要获取头提交树，请调用
git.getRepository().resolve( "HEAD^{tree}" )并获取HEAD提交的父级的树，请调用
git.getRepository().resolve( "HEAD~1^{tree}" )如果您对更多详细信息感兴趣，请搜索“ Git caret and tilde”。
总而言之，这里有一个片段，用于计算两次提交的差异：
File file = new File( git.getRepository().getWorkTree(), "file.txt" );writeFile( file, "first version" );RevCommit newCommit = commitChanges();writeFile( file, "second version" );RevCommit oldCommit = commitChanges();ObjectReader reader = git.getRepository().newObjectReader();CanonicalTreeParser oldTreeIter = new CanonicalTreeParser();ObjectId oldTree = git.getRepository().resolve( "HEAD^{tree}" ); // equals newCommit.getTree()oldTreeIter.reset( reader, oldTree );CanonicalTreeParser newTreeIter = new CanonicalTreeParser();ObjectId newTree = git.getRepository().resolve( "HEAD~1^{tree}" ); // equals oldCommit.getTree()newTreeIter.reset( reader, newTree );DiffFormatter df = new DiffFormatter( new ByteArrayOutputStream() ); // use NullOutputStream.INSTANCE if you don't need the diff outputdf.setRepository( git.getRepository() );List<DiffEntry> entries = df.scan( oldTreeIter, newTreeIter );for( DiffEntry entry : entries ) { System.out.println( entry );}private RevCommit commitChanges() throws GitAPIException { git.add().addFilepattern( "." ).call(); return git.commit().setMessage( "commit message" ).call();}private static void writeFile( File file, String content ) throws IOException { FileOutputStream outputStream = new FileOutputStream( file ); outputStream.write( content.getBytes( "UTF-8" ) ); outputStream.close();}有关显示提交之间的更改的进一步考虑，您可能需要阅读JGit差异API的深入讨论，可以在以下位置找到：http : //www.preaffine.com/2016/06/16/jgit-
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