【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