Java Answers Forum - i want to check if a string exists in a file

Articles |
News |
Weblogs |
Books |
Forums

Artima Forums | Articles | Weblogs | Java Answers | News

Sponsored Link •

Java Answers Forum
i want to check if a string exists in a file

2 replies on 1 page. Most recent reply: Sep 2, 2003 12:59 AM by swan

Welcome Guest
Sign In

Back to Topic List

Reply to this Topic

Search Forum

Threaded View


Previous Topic		Next Topic

Flat View: This topic has 2 replies on 1 page

aj3423 aj

Posts: 16
Nickname: aj3423
Registered: Aug, 2003

i want to check if a string exists in a file

Posted: Aug 16, 2003 7:56 AM

i got a Exception when i run it :
D:\java>java Test
imput the filename : a.txt
imput the word to search : a

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at Test.Check(Test.java:57)
at Test.main(Test.java:19)

Here is my code :

import java.io.* ;

public class Test {
public static void main(String args[]) throws IOException {
boolean flag = true;
while(flag) {
flag = false;
prt("imput the filename : ");
File Fname = new File(ImputString());
if (Fname.exists()) {
prt("imput the word to search : ");
String theWord = ImputString();
int length = theWord.length();
Check(Fname, ImputString(), length);
prt("the word not found .");
//Fname.close(); ,is this right ?
System.exit(0);
}else{
System.out.println("file not found : " + Fname);
prt("try again ?(y/n) : ");
BufferedReader YorN = new BufferedReader(new InputStreamReader(System.in));
String Choice = YorN.readLine();
if (Choice.toLowerCase().equals("y")) {
//check "y" or "n"
flag=true;
} else {
System.exit(0);
}
}
}
}

static String ImputString() throws IOException {
String str = null;
BufferedReader read = new BufferedReader(newInputStreamReader(System.in));
str = read.readLine();
return str;
}

static void Check(File theFile, String word, int length) throws IOException {
String theLine = null;
int i = 0;
int x = 0;
int m = 0;
int p = 0;
char Array[] = word.toCharArray();
FileInputStream fis = new FileInputStream(theFile);
DataInputStream in = new DataInputStream(new BufferedInputStream(fis));
while(in.available() != 0) {
while((char)in.read() == Array[p]) {
in.skip(1);
p++;
if(p == length) {
prt("found .");
fis.close();
System.exit(0);
}
}
}
}

static void prt(String s) {
System.out.print(s);
}
}

mausam

Posts: 243
Nickname: mausam
Registered: Sep, 2003

Re: i want to check if a string exists in a file

Posted: Sep 2, 2003 12:38 AM

Ok here is the code .
this takes two arguments
1 - string to find
2 - filename

import java.io.*;
 
class FindString
{
	public static void main(String[] args) throws IOException    
	{
		if(args.length != 2)
    	{ 
			System.out.println("Usage: FindString <string><filename>");
			System.exit(1);
    	}
		
		RandomAccessFile in = new RandomAccessFile(args[1],"r");
		String s = null;
 
		int i, loc = 0;
		for(i=1;(s = in.readLine()) != null;i++)
    	{
			loc = s.indexOf(args[0]);
			if (loc == -1)
				continue;	
			else
       		{
				System.out.println(args[0]+" found in line - "+i);				
				System.out.println(s);			
			}
		}
		
		System.out.println(args[0]+" found "+--i+"no of times in the file "+args[1]);
	}
}

swan

Posts: 7
Nickname: swan
Registered: Aug, 2003

Re: i want to check if a string exists in a file

Posted: Sep 2, 2003 12:59 AM

Hi there,

Here is your code, modified, and the place where the mistake was committed.

import java.io.* ;

public class Test
{
public static void main(String args[]) throws IOException
{
boolean flag = true;
while(flag)
{
flag = false;
prt("imput the filename : ");
File Fname = new File(ImputString());
if (Fname.exists())
{
prt("imput the word to search : ");
String theWord = ImputString();
int length = theWord.length();
Check(Fname,theWord, length); // earlier it was ImputString() instead of theWord
prt("the word not found .");
//Fname.close(); ,is this right ?
System.exit(0);
}
else
{
System.out.println("file not found : " + Fname);
prt("try again ?(y/n) : ");
BufferedReader YorN = new BufferedReader(new InputStreamReader(System.in));
String Choice = YorN.readLine();
if (Choice.toLowerCase().equals("y"))
{
//check "y" or "n"
flag=true;
}
else
{
System.exit(0);
}
}
}
}

static String ImputString() throws IOException
{
String str = null;
BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
str = read.readLine();
return str;
}

static void Check(File theFile, String word, int length) throws IOException
{
String theLine = null;
int i = 0;
int x = 0;
int m = 0;
int p = 0;

char Array[] = word.toCharArray();

FileInputStream fis = new FileInputStream(theFile);
DataInputStream in = new DataInputStream(new BufferedInputStream(fis));
while(in.available() != 0)
{
while((char)in.read() == Array[p])
{
in.skip(1);
p++;
if(p == length)
{
prt("found .");
fis.close();
System.exit(0);
}
}
}
}

static void prt(String s)
{
System.out.print(s);
}

}

Flat View: This topic has 2 replies on 1 page

Previous Topic

Next Topic


	Web Artima.com