使用 Diff-Match-Patch 在 Java 中逐行区分两个字符串 [英] Diff Two Strings Line-By-Line in Java using Diff-Match-Patch

问题描述

我一直在寻找一种简单的方法来在 Java 中对两个字符串逐行进行 Myers Diff.

I was looking for an easy way to do a Myers Diff on two Strings line-by-line in Java.

根据this，Google diff-match-patch 库 具有此功能.但是，在 Java 版本中，引用的那些方法是受保护的和/或受包保护的！

According to this, the Google diff-match-patch library has this feature. But, in the Java version, those methods referenced are protected and/or package-protected!

我找不到其他库 (1) 执行此操作，并且 (2) 似乎维护良好.

I couldn't find another library that (1) does this, and (2) appears to be well-maintained.

所以我最终使用反射让谷歌让我这样做.我想避免任何人不得不重新实现它，所以我会发布我所做的作为答案.

So I ended up using reflection to get the Google one to let me do this. I want to avoid anyone having to re-implement it, so I will post what I did as an answer.

推荐答案

这是我想出的代码.随意编辑/修复.

Here is the code I came up with. Feel free to edit/fix.

我不确定任何反思的最佳实践(除了不要")，但如果有人有想法，我肯定想了解.

I'm not sure about any best-practices for reflection (besides "don't"), but I would definitely like to learn if anyone has thoughts.

List<Diff> diff = new diff_match_patch() {
    // anonymous extension
    List<Diff> getLineDiff(String a, String b) throws NoSuchFieldException, IllegalAccessException {
        LinesToCharsResult res = this.diff_linesToChars(a, b);

        // extract protected fields
        Class<?> clazz = res.getClass();
        Field chars1 = clazz.getDeclaredField("chars1");
        Field chars2 = clazz.getDeclaredField("chars2");
        Field lineArray = clazz.getDeclaredField("lineArray");
        chars1.setAccessible(true);
        chars2.setAccessible(true);
        lineArray.setAccessible(true);

        // follow the docs https://github.com/google/diff-match-patch/wiki/Line-or-Word-Diffs
        String chars1Inst = (String) chars1.get(res);
        String chars2Inst = (String) chars2.get(res);
        List<String> lineArrayInst = (List<String>) lineArray.get(res);
        LinkedList<Diff> diff = this.diff_main(chars1Inst, chars2Inst, false);

        // convert back to original strings
        this.diff_charsToLines(diff, lineArrayInst);

        return diff;
    }
}.getLineDiff(expected, output);

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