@Test
public void testU() {

    assertThat(Functions.u(null), is(""));
    assertThat(Functions.u(""), is(""));
    assertThat(Functions.u("あいうえお"), is(
            "%E3%81%82%E3%81%84%E3%81%86%E3%81%88%E3%81%8A"));
    assertThat(Functions.u("http://localhost:8080/spring"), is(
            "http://localhost:8080/spring"));
    assertThat(Functions.u("http://localhost:8080/あいうえお"), is(
            "http://localhost:8080/%E3%81%82%E3%81%84%E3%81%86%E3%81%88%E3%81%8A"));
}