File Demo

package org.springside.examples.showcase.utilities.io;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.StringWriter;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import junit.framework.Assert;

import org.apache.commons.io.FileSystemUtils;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.input.ReaderInputStream;
import org.apache.commons.io.output.WriterOutputStream;
import org.junit.Test;
import org.springside.modules.utils.Exceptions;

import com.google.common.base.Charsets;

public class IODemo {

	@Test
	public void workWithFileContent() {
		File file = new File("woop.txt");
		try {
			// text -> file
			FileUtils.write(file, "Hey sailor!\nHaha\n", "UTF-8");

			// file -> outputstream
			System.out.println("copy File to outputstream:");
			FileUtils.copyFile(file, System.out);

			// file -> string
			System.out.println("File to String:");
			System.out.println(FileUtils.readFileToString(file, "UTF-8"));

			// file -> list<string>
			System.out.println("File to List<String>:");
			List<String> lines = FileUtils.readLines(file, "UTF-8");
			for (String string : lines) {
				System.out.println(string);
			}
		} catch (IOException e) {
			Exceptions.unchecked(e);
		}
	}

	/*
	 * Input/OutputStream
	 */
	@Test
	public void workWithStream() {
		InputStream in = null;
		try {
			String content = "Stream testing";

			// String - > InputStream
			in = IOUtils.toInputStream(content, "UTF-8");

			// String - > OutputStream
			System.out.println("String to OutputStram:");
			IOUtils.write(content, System.out, "UTF-8");

			// InputStream/Reader -> String
			System.out.println("\nInputStram to String:");
			System.out.println(IOUtils.toString(in, "UTF-8"));

			// InputStream/Reader -> OutputStream/Writer
			InputStream in2 = IOUtils.toInputStream(content);
			System.out.println("InputStram to OutputStream:");
			IOUtils.copy(in2, System.out);

			// InputStream ->Reader
			InputStreamReader reader = new InputStreamReader(in, Charsets.UTF_8);
			// Reader->InputStream
			ReaderInputStream in3 = new ReaderInputStream(reader,
					Charsets.UTF_8);

			// OutputStream ->Writer
			OutputStreamWriter writer = new OutputStreamWriter(System.out,
					Charsets.UTF_8);
			// Writer->OutputStream
			WriterOutputStream out2 = new WriterOutputStream(writer,
					Charsets.UTF_8);

			// 收集Writer的内容到String.
			StringWriter sw = new StringWriter();
			sw.write("\nI am String writer");
			System.out.println(sw.toString());

		} catch (IOException e) {
			Exceptions.unchecked(e);
		} finally {
			// 安静的关闭Stream
			IOUtils.closeQuietly(in);

		}
	}

	@Test
	public void workWithFileAndDir() {
		try {
			long size = FileSystemUtils.freeSpaceKb("C:");
			System.out.println("c盘空闲大小:" + (size / 1024 / 1024) + "g");
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Test
	public void copyFile() {

		File srcFile = new File("c:\\test.txt");
		File destFile = new File("d:\\test.txt");
		try {
			FileUtils.deleteQuietly(destFile);
			if (!srcFile.exists())
				srcFile.createNewFile();
			FileUtils.copyFile(srcFile, destFile);
			Assert.assertTrue(destFile.exists());
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Test
	public void writerFile() {
		File f = new File("c:\\test1.txt");
		try {
			List<String> list = new ArrayList<String>();
			list.add("test1");
			list.add("1");
			FileUtils.writeLines(f, list); // 写集合
			// FileUtils.writeStringToFile(f, data); //写字符串
			System.out.println("写成功");
		} catch (IOException ex) {
			ex.printStackTrace();
		}
	}

	@Test
	public void testFileURL() {
		File f = new File("c:\\test2.txt");
		URL url;
		try {
			url = new URL("http://www.iteye.com/topic/575996");
			FileUtils.copyURLToFile(url, f);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	@Test
	public void testJDKFile() {
		File f = new File("c:\\test2.txt");
		try {
			System.out.println(f.getCanonicalFile());
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}