【java】io流之字节输出流：java.io.OutputStream类及子类java.io.FileOutputStream

 package 文件操作;

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

 public class TestOutputStream {
     public static void main(String[] args) throws IOException {
         File file=new File("D:"+File.separator+"test.txt");
         OutputStream outputStream=new FileOutputStream(file);
         String str="每天进步一点点！";
         byte[] bytes=str.getBytes();
         outputStream.write(bytes);
         outputStream.close();
     }
 }

OutputStream

 package 文件操作;

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

 public class TestOutputStream {
     public static void main(String[] args) throws IOException {
         File file=new File("D:"+File.separator+"test.txt");
         OutputStream outputStream=new FileOutputStream(file);
         String str="让世界充满爱！";
         byte[] bytes=str.getBytes();

 //        outputStream.write(bytes);

         for(byte b:bytes){
             outputStream.write(b);//单个字节输出
         }

         outputStream.close();
     }
 }

单个字节输出

 package 文件操作;

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

 public class TestOutputStream {
     public static void main(String[] args) throws IOException {
         File file=new File("D:"+File.separator+"test.txt");
         OutputStream outputStream=new FileOutputStream(file);
         String str="让世界充满爱！";
         byte[] bytes=str.getBytes();
 //        outputStream.write(bytes, 1, 3);//这样输出中文会有乱码:檬?
         outputStream.write(bytes, 2, 4);//输出：世界
         outputStream.close();
     }
 }

输出一部分

 package 文件操作;

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

 public class TestOutputStream {
     public static void main(String[] args) throws IOException {
         File file=new File("D:"+File.separator+"test.txt");
         OutputStream outputStream=new FileOutputStream(file,true);//文件内容追加，而不是覆盖。
         String str="让世界充满爱！";
         byte[] bytes=str.getBytes();
         outputStream.write(bytes);
         outputStream.close();
     }
 }

文件内容追加而不是覆盖

 package 文件操作;

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

 public class TestOutputStream {
     public static void main(String[] args) throws IOException {
         File file=new File("D:"+File.separator+"test.txt");
         OutputStream outputStream=new FileOutputStream(file,true);//文件内容追加，而不是覆盖。
         String str="让世界充满爱！\r\n";//每次输出写回文件换行
         byte[] bytes=str.getBytes();
         outputStream.write(bytes);
         outputStream.close();
     }
 }

每次输出内容到文件换行追加

字节流可以不用关闭操作即可将内容写进文件。