Add unified application path resolver

src/main/java/com/example/workutils/system/support/ApplicationPaths.java

@@ -0,0 +1,68 @@
+package com.example.workutils.system.support;
+
+import java.nio.file.Path;
+import java.util.Arrays;
+
+/** Resolves every WorkUtils runtime path from one stable application home. */
+public final class ApplicationPaths {
+
+    public static final String HOME_PROPERTY = "workutils.home";
+    public static final String HOME_ENV = "WORKUTILS_HOME";
+
+    private final Path home;
+
+    private ApplicationPaths(Path home) {
+        this.home = home.toAbsolutePath().normalize();
+    }
+
+    public static ApplicationPaths current() {
+        return resolve(System.getProperty(HOME_PROPERTY), System.getenv(HOME_ENV),
+                System.getProperty("user.dir"));
+    }
+
+    public static ApplicationPaths of(Path home) {
+        if (home == null) {
+            throw new IllegalArgumentException("Application home must not be null");
+        }
+        return new ApplicationPaths(home);
+    }
+
+    static ApplicationPaths resolve(String property, String environment, String userDirectory) {
+        String selected = firstNonBlank(property, environment, userDirectory);
+        if (selected == null) {
+            throw new IllegalStateException("Application home is unavailable");
+        }
+        return new ApplicationPaths(Path.of(selected.trim()));
+    }
+
+    public Path home() {
+        return home;
+    }
+
+    public Path resolve(String first, String... more) {
+        return home.resolve(Path.of(first, more)).normalize();
+    }
+
+    public Path resolveConfigured(String configured, String... fallbackSegments) {
+        Path value;
+        if (configured == null || configured.isBlank()) {
+            if (fallbackSegments.length == 0) {
+                throw new IllegalArgumentException("A fallback path is required");
+            }
+            value = Path.of(fallbackSegments[0],
+                    Arrays.copyOfRange(fallbackSegments, 1, fallbackSegments.length));
+        } else {
+            value = Path.of(configured.trim());
+        }
+        return (value.isAbsolute() ? value : home.resolve(value)).normalize();
+    }
+
+    private static String firstNonBlank(String... values) {
+        for (String value : values) {
+            if (value != null && !value.isBlank()) {
+                return value;
+            }
+        }
+        return null;
+    }
+}

src/test/java/com/example/workutils/system/support/ApplicationPathsTest.java

@@ -0,0 +1,64 @@
+package com.example.workutils.system.support;
+
+import org.junit.jupiter.api.Test;
+
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class ApplicationPathsTest {
+
+    @Test
+    void systemPropertyWinsOverEnvironmentAndWorkingDirectory() {
+        ApplicationPaths paths = ApplicationPaths.resolve(
+                " build/系统 属性 ", "build/环境变量", "build/工作目录");
+
+        assertEquals(Path.of("build", "系统 属性").toAbsolutePath().normalize(), paths.home());
+    }
+
+    @Test
+    void environmentWinsWhenSystemPropertyIsBlank() {
+        ApplicationPaths paths = ApplicationPaths.resolve(
+                "  ", "build/环境 变量", "build/工作目录");
+
+        assertEquals(Path.of("build", "环境 变量").toAbsolutePath().normalize(), paths.home());
+    }
+
+    @Test
+    void blankOverridesFallBackToWorkingDirectory() {
+        ApplicationPaths paths = ApplicationPaths.resolve(" ", "", "build/工作 目录");
+
+        assertEquals(Path.of("build", "工作 目录").toAbsolutePath().normalize(), paths.home());
+    }
+
+    @Test
+    void missingAllSourcesIsRejected() {
+        assertThrows(IllegalStateException.class,
+                () -> ApplicationPaths.resolve(null, " ", null));
+    }
+
+    @Test
+    void configuredRelativePathUsesApplicationHome() {
+        ApplicationPaths paths = ApplicationPaths.of(Path.of("build", "运行 根目录"));
+
+        assertEquals(paths.home().resolve(Path.of("data", "plugins.config")),
+                paths.resolveConfigured("data/plugins.config"));
+    }
+
+    @Test
+    void configuredAbsolutePathIsPreserved() {
+        ApplicationPaths paths = ApplicationPaths.of(Path.of("build", "运行 根目录"));
+        Path absolute = Path.of(System.getProperty("java.io.tmpdir"), "绝对 配置").toAbsolutePath().normalize();
+
+        assertEquals(absolute, paths.resolveConfigured(absolute.toString()));
+    }
+
+    @Test
+    void fallbackSegmentsAreResolvedWithoutEmbeddedSeparators() {
+        ApplicationPaths paths = ApplicationPaths.of(Path.of("build", "运行 根目录"));
+
+        assertEquals(paths.home().resolve(Path.of("data", "api_base_classes.json")),
+                paths.resolveConfigured(null, "data", "api_base_classes.json"));
+    }
+}