‎AddAndSubtractPaths.java‎

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// files/AddAndSubtractPaths.java
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// (c)2020 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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import java.nio.file.*;
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import java.io.IOException;
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public class AddAndSubtractPaths {
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static Path base = Paths.get("..", "..", "..")
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.toAbsolutePath()
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.normalize();
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static void show(int id, Path result) {
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if(result.isAbsolute())
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System.err.println("(" + id + ")[relativize] " +
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base.relativize(result));
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else
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System.err.println("(" + id + ") " + result);
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try {
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System.err.println("RealPath: "
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+ result.toRealPath());
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} catch(IOException e) {
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System.err.println(e);
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}
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}
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public static void main(String[] args) {
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System.err.println(System.getProperty("os.name"));
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System.err.println(base);
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Path p = Paths.get("AddAndSubtractPaths.java")
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.toAbsolutePath();
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show(1, p);
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Path convoluted = p.getParent().getParent()
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.resolve("strings")
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.resolve("..")
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.resolve(p.getParent().getFileName());
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show(2, convoluted);
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show(3, convoluted.normalize());
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Path p2 = Paths.get("..", "..");
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show(4, p2);
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show(5, p2.normalize());
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show(6, p2.toAbsolutePath().normalize());
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Path p3 = Paths.get(".").toAbsolutePath();
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Path p4 = p3.resolve(p2);
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show(7, p4);
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show(8, p4.normalize());
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Path p5 = Paths.get("").toAbsolutePath();
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show(9, p5);
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show(10, p5.resolveSibling("strings"));
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show(11, Paths.get("nonexistent"));
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}
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}
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/* Output:
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Windows 10
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C:\Users\Bruce\Documents\GitHub
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(1)r on-
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java\ExtractedExamples\files\AddAndSubtractPaths.java
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RealPath: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files\AddAndSubtractPaths.java
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(2)r on-java\ExtractedExamples\strings\..\files
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RealPath: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files
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(3)r on-java\ExtractedExamples\files
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RealPath: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files
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(4) ..\..
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RealPath: C:\Users\Bruce\Documents\GitHub\on-java
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(5) ..\..
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RealPath: C:\Users\Bruce\Documents\GitHub\on-java
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(6)r on-java
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RealPath: C:\Users\Bruce\Documents\GitHub\on-java
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(7)r on-java\ExtractedExamples\files\.\..\..
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RealPath: C:\Users\Bruce\Documents\GitHub\on-java
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(8)r on-java
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RealPath: C:\Users\Bruce\Documents\GitHub\on-java
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(9)r on-java\ExtractedExamples\files
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RealPath: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files
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(10)r on-java\ExtractedExamples\strings
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RealPath: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\strings
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(11) nonexistent
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java.nio.file.NoSuchFileException:
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C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files\nonexistent
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*/

‎Directories.java‎

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// files/Directories.java
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// (c)2020 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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import java.util.*;
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import java.nio.file.*;
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//import onjava.RmDir;
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public class Directories {
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static Path test = Paths.get("test");
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static String sep =
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FileSystems.getDefault().getSeparator();
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static List<String> parts =
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Arrays.asList("foo", "bar", "baz", "bag");
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static Path makeVariant() {
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Collections.rotate(parts, 1);
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return Paths.get("test", String.join(sep, parts));
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}
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static void refreshTestDir() throws Exception {
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if(Files.exists(test))
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RmDir.rmdir(test);
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if(!Files.exists(test))
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Files.createDirectory(test);
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}
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public static void
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main(String[] args) throws Exception {
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refreshTestDir();
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Files.createFile(test.resolve("Hello.txt"));
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Path variant = makeVariant();
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// Throws exception (too many levels):
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try {
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Files.createDirectory(variant);
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} catch(Exception e) {
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System.err.println("Nope, that doesn't work.");
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}
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populateTestDir();
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Path tempdir =
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Files.createTempDirectory(test, "DIR_");
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Files.createTempFile(tempdir, "pre", ".non");
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Files.newDirectoryStream(test)
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.forEach(System.out::println);
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System.err.println("*********");
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Files.walk(test).forEach(System.out::println);
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}
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static void populateTestDir() throws Exception {
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for(int i = 0; i < parts.size(); i++) {
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Path variant = makeVariant();
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if(!Files.exists(variant)) {
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Files.createDirectories(variant);
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Files.copy(Paths.get("Directories.java"),
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variant.resolve("File.txt"));
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Files.createTempFile(variant, null, null);
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}
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}
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}
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}
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/* Output:
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Nope, that doesn't work.
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test\bag
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test\bar
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test\baz
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test\DIR_5142667942049986036
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test\foo
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test\Hello.txt
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*********
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test
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test\bag
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test\bag\foo
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test\bag\foo\bar
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test\bag\foo\bar\baz
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test\bag\foo\bar\baz\8279660869874696036.tmp
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test\bag\foo\bar\baz\File.txt
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test\bar
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test\bar\baz
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test\bar\baz\bag
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test\bar\baz\bag\foo
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test\bar\baz\bag\foo\1274043134240426261.tmp
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test\bar\baz\bag\foo\File.txt
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test\baz
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test\baz\bag
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test\baz\bag\foo
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test\baz\bag\foo\bar
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test\baz\bag\foo\bar\6130572530014544105.tmp
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test\baz\bag\foo\bar\File.txt
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test\DIR_5142667942049986036
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test\DIR_5142667942049986036\pre7704286843227113253.non
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test\foo
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test\foo\bar
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test\foo\bar\baz
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test\foo\bar\baz\bag
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test\foo\bar\baz\bag\5412864507741775436.tmp
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test\foo\bar\baz\bag\File.txt
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test\Hello.txt
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*/

‎PartsOfPaths.java‎

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// files/PartsOfPaths.java
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// (c)2020 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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import java.nio.file.*;
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7+
public class PartsOfPaths {
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public static void main(String[] args) {
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System.err.println(System.getProperty("os.name"));
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Path p = Paths.get("PartsOfPaths.java").toAbsolutePath();
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System.err.println(p);
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System.err.println(Files.exists(p));
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for(int i = 0; i < p.getNameCount(); i++)
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System.err.println("第" + i + "部分--"+p.getName(i));
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System.err.println("ends with '.java': " +
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p.endsWith(".java"));
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for(Path pp : p) {
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System.err.print(pp + ": ");
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System.err.print(p.startsWith(pp) + " : ");
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System.err.println(p.endsWith(pp));
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}
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System.err.println("Starts with " + p.getRoot() +
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" " + p.startsWith(p.getRoot()));
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}
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}
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/* Output:
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Windows 10
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Users
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Bruce
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Documents
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GitHub
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on-java
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ExtractedExamples
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files
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PartsOfPaths.java
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ends with '.java': false
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Users: false : false
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Bruce: false : false
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Documents: false : false
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GitHub: false : false
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on-java: false : false
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ExtractedExamples: false : false
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files: false : false
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PartsOfPaths.java: false : true
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Starts with C:\ true
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*/

‎PathInfo.java‎

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// files/PathInfo.java
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// (c)2020 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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import java.nio.file.*;
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import java.net.URI;
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import java.io.File;
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import java.io.IOException;
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public class PathInfo {
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static void show(String id, Object p) {
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System.err.println(id + ": " + p);
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}
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static void info(Path p) {
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show("toString", p);
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show("Exists", Files.exists(p));
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show("RegularFile", Files.isRegularFile(p));
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show("Directory", Files.isDirectory(p));
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show("Absolute", p.isAbsolute());
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show("FileName", p.getFileName());
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show("Parent", p.getParent());
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show("Root", p.getRoot());
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System.err.println("******************");
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}
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public static void main(String[] args) {
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System.err.println(System.getProperty("os.name"));
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28+
info(Paths.get(
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"C:", "path", "to", "nowhere", "NoFile.txt"));
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Path p = Paths.get("PathInfo.java");
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info(p);
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34+
Path ap = p.toAbsolutePath();
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info(ap);
36+
37+
info(ap.getParent());
38+
39+
try {
40+
info(p.toRealPath());
41+
} catch(IOException e) {
42+
System.err.println(e);
43+
}
44+
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URI u = p.toUri();
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System.err.println("URI: " + u);
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48+
Path puri = Paths.get(u);
49+
System.err.println(Files.exists(puri));
50+
51+
File f = ap.toFile(); // Don't be fooled
52+
}
53+
}
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/* Output:
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Windows 10
56+
toString: C:\path\to\nowhere\NoFile.txt
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Exists: false
58+
RegularFile: false
59+
Directory: false
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Absolute: true
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FileName: NoFile.txt
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Parent: C:\path\to\nowhere
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Root: C:\
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******************
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toString: PathInfo.java
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Exists: true
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RegularFile: true
68+
Directory: false
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Absolute: false
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FileName: PathInfo.java
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Parent: null
72+
Root: null
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******************
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toString: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files\PathInfo.java
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Exists: true
77+
RegularFile: true
78+
Directory: false
79+
Absolute: true
80+
FileName: PathInfo.java
81+
Parent: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files
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Root: C:\
84+
******************
85+
toString: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files
87+
Exists: true
88+
RegularFile: false
89+
Directory: true
90+
Absolute: true
91+
FileName: files
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Parent: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples
94+
Root: C:\
95+
******************
96+
toString: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files\PathInfo.java
98+
Exists: true
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RegularFile: true
100+
Directory: false
101+
Absolute: true
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FileName: PathInfo.java
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Parent: C:\Users\Bruce\Documents\GitHub\on-
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java\ExtractedExamples\files
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Root: C:\
106+
******************
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URI: file:///C:/Users/Bruce/Documents/GitHub/on-
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java/ExtractedExamples/files/PathInfo.java
109+
true
110+
*/

‎files/AddAndSubtractPaths.java‎

Lines changed: 6 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,21 +10,25 @@ public class AddAndSubtractPaths {
1010
.toAbsolutePath()
1111
.normalize();
1212
static void show(int id, Path result) {
13+
// System.err.println("AAA*---"+result);
1314
if(result.isAbsolute())
14-
System.err.println("(" + id + ")r " +
15+
System.err.println("(" + id + ")[relativize] " +
1516
base.relativize(result));
1617
else
1718
System.err.println("(" + id + ") " + result);
1819
try {
1920
System.err.println("RealPath: "
2021
+ result.toRealPath());
2122
} catch(IOException e) {
22-
System.err.println(e);
23+
System.err.println("--------------------------"+e);
2324
}
25+
System.err.println();
26+
System.err.println();
2427
}
2528
public static void main(String[] args) {
2629
System.err.println(System.getProperty("os.name"));
2730
System.err.println(base);
31+
2832
Path p = Paths.get("AddAndSubtractPaths.java")
2933
.toAbsolutePath();
3034
show(1, p);

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