set encoding as UTF-8 for a FileWriter [duplicate]

This question already has an answer here:

Write a file in UTF-8 using FileWriter (Java)? 7 answers

Below is my code, it is intended to take two .ckl files, compare the two, add the new items and create a new merged file. The program executes correctly when run in Netbeans however, when executing the .jar the program doesn't appear to be encoding the file in UTF-8. I am rather new to programming and would like to know where or how I might need to be enforcing this encoding to take place?

** I have removed the Swing code and other lines so that only my method is shown, the method that does all of the comparing and merging.

public void mergeFiles(File[] files, File mergedFile) {

    ArrayList<String> list = new ArrayList<String>();

    FileWriter fstream = null;
    BufferedWriter out = null;
    try {
        fstream = new FileWriter(mergedFile, false);
        out = new BufferedWriter(fstream);
      } catch (IOException e1) {
        e1.printStackTrace();
    }
    // Going in a different direction. We are using a couple booleans to tell us when we want to copy or not. So at the beginning since we start
    // with our source file we set copy to true, we want to copy everything and insert vuln names into our list as we go. After that first file 
    // we set the boolean to false so that we dont start copying anything from the second file until it is a vuln. We set to true when we see vuln
    // and set it to false if we already have that in our list. 
    // We have a tmpCopy to store away the value of copy when we see a vuln, and reset it to that value when we see an </VULN>
    Boolean copy = true;
    Boolean tmpCopy = true;
    for (File f : files) {
        textArea1.append("merging files into: " + mergedFilePathway + "\n");
        FileInputStream fis;
        try {
            fis = new FileInputStream(f);
//                BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(mergedFile), "UTF-8"));
            BufferedReader in = new BufferedReader(new InputStreamReader(fis));
            String aLine;
            while ((aLine = in.readLine()) != null) {
                // Skip the close checklist and we can write it in at the end
                if (aLine.trim().equals("</iSTIG>")) {
                    continue;
                }
                if (aLine.trim().equals("</STIGS>")) {
                    continue;
                }
                if (aLine.trim().equals("</CHECKLIST>")) {
                    continue;
                }
                if (aLine.trim().equals("<VULN>")) {
                    // Store our current value of copy
                    tmpCopy = copy;
                    copy = true;
                    String aLine2 = in.readLine();
                    String aLine3 = in.readLine();
                    String nameLine = in.readLine();

                    if (list.contains(nameLine.trim())) {
                        textArea1.append("Skipping: " + nameLine + "\n");
                        copy = false;
                        while (!(aLine.trim().equals("</VULN>"))) {
                            aLine = in.readLine();
                        }
                        continue; // this would skip the writing out to file part
                    } else {
                        list.add(nameLine.trim());
                        textArea1.append("::: List is now :::");
                        textArea1.append(list.toString() + "\n");
                    }
                    if (copy) {
                        out.write(aLine);
                        out.newLine();
                        out.write(aLine2);
                        out.newLine();
                        out.write(aLine3);
                        out.newLine();
                        out.write(nameLine);
                        out.newLine();
                    }
                } else if (copy) {
                    out.write(aLine);
                    out.newLine();
                }
                // after we have written to file, if the line was a close vuln, switch copy back to original value
                if (aLine.trim().equals("</VULN>")) {
                    copy = tmpCopy;
                }
            }

            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        copy = false;
    }

    // Now lets add the close checklist tag we omitted before
    try {
        out.write("</iSTIG>");
        out.write("</STIGS>");
        out.write("</CHECKLIST>");
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        out.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

回答1:

Java has extensive, highly informative documentation. Keep it bookmarked. Refer to it first, whenever you have difficulty. You'll find it's frequently helpful.

In this case, the documentation for FileWriter says:

The constructors of this class assume that the default character encoding and the default byte-buffer size are acceptable. To specify these values yourself, construct an OutputStreamWriter on a FileOutputStream.

If you want to be sure your file will be written as UTF-8, replace this:

FileWriter fstream = null;
BufferedWriter out = null;
try {
    fstream = new FileWriter(mergedFile, false);

with this:

Writer fstream = null;
BufferedWriter out = null;
try {
    fstream = new OutputStreamWriter(new FileOutputStream(mergedFile), StandardCharsets.UTF_8);

回答2:

For those, who use FileWriter in order to append to an existing file, the following will work

try (BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true), StandardCharsets.UTF_8)) {

    //code

}

回答3:

You can just run it with the command java -Dfile.encoding=UTF-8 -jar yourjar.jar.

Follow this for more info.

回答4:

Here is a good example of how to construct a BufferWriter with an OutputStream that specifies UTF encoding.