这也适用于Java 8:

Path file = Paths.get("Some path");
file = Paths.get(file + "Some other path");

您应该使用一个用于表示文件系统路径的类，而不是保持所有内容都基于字符串。

如果你使用的是Java 7或Java 8，你应该强烈考虑使用Java .nio.file. path;路径。解析可用于将一个路径与另一个路径或与字符串组合。Paths助手类也很有用。例如:

Path path = Paths.get("foo", "bar", "baz.txt");

如果需要适应java -7之前的环境，可以使用java.io。文件，像这样:

File baseDirectory = new File("foo");
File subDirectory = new File(baseDirectory, "bar");
File fileInDirectory = new File(subDirectory, "baz.txt");

如果稍后希望它以字符串形式返回，可以调用getPath()。实际上，如果您真的想模仿Path。结合起来，你可以这样写:

public static String combine(String path1, String path2)
{
    File file1 = new File(path1);
    File file2 = new File(file1, path2);
    return file2.getPath();
}

也许来晚了，但我想分享一下我对这件事的看法。我不喜欢把整个库都拉来做这样的事情。相反，我使用Builder模式，并允许方便地链式附加(更多)调用。它甚至允许混合文件和字符串，并且可以很容易地扩展到支持路径。此外，它可以在Linux、Macintosh等上自动正确地处理不同的路径分隔符。

public class Files  {
    public static class PathBuilder {
        private File file;

        private PathBuilder ( File root ) {
            file = root;
        }

        private PathBuilder ( String root ) {
            file = new File(root);
        }

        public PathBuilder append ( File more ) {
            file = new File(file, more.getPath()) );
            return this;
        }

        public PathBuilder append ( String more ) {
            file = new File(file, more);
            return this;
        }

        public File buildFile () {
            return file;
        }
    }

    public static PathBuilder buildPath ( File root ) {
        return new PathBuilder(root);
    }

    public static PathBuilder buildPath ( String root ) {
        return new PathBuilder(root);
    }
}

用法示例:

File root = File.listRoots()[0];
String hello = "hello";
String world = "world";
String filename = "warez.lha"; 

File file = Files.buildPath(root).append(hello).append(world)
              .append(filename).buildFile();
String absolute = file.getAbsolutePath();

生成的绝对值将包含如下内容:

/hello/world/warez.lha

或者甚至:

A:\hello\world\warez.lha

这也适用于Java 8:

Path file = Paths.get("Some path");
file = Paths.get(file + "Some other path");

该解决方案提供了一个接口，用于连接String[]数组中的路径片段。它使用java.io.File。文件(父字符串，子字符串):

    public static joinPaths(String[] fragments) {
        String emptyPath = "";
        return buildPath(emptyPath, fragments);
    }

    private static buildPath(String path, String[] fragments) {
        if (path == null || path.isEmpty()) {
            path = "";
        }

        if (fragments == null || fragments.length == 0) {
            return "";
        }

        int pathCurrentSize = path.split("/").length;
        int fragmentsLen = fragments.length;

        if (pathCurrentSize <= fragmentsLen) {
            String newPath = new File(path, fragments[pathCurrentSize - 1]).toString();
            path = buildPath(newPath, fragments);
        }

        return path;
    }

然后你可以这样做:

String[] fragments = {"dir", "anotherDir/", "/filename.txt"};
String path = joinPaths(fragments);

返回:

"/dir/anotherDir/filename.txt"

平台独立的方法(使用File。分隔符，即将工作取决于代码运行的操作系统:

java.nio.file.Paths.get(".", "path", "to", "file.txt")
// relative unix path: ./path/to/file.txt
// relative windows path: .\path\to\filee.txt

java.nio.file.Paths.get("/", "path", "to", "file.txt")
// absolute unix path: /path/to/filee.txt
// windows network drive path: \\path\to\file.txt

java.nio.file.Paths.get("C:", "path", "to", "file.txt")
// absolute windows path: C:\path\to\file.txt