Java snakeyaml 修改yaml文件保留注释工具类封装
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.SneakyThrows;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.StringUtils;
import java.io.File;
import java.nio.charset.StandardCharsets;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class CommentUtils {
public static final String END = "END###";
public static final Pattern COMMENT_LINE = Pattern.compile("^\\s*#.*$");
public static final Pattern BLANK_LINE = Pattern.compile("^\\s*$");
// 带注释的有效行, 使用非贪婪模式匹配有效内容
public static final Pattern LINE_WITH_COMMENT = Pattern.compile("^(.*?)\\s+#.*$");
@Data
@AllArgsConstructor
public static class Comment {
private String lineNoComment;
private String lineWithComment;
private Integer indexInDuplicates; // 存在相同行时的索引 (不同key下相同的行, 如 a:\n name: 1 和 b:\n name: 1 )
private boolean isEndLine() {
return END.equals(lineNoComment);
}
}
@SneakyThrows
public static CommentHolder buildCommentHolder(File file) {
List<Comment> comments = new ArrayList<>();
Map<String, Integer> duplicatesLineIndex = new HashMap<>();
CommentHolder holder = new CommentHolder(comments);
List<String> lines = FileUtils.readLines(file, StandardCharsets.UTF_8);
// 末尾加个标志, 防止最后的注释丢失
lines.add(END);
StringBuilder lastLinesWithComment = new StringBuilder();
for (String line : lines) {
if (StringUtils.isBlank(line) || BLANK_LINE.matcher(line).find()) {
lastLinesWithComment.append(line).append('\n');
continue;
}
// 注释行/空行 都拼接起来
if (COMMENT_LINE.matcher(line).find()) {
lastLinesWithComment.append(line).append('\n');
continue;
}
String lineNoComment = line;
boolean lineWithComment = false;
// 如果是带注释的行, 也拼接起来, 但是记录非注释的部分
Matcher matcher = LINE_WITH_COMMENT.matcher(line);
if (matcher.find()) {
lineNoComment = matcher.group(1);
lineWithComment = true;
}
// 去除后面的空格
lineNoComment = lineNoComment.replace("\\s*$", "");
// 记录下相同行的索引
Integer idx = duplicatesLineIndex.merge(lineNoComment, 1, Integer::sum);
// 存在注释内容, 记录
if (lastLinesWithComment.length() > 0 || lineWithComment) {
lastLinesWithComment.append(line);
comments.add(new Comment(lineNoComment, lastLinesWithComment.toString(), idx));
// 清空注释内容
lastLinesWithComment = new StringBuilder();
}
}
return holder;
}
@AllArgsConstructor
public static class CommentHolder {
private List<Comment> comments;
/**
* 通过正则表达式移除匹配的行 (防止被移除的行携带注释信息, 导致填充注释时无法正常匹配)
*/
public void removeLine(String regex) {
comments.removeIf(comment -> comment.getLineNoComment().matches(regex));
}
@SneakyThrows
public void fillComments(File file) {
if (comments == null || comments.isEmpty()) {
return;
}
if (file == null || !file.exists()) {
throw new IllegalArgumentException("file is not exist");
}
List<String> lines = FileUtils.readLines(file, StandardCharsets.UTF_8);
Map<String, Integer> duplicatesLineIndex = new HashMap<>();
int comIdx = 0;
StringBuilder res = new StringBuilder();
for (String line : lines) {
Integer idx = duplicatesLineIndex.merge(line, 1, Integer::sum);
Comment comment = getOrDefault(comments, comIdx, null);
if (comment != null &&
Objects.equals(line, comment.lineNoComment)
&& Objects.equals(comment.indexInDuplicates, idx)) {
res.append(comment.lineWithComment).append('\n');
comIdx++;
} else {
res.append(line).append('\n');
}
}
Comment last = comments.get(comments.size() - 1);
if (last.isEndLine()) {
res.append(last.lineWithComment.substring(0, last.lineWithComment.indexOf(END)));
}
FileUtils.write(file, res.toString(), StandardCharsets.UTF_8);
}
}
public static <T> T getOrDefault(List<T> vals, int index, T defaultVal) {
if (vals == null || vals.isEmpty()) {
return defaultVal;
}
if (index >= vals.size()) {
return defaultVal;
}
T v = vals.get(index);
return v == null ? defaultVal : v;
}
}