小编Jin*_*Jin的帖子

我试图从Thinking in Java中理解这个例子:

package c07;
import com.bruceeckel.simpletest.*;

class Meal {
    Meal() { System.out.println("Meal()"); }
}

class Bread {
    Bread() { System.out.println("Bread()"); }
}

class Cheese {
    Cheese() { System.out.println("Cheese()"); }
}

class Lettuce {
    Lettuce() { System.out.println("Lettuce()"); }
}

class Lunch extends Meal {
    Lunch() { System.out.println("Lunch()"); }
}

class PortableLunch extends Lunch {
    PortableLunch() { System.out.println("PortableLunch()");}
}

public class Sandwich extends PortableLunch {
    private static Test monitor = new Test();
    private Bread b = new …

我正在尝试实现子串替换,但我没有得到预期的结果.有人可以评论我在这里可能缺少的东西吗？

public class SubtringReplacement {

    public static void main (String[] args){

        String input = "xPIy";
        if (input.contains("PI") || input.contains("pi") || input.contains("Pi")){
            input.replace("PI", "3.14");
        }
        System.out.println(input);
    }

}

我不明白为什么以下代码似乎跳过第一个输入字符.

import java.io.*;
import java.util.Arrays;

public class Input
{
    public static void main (String args[])
    {
        try {
            echo(System.in);
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }

    static void echo(InputStream stream) throws IOException
    {
        byte[] input = new byte[10];

        char[] inputChar = new char[10];
        int current;
        while ((current = stream.read()) > 0){
            stream.read(input);

            int i = 0;
            while (input[i] != 0) {
                inputChar[i] = (char)input[i];
                if (i < 9) {
                    i++;
                }
                else {
                    break;
                }
            }   
            System.out.println(Arrays.toString(inputChar));
        }
    } …

我读到我们应该使用Reader/Writer来读/写字符数据,使用InputStream/OutputStream来读/写二进制数据.另外,java字符是2个字节.我想知道以下程序是如何工作的.它从标准输入读取字符将它们存储在一个字节中并打印出来.两个字节字符如何适合一个字节？

http://www.cafeaulait.org/course/week10/06.html