import java.io.*;
class LineNumberReaderDemo
{
public static void main(String[] args)throws IOException
{
FileReader fr = new FileReader("FileWriterDemo.java");
LineNumberReader lnr = new LineNumberReader(fr);
String line = null;
lnr.setLineNumber(10);
while((line=lnr.readLine())!=null)
{
System.out.println(lnr.getLineNumber()+":"+line);
}
lnr.close();
}
}
因为上面设置了行号为10;所以从11开始。
就LineNumberReader原理,用代码实现它的运行机理。
import java.io.*;
class MyLineNumberReader
{
private Reader r;
private int linNumber;
MyLineNumberReader(Reader r)
{
this.r = r;
}
public String myReadLine() throws IOException
{
linNumber++;
StringBuilder sb = new StringBuilder();
int ch = 0;
while((ch=r.read())!=-1)
{
if(ch=='\r')
continue;
if(ch=='\n')
return sb.toString();
else
sb.append((char)ch);
}
if(sb.length()!=0)
return sb.toString();
return null;
}
public void setLineNumber(int lineNumber)
{
this.linNumber = lineNumber;
}
public int getLineNumber()
{
return linNumber;
}
public void myClose()throws IOException
{
r.close();
}
}
class MyLineNumberDemo
{
public static void main(String[] args)throws IOException
{
FileReader fr = new FileReader("DateDeme.java");
MyLineNumberReader mylnr = new MyLineNumberReader(fr);
mylnr.setLineNumber(10);
String line = null;
while((line=mylnr.myReadLine())!=null)
{
System.out.println(mylnr.getLineNumber()+"::"+line);
}
mylnr.myClose();
}
}
运行结果如下:
11::import java.util.*;
12::import java.text.*;
13::class DateDeme
14::{
15:: public static void main(String[] args)
16:: {
17:: Date d = new Date();
18:: //这样打印格式看不懂。
19:: // System.out.println(d);
20:: //将模式封装到simpleDateformat对象中
21:: SimpleDateFormat sdf = new SimpleDateFormat("yyy年MM月dd日E hh:mm:ss");
22:: //调用format方法让模式格式化指定Date对象
23:: String time = sdf.format(d);
24:: System.out.println("time ="+time); //time =2016年05月21日星期六 10:58:08
25::
26::
27::
28:: System.out.println("----------");
29:: long l = System.currentTimeMillis();
30:: Date d1 = new Date(l);
31:: System.out.println("d1:"+d1); //d1:Sat May 21 10:58:08 CST 2016
32::
33:: }
34::}