package System输入输出;

 import java.io.ByteArrayOutputStream;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.OutputStream;

 import java.util.function.Consumer;

 public class Test {

     public static void main(String[] args) throws IOException {

         /*

         try{

             int i=3/0;

         }catch(Exception e){

             e.printStackTrace();

             System.out.println(e);//输出信息红色

             System.err.println(e);//输出信息黑色

         }

         */

         //输出到屏幕

         OutputStream out=System.out;

         //输出到文件

         OutputStream out2=new FileOutputStream(new File("D:"+File.separator+"test.txt"));

         //输出到内存

         OutputStream out3=new ByteArrayOutputStream();

         //以上体现多态性

         out.write("Welcom to 中国\n".getBytes());

         Consumer<String> consumer=System.out::println;

         consumer.accept("北京欢迎你！");

     }

 }

 package System输入输出;

 import java.io.IOException;

 import java.io.InputStream;

 public class Test {

     public static void main(String[] args) throws IOException {

         InputStream in=System.in;

         byte[] b=new byte[1024];

         System.out.println("请输入数据：");

         int len=in.read(b);

         System.out.println(new String(b,0,len));

     }

 }

 package System输入输出;

 import java.io.IOException;

 import java.io.InputStream;

 public class Test {

     public static void main(String[] args) throws IOException {

         InputStream in=System.in;

         StringBuffer sb=new StringBuffer();

         System.out.println("请输入数据：");

         int tmp=0;

         while((tmp=in.read())!=-1){

             if(tmp=='\n')

                 break;

             sb.append((char)tmp);

         }

         System.out.println(sb);

     }

 }