使用JGit按分支或提交ID签出Git存储库

import org.eclipse.jgit.api.CheckoutCommand;
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;

public class JGitExample {
    public static void main(String[] args) {
        try {
            // 1. 创建Git存储库对象
            Repository repository = new FileRepositoryBuilder()
                    .setGitDir(new File("/path/to/git/repository/.git"))
                    .build();

            // 2. 打开Git存储库
            Git git = new Git(repository);

            // 3. 检出分支或提交
            String branchName = "master"; // 要检出的分支名称
            String commitId = "abcdef123456"; // 要检出的提交ID

            CheckoutCommand checkout = git.checkout();
            Ref ref = repository.findRef(branchName); // 根据分支名称获取引用
            if (ref == null) {
                ref = repository.findRef(commitId); // 根据提交ID获取引用
            }
            checkout.setStartPoint(ref.getObjectId())
                    .setName(branchName)
                    .call();

            System.out.println("Checkout completed successfully.");

            // 关闭Git存储库
            git.close();
        } catch (IOException | GitAPIException e) {
            e.printStackTrace();
        }
    }
}