最近设计基于gitops新的CICD方案,需要通过java读写git仓库，这里简单记录下。

JGit是一款pure java的软件包，可以读写git仓库，下面介绍基本使用。

引入jgit

maven引入：

        <!-- https://mvnrepository.com/artifact/org.eclipse.jgit/org.eclipse.jgit -->
        <dependency>
            <groupId>org.eclipse.jgit</groupId>
            <artifactId>org.eclipse.jgit</artifactId>
            <version>5.6.0.201912101111-r</version>
        </dependency>

jgit 有一个Git类，可以用来执行常规的git操作

凭证管理

通过CredentialsProvider管理凭证，常用的是UsernamePasswordCredentialsProvider

通过下面代码初始化：

public static CredentialsProvider createCredential(String userName, String password) {
        return new UsernamePasswordCredentialsProvider(userName, password);
    }

clone远程仓库

git 命令：

git clone {repoUrl}

通过Git.cloneRepository 来clone远程仓库，如果需要凭证，则需要指定credentialsProvider

 public static Git fromCloneRepository(String repoUrl, String cloneDir, CredentialsProvider provider) throws GitAPIException {
        Git git = Git.cloneRepository()
            .setCredentialsProvider(provider)
            .setURI(repoUrl)
            .setDirectory(new File(cloneDir)).call();
        return git;
    }

commit

git 命令：

git commit -a -m '{msg}'

commit比较简单，对应commit方法, 注意需要先add

    public static void commit(Git git, String message, CredentialsProvider provider) throws GitAPIException {
        git.add().addFilepattern(".").call();
        git.commit()
            .setMessage(message)
            .call();
    }

push

git 命令：

git push origin branchName

push直接调用push即可, 需要指定credentialsProvider

   public static void push(Git git, CredentialsProvider provider) throws GitAPIException, IOException {
        push(git,null,provider);
    }

    public static void push(Git git, String branch, CredentialsProvider provider) throws GitAPIException, IOException {
        if (branch == null) {
            branch = git.getRepository().getBranch();
        }
        git.push()
            .setCredentialsProvider(provider)
            .setRemote("origin").setRefSpecs(new RefSpec(branch)).call();
    }

读取已有仓库

如果git已经clone了，想直接读取，怎么办？

 public static Repository getRepositoryFromDir(String dir) throws IOException {
        return new FileRepositoryBuilder()
            .setGitDir(Paths.get(dir, ".git").toFile())
            .build();
    }

读取仓库日志

可以通过RevWalk读取仓库日志。

• revWalk.parseCommit 可读取一条commit
• 遍历revWalk，可读取所有日志

 public static List<String> getLogs(Repository repository) throws IOException {
        return getLogsSinceCommit(repository, null, null);
    }

    public static List<String> getLogsSinceCommit(Repository repository, String commit) throws IOException {
        return getLogsSinceCommit(repository, null, commit);
    }

    public static List<String> getLogsSinceCommit(Repository repository, String branch, String commit) throws IOException {
        if (branch == null) {
            branch = repository.getBranch();
        }
        Ref head = repository.findRef("refs/heads/" + branch);
        List<String> commits = new ArrayList<>();
        if (head != null) {
            try (RevWalk revWalk = new RevWalk(repository)) {
                revWalk.markStart(revWalk.parseCommit(head.getObjectId()));
                for (RevCommit revCommit : revWalk) {
                    if (revCommit.getId().getName().equals(commit)) {
                        break;
                    }
                    commits.add(revCommit.getFullMessage());
                    System.out.println("\nCommit-Message: " + revCommit.getFullMessage());
                }
                revWalk.dispose();
            }
        }

        return commits;
    }

测试

我们来先clone仓库，然后修改，最后push

 String yaml = "dependencies:\n" +
            "- name: springboot-rest-demo\n" +
            "  version: 0.0.5\n" +
            "  repository: http://hub.hubHOST.com/chartrepo/ainote\n" +
            "  alias: demo\n" +
            "- name: exposecontroller\n" +
            "  version: 2.3.82\n" +
            "  repository: http://chartmuseum.jenkins-x.io\n" +
            "  alias: cleanup\n";
        CredentialsProvider provider = createCredential("USR_NAME", "PASSWORD");

        String cloneDir = "/tmp/test";

        Git git = fromCloneRepository("http://gitlab.GITHOST.cn/datahub/env-test.git", cloneDir, provider);

        // 修改文件

        FileUtils.writeStringToFile(Paths.get(cloneDir, "env", "requirements.yaml").toFile(), yaml, "utf-8");
      
        // 提交
        commit(git, "deploy(app): deploy  springboot-rest-demo:0.0.5 to env test", provider);
        // push 到远程仓库
        push(git, "master", provider);

        git.clean().call();
        git.close();

        FileUtils.deleteDirectory(new File(cloneDir));

读取已有仓库的日志：

        Repository repository = getRepositoryFromDir("GIT_DIR");
        List<String> logs = getLogs(repository);
        System.out.println(logs);

        RevCommit head = getLastCommit(repository);
        System.out.println(head.getFullMessage());

小结

本文讲述了如何通过jgit完成常规的git操作。

---

作者：Jadepeng
出处：jqpeng的技术记事本--http://www.cnblogs.com/xiaoqi
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