package lianxi1;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import org.junit.Test;public class TestFileInputStream {    @Test //要读取的文件一定要存在   public void test1(){    FileInputStream fis = null;    try {            File file1 = new File("d:\\io\\helloworld.txt");            fis = new FileInputStream(file1);            int b = fis.read();            while(b!=-1){                System.out.print((char)b);                b = fis.read();            }        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        finally{            try {                fis.close();            } catch (IOException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }    @Test    // 要读取的文件一定要存在    public void test2() {        FileInputStream fis = null;        try {            File file1 = new File("d:\\io\\helloworld.txt");            fis = new FileInputStream(file1);            byte[] b = new byte[6];            int len;//            int len = fis.read(b);//            while (len != -1) {//                for(int i=0;i<len;i++){//                   System.out.print((char)b[i]);//                }//                len = fis.read(b);//            }            while ((len=fis.read(b))!= -1) {  //注意  b是存储数据的缓冲器，len是返回读入缓冲区的字节总数                                              //所以len<=b.length                for(int i=0;i<len;i++){   //是len，不是b.length                   System.out.print((char)b[i]);                }                        }        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } finally {            try {                fis.close();            } catch (IOException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }}
package lianxi1;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import org.junit.Test;public class TestFileOutputStream {@Test //要写入的文件不一定要存在,不存在可以被创建，存在的话内容会被覆盖    public void test1(){    FileOutputStream fos = null;       try {        File file1 = new File("GoodMood");        fos = new FileOutputStream(file1);        fos.write(new String("Have a good night!").getBytes());    } catch (Exception e) {        e.printStackTrace();    }    finally{        try {            fos.close();        } catch (IOException e) {            e.printStackTrace();        }    }    }@Test //从一个文件中读入数据，写入另一个文件    public void test2(){    FileInputStream fis = null;    FileOutputStream fos = null;    try{        File file1 = new File("d:/io/helloworld.txt");        File file2 = new File("GoodMood");        fis = new FileInputStream(file2);        fos = new FileOutputStream(file1);        int len;        byte[] b = new byte[4];        while((len = fis.read(b))!=-1){                fos.write(b, 0, len);            }    }catch(Exception ex){ ex.printStackTrace();}    finally{        if(fis!=null){            try {                fis.close();            } catch (IOException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        if(fos!=null){            try {                fos.close();            } catch (IOException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }}}