Reputation: 2374
I want to write an ArrayList<String>
into a text file.
The ArrayList
is created with the code:
ArrayList arr = new ArrayList();
StringTokenizer st = new StringTokenizer(
line, ":Mode set - Out of Service In Service");
while(st.hasMoreTokens()){
arr.add(st.nextToken());
}
Upvotes: 68
Views: 287772
Reputation: 1395
FileWriter writer = new FileWriter("output.txt");
Arrays.asStream(arr.stream()
.forEach(i -> {
try{
writer.write(i + ",");
}
catch (Exception e){}
}));
writer.close();
Upvotes: -1
Reputation: 721
You can do that with a single line of code nowadays using Java NIO.
Create the arrayList and the Path
object representing the file where you want to write into:
Path out = Paths.get("output.txt");
List<String> arrayList = new ArrayList<> ( Arrays.asList ( "a" , "b" , "c" ) );
Create the actual file, and fill it with the text in the ArrayList by calling on java.nio.file.Files
utility class.
Files.write(out,arrayList,Charset.defaultCharset());
Upvotes: 72
Reputation: 9
Write a array list to text file using JAVA
public void writeFile(List<String> listToWrite,String filePath) {
try {
FileWriter myWriter = new FileWriter(filePath);
for (String string : listToWrite) {
myWriter.write(string);
myWriter.write("\r\n");
}
myWriter.close();
System.out.println("Successfully wrote to the file.");
} catch (IOException e) {
System.out.println("An error occurred.");
e.printStackTrace();
}
}
Upvotes: -1
Reputation: 20683
import java.io.FileWriter;
...
FileWriter writer = new FileWriter("output.txt");
for(String str: arr) {
writer.write(str + System.lineSeparator());
}
writer.close();
Upvotes: 118
Reputation: 49
I think you can also use BufferedWriter :
BufferedWriter writer = new BufferedWriter(new FileWriter(new File("note.txt")));
String stuffToWrite = info;
writer.write(stuffToWrite);
writer.close();
and before that remember too add
import java.io.BufferedWriter;
Upvotes: 1
Reputation: 778
I would suggest using FileUtils from Apache Commons IO library.It will create the parent folders of the output file,if they don't exist.while Files.write(out,arrayList,Charset.defaultCharset());
will not do this,throwing exception if the parent directories don't exist.
FileUtils.writeLines(new File("output.txt"), encoding, list);
Upvotes: 22
Reputation: 2237
If you need to create each ArrayList item in a single line then you can use this code
private void createFile(String file, ArrayList<String> arrData)
throws IOException {
FileWriter writer = new FileWriter(file + ".txt");
int size = arrData.size();
for (int i=0;i<size;i++) {
String str = arrData.get(i).toString();
writer.write(str);
if(i < size-1)**//This prevent creating a blank like at the end of the file**
writer.write("\n");
}
writer.close();
}
Upvotes: 5
Reputation: 6050
You might use ArrayList overloaded method toString()
String tmp=arr.toString();
PrintWriter pw=new PrintWriter(new FileOutputStream(file));
pw.println(tmp.substring(1,tmp.length()-1));
Upvotes: 3
Reputation: 2460
If you want to serialize the ArrayList object to a file so you can read it back in again later use ObjectOuputStream/ObjectInputStream writeObject()/readObject() since ArrayList implements Serializable. It's not clear to me from your question if you want to do this or just write each individual item. If so then Andrey's answer will do that.
Upvotes: 4