user2900314 user2900314 - 7 months ago 18
Java Question

Unable to write large String to a file

I am trying to print a large string(single line) into a file. But the string is getting truncated in between. Any idea on why this is happening?

void writeToFile(String schemaString,String message){

try{
FileWriter fw = new FileWriter("D:\\Servicelog.txt", true);
java.util.Date date= new java.util.Date();
fw.write(new Timestamp(date.getTime())+"\n");
fw.write(message+"\n");
fw.write("schemaBegins\n"+schemaString+"\n"+"schemaEnds");
}catch(Exception e){
e.printStackTrace();
}

}

Answer

You should remember to close the file.

FileWriter fw = null;
try {
    fw = new FileWriter("D:\\Servicelog.txt", true);
    java.util.Date date = new java.util.Date();
    fw.write(new Timestamp(date.getTime()) + "\n");
    fw.write(message + "\n");
    fw.write("schemaBegins\n" + schemaString + "\n" + "schemaEnds");
} catch (Exception e) {
    e.printStackTrace();
} finally {
    if ( fw != null ) {
        fw.close();
    }
}

Java7 and newer encapsulate that mechanism using try-with-resources:

try (FileWriter fw = new FileWriter("D:\\Servicelog.txt", true) ) {
    java.util.Date date = new java.util.Date();
    fw.write(new Timestamp(date.getTime()) + "\n");
    fw.write(message + "\n");
    fw.write("schemaBegins\n" + schemaString + "\n" + "schemaEnds");
} catch (Exception e) {
    e.printStackTrace();
}

Writing to any Writer can be buffered, leaving some of the data unwritten if you do not close it.