springboot 读取文件夹返回树给前端

可以使用递归的方式遍历文件夹，并将文件夹及其子文件夹信息封装成树形结构返回给前端。以下是一个示例代码：

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

@Controller
public class FileController {

    @GetMapping("/tree")
    @ResponseBody
    public List<TreeNode> getFileTree() {
        String rootPath = "D:/files"; // 文件夹根路径
        File rootFile = new File(rootPath);
        if (!rootFile.exists() || !rootFile.isDirectory()) {
            return null;
        }
        TreeNode root = new TreeNode(rootFile.getName(), true);
        buildFileTree(root, rootFile);
        List<TreeNode> treeNodes = new ArrayList<>();
        treeNodes.add(root);
        return treeNodes;
    }

    private void buildFileTree(TreeNode parent, File parentFile) {
        File[] files = parentFile.listFiles();
        if (files != null && files.length > 0) {
            for (File file : files) {
                if (file.isDirectory()) {
                    TreeNode treeNode = new TreeNode(file.getName(), true);
                    parent.addChild(treeNode);
                    buildFileTree(treeNode, file);
                } else {
                    TreeNode treeNode = new TreeNode(file.getName(), false);
                    parent.addChild(treeNode);
                }
            }
        }
    }

    private static class TreeNode {
        private String name;
        private boolean directory;
        private List<TreeNode> children;

        public TreeNode(String name, boolean directory) {
            this.name = name;
            this.directory = directory;
        }

        public String getName() {
            return name;
        }

        public boolean isDirectory() {
            return directory;
        }

        public List<TreeNode> getChildren() {
            return children;
        }

        public void addChild(TreeNode child) {
            if (children == null) {
                children = new ArrayList<>();
            }
            children.add(child);
        }
    }

}

通过访问 `/tree` 接口，可以获取文件夹树形结构的数据，前端可以根据这些数据进行展示。