遇到一个比较头疼的问题,请大家指教啊1.读入一个顺序文件,例如
a 20 30
b 40 452.然后将第三个数据修改为它的两倍后写入同一个文件
得到:
a 20 60
b 40 90希望高手解释的详细点,最好给出代码,先谢谢了哈。
a 20 30
b 40 452.然后将第三个数据修改为它的两倍后写入同一个文件
得到:
a 20 60
b 40 90希望高手解释的详细点,最好给出代码,先谢谢了哈。
Integer.parseInt(str.split(" ")[2])*2
写入
spite拆分
import java.io.*;public class ReadFile
{
public static void main(String[]args)
{
try
{
BufferedReader in = new BufferedReader(new FileReader("employee.txt"));
PrintWriter out = new PrintWriter(new FileWriter("employee1.txt"));
String line,linestr;
String inttxt;
while((line = in.readLine()) !=null)
{
inttxt = String.valueOf(Integer.parseInt(line.split(" ")[2])*2);
System.out.println(inttxt);
linestr=line.replaceAll(String.valueOf(Integer.parseInt(line.split(" ")[2])),inttxt);
System.out.println(linestr);
out.append(linestr);
}
out.close();
in.close();
}
catch(Exception e)
{
}
}
}
{
public static void main(String[]args)
{
try
{
BufferedReader in = new BufferedReader(new FileReader("employee.txt"));
PrintWriter out = new PrintWriter(new FileWriter("employee1.txt"));
String line,linestr;
String inttxt;
while((line = in.readLine()) !=null)
{
inttxt = String.valueOf(Integer.parseInt(line.split(" ")[2])*2);
System.out.println(inttxt);
linestr=line.replaceAll(String.valueOf(Integer.parseInt(line.split(" ")[2])),inttxt);
System.out.println(linestr);
out.println(linestr);
}
out.close();
in.close();
}
catch(Exception e)
{
}
}
}
import java.io.*;public class ReadFile
{
public static void main(String[]args)
{
try
{
BufferedReader in = new BufferedReader(new FileReader("employee.txt"));
PrintWriter out = new PrintWriter(new FileWriter("employee.txt",true));
String line,linestr;
String inttxt;
while((line = in.readLine()) !=null)
{
inttxt = String.valueOf(Integer.parseInt(line.split(" ")[2])*2);
System.out.println(inttxt);
linestr=line.replaceAll(String.valueOf(Integer.parseInt(line.split(" ")[2])),inttxt);
System.out.println(linestr);
out.println(linestr);
}
out.close();
in.close();
}
catch(Exception e)
{
}
}
}