add FindOsUrl function

redistruable/javaentities/java.go

@@ -19,8 +19,17 @@ type JavaMetas struct {
 	JavaVersions []JavaMeta `json:"javaVersions"`
 }
 
-func (jm JavaMetas) GetOsURL() (string, error) {
-
+func (jm JavaMetas) FindOsURL(MajorVersion string) (SpecificJavaVersion, error) {
+	for _, v := range jm.JavaVersions {
+		if MajorVersion == v.Version.Major {
+			jv, err := v.getOsJava()
+			if err != nil {
+				continue
+			}
+			return jv, nil
+		}
+	}
+	return SpecificJavaVersion{}, errors.New("cant find os url")
 }
 
 type JavaMeta struct {