Question

如何重写此方法以最大限度地提高代码效率并最小化代码长度？

注意：HEADER是之前定义的常量。

private static URL getURL(String OS, String type, String size) {
        String prefix = "";
        String prefixLarge = "";
        if (type.equals("image")) {
            prefix = HEADER + "/image";
            prefixLarge = HEADER + "/image_large";
        } else {
            prefix = HEADER + "/file";
            prefixLarge = HEADER + "/file_raw";
        }
        String suffix = ".zip";
        String url = "";
        if (OS.contains("Win7.32bit")) {
            // win7-32bit system
            url = prefix + "Win7.32bit" + suffix;
            if (size.contains("origin")) {
                url = prefixLarge + "Win7.32bit" + suffix;
            }
        } else if (OS.contains("Win7.64bit")) {
            // win7-64bit system
            url = prefix + "Win7.64bit" + suffix;
            if (size.contains("origin")) {
                url = prefixLarge + "Win7.64bit" + suffix;
            }
        } else if (OS.contains("WinXP")) {
            // winxp-32bit system
            url = prefix + "WinXP" + suffix;
            if (size.contains("origin")) {
                url = prefixLarge + "WinXP" + suffix;
            }
        } else if (OS.contains("WinXP.64bit")) {
            // winxp-64bit system
            url = prefix + "WinXP.64bit" + suffix;
            if (size.contains("origin")) {
                url = prefixLarge + "WinXP.64bit" + suffix;
            }
        } else if (OS.contains("10.04")) {
            // ubuntu10.04 system
            url = prefix + "ubuntu10.04" + suffix;
            if (size.contains("origin")) {
                url = prefixLarge + "ubuntu10.04" + suffix;
            }
        } else if (OS.contains("12.04")) {
            // ubuntu12.04 system
            url = prefix + "ubuntu12.04" + suffix;
            if (size.contains("origin")) {
                url = prefixLarge + "ubuntu12.04" + suffix;
            }
        }
        return url;
    }

Answer 1

创建一个包含所有操作系统名称的Strings数组。然后使用for循环遍历该数组。

像这样：

String[] osNames = { "Win7.32bit", "Win7.64bit", "10.04" };
String[] osTypes = { "Win7.32bit", "Win7.64bit", "ubuntu10.04" };
for (int i = 0; i < Math.min(osNames.length, osTypes.length); i++) {
    if (OS.contains(osName[i])) {
        url = prefix + osType[i] + suffix;
        if (size.contains("origin")) {
            url = prefixLarge + osType[i] + suffix;
        }
        break;
    }
}

Answer 2

    private static Map <String, String> osMap = new HashMap<String, String>();
    static {
      osMap.put("Win7.32bit", "Win7.32bit");
      osMap.put("Win7.64bit", "Win7.64bit");
      osMap.put("WinXP", "WinXP");
      osMap.put("WinXP.64bit", "WinXP.64bit");
      osMap.put("10.04", "ubuntu10.04");
      osMap.put("12.04", "ubuntu12.04");
    }

    private static URL getURL(String os, String type, String size) {
        String prefix = "";
        String prefixLarge = "";
        if (type.equals("image")) {
            prefix = HEADER + "/image";
            prefixLarge = HEADER + "/image_large";
        } else {
            prefix = HEADER + "/file";
            prefixLarge = HEADER + "/file_raw";
        }
        String suffix = ".zip";
        String url = "";
        String systemType = "";

        for(String key : osMap.keySet()) {
           if(os.contains(key) {           
              url = prefix + osMap.get(key) + suffix;
              if (size.contains("origin")) {
                url = prefixLarge + osMap.get(key) + suffix;
              }
              break;
           }
        }
        return url;
 }

Answer 3

private static URL getURL(String OS, String type, String size) {

    return  HEADER
            +
            size.contains("origin") 
                            ? ((type.equals("image") ? "/image_large" : "/file_raw" ))
                            : ((type.equals("image") ? "/image" : "/file" )) 
            +
            OS.contains("Win7.32bit")   ? "Win7.32bit" :
            OS.contains("Win7.64bit")   ? "Win7.64bit" : 
            OS.contains("WinXP.64bit")  ? "WinXP.64bit" :       
            OS.contains("WinXP")        ? "WinXP" : 
            OS.contains("10.04")        ? "ubuntu10.04" : 
            OS.contains("12.04")        ? "ubuntu12.04" : 
            ""
            +
            ".zip";
}

Answer 4

String[] osNames={"Win7.32bit", "Win7.64bit"};
        for(String os : osNames){
            if(OS.contains(os)){
                url = prefix + os + suffix;
                if (size.contains("origin")) {
                    url = prefixLarge + os + suffix;
                }
                break;
            }
        }

这是删除if-else条件的代码的一部分。注意break语句。

如何重写此方法以删除冗余的if语句？

4 个答案: