将 FileWriter 的编码设置为 UTF-8 [重复]

Question

下面是我的代码，它打算获取两个 .ckl 文件，比较两者，添加新项目并创建一个新的合并文件。该程序在 Netbeans 中运行时可以正确执行，但是在执行 .jar 时，该程序似乎没有以 UTF-8 对文件进行编码。我对编程比较陌生，想知道我可能需要在哪里或如何强制执行这种编码？

** 我删除了 Swing 代码和其他行，以便只显示我的方法，该方法执行所有比较和合并。

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();
    }

}                                        

Answer 1

Java 有extensive, highly informative documentation。保留它的书签。有困难时先参考它。您会发现它经常很有帮助。

在这种情况下，documentation for FileWriter 表示：

此类的构造函数假定默认字符编码和默认字节缓冲区大小是可以接受的。要自己指定这些值，请在 FileOutputStream 上构造一个 OutputStreamWriter。

如果您想确保您的文件将被写入为 UTF-8，请替换为：

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

用这个：

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

Answer 2

对于那些使用FileWriter 来追加到现有文件的人，以下将起作用

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

    //code

}

Answer 3

您可以使用命令java -Dfile.encoding=UTF-8 -jar yourjar.jar 运行它。

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