文档介绍：标准输出
向标准输出流输出(Stream)
在DOS窗口上显示
通常用于程序调试
(…)
();
(“Hello World!”);
1
标准输出
(…)
public static final PrintStream out
public void print(boolean b)
public void print(char c)
public void print(int i)
(long l) (double d) (float f) (char[] s) (String s)
public void println()
public void println(boolean x)
public void println(char x)
public void println(int i)
(long l) (double d) (float f) (char[] s) (String s)
2
标准输出
()/println()的区别
是否存在“回车/换行”
C:\>java Test
a=true
b=A
c=100
C:\>
class Test {
public static void main(String args[]) {
boolean a = true;
char b = ‘A’;
int c = 100;
(“a=”+ a);
(“b=”+ b);
(“c=”+ c);
}
}
class Test {
public static void main(String args[]) {
boolean a = true;
char b = ‘A’;
int c = 100;
(“a=”+ a);
(“ b=”+ b);
(“ c=”+ c);
}
}
C:\>java Test
a=true b=A c=100
C:\>
3
标准输入
从标准输入流读入(Stream)
从键盘输入流读入
通常用于实现程序的交互性
()
();
4
标准输入
()
public static final InputStream in
public abstract int read() throws IOException
public int read(byte[] b) throws IOException
public int read(byte[] b, int off, int len) throws IOException
5
标准输入
public abstract int read() throws IOException
关键字: public、abstract、int、throws
异常: IOException ()
方法描述
从输入流读入下一个字节
返回值为(0~255)的整数
若到达流的尽头,则返回-1
若发生IO错误,则抛出异常
6
标准输入
public abstract int read() throws IOException
import ;
class Test {
public static void main(String args[]) throws IOException {
char c;
("Please input a char: ");
c = (char)();
("Received char=" + c);
}
}
C:\>java Test
Please input a char:
A
Received char=A
C:\>
7
标准输入
public in