要获取提交的差异，可以使用Bitbucket服务器插件中的REST API来实现。下面是一个使用Java代码示例的解决方法：

import com.atlassian.bitbucket.commit.Commit;
import com.atlassian.bitbucket.commit.CommitService;
import com.atlassian.bitbucket.commit.DiffChange;
import com.atlassian.bitbucket.commit.DiffService;
import com.atlassian.bitbucket.commit.DiffSummary;
import com.atlassian.bitbucket.diff.DiffSegment;
import com.atlassian.bitbucket.diff.DiffType;
import com.atlassian.bitbucket.diff.DiffWhitespace;
import com.atlassian.bitbucket.nav.NavBuilder;
import com.atlassian.bitbucket.project.Project;
import com.atlassian.bitbucket.repository.Repository;
import com.atlassian.plugin.spring.scanner.annotation.imports.ComponentImport;
import org.springframework.beans.factory.annotation.Autowired;

import javax.ws.rs.*;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import java.util.ArrayList;
import java.util.List;

// 声明为JAX-RS资源
@Path("/diff")
public class DiffResource {

    private final CommitService commitService;
    private final DiffService diffService;
    private final NavBuilder navBuilder;

    @Autowired
    public DiffResource(@ComponentImport CommitService commitService,
                        @ComponentImport DiffService diffService,
                        @ComponentImport NavBuilder navBuilder) {
        this.commitService = commitService;
        this.diffService = diffService;
        this.navBuilder = navBuilder;
    }

    // 定义GET请求，获取提交的差异
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response getDiff(@QueryParam("projectId") String projectId,
                            @QueryParam("repositorySlug") String repositorySlug,
                            @QueryParam("commitId") String commitId) {
        // 获取项目和代码库
        Project project = commitService.getProject(Long.parseLong(projectId));
        Repository repository = commitService.getRepository(project, repositorySlug);
        
        // 获取提交
        Commit commit = commitService.getCommit(repository, commitId);
        
        // 获取差异摘要
        DiffSummary diffSummary = diffService.getDiffSummary(repository, commit.getId());
        
        // 获取差异变化
        List diffChanges = diffService.getDiffChanges(repository, diffSummary, commit.getId(), DiffWhitespace.IGNORE_ALL);
        
        // 构建差异对象列表
        List diffs = new ArrayList<>();
        for (DiffChange diffChange : diffChanges) {
            DiffType type = diffChange.getType();
            String path = diffChange.getPath().toString();
            
            // 获取差异段落
            List diffSegments = diffService.getDiffSegments(repository, diffChange);
            List lines = new ArrayList<>();
            for (DiffSegment diffSegment : diffSegments) {
                lines.addAll(diffSegment.getLines());
            }
            
            Diff diff = new Diff(type, path, lines);
            diffs.add(diff);
        }
        
        return Response.ok(diffs).build();
    }

    // 定义差异对象
    public static class Diff {
        private final DiffType type;
        private final String path;
        private final List lines;

        public Diff(DiffType type, String path, List lines) {
            this.type = type;
            this.path = path;
            this.lines = lines;
        }

        // 省略getter方法
    }
}

这个示例中的DiffResource类定义了一个REST API资源，使用了Bitbucket服务器插件的CommitService和DiffService来获取提交的差异。GET请求可以通过查询参数指定项目ID、代码库slug和提交ID，然后返回包含差异信息的JSON响应。Diff类定义了差异对象的数据结构。

注意：这个示例使用了Spring Framework和JAX-RS，你需要根据你的项目和环境进行相应的配置和依赖项管理。