DevOps系列文章之 Java使用jgit管理git仓库-编程知识

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。

在jgit中，存在最核心的三个组件：Git类，Repository类。Git类中包含了push commit之类的常见git操作，而Repository则实现了仓库的初始化和基本的管理功能。
Git类的实例都会持有一个Repository实例。

Repository类的初始化

针对一个git仓库，我们一般会有三种方式获得
1.新建一个空仓库

 Git git = Git.init().setDirectory(localPath).call()

2.加载一个已存在的仓库

Repository repository = builder.setGitDir(repoDir).readEnvironment() // scan environment GIT_* variables.findGitDir() // scan up the file system tree.build()

3.从远程仓库下载

Git result = Git.cloneRepository().setURI(REMOTE_URL).setDirectory(localPath).call()

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：

        <!-- jgit --><dependency><groupId>org.eclipse.jgit</groupId><artifactId>org.eclipse.jgit</artifactId><version>5.8.0.202006091008-r</version></dependency><dependency><groupId>commons-io</groupId><artifactId>commons-io</artifactId><version>2.6</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

package com.devops.autocicdstore.git;import org.apache.commons.io.FileUtils;
import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.api.errors.GitAPIException;
import org.eclipse.jgit.transport.CredentialsProvider;import java.io.File;
import java.io.IOException;
import java.nio.file.Paths;import static com.devops.autocicdstore.git.GetRepositoryMgr.*;/*** @Author 虎哥* @Description //TODO* |要带着问题去学习,多猜想多验证|**/
public class TestMain {public static void main(String[] args) throws GitAPIException, IOException {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("https://gitee.com/JavaBigDataStudy/auto-cicd-store.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));}
}

package com.devops.autocicdstore.git;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.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
import org.eclipse.jgit.transport.CredentialsProvider;
import org.eclipse.jgit.transport.RefSpec;
import org.eclipse.jgit.transport.UsernamePasswordCredentialsProvider;import java.io.File;
import java.io.IOException;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;/*** @Author 虎哥* @Description //TODO* |要带着问题去学习,多猜想多验证|**/
public class GetRepositoryMgr {public static CredentialsProvider createCredential(String userName, String password) {return new UsernamePasswordCredentialsProvider(userName, password);}public static void main(String[] args) throws GitAPIException, IOException {
//        String localPath = "D:\\SoftwareDev\\Code\\auto-cicd-store\\git-res";
//        String remotePath = "https://gitee.com/JavaBigDataStudy/auto-cicd-store.git";
//        CredentialsProvider provider = createCredential("XXXX","XXX");
//        //1
//
//        Git git = fromCloneRepository(remotePath,localPath,provider);
//        //2
//        commit(git,"test",provider);
//        //3
//        push(git,"dev",provider);
//        //4
//      //  getLogs()lRepository repository = getRepositoryFromDir("D:\\\\SoftwareDev\\\\Code\\\\auto-cicd-store\\\\git-res");List<String> logs = getLogs(repository);System.out.println(logs);}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;}public static Repository getRepositoryFromDir(String dir) throws IOException {return new FileRepositoryBuilder().setGitDir(Paths.get(dir, ".git").toFile()).build();}public static void commit(Git git, String message, CredentialsProvider provider) throws GitAPIException {git.add().addFilepattern(".").call();git.commit().setMessage(message).call();}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();}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;}}

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());