【java】打印流的基本实现及java.io.PrintStream、java.io.PrintWriter示例

 package 打印流;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.OutputStream;

 class MyPrint{

     private OutputStream out;

     public MyPrint(OutputStream out){

         this.out=out;

     }

     public void print(String str) throws IOException{

         out.write(str.getBytes());

     }

     public void print(int i) throws IOException{

         print(String.valueOf(i));

     }

     public void print(byte b) throws IOException{

         print(String.valueOf(b));

     }

     public void print(short s) throws IOException{

         print(String.valueOf(s));

     }

     public void print(long l) throws IOException{

         print(String.valueOf(l));

     }

     public void print(float f) throws IOException{

         print(String.valueOf(f));

     }

     public void print(double d) throws IOException{

         print(String.valueOf(d));

     }

     public void print(boolean b) throws Exception{

         print(String.valueOf(b));

     }

     public void print(char c) throws IOException{

         print(String.valueOf(c));

     }

     public void close() throws IOException{

         out.close();

     }

 }

 public class TestPrint {

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

         MyPrint myPrint=new MyPrint(new FileOutputStream(new File("D:"+File.separator+"testA.txt")));

         myPrint.print(8.8);

         myPrint.print('a');

         myPrint.close();

     }

 }

MyPrint

 package 打印流;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.FileWriter;

 import java.io.IOException;

 import java.io.PrintStream;

 import java.io.PrintWriter;

 public class TestPrintStream {

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

         PrintStream printStream=new PrintStream(new FileOutputStream(new File("D:"+File.separator+"Test.txt")));

         printStream.print(true);

         printStream.println("abc中国人");

         printStream.close();

         PrintWriter printWriter=new PrintWriter(new FileWriter(new File("D:"+File.separator+"testA.txt")));

         printWriter.print(false);

         printWriter.println(89898.23);

         printWriter.close();

     }

 }

PrintStream和PrintWriter

 package 打印流;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.PrintStream;

 public class TestPrintStream {

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

         String name = "张三";

         int age = 20;

         float height = 1.7586f;

         PrintStream printStream = new PrintStream(new FileOutputStream(

                 new File("D:" + File.separator + "Test.txt")));

         printStream.printf("姓名：%s，年龄：%d，身高：%1.2f", name, age, height);

         printStream.close();

         // PrintWriter printWriter=new PrintWriter(new FileWriter(new

         // File("D:"+File.separator+"testA.txt")));

         // printWriter.close();

         System.out.println(String.format("姓名：%s，年龄：%d，身高：%1.2f", name, age,

                 height));

     }

 }

格式化输出

输出操作建议用打印流，而不是输出流