Swiftで作ったサンプルのJava版です。 仕様などはSwift版と同様なので→ Swift版

こちらもJavaで正規表現を利用するサンプルにもなってます。

使い方

String sampleText = "てめえらの｜血《ち》は｜何色《なにいろ》だーっ！！";
AozoraRubyParser parser = new AozoraRubyParser(sampleText);
List<AozoraRubyParser.Result> tokens = parser.parse();
for (AozoraRubyParser.Result r : tokens){
  Log.d("", r.text +  (r.ruby != null ? "[" + r.ruby + "]" : "") );
}

パーサーのコード

public class AozoraRubyParser {

  static public class Result {
    public String text;
    public String ruby;

    public Result(String t, String r) {
      this.text = t;
      this.ruby = r;
    }
  }


  private String text;

  public AozoraRubyParser(String text) {
    this.text = text;
  }

  public List<Result> parse() {

    ArrayList<Result> result = new ArrayList<>();

    String patternStr = "｜(.+?)《(.+?)》";
    Pattern ptn = Pattern.compile(patternStr);

    int position = 0;

    Matcher matcher = ptn.matcher(text);
    while (matcher.find()) {
      if (position < matcher.start()) {
        String subText = this.text.substring(position, matcher.start());
        result.add(new Result(subText, null));
      }
      position = matcher.end();

      // 文字と読み仮名を抽出
      result.add(new Result(matcher.group(1), matcher.group(2)));
    }

    // 文末の残りを追加
    if (this.text.length() > position) {
      String subText = this.text.substring(position, this.text.length());
      result.add(new Result(subText, null));
    }

    return result;
  }
}