Java编程思想:File类getCanonicalFile()方法,listFile()方法
作者:互联网
import java.io.IOException; import java.util.*; import java.util.regex.Pattern; import java.io.File; import java.io.FilenameFilter; public class Test { public static void main(String[] args) { // DirectoryDemo.test(); ProcessFileTest.test(); ProcessFileTest.test2(); } } /* local():产生由本地目录中的文件构成的File对象数组 walk():产生给定目录下的由整个目录书中所有文件构成的List<File> */ class Directory { public static File[] local(File dir, String regex) { return dir.listFiles(new FilenameFilter() { Pattern pattern = Pattern.compile(regex); @Override public boolean accept(File dir, String name) { return pattern.matcher(name).matches(); } }); } public static class TreeInfo implements Iterable<File>{ public List<File> dirs = new ArrayList<>(); public List<File> files = new ArrayList<>(); public TreeInfo() { } public void addAll(TreeInfo infos) { this.dirs.addAll(infos.dirs); this.files.addAll(infos.files); } @Override public Iterator<File> iterator() { return files.iterator(); } public String toString() { return "dirs: " + PPrint.pformat(dirs) + "\n\nfiles:" + PPrint.pformat(files); } } public static File[] local(String path, String regex) { return local(new File(path),regex); } private static TreeInfo recurseDirs(File startDir, String regex) { TreeInfo result = new TreeInfo(); for (File item : startDir.listFiles()) { if (item.isDirectory()) { result.dirs.add(item); result.addAll(recurseDirs(item,regex)); } else { //这个地方的写法和我之前看到的不太一样 if (item.getName().matches(regex)) { result.files.add(item); } } } return result; } public static TreeInfo walk(String start, String regex) { return recurseDirs(new File(start),regex); } public static TreeInfo walk(File start, String regex) { return recurseDirs(start, regex); } public static TreeInfo walk(String start) { return recurseDirs(new File(start), ".*"); } } class PPrint { public static String pformat(Collection<?> collection) { if (collection.size() == 0) { return "[]"; } StringBuilder result = new StringBuilder("["); for (Object elem : collection) { if (collection.size() != 1) { result.append("\n "); } result.append(elem); } if (collection.size() != 1) { result.append("\n"); } result.append("]"); return result.toString(); } public static void pprint(Collection<?> c) { System.out.println(pformat(c)); } public static void pprint(Object[] objects) { System.out.println(pformat(Arrays.asList(objects))); } } class DirectoryDemo { public static void test() { PPrint.pprint(Directory.walk(".").dirs); } } /* 创建一个工具,它可以在目录中穿行,并且根据Strategy对象来处理这些目录中的文件 书中案例的逻辑: 1.针对上一个案例中walk方法计算出来的所有文件,执行一个策略方法 */ //书中原代码: /* ProcessFiles的工作是:执行查找具有特定扩展名的文件的所有工作 Strategy的工作是:查找到指定的文件后,执行某个指定的算法 */ class ProcessFiles { public interface Strategy { void process(File file); } private Strategy strategy; private String ext; public ProcessFiles(Strategy s,String ext){ this.strategy=s; this.ext=ext; } public void processDirectoryTree(File root) throws IOException { for (File file : Directory.walk(root.getAbsolutePath(), ".*\\." + ext)) { strategy.process(file.getCanonicalFile()); } } public void start(String[] args) { try { if (args.length == 0) { processDirectoryTree(new File(".")); }else{ for (String arg : args) { File fileArg = new File(arg); if (fileArg.isDirectory()) { processDirectoryTree(fileArg); }else{ if(!arg.endsWith("."+ext)) arg+="."+ext; strategy.process(new File(arg).getCanonicalFile()); } } } } catch (IOException e) { e.printStackTrace(); } } } //改进后代码 interface IStrategy{ void process(File file); } class ProcessFiles1 { private IStrategy strategy; private String ext; public ProcessFiles1(IStrategy strategy, String ext) { this.strategy=strategy; this.ext=ext; } public void start(String[] paths){ for(String path:paths){ start(path); } } public void start(String path) { core(new File(path)); } public void start(){ start("."); } private void core(File root){ if(root.isFile()){ strategy.process(root); return; } for (File item : Directory.walk(root.getAbsolutePath(), ".*\\." + ext)) { strategy.process(root); } return; } } class ProcessFileTest { public static void test() { new ProcessFiles(new ProcessFiles.Strategy(){ public void process(File file) { System.out.println(file); } },"java").start(new String[0]); } public static void test2() { new ProcessFiles1(new IStrategy(){ public void process(File file) { try { System.out.println(file.getCanonicalFile()); } catch (IOException e) { e.printStackTrace(); } } },"java").start(); } }
标签:getCanonicalFile,Java,String,void,listFile,static,File,new,public 来源: https://www.cnblogs.com/junjie2019/p/10537995.html