Here is an error message that keeps coming up as I try to disply results on my program.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at AddressBookIO.getEntriesString(AddressBookIO.java:38)
at AddressBookEntryApp.main(AddressBookEntryApp.java:42)
I am almost certain my code is correct. My program does everything it is suppose to do except display my results. The ""main" java.lang.ArrayIndexOutOfBoundsException: 0" is the part that confuses me.
Heres the code for AddressBookIO.java, and AddressBookEntryApp
import java.io.*;
public class AddressBookIO
{
private static File addressBookFile = new File("address_book.txt");
private static final String FIELD_SEP = "\t";
private static final int COL_WIDTH = 20;
// use this method to return a string that displays
// all entries in the address_book.txt file
public static String getEntriesString()
{
BufferedReader in = null;
try
{
checkFile();
in = new BufferedReader(
new FileReader(addressBookFile));
// define the string and set a header
String entriesString = "";
entriesString = padWithSpaces("Name", COL_WIDTH)
+ padWithSpaces("Email", COL_WIDTH)
+ padWithSpaces("Phone", COL_WIDTH)
+ "\n";
entriesString += padWithSpaces("------------------", COL_WIDTH)
+ padWithSpaces("------------------", COL_WIDTH)
+ padWithSpaces("------------------", COL_WIDTH)
+ "\n";
// append each line in the file to the entriesString
String line = in.readLine();
while(line != null)
{
String[] columns = line.split(FIELD_SEP);
String name = columns[0];
String emailAddress = columns[1];
String phoneNumber = columns[2];
entriesString +=
padWithSpaces(name, COL_WIDTH) +
padWithSpaces(emailAddress, COL_WIDTH) +
padWithSpaces(phoneNumber, COL_WIDTH) +
"\n";
line = in.readLine();
}
return entriesString;
}
catch(IOException ioe)
{
ioe.printStackTrace();
return null;
}
finally
{
close(in);
}
}
// use this method to append an address book entry
// to the end of the address_book.txt file
public static boolean saveEntry(AddressBookEntry entry)
{
PrintWriter out = null;
try
{
checkFile();
// open output stream for appending
out = new PrintWriter(
new BufferedWriter(
new FileWriter(addressBookFile, true)));
// write all entry to the end of the file
out.print(entry.getName() + FIELD_SEP);
out.print(entry.getEmailAddress() + FIELD_SEP);
out.print(entry.getPhoneNumber() + FIELD_SEP);
out.println();
}
catch(IOException ioe)
{
ioe.printStackTrace();
return false;
}
finally
{
close(out);
}
return true;
}
// a private method that creates a blank file if the file doesn't already exist
private static void checkFile() throws IOException
{
// if the file doesn't exist, create it
if (!addressBookFile.exists())
addressBookFile.createNewFile();
}
// a private method that closes the I/O stream
private static void close(Closeable stream)
{
try
{
if (stream != null)
stream.close();
}
catch(IOException ioe)
{
ioe.printStackTrace();
}
}
// a private method that is used to set the width of a column
private static String padWithSpaces(String s, int length)
{
if (s.length() < length)
{
StringBuilder sb = new StringBuilder(s);
while(sb.length() < length)
{
sb.append(" ");
}
return sb.toString();
}
else
{
return s.substring(0, length);
}
}
}
And
import java.util.Scanner;
public class AddressBookEntryApp
{
public static void main(String args[])
{
// display a welcome message
System.out.println("Welcome to the Address Book application");
System.out.println();
Scanner sc = new Scanner(System.in);
int menuNumber = 0;
while (menuNumber != 3)
{
// display menu
System.out.println("1 - List entries");
System.out.println("2 - Add entry");
System.out.println("3 - Exit\n");
// get input from user
menuNumber = Validator.getIntWithinRange(sc, "Enter menu number: ", 0, 4);
System.out.println();
switch (menuNumber)
{
case 1:
{
String entriesString = AddressBookIO.getEntriesString();
System.out.println(entriesString);
break;
}
case 2:
{
// get data from user
String name = Validator.getRequiredString(sc, "Enter name: ");
String emailAddress = Validator.getRequiredString(sc, "Enter email address: ");
String phoneNumber = Validator.getRequiredString(sc, "Enter phone number: ");
// create AddressBookEntry object and fill with data
AddressBookEntry entry = new AddressBookEntry();
entry.setName(name);
entry.setEmailAddress(emailAddress);
entry.setPhoneNumber(phoneNumber);
AddressBookIO.saveEntry(entry);
System.out.println();
System.out.println("This entry has been saved.\n");
break;
}
case 3:
{
System.out.println("Goodbye.\n");
break;
}
}
}
}
}
The exception means that you are accessing an array's element beyond the size of the array. So, you need to provide the details of your code to be able to let you know the cause of the issue.
It indicates that an array has been accessed with an illegal index. The index is either negative or greater than or equal to the size of the array.
As per your error logs..code at line no:38 in AddressBookIO.java is throwing this exception.
Could be here..
String name = columns[0];
String emailAddress = columns[1];
String phoneNumber = columns[2];
if there is no element at either 0, 1 or 2..
The error message is pretty clear: The 1st element (index 0) of an array with no elements has been incorrectly accessed.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: [index is] 0
For instance, this would throw that exception:
int bad = (new int[0])[0]; // no elements :(
While the following is okay:
int ok = (new int[1])[0]; // one element, can access it!
I suspect it is this:
String[] columns = line.split(FIELD_SEP); // empty array?
String name = columns[0]; // KABOOM!
In any case, check the code on the line reported in the exception.
at AddressBookIO.getEntriesString(AddressBookIO.java:38)
A blank line in 'address_book.txt' perhaps?
You are trying to access the first element of an empty array. It doesn't exist, so you get an exception from the run time.
The array that you are trying to access is the result of the split() method. This will only return an empty array if you pass a string of delimiters: "\t"
So, there must be some lines that contain only tabs with nothing between them.
Instead of using split(), you should consider applying regular expression to each line. This way, you can validate the format of the line and apply "capture groups" at the same time to easily extract values for each field, even if they are empty strings.
Pattern p = Pattern.compile("([^\t]*)\t([^\t]*)\t([^\t]*)");
...
Matcher m = p.matcher(line);
if (!m.matches()) {
/* The line is invalid; skip it or throw an exception. */
...
}
String name = m.group(1);
String emailAddress = m.group(2);
String phoneNumber = m.group(3);
ArrayIndexOutOfBoundsException is thrown when you try to access an Index, which is more than the size of the specified array.
Try to change this :
while(line != null)
{
String[] columns = line.split(FIELD_SEP);
String name = columns[0];
String emailAddress = columns[1];
String phoneNumber = columns[2];
entriesString += padWithSpaces(name, COL_WIDTH) +
padWithSpaces(emailAddress, COL_WIDTH) +
padWithSpaces(phoneNumber, COL_WIDTH) +
"\n";
line = in.readLine();
}
to this :
while(line != null)
{
String[] columns = line.split(FIELD_SEP);
if (columns.length > 2)
{
String name = columns[0];
String emailAddress = columns[1];
String phoneNumber = columns[2];
entriesString += padWithSpaces(name, COL_WIDTH) +
padWithSpaces(emailAddress, COL_WIDTH) +
padWithSpaces(phoneNumber, COL_WIDTH) +
"\n";
}
line = in.readLine();
}
Related
File Roster: roster.txt
Reagan rebradshaw835
Ryley rbarber894
Peyton pstott885
Tyrese tmayo945
Caius ccharlton329
The program has to do with exception handling. Problem I am trying to overcome at the moment is being able to get the proper output. I don't know if there is a specific way to find the line that contains the name, and return everything in the line except the name.
so that we are able to return the username assigned.
For example, first line shows:
Reagan rebradshaw835
Method returns just rebradshaw835
Here is the code: (updated code)
vhthanh really helped me to understand how to read from a file!
I decided to edit the code using replace string commands. Without vhthanhI probably wouldn't have learned how to interact with the file.
package chapter11;
import java.util.Scanner;
import java.io.FileInputStream;
import java.io.IOException;
public class LabProgram {
public static String findID(String studentName, Scanner infoScnr) throws Exception {
while (infoScnr.hasNextLine()) {
String line = infoScnr.nextLine();
//String[] values = line.split(" ", 2);
if (line.contains(studentName)) {
line = line.replace(studentName + " ", "");
return line;
}
}
throw new Exception ("Student ID not found for " + studentName);
}
public static String findName(String studentID, Scanner infoScnr) throws Exception {
while (infoScnr.hasNextLine()) {
String line = infoScnr.nextLine();
//String[] values = line.split(" ", 2);
if (line.contains(studentID)) {
line = line.replace(studentID + " ", "");
return line;
}
}
throw new Exception ("Student name not found for " + studentID);
}
public static void main(String[] args) throws IOException {
Scanner scnr = new Scanner(System.in);
String studentName;
String studentID;
String studentInfoFileName;
FileInputStream studentInfoStream = null;
Scanner studentInfoScanner = null;
// Read the text file name from user
studentInfoFileName = scnr.next();
// Open the text file
studentInfoStream = new FileInputStream(studentInfoFileName);
studentInfoScanner = new Scanner(studentInfoStream);
// Read search option from user. 0: findID(), 1: findName()
int userChoice = scnr.nextInt();
// FIXME: findID() and findName() may throw an Exception.
// Insert a try/catch statement to catch the exception and output the exception message.
try {
if (userChoice == 0) {
studentName = scnr.next();
studentID = findID(studentName, studentInfoScanner);
System.out.println(studentID);
}
else {
studentID = scnr.next();
studentName = findName(studentID, studentInfoScanner);
System.out.println(studentName);
}
studentInfoStream.close();
}
catch (Exception exp) {
System.out.println(exp.getMessage());
}
}
}
You need to read the every single line from the Scanner and split() the string into an array of 2 values and then compare it.
Try this code:
public static String findID(String studentName, Scanner infoScnr) throws Exception {
while (infoScnr.hasNextLine()) {
String line = infoScnr.nextLine();
String[] values = line.split(" ", 2);
if (studentName != null && studentName.equals(values[0])) {
return values[1];
}
}
throw new Exception ("Student name not found for " + studentName);
}
public static String findName(String studentID, Scanner infoScnr) throws Exception {
while (infoScnr.hasNextLine()) {
String line = infoScnr.nextLine();
String[] values = line.split(" ", 2);
if (studentID != null && values.length > 1 && studentID.equals(values[1])) {
return values[0];
}
}
throw new Exception ("Student id not found for " + studentID);
}
.split (" ")
for spacing
.split ("/n")
for new line (nextLine)
I currently have 2 loops, one which gets a timestamp, and another while loop to find the mapped information based off that time stamp and output in a certain way.
Issue I have is I am currently looping through a text, and want it to start reading the file from the beginning again when the isdone="N" for the second loop, however, this does not seem to be the case.
Code so far:
public static void organiseFile() throws FileNotFoundException {
String directory = "C:\\Users\\xxx\\Desktop\\Files\\ex1";
Scanner fileIn = new Scanner(new File(directory + "_temp.txt"));
Scanner readIn = new Scanner(new File(directory + ".txt"));
PrintWriter out = new PrintWriter(directory + "_ordered.txt");
ArrayList<String> lines = new ArrayList<String>();
String readTimeStamp = "";
String timeStampMapping = "";
String outputFirst = "";
String outputSecond = "";
String outputThird = "";
String previousTimeStamp = "";
String doneList = "";
String isdone = "";
int counter = 1;
// Loop to get time stamps
while(fileIn.hasNextLine()) {
readTimeStamp = fileIn.nextLine();
if(readTimeStamp != null && readTimeStamp.trim().length() > 0) {
readTimeStamp = readTimeStamp.substring(12, 25);
System.out.println(readTimeStamp);
// Previous time stamp found, no need to loop through it again
if(doneList.contains(readTimeStamp))
isdone = "Y";
// Counter in place to stop outputting the first record, otherwise output file and clear variables down
else if(!previousTimeStamp.equals(readTimeStamp) && counter > 1) {
out.println(outputFirst + outputSecond + outputThird);
System.out.println("Outputting....");
outputFirst = "";
outputSecond = "";
outputThird = "";
counter = 1;
}
// New time stamp found, start finding values in second loop
else
isdone = "N";
// Secondary loop to find match of record
while(readIn.hasNextLine() && isdone.equals("N")) {
System.out.println("Mapping...");
timeStampMapping = readIn.nextLine();
System.out.println(timeStampMapping);
// When a record has been found with matching time stamps, start ordering
if(timeStampMapping.contains(readTimeStamp)) {
previousTimeStamp = readTimeStamp;
System.out.println(previousTimeStamp);
if(timeStampMapping.contains("[EVENT=agentStateEvent]")) {
outputFirst += timeStampMapping + "\r\n";
} else if(timeStampMapping.contains("[EVENT=TerminalConnectionCreated]")) {
outputSecond += timeStampMapping + "\r\n";
} else {
outputThird += timeStampMapping + "\r\n";
doneList += readTimeStamp + ",";
}
counter++;
}
}
}
}
System.out.println("Outputting final record");
out.println(outputFirst + outputSecond + outputThird);
System.out.println("Complete!");
out.close();
}
You can use Scanner.reset() to reset it to the beginning of the file. For example, after your second while-loop include:
if (isdone.equals("Y")) {
fileIn.reset();
}
Btw: why are you using String for isdone instead of boolean??
I am facing a problem in the following code. I am trying to run the program and it terminates when it hits empty space in my input. How else I should approach this.
try {
BufferedReader sc = new BufferedReader(new FileReader(text.txt);
ArrayList<String> name = new ArrayList<>();
ArrayList<String> id = new ArrayList<>();
ArrayList<String> place = new ArrayList<>();
ArrayList<String> details = new ArrayList<>();
String line = null;
while ((line = sc.readLine()) !=null) {
if (!line.trim().equals("")) {
System.out.println(line);
if (line.toLowerCase().contains("name")) {
name.add(line.split("=")[1].trim());
}
if (line.toLowerCase().contains("id")) {
id.add(line.split("=")[1].trim());
}
if (line.toLowerCase().contains("location")) {
place.add(line.split("=")[1].trim());
}
if (line.toLowerCase().contains("details")) {
details.add(line.split("=")[1].trim());
}
}
}
PrintWriter pr = new PrintWriter(new File(text.csv));
pr.println("Name;Id;;Location;Details");
for (int i = 0; i < name.size(); i++) {
pr.println(name.get(i) + ";" + id.get(i) + ";" + place.get(i) + ";" + details.get(i));
}
pr.close();
sc.close();
} catch (Exception e) {
e.printStackTrace();
} }
My Input looks like
name = abc
id = 123
place = xyz
details = hsdyhuslkjaldhaadj
name = ert
id = 7872
place =
details = shahkjdhksdhsala
name = sfd
id = 4343
place = ksjks
Details = kljhaljs
when im trying to execute then above text my program terminates at place = "null" because of no value there.I need the output as an empty space created in place ="null" and print the rest as follows in a .csv file
If you process the location, line.split("=")[1] could result in an ArrayIndexOutOfBoundException and line.split("=")[1].trim() could result in a NullPointerException.
You can avoid this by testing your parsed result.
Instead of place.add(line.split("=")[1].trim());, do place.add(parseContentDefaultEmpty(line));, with:
private String parseContentDefaultEmpty(final String line) {
final String[] result = line.split("=");
if(result.length <= 1) {
return "";
}
final String content = line.split("=")[1];
return content != null ? content.trim() : "";
}
First there is a issue,your input file contains key as "place" but your are trying for word "location"
if (line.toLowerCase().contains("location")) { //this must be changed to place
place.add(line.split("=")[1].trim());
}
Modified the code snippet as below.check it
while ((line = sc.readLine()) != null) {
if (!line.trim().equals("")) {
System.out.println(line);
if (line.toLowerCase().contains("name")) {
name.add(line.split("=")[1].trim());
}
if (line.toLowerCase().contains("id")) {
id.add(line.split("=")[1].trim());
}
if (line.toLowerCase().contains("place")) {
// change done here to add space if no value
place.add(line.split("=").length > 1 ? line.split("=")[1]
.trim() : " ");
}
if (line.toLowerCase().contains("details")) {
details.add(line.split("=")[1].trim());
}
}
}
Setting question to line doesn't appear to change what line is read later (if you're wanting the line to advance before it hits the while loop).
hey ive got a chunk of code thats supposed loads lines of csv file into an array of objects:
public static WarehouseItem[] loadRecords(WarehouseItem[] records) {
FileInputStream fileStrm = null;
InputStreamReader rdr;
BufferedReader bufRdr;
int numRows = 0;
String warehouseItem;
String filename;
filename = ConsoleInput.readLine("Please enter the filename (DataMillion.csv OR DataThousand.csv)");
try {
fileStrm = new FileInputStream(filename);
rdr = new InputStreamReader(fileStrm);
bufRdr = new BufferedReader(rdr);
warehouseItem = bufRdr.readLine();
records[numRows] = new WarehouseItem(warehouseItem); //NULL POINTER EXCEPTION HERE
System.out.println(records[0].toString(records[0].columnVals));
while (warehouseItem != null) {
numRows++;
records[numRows] = new WarehouseItem(warehouseItem);
warehouseItem = bufRdr.readLine();
}
fileStrm.close();
}
catch (IOException e) {
if (fileStrm != null) {
try {
fileStrm.close();
} catch (IOException ex2) {}
}
System.out.println("Error in file processing: " + e.getMessage());
}
main(null);
return records;
}
but when i run it, i get a NullPointerException on the line
records[numRows] = new WarehouseItem(warehouseItem);
is there anything that i missed??
heres the WarehouseItem constructor + toString:
public class WarehouseItem {
String[] columnVals;
int numColumns = 5;
public WarehouseItem(String warehouseItem) {
String key, brand, model, price, weightInKG;
int intWeightInKG;
double doublePrice;
StringTokenizer strTok;
strTok = new StringTokenizer(warehouseItem, ",");
key = strTok.nextToken();
brand = strTok.nextToken();
model = strTok.nextToken();
intWeightInKG = Integer.parseInt(strTok.nextToken());
doublePrice = Double.valueOf(strTok.nextToken());
weightInKG = String.valueOf(intWeightInKG);
price = String.valueOf(doublePrice);
String[] columnVals = {key, brand, model, weightInKG, price};
if(columnVals.length != 5)
throw new IllegalStateException("Invalid CSV: not enough columns");
}
public String toString(String[] columnVals) {
return ("Key: " + columnVals[0] + "\n" +
"Brand: " + columnVals[1] + "\n" +
"Model: " + columnVals[2] + "\n" +
"Weight: " + columnVals[3] + "\n" + " kg" +
"Price: " + "$" + columnVals[4] + "\n");
}
}
What my problem is the values aren't getting stored into the array records properly and im not sure why
You didn't initialize array, that was a cause NullPointerException in your code, but if you can't use array don't use it.
The number of lines might exceed the capacity of array, use List instead
List<WarehouseItem> records = new ArrayList<>();
String line = bufRdr.readLine();
while (line != null) {
WarehauseItem warehauseItem = new WarehauseItem();
records.add(warehauseItem);
warehauseItem.processLine(line);
line = bufRdr.readLine();
}
numRows = records.size();
When you create an array of objects in Java, it is initialized with all nulls. That is why you get a nullpointerexception.
So you need to create an object for each array position. In fact instead of calling a method you could just make that method a constructor; that would be simpler.
I also noticed another mistake: the method sets local variables, which only exist for the lifetime of the method, when in fact it should set instance variables.
Then I noticed a third mistake: You just caught exception, and assumed that that indicated missing columns; in fact it could indicate invalidly-typed data inside a column (e.g. string instead of integer).
You missed object creation records[numRows]=new WarehouseItem();
Your code need to be like this.
while (warehouseItem != null) {
records[numRows]=new WarehouseItem(); //here you forgot the object creation.
warehouseItem = bufRdr.readLine();
records[numRows].processLine(warehouseItem);
numRows++;
}
Because you haven't assigned anything to records[numRows]. You only defined records as an array of WarehouseItem objects.
You should assign a new WarehouseItem to that index of the array before you can use.
records[numRows] = new WarehouseItem();
warehouseItem = bufRdr.readLine();
records[numRows].processLine(wareHouseitem);
I am wondering how to find the maven repository close to my home?
Actually, the listing at http://docs.codehaus.org/display/MAVENUSER/Mirrors+Repositories is problematic. Is Central in San Francisco, California or in St. Louis, Missouri? (I guess this is an inadvertent lesson on why code, or even xml, should not be commented). To make things more confusing, the owner of the domain (according to http://whois.net/whois/maven.org) is in Fulton, MD.
Maybe the question was not "Where are the repositories?" (which esaj answered), but really:
"How can I find the maven repository closest to my home?"
That question bugged me, too.
On the other hand, does it really matter, given how fast packets travel across the world?
But it still bugged me.
There are two ways to find out which host is the closest:
Open a browser, go to http://freegeoip.net, and type in the hostname. If you know where you are, then you can go to GoogleMaps, get directions, and check the distance.
Open a terminal window, and ping the hostname to find the average round trip transit time in milliseconds. This will give you the electronic distance, which is really more important for file transfer times.
Repeat for each hostname (i.e. about 40 times, if you're looking at the download sites for Maven itself)
Sort by the distance measured by the GoogleMaps directions, or by the transit time.
For 40 hosts you could probably do that manually in 20 tedious minutes, but a true professional would rather spend a few hours writing the Selenium and java code that could do it in 5 minutes.
In my copious amounts of spare time, I threw together only half the job (i.e. no Selenium):
public class ClosestUrlFinder {
/**
* Find out where a hostname is.
* Adapted from http://www.mkyong.com/java/how-to-send-http-request-getpost-in-java/
* Send HTTP GET requests to: freegeoip.net/{format}/{ip_or_hostname}
* The API supports both HTTP and HTTPS.
* Supported formats are csv, xml or json.
* E.G. http://freegeoip.net/xml/www.poolsaboveground.com
* returns <Response><Ip>207.58.184.93</Ip><CountryCode>US</CountryCode>
* <CountryName>United States</CountryName><RegionCode>VA</RegionCode><RegionName>Virginia</RegionName>
* <City>Mclean</City><ZipCode>22101</ZipCode>
* <Latitude>38.9358</Latitude><Longitude>-77.1621</Longitude>
* <MetroCode>511</MetroCode><AreaCode>703</AreaCode></Response>
* #param urlOrHostname
* #return
*/
public String getUrlLocation(String urlOrHostname) {
String USER_AGENT = "Mozilla/5.0";
BufferedReader in = null;
URL urlObject;
StringBuilder response = null;
try {
urlObject = new URL("http://freegeoip.net/xml/" + urlOrHostname);
HttpURLConnection connection = (HttpURLConnection) urlObject.openConnection();
connection.setRequestMethod("GET");
connection.setRequestProperty("User-Agent", USER_AGENT);
int responseCode = connection.getResponseCode();
System.out.println("\nSending 'GET' request to URL : " + urlOrHostname);
System.out.println("Response Code : " + responseCode);
in = new BufferedReader( new InputStreamReader(connection.getInputStream()));
String inputLine;
response = new StringBuilder();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (in != null) {
try { in.close(); }
catch (IOException e) {
e.printStackTrace();
}
}
}
//System.out.println(response.toString());
return response.toString();
}
/*
* Fixed version of code from http://stackoverflow.com/questions/11506321/java-code-to-ping-an-ip-address
*/
public String runDosCommand(List<String> command)
{
String string = "", result = "";
ProcessBuilder pBuilder = new ProcessBuilder(command);
Process process;
try {
process = pBuilder.start();
BufferedReader stdInput = new BufferedReader(new InputStreamReader(process.getInputStream()));
BufferedReader stdError = new BufferedReader(new InputStreamReader(process.getErrorStream()));
//System.out.println("Standard output of the command:");
while ((string = stdInput.readLine()) != null)
{
System.out.println(string);
result = result + "\n" + string;
}
while ((string = stdError.readLine()) != null)
{
System.out.println("stdError: "+ string);
result = result + "\nstdError: " + string;
}
} catch (IOException e) {
System.out.println("Error with command "+command);
e.printStackTrace();
}
return result;
}
public String pingUrl(String url) {
List<String> command = new ArrayList<String>();
String averagePingTime = "0", geoText = "", loss = "";
command.add("ping");
command.add("-n");
command.add("2");
url = url.replace("ftp://", "");
url = Utils.first(url.replace("/", " "));
url = Utils.first(url.replace(":", " "));
command.add(url);
System.out.println("command is: "+command);
String pingResult = runDosCommand(command);
String timeoutString = "Request timed out";
String timeout = Utils.grep(timeoutString, pingResult);
String noHostString = "Ping request could not find host";
String noHost = Utils.grep(noHostString, pingResult);
String unreachableString = "Destination net unreachable";
String unreachable = Utils.grep(unreachableString, pingResult);
if (Utils.isNullOrEmptyString(timeout) && Utils.isNullOrEmptyString(noHost)
&& Utils.isNullOrEmptyString(unreachable)) {
String lostString = "Lost =";
loss = Utils.grep(lostString, pingResult);
int index = loss.indexOf(lostString);
loss = loss.substring(index);
if (!loss.equals("Lost = 0 (0% loss),")) {
System.out.println("Non-zero loss for " + url);
averagePingTime = "0";
} else {
String replyString = "Reply from";
String replyFrom = Utils.grep(replyString, pingResult);
String ipAddress = Utils.nth(replyFrom, 3);
System.out.println("reply Ip="+ipAddress.replace(":", ""));
String averageString = "Average =";
averagePingTime = Utils.grep(averageString, pingResult);
index = averagePingTime.indexOf(averageString);
averagePingTime = averagePingTime.substring(index);
averagePingTime = Utils.last(averagePingTime).replace("ms", "");
String xml = getUrlLocation(url);
//System.out.println("xml="+xml);
geoText = extractTextFromXML(xml);
System.out.println("geoText="+geoText);
}
} else {
averagePingTime = "0";
System.out.println("Error. Either could not find host, Request timed out, or unreachable network for " + url);;
}
System.out.println("Results for " + url + " are: " + loss + " " + averagePingTime + " miliseconds.");
return url + " " + averagePingTime + " " + geoText ;
}
public ArrayList<Entry<String,Integer>> pingManyUrls() {
ArrayList<Entry<String,Integer>> mirrorTimeList = new ArrayList<>();
String[] urls = Utils.readTextFile("resources/MavenUrls.txt").split("\\s+");
System.out.println("Start pingManyUrls with "+urls.length + " urls.");
for (String url : urls) {
url = url.trim();
System.out.println("************************************\npingManyUrls: Check Url " + url);
if (arrayListContainsKey(url, mirrorTimeList)) {
System.out.println("Key " + url + " already in array.");
} else {
String pingInfo = pingUrl(url);
String averagePingString = Utils.nth(pingInfo, 2);
if (!averagePingString.equals("0")) {
int averagePingMilliseconds = Integer.parseInt(averagePingString);
pingInfo = Utils.rest(pingInfo); //chop the first term (the url)
pingInfo = Utils.rest(pingInfo); // chop the 2nd term (the time)
url = url + " " + pingInfo;
System.out.println(" Adding Key " + url + " " + averagePingMilliseconds + " to array.");
Entry<String,Integer> urlTimePair = new java.util.AbstractMap.SimpleEntry<>(url, averagePingMilliseconds);
mirrorTimeList.add(urlTimePair);
} else { System.out.println("Url " + url + " has a problem and therefore will be not be included."); }
}
}
Collections.sort(mirrorTimeList, new Comparator<Entry<String,Integer>>() {
#Override
public int compare (Entry<String,Integer> pair1, Entry<String,Integer> pair2) {
return pair1.getValue().compareTo(pair2.getValue());
}
});
return mirrorTimeList;
}
public boolean arrayListContainsKey(String key, ArrayList<Entry<String,Integer>> arrayList) {
for (Entry<String,Integer> keyValuePair : arrayList) {
//System.out.println(keyValuePair.getKey() + " =? " + key);
if (key.equalsIgnoreCase(keyValuePair.getKey())) { return true; }
}
return false;
}
public String extractFirstTagContents(Element parentElement, String tagname) {
NodeList list = parentElement.getElementsByTagName(tagname);
if (list != null && list.getLength()>0) {
String contents = list.item(0).getTextContent();
System.out.println("Tagname=" + tagname + " contents="+contents);
return contents;
}
return "";
}
public String extractTextFromXML(String xml) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder;
String content = "";
try {
builder = factory.newDocumentBuilder();
Document document = builder.parse(new InputSource(new StringReader(xml)));
Element rootElement = document.getDocumentElement();
content = rootElement.getTextContent();
//System.out.println("content="+content);
// String city = extractFirstTagContents(rootElement, "City");
// String state = extractFirstTagContents(rootElement, "RegionName");
// String zipCode = extractFirstTagContents(rootElement, "ZipCode");
// String country = extractFirstTagContents(rootElement, "CountryName");
// String latitude = extractFirstTagContents(rootElement, "Latitude");
// String longitude = extractFirstTagContents(rootElement, "Longitude");
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException saxex) {
// TODO Auto-generated catch block
saxex.printStackTrace();
} catch (IOException ioex) {
// TODO Auto-generated catch block
ioex.printStackTrace();
}
return content;
}
public static void main(String[] args) {
System.out.println("Starting ClosestUrlFinder");
ClosestUrlFinder ping = new ClosestUrlFinder();
ArrayList<Entry<String,Integer>> mirrorList = ping.pingManyUrls();
System.out.println("Final Results, sorted by trip travel time (out of "+mirrorList.size()+" successful pings).");
for (Entry<String,Integer> urlTime : mirrorList) {
System.out.println(urlTime.getKey() + " " + urlTime.getValue());
}
}
} // End of Class
Where the data in MavenUrls.txt is:
apache.claz.org
apache.cs.utah.edu
apache.mesi.com.ar
apache.mirrors.hoobly.com
apache.mirrors.lucidnetworks.net
apache.mirrors.pair.com
apache.mirrors.tds.net
apache.osuosl.org
apache.petsads.us
apache.spinellicreations.com
apache.tradebit.com
download.nextag.com
ftp.osuosl.org
ftp://mirror.reverse.net/pub/apache/
mirror.cc.columbia.edu/pub/software/apache/
mirror.cogentco.com/pub/apache/
mirror.metrocast.net/apache/
mirror.nexcess.net/apache/
mirror.olnevhost.net/pub/apache/
mirror.reverse.net/pub/apache/
mirror.sdunix.com/apache/
mirror.symnds.com/software/Apache/
mirror.tcpdiag.net/apache/
mirrors.gigenet.com/apache/
mirrors.ibiblio.org/apache/
mirrors.sonic.net/apache/
psg.mtu.edu/pub/apache/
supergsego.com/apache/
www.bizdirusa.com
www.bizdirusa.com/mirrors/apache/
www.carfab.com/apachesoftware/
www.dsgnwrld.com/am/
www.eng.lsu.edu/mirrors/apache/
www.gtlib.gatech.edu/pub/apache/
www.interior-dsgn.com/apache/
www.motorlogy.com/apache/
www.picotopia.org/apache/
www.poolsaboveground.com/apache/
www.trieuvan.com/apache/
www.webhostingjams.com/mirror/apache/
And my Utils class includes the following:
/**
* Given a string of words separated by spaces, returns the first word.
* #param string
* #return
*/
public static String first(String string) {
if (isNullOrEmptyString(string)) { return ""; }
string = string.trim();
int index = string.indexOf(" "); //TODO: shouldn't this be "\\s+" to handle double spaces and tabs? That means regexp version of indexOf
if (index<0) { return string; }
return string.substring(0, index);
}
/**
* Given a string of words separated by spaces, returns the rest of the string after the first word.
* #param string
* #return
*/
public static String rest(String string) {
if (isNullOrEmptyString(string)) { return ""; }
string = string.trim();
int index = string.indexOf(" "); //TODO: shouldn't this be "\\s+" to handle double spaces and tabs? That means regexp version of indexOf
if (index<0) { return ""; }
return string.substring(index+1);
}
public static String grep(String regexp, String multiLineStringToSearch) {
String result = "";
//System.out.println("grep for '"+ regexp + "'");
String[] lines = multiLineStringToSearch.split("\\n");
//System.out.println("grep input string contains "+ lines.length + " lines.");
Pattern pattern = Pattern.compile(regexp);
for (String line : lines) {
Matcher matcher = pattern.matcher(line);
if (matcher.find()) {
//System.out.println("grep found match="+ line);
result = result + "\n" + line;
}
}
return result.trim();
}
/**
* Given the path and name of a plain text (ascii) file,
* reads it and returns the contents as a string.
* #param filePath
* #return
*/
public static String readTextFile(String filePath) {
BufferedReader reader;
String result = "";
int counter = 0;
try {
reader = new BufferedReader(new FileReader(filePath));
String line = "";
StringBuilder stringBuilder = new StringBuilder();
String lineSeparator = System.getProperty("line.separator");
while ((line = reader.readLine()) != null) {
counter = counter + 1;
stringBuilder.append(line);
stringBuilder.append(lineSeparator);
}
reader.close();
result = stringBuilder.toString();
logger.info("readTextFile: Read "+filePath+" with "+ counter + " lines, "+result.length()+" characters.");
return result;
} catch (FileNotFoundException e) {
logger.fatal("readTextFile: Could not find file "+filePath+".");
e.printStackTrace();
} catch (IOException e) {
logger.fatal("readTextFile: Could not read file "+filePath+".");
e.printStackTrace();
}
return "";
}
public static boolean isNullOrEmptyString(String s) {
return (s==null || s.equals(""));
}
/**
* Given a string of words separated by one or more whitespaces, returns the Nth word.
* #param string
* #return
*/
public static String nth(String string, int n) {
string = string.trim();
String[] splitstring = string.split("\\s+");
String result = "";
if (splitstring.length<n) { return ""; }
else {
result = splitstring[n - 1];
}
return result.trim();
}
/**
* Given a string of words separated by spaces, returns the last word.
* #param string
* #return
*/
public static String last(String string) {
return string.substring(string.trim().lastIndexOf(" ")+1, string.trim().length());
}
Enjoy!
Here's there official central repository mirror listing (as xml-file) and here's another list of central repository mirrors.