用java编写如下程序：java中获取同一个类中不同次代码提交变更的方法： 1.代码差异可通过git diff 比对两次commit id获取 2.变更代码解析对应的类文件及内部的方法并存储

以下是一个示例程序，可以实现获取同一个 Java 类中不同次代码提交变更的方法，以及将变更代码解析对应的类文件及内部的方法并存储：

import org.eclipse.jgit.api.Git;
import org.eclipse.jgit.diff.DiffEntry;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.CanonicalTreeParser;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.filter.PathFilter;

import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.*;

public class JavaCodeChanges {
    public static void main(String[] args) throws IOException {
        String repoDir = "/path/to/your/repo"; // Git 仓库的本地路径
        String filePath = "src/main/java/YourClass.java"; // Java 类文件的路径

        try (Git git = Git.open(Paths.get(repoDir))) {
            Iterable<RevCommit> commits = git.log().addPath(filePath).call();

            Map<String, Set<String>> methodsMap = new HashMap<>(); // 保存方法名的映射

            RevCommit prevCommit = null;
            for (RevCommit commit : commits) {
                if (prevCommit != null) {
                    RevWalk walk = new RevWalk(git.getRepository());

                    // 获取两个提交之间的差异
                    ObjectReader reader = git.getRepository().newObjectReader();
                    CanonicalTreeParser oldTreeIter = new CanonicalTreeParser();
                    oldTreeIter.reset(reader, prevCommit.getTree());
                    CanonicalTreeParser newTreeIter = new CanonicalTreeParser();
                    newTreeIter.reset(reader, commit.getTree());
                    List<DiffEntry> diffs = git.diff()
                            .setOldTree(oldTreeIter)
                            .setNewTree(newTreeIter)
                            .setPathFilter(PathFilter.create(filePath))
                            .call();

                    // 解析差异中的变更代码
                    for (DiffEntry diff : diffs) {
                        String[] lines = git.show().setPath(diff.getNewPath()).call().split("\n");
                        for (String line : lines) {
                            if (line.matches("^\\s*public.*\\(.*\\)\\s*\\{\\s*$")) {
                                String method = line.replaceFirst("^\\s*public\\s*", "")
                                        .replaceFirst("\\(.*\\)\\s*\\{\\s*$", "");

                                // 将方法名及对应的提交 ID 添加到映射中
                                if (!methodsMap.containsKey(method)) {
                                    methodsMap.put(method, new HashSet<>());
                                }
                                methodsMap.get(method).add(commit.getName());
                            }
                        }
                    }

                    walk.dispose();
                }

                prevCommit = commit;
            }

            // 解析每个提交对应的类文件，并提取其中的方法
            for (Map.Entry<String, Set<String>> entry : methodsMap.entrySet()) {
                String method = entry.getKey();
                Set<String> commitIds = entry.getValue();

                for (String commitId : commitIds) {
                    Path classFilePath = Paths.get(repoDir, ".git", "objects", commitId.substring(0, 2), commitId.substring(2));
                    byte[] classFileData = git.getRepository().open(classFilePath).getBytes();
                    byte[] decompressedData = org.eclipse.jgit.util.IO.readFully(classFileData);
                    byte[] classBytes = org.eclipse.jgit.lib.Constants.encodedTypeString(org.eclipse.jgit.lib.Constants.OBJ_BLOB).getBytes(StandardCharsets.US_ASCII);
                    byte[] allBytes = new byte[classBytes.length + decompressedData.length];
                    System.arraycopy(classBytes, 0, allBytes, 0, classBytes.length);
                    System.arraycopy(decompressedData, 0, allBytes, classBytes.length, decompressedData.length);

                    // 解析类文件中的方法
                    ClassReader classReader = new ClassReader(allBytes);
                    ClassNode classNode = new ClassNode();
                    classReader.accept(classNode, 0);
                    for (MethodNode methodNode : classNode.methods) {
                        if (methodNode.name.equals(method)) {
                            // 保存方法名及对应的类名和提交 ID
                            Path outputDir = Paths.get("output");
                            Files.createDirectories(outputDir);
                            Path outputFile = outputDir.resolve(method + ".txt");
                            String output = classNode.name + " (" + commitId + ")";
                            Files.write(outputFile, Collections.singleton(output), StandardCharsets.UTF_8);
                        }
                    }
                }
            }
        }
    }
}

这个程序使用 JGit 库来访问 Git 仓库，并使用 `git diff` 命令来比较两个提交之间 Java 类文件的差异。它会输出所有变更过的方法名，并将变更代码解析对应的类文件及内部的方法，并存储到一个文本文件中。你需要替换 `repoDir` 和 `filePath` 变量为你自己的值。