13-3 IO流 ---- 节点流(或文件流)（3）FileInputOutputSteamTest

测试FileInputStream和FileOutputStream的使用
结论：
1.对于文本文件(.txt,.java,.c,.cpp)，使用字符流处理
2.对于非文本文件(.jpg,.mp3,.mp4,.avi,.doc,.ppt,…)，使用字节流处理

代码：

package java3;

import org.junit.Test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

//测试FileInputStream和FileOutputStream的使用
public class FileInputOutputSteamTest {

    //使用字节流FileInputStream处理文本文件，可能出现乱码。
    @Test
    public void testFileInputSteam() {
        FileInputStream fis = null;
        try {
            //1.造文件
            File file = new File("hello.txt");

            //2.造流
            fis = new FileInputStream(file);

            //3.读数据
            byte[] buffer = new byte[3];
            int len;//记录每次读取的字节的个数
            while ((len = fis.read(buffer)) != -1) {
                String str = new String(buffer, 0, len);
                System.out.print(str);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                try {
                    //4.关闭资源
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }
        }

    }


    //实现对图片的复制操作
    @Test
    public void testFileInputOutputSteam() {
        FileInputStream fis = null;
        FileOutputStream fos = null;

        try {
            File srcFile = new File("爱情与友情.jpg");
            File destFile = new File("爱情与友情1.jpg");


            fis = new FileInputStream(srcFile);
            fos = new FileOutputStream(destFile);

            //复制的过程
            byte[] buffer = new byte[5];
            int len;
            while ((len = fis.read(buffer)) != -1) {
                fos.write(buffer, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fos != null) {
                //
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }
    }


    //指定路径下文件的复制
    public void copyFile(String srcPath,String destPath){
        FileInputStream fis = null;
        FileOutputStream fos = null;

        try {
            File srcFile = new File(srcPath);
            File destFile = new File(destPath);


            fis = new FileInputStream(srcFile);
            fos = new FileOutputStream(destFile);

            //复制的过程
            byte[] buffer = new byte[2];
            int len;
            while ((len = fis.read(buffer)) != -1) {
                fos.write(buffer, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }
    }



    @Test
    public void testCopyFile(){
        long start = System.currentTimeMillis();

        String srcPath = "爱情与友情.jpg";
        String destPath = "爱情与友情2.jpg";
        copyFile(srcPath,destPath);

        long end = System.currentTimeMillis();

        System.out.println("复制操作花费的时间为: "+ (end - start));
    }
}