java_IO流之FileInputStream和FileOutputStream

看，API说的多简单啊：

FileInputStream 用于读取诸如图像数据之类的原始字节流。要读取字符流，请考虑使用FileReader。

FileOutputStream 用于写入诸如图像数据之类的原始字节的流。要写入字符流，请考虑使用FileWriter。 

FileInputStream与FileOutputStream都是字节流，所以它们都是用来读byte与写byte的。

上例子：

import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class FileStreamTest {public static void main(String[] args) {// writeTest();// readTest_1();// readTest_2();// readTest_3();// copyFile();}// 用字节流文件的读写。private static void copyFile() {FileInputStream fis = null;FileOutputStream fos = null;try {fis = new FileInputStream("F:\\library.rar");fos = new FileOutputStream("F:\\library_copy.rar");byte[] buf = new byte[1024];int len = 0;while ((len = fis.read(buf)) != -1) {fos.write(buf, 0, len);}System.out.println("复制完成");} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {if (fis != null) {fis.close();}} catch (IOException e) {e.printStackTrace();}try {if (fos != null) {fos.close();}} catch (IOException e) {e.printStackTrace();}}}private static void readTest_3() {FileInputStream fis = null;try {fis = new FileInputStream("D:\\log.txt");// available()方法是用于创建一个大小刚刚适合的缓冲区，不过如果资源文件过大的话，很容易造成内在溢出的问题。byte[] buf = new byte[fis.available()];fis.read(buf);System.out.println(new String(buf));} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {if (fis != null) {fis.close();}} catch (IOException e) {e.printStackTrace();}}}private static void readTest_2() {FileInputStream fis = null;try {fis = new FileInputStream("D:\\log.txt");byte[] buf = new byte[1024];int len = 0;while ((len = fis.read(buf)) != -1) {System.out.println(new String(buf, 0, len));}} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {if (fis != null) {fis.close();}} catch (IOException e) {e.printStackTrace();}}}private static void readTest_1() {FileInputStream fis = null;try {fis = new FileInputStream("D:\\log.txt");int b = 0;while ((b = fis.read()) != -1) {System.out.println((char) b);}} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {if (fis != null) {fis.close();}} catch (IOException e) {e.printStackTrace();}}}private static void writeTest() {FileOutputStream fos = null;try {fos = new FileOutputStream("D:\\log.txt");// 字节流操作的是字节数组。字符流操作的是字符数组。fos.write("abcdefg".getBytes());} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {if (fos != null) {fos.close();}} catch (IOException e) {e.printStackTrace();}}}}