Docker 交付入门：镜像、网络与数据卷分别负责什么

Path mount = fileSystem.getPath("/app/data");
Path target = fileSystem.getPath("/app/data/item.json"); // fileSystem必须对应所解释的平台路径语义。
if (target.startsWith(mount)) { // 按路径组件判断，不用普通字符串前缀。
    Path relative = mount.relativize(target); // 得到挂载内部相对位置。
    inspectLogicalMapping(relative); // 只解释路径映射，未实际访问或移动文件。
}

import java.util.*;
public class Main {
    static class Node {Map<String,Node> children=new HashMap<>();String volume;}
    static String[] parts(String path){
        if(path==null||!path.startsWith("/")||path.indexOf(92)>=0)throw new IllegalArgumentException("path");
        if(path.equals("/"))return new String[0];String[] p=path.substring(1).split("/",-1);
        for(String s:p)if(s.isEmpty()||s.equals(".")||s.equals("..")||s.indexOf(0)>=0)throw new IllegalArgumentException("component");return p; // 有限规范语法，不模拟符号链接。
    }
    static Node mounts(String[][] mappings){
        Node root=new Node();for(String[] pair:mappings){if(pair.length!=2||pair[1]==null||pair[1].isBlank())throw new IllegalArgumentException("mapping");Node n=root;
            for(String p:parts(pair[0]))n=n.children.computeIfAbsent(p,k->new Node());
            if(n.volume!=null)throw new IllegalArgumentException("duplicate");n.volume=pair[1]; // 同一挂载目标只接受一个定义。
        }return root;
    }
    static String resolve(Node root,String path){
        String[] p=parts(path);Node n=root;String best=n.volume==null?"IMAGE":n.volume;
        for(String part:p){n=n.children.get(part);if(n==null)break;if(n.volume!=null)best=n.volume;} // 记住最后一个完整组件前缀。
        return best;
    }
    static void eq(String e,String a){if(!e.equals(a))throw new AssertionError(a);}
    public static void main(String[] args){
        Node n=mounts(new String[][]{{"/app","A"},{"/app/data","B"}});
        eq("B",resolve(n,"/app/data/x"));eq("A",resolve(n,"/app/log"));eq("IMAGE",resolve(n,"/application/x"));
        eq("B",resolve(n,"/app/data"));eq("IMAGE",resolve(mounts(new String[][]{}),"/"));
        eq("ROOT",resolve(mounts(new String[][]{{"/","ROOT"}}),"/any"));
        try{resolve(n,"/app/../secret");throw new AssertionError();}catch(IllegalArgumentException expected){}
        try{mounts(new String[][]{{"/a","A"},{"/a","B"}});throw new AssertionError();}catch(IllegalArgumentException expected){}
        System.out.println("PASS 8 tests");
    }
}