I have a question about scanner please;I working at a small company; we have a software; it generate a big text file; and we must get some useful information from it ; i want write a simple application with java for saving time; could you please guide me ?
for example i want this output ;
Output
RFID : 25 BLUID : 562 WifiID : 2610 RFID : 33
RFID Count : 2
and for example ;this is my Text file, because each generated file with our software has 14000 lines :)
--------------------------
AAAAAAAAAAAA;RFID=25;
BBBB;BBBBBBBB;BBBBBBBBBB;
CCCCC;fffdsfdsfdfsd;BLUID=562;dfsdfsf;
fgfdgdf;terter;fdgfdgtryt;
trtretrre;WifiID=2610;trterytuytutyu;
zxzxzxzxz;popopopwwepp;RFID:33;aasasds…
gfdgfgfd;gfdgfdgfd;fdgfgfgfd;
I test it with this source code but i can't handle it;
Scanner scanner = new Scanner("i:\1.txt");
scanner.findInLine("RFID=");
if (scanner.hasNext())
System.out.println(scanner.next());
else
System.out.println("Error!");
please help me ;
Thanks a lot ...
Well your suggested source would not do what you want. Scanner breaks up input using a delimiter. The default delimiter is whitespace (spaces, tabs or newlines). Scanner.hasNext() simply tells you if there is a new whitespace delimted token. Scanner.next() simply returns that token. Note that none of these are effected by Scanner.findInLine(pattern) as all it does is search the current line for the provided pattern.
Maybe something like this (I have not tested this):
Scanner scanner = new Scanner("i:\\1.txt");
scanner.useDelimiter(";");
Pattern words = Pattern.compile("(RFID=|BLUID=|WifiID=)");//just separate patterns with |
while (scanner.hasNextLine()) {
key = scanner.findInLine(words);
while (key != null) {
String value = scanner.next();
if (key.equals("RFID=") {
System.out.print("RFID:" + value);
} //continue with else ifs for other keys
key = scanner.findInLine(words);
}
scanner.nextLine();
}
I would recommend you forget about using scanner and just use a BufferedReader and a couple of Pattern objects as that method is more flexible for what you want to do.
Here's an example using StreamTokenizer:
import java.io.IOException;
import java.io.StreamTokenizer;
import java.io.StringReader;
import java.util.HashMap;
import java.util.Scanner;
public class ScannerTest {
private static final String s = ""
+ "AAAAAAAAAAAA;RFID=25;\n"
+ "BBBB;BBBBBBBB;BBBBBBBBBB;\n"
+ "CCCCC;fffdsfdsfdfsd;BLUID=562;dfsdfsf;\n"
+ "fgfdgdf;terter;fdgfdgtryt;\n"
+ "trtretrre;WifiID=2610;trterytuytutyu;\n"
+ "zxzxzxzxz;popopopwwepp;RFID:33;aasasds…\n"
+ "gfdgfgfd;gfdgfdgfd;fdgfgfgfd;\n";
public static void main(String[] args) {
long start = System.nanoTime();
tokenize(s);
System.out.println(System.nanoTime() - start);
start = System.nanoTime();
scan(s);
System.out.println(System.nanoTime() - start);
}
private static void tokenize(String s) {
HashMap<String, Integer> map = new HashMap<String, Integer>();
StreamTokenizer tokens = new StreamTokenizer(new StringReader(s));
tokens.whitespaceChars(';', ';');
try {
int token;
String id;
do {
id = tokens.sval;
token = tokens.nextToken();
if (token == '=' || token == ':') {
token = tokens.nextToken();
Integer count = map.get(id);
map.put(id, count == null ? 1 : count + 1);
System.out.println(id + ":" + (int) tokens.nval);
}
} while (token != StreamTokenizer.TT_EOF);
System.out.println("Counts:" + map);
} catch (IOException e) {
e.printStackTrace();
}
}
private static void scan(String s) {
HashMap<String, Integer> map = new HashMap<String, Integer>();
Scanner scanner = new Scanner(s).useDelimiter(";");
while (scanner.hasNext()) {
String token = scanner.next();
String[] split = token.split(":");
if (split.length == 2) {
Integer count = map.get(split[0]);
map.put(split[0], count == null ? 1 : count + 1);
System.out.println(split[0] + ":" + split[1]);
} else {
split = token.split("=");
if (split.length == 2) {
Integer count = map.get(split[0]);
map.put(split[0], count == null ? 1 : count + 1);
System.out.println(split[0] + ":" + split[1]);
}
}
}
scanner.close();
System.out.println("Counts:" + map);
}
}
RFID:25
BLUID:562
WifiID:2610
RFID:33
Counts:{RFID=2, BLUID=1, WifiID=1}
1103000
RFID:25
BLUID:562
WifiID:2610
RFID:33
Counts:{RFID=2, BLUID=1, WifiID=1}
22772000
ready to run:
public class ScannerTest {
private static void readFile(String fileName) {
try {
HashMap<String, Integer> map = new HashMap<String, Integer>();
File file = new File(fileName);
Scanner scanner = new Scanner(file).useDelimiter(";");
while (scanner.hasNext()) {
String token = scanner.next();
String[] split = token.split(":");
if (split.length == 2) {
Integer count = map.get(split[0]);
map.put(split[0], count == null ? 1 : count + 1);
System.out.println(split[0] + ":" + split[1]);
} else {
split = token.split("=");
if (split.length == 2) {
Integer count = map.get(split[0]);
map.put(split[0], count == null ? 1 : count + 1);
System.out.println(split[0] + ":" + split[1]);
}
}
}
scanner.close();
System.out.println("Counts:" + map);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
readFile("test.txt");
}
}
Your first line is problematic.
- You need to escape back-slashes inside string literals (
"i:\\1.txt"not"i:\1.txt") - The
Scannerconstructor for reading from a file takes aFileargument (or anInputStreamargument). The constructor which takes aStringargument is reading from that actual string. See the javadoc.
Try
Scanner scanner = new Scanner(new File("i:\\1.txt"));
Some starting code:
String filename = "your_text_file";
Scanner sc = new Scanner(filename);
// use the scanner to iterate through every line in the file:
try{
while(sc.hasNextLine()){
String line = sc.nextLine();
// split the line up into space-separated tokens:
String[] tokens = line.split();
// look through the tokens to find what you are looking for:
for(int i = 0; i<tokens.length; i++){
if(tokens[i].equals("search_word){
// Do stuff
}
}
}
} // end try
catch(Exception e){}
来源：https://stackoverflow.com/questions/2080403/how-can-i-handle-it-with-scanner-java