使用JGit对上一次提交进行文件差异

Question

我正在尝试使用JGit来获取从上次提交到最近未提交的更改的文件差异。我该如何使用JGit？（使用命令行将是的输出git diff HEAD）

经过几次讨论（link1，link2），我附带了一段代码，该代码可以查找未提交的文件，但无法获取文件的区别

Repository db = new FileRepository("/path/to/git");
Git git = new Git(db);

AbstractTreeIterator oldTreeParser = this.prepareTreeParser(db, Constants.HEAD);

List<DiffEntry> diff = git.diff().setOldTree(oldTreeParser).call();

for (DiffEntry entry : diff) {
    System.out.println("Entry: " + entry + ", from: " + entry.getOldId() + ", to: " + entry.getNewId());
    DiffFormatter formatter = new DiffFormatter(System.out);
    formatter.setRepository(db);
    formatter.format(entry);

}

更新

这个问题是很久以前的。我现有的for确实显示了未提交的代码。prepareTreeParser在显示差异的上下文中，我正在使用的当前代码是：

public void gitDiff() throws Exception {
    Repository db = new FileRepository("/path/to/git" + DEFAULT_GIT);
    Git git = new Git(db);

    ByteArrayOutputStream out = new ByteArrayOutputStream();
    DiffFormatter formatter = new DiffFormatter( out );
    formatter.setRepository(git.getRepository());
    AbstractTreeIterator commitTreeIterator = prepareTreeParser(git.getRepository(), Constants.HEAD);
    FileTreeIterator workTreeIterator = new FileTreeIterator( git.getRepository() );
    List<DiffEntry> diffEntries = formatter.scan( commitTreeIterator, workTreeIterator );

    for( DiffEntry entry : diffEntries ) {
        System.out.println("DIFF Entry: " + entry + ", from: " + entry.getOldId() + ", to: " + entry.getNewId());
        formatter.format(entry);
        String diffText = out.toString("UTF-8");
        System.out.println(diffText);
        out.reset();
    }
    git.close();
    db.close();

    // This code is untested. It is slighting different for the code I am using in production,
    // but it should be very easy to adapt it for your needs
}
private static AbstractTreeIterator prepareTreeParser(Repository repository, String ref) throws Exception {
    Ref head = repository.getRef(ref);
    RevWalk walk = new RevWalk(repository);
    RevCommit commit = walk.parseCommit(head.getObjectId());
    RevTree tree = walk.parseTree(commit.getTree().getId());

    CanonicalTreeParser oldTreeParser = new CanonicalTreeParser();
    ObjectReader oldReader = repository.newObjectReader();
    try {
        oldTreeParser.reset(oldReader, tree.getId());
    } finally {
        oldReader.release();
    }
    return oldTreeParser;
}

Answer 1

以下设置适用于我：

DiffFormatter formatter = new DiffFormatter( System.out );
formatter.setRepository( git.getRepository() );
AbstractTreeIterator commitTreeIterator = prepareTreeParser( git.getRepository(),  Constants.HEAD );
FileTreeIterator workTreeIterator = new FileTreeIterator( git.getRepository() );
List<DiffEntry> diffEntries = formatter.scan( commitTreeIterator, workTreeIterator );

for( DiffEntry entry : diffEntries ) {
  System.out.println( "Entry: " + entry + ", from: " + entry.getOldId() + ", to: " + entry.getNewId() );
  formatter.format( entry );
}

通过可以访问未提交的更改FileTreeIterator。使用formatter.scan()代替DiffCommand的优点是格式化程序已正确设置以处理FileTreeIterator。否则MissingObjectException，当格式化程序尝试从存储库中的工作树中查找更改时，您将得到。