io read/write

GZipFileWriteTest.java

import static org.junit.Assert.assertEquals;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

import org.apache.commons.io.IOUtils;
import org.junit.Test;

public class GZipFileWriteTest {

	@Test
	public void testWriteGZip() throws FileNotFoundException, IOException {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		FileInputStream in = new FileInputStream("e:/tmp/filter.io");
		IOUtils.copy(in, out);
		in.close();

		FileOutputStream fileOut = new FileOutputStream("e:/tmp/gzip.filter.io");
		GZIPOutputStream gzipout = new GZIPOutputStream(fileOut);
		IOUtils.write(out.toByteArray(), gzipout);
		gzipout.finish(); // 可以不写，close会调用finish
		gzipout.flush();
		gzipout.close();// 必须 http://snowolf.iteye.com/blog/643010
		fileOut.close();
	}

	@Test
	public void testReadGZip() throws FileNotFoundException, IOException {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		FileInputStream fileIn = new FileInputStream("e:/tmp/gzip.filter.io");
		GZIPInputStream gzipIn = new GZIPInputStream(fileIn);
		IOUtils.copy(gzipIn, out);
		gzipIn.close();
		fileIn.close();

		FileOutputStream fileOut = new FileOutputStream("e:/tmp/filter.io2");
		IOUtils.copy(new ByteArrayInputStream(out.toByteArray()), fileOut);
		fileOut.close();
	}
	
	@Test
	public void testOpenFile() throws IOException{
		String file = "e:/tmp/open-filter.io";
		
		BufferedWriter writer = new BufferedWriter(new FileWriter(file));
		writer.write("abc");
		writer.close();
		
		BufferedReader reader = new BufferedReader(new FileReader(file));
		assertEquals("abc", reader.readLine());
		reader.close();
		
		FileOutputStream fileOut = new FileOutputStream(file);
		fileOut.close();
		
		BufferedReader readerEmpty = new BufferedReader(new FileReader(file));
		assertEquals("", readerEmpty.readLine());
		readerEmpty.close();
	}
	
}