如何将Spring-Mobile项目中的这段Java代码改写为Switch Case形式？

Got it, let's clean up your code into a more maintainable switch-case structure while fixing a small bug I spotted in your original tablet error handling. Here's how to do it right for your Spring Mobile project:

First, let's address the issue in your original code: your tablet catch block was incorrectly setting the success redirect URL on failure—we'll fix that to use the proper failure URL instead.

Option 1: Using String-Based Switch (Quick and Simple) #

This approach is straightforward if you don't want to add extra enum definitions:

// First, categorize the device type
String deviceType;
if (device.isMobile()) {
    deviceType = "MOBILE";
} else if (device.isTablet()) {
    deviceType = "TABLET";
} else if (device.isNormal()) {
    deviceType = "NORMAL";
} else {
    // Fallback to normal web device if type is unknown
    deviceType = "NORMAL";
}

// Handle success and failure with consolidated try-catch
try {
    switch (deviceType) {
        case "MOBILE":
            redirectUri = cfg.getEmail().getVerification().getMobile_success_redirect_url();
            break;
        case "TABLET":
            redirectUri = cfg.getEmail().getVerification().getTablet_success_redirect_url();
            break;
        case "NORMAL":
        default:
            redirectUri = cfg.getEmail().getVerification().getWeb_success_redirect_url();
            break;
    }
} catch (Exception ex) {
    // Set failure URL based on device type
    switch (deviceType) {
        case "MOBILE":
            redirectUri = cfg.getEmail().getVerification().getMobile_failure_redirect_url();
            break;
        case "TABLET":
            redirectUri = cfg.getEmail().getVerification().getTablet_failure_redirect_url(); // Fixed your original typo here
            break;
        case "NORMAL":
        default:
            redirectUri = cfg.getEmail().getVerification().getWeb_failure_redirect_url();
            break;
    }
    logger.error("Failed to verify email. Cause: {}", ex);
}

response.sendRedirect(redirectUri);

Option 2: Using Enum (Type-Safe and Clean) #

For better type safety and to avoid string typos, define an enum for device types:

// Define an enum (can be a top-level class or nested inside your component)
private enum DeviceType {
    MOBILE, TABLET, NORMAL
}

// Determine the device type using the enum
DeviceType deviceType;
if (device.isMobile()) {
    deviceType = DeviceType.MOBILE;
} else if (device.isTablet()) {
    deviceType = DeviceType.TABLET;
} else {
    deviceType = DeviceType.NORMAL;
}

// Switch with enum for type-safe logic
try {
    switch (deviceType) {
        case MOBILE:
            redirectUri = cfg.getEmail().getVerification().getMobile_success_redirect_url();
            break;
        case TABLET:
            redirectUri = cfg.getEmail().getVerification().getTablet_success_redirect_url();
            break;
        case NORMAL:
            redirectUri = cfg.getEmail().getVerification().getWeb_success_redirect_url();
            break;
    }
} catch (Exception ex) {
    switch (deviceType) {
        case MOBILE:
            redirectUri = cfg.getEmail().getVerification().getMobile_failure_redirect_url();
            break;
        case TABLET:
            redirectUri = cfg.getEmail().getVerification().getTablet_failure_redirect_url();
            break;
        case NORMAL:
            redirectUri = cfg.getEmail().getVerification().getWeb_failure_redirect_url();
            break;
    }
    logger.error("Failed to verify email. Cause: {}", ex);
}

response.sendRedirect(redirectUri);

Key Improvements: #

• Consolidated Try-Catch: Instead of wrapping each device check in its own try-catch, we use a single block since all the cfg.getEmail() calls can throw the same exceptions—this reduces redundant code.
• Fixed Bug: Corrected the tablet failure redirect URL (your original code used the success URL here, which was likely a mistake).
• Cleaner Logic: Switch-case makes the device-specific logic easier to read and maintain compared to multiple separate if-try-catch blocks.

内容的提问来源于stack exchange，提问作者Sharmistha Chakraborty