IO流從入門到精通（五）

目錄

CommonsIO的使用

1.環境搭建

2.使用案例

2.1 擷取檔案大小

2.2 列出子孫級目錄 

2.3 讀取檔案内容 

2.4 寫出檔案内容 

2.5 拷貝檔案 

CommonsIO的使用

1.環境搭建

引入jar包

2.使用案例

2.1 擷取檔案大小

/**
 * 擷取檔案大小
 *
 */
public class CIOTest01 {

	public static void main(String[] args) {
		//檔案大小
		long len =FileUtils.sizeOf(new File("src/com/sxt/commons/CIOTest01.java"));
		System.out.println(len);
		//目錄大小
		len = FileUtils.sizeOf(new File("D:/java300/IO_study04"));
		System.out.println(len);
	}

}
           

2.2 列出子孫級目錄 

/**
 * 列出子孫級
 *
 */
public class CIOTest02 {

	public static void main(String[] args) {
		Collection<File> files =FileUtils.listFiles(new File("D:\\java300\\IO_study04"),
				EmptyFileFilter.NOT_EMPTY, null);
		for (File file : files) {
			System.out.println(file.getAbsolutePath());
		}
		System.out.println("---------------------");
		 files =FileUtils.listFiles(new File("D:\\java300\\IO_study04"),
					EmptyFileFilter.NOT_EMPTY, DirectoryFileFilter.INSTANCE);
		for (File file : files) {
			System.out.println(file.getAbsolutePath());
		}
		System.out.println("---------------------");
		 files =FileUtils.listFiles(new File("D:\\java300\\IO_study04"),
					new SuffixFileFilter("java"), DirectoryFileFilter.INSTANCE);
		for (File file : files) {
			System.out.println(file.getAbsolutePath());
		}
		System.out.println("---------------------");
		 files =FileUtils.listFiles(new File("D:\\java300\\IO_study04"),
					FileFilterUtils.or(new SuffixFileFilter("java"),
							new SuffixFileFilter("class"),EmptyFileFilter.EMPTY), DirectoryFileFilter.INSTANCE);
		for (File file : files) {
			System.out.println(file.getAbsolutePath());
		}
		
		System.out.println("---------------------");
		 files =FileUtils.listFiles(new File("D:\\java300\\IO_study04"),
					FileFilterUtils.and(new SuffixFileFilter("java"),
							EmptyFileFilter.NOT_EMPTY), DirectoryFileFilter.INSTANCE);
		for (File file : files) {
			System.out.println(file.getAbsolutePath());
		}
	}

}
           

2.3 讀取檔案内容 

/**
 * 讀取内容
 *
 */
public class CIOTest03 {

	public static void main(String[] args) throws IOException {
		//讀取檔案
		String msg =FileUtils.readFileToString(new File("emp.txt"),"UTF-8");
		System.out.println(msg);
		byte[] datas = FileUtils.readFileToByteArray(new File("emp.txt"));
		System.out.println(datas.length);
		
		//逐行讀取
		 List<String> msgs= FileUtils.readLines(new File("emp.txt"),"UTF-8");
		 for (String string : msgs) {
			System.out.println(string);
		}
		LineIterator it =FileUtils.lineIterator(new File("emp.txt"),"UTF-8");
		while(it.hasNext()) {
			System.out.println(it.nextLine());
		}
		
	}

}
           

2.4 寫出檔案内容 

/**
 * 寫出内容
 *
 */
public class CIOTest04 {

	public static void main(String[] args) throws IOException {
		//寫出檔案
		FileUtils.write(new File("happy.sxt"), "學習是一件偉大的事業\r\n","UTF-8");
		FileUtils.writeStringToFile(new File("happy.sxt"), "學習是一件辛苦的事業\r\n","UTF-8",true);
		FileUtils.writeByteArrayToFile(new File("happy.sxt"), "學習是一件幸福的事業\r\n".getBytes("UTF-8"),true);
		
		//寫出清單
		List<String> datas =new ArrayList<String>();
		datas.add("馬雲");
		datas.add("馬化騰");
		datas.add("弼馬溫");
		
		FileUtils.writeLines(new File("happy.sxt"), datas,"。。。。。",true);
	}

}
           

2.5 拷貝檔案 

/**
 * 拷貝
 *
 */
public class CIOTest05 {

	public static void main(String[] args) throws IOException {
		//複制檔案
		//FileUtils.copyFile(new File("p.png"),new File("p-copy.png"));
		//複制檔案到目錄
		//FileUtils.copyFileToDirectory(new File("p.png"),new File("lib"));
		//複制目錄到目錄
		//FileUtils.copyDirectoryToDirectory(new File("lib"),new File("lib2"));
		//複制目錄
		//FileUtils.copyDirectory(new File("lib"),new File("lib2"));
		//拷貝URL内容
		//String url = "https://pic2.zhimg.com/v2-7d01cab20858648cbf62333a7988e6d0_qhd.jpg";
		//FileUtils.copyURLToFile(new URL(url), new File("marvel.jpg"));
		String datas =IOUtils.toString(new URL("http://www.163.com"), "gbk");
		System.out.println(datas);
	}

}