Spring MVC同一控制器内方法调用失败，求正确实现方式

Hey Sachin, let's figure out why your method call isn't working and fix it up!

First, let's diagnose the core issue: Your getPaymentDetails method uses @PathVariable to fetch the msg value, but when you do redirect:/getPaymentDetails?msg=msg, you're passing msg as a request parameter (not a path variable). That's why Spring can't bind the value correctly, leading to the failed call.

Here are a few solid ways to achieve what you want:

1. Switch to @RequestParam (keep the redirect approach) #

Modify the getPaymentDetails method to accept msg as a request parameter, which matches how you're passing it in the redirect URL:

@RequestMapping(value="/getDonationDetails" , method={RequestMethod.GET,RequestMethod.POST})
public String getDonationDetails() throws IOException {
    return "redirect:/getPaymentDetails?msg=hello";
}

@RequestMapping(value="/getPaymentDetails", method={RequestMethod.GET, RequestMethod.POST})
// Replace @PathVariable with @RequestParam
public String getPaymentDetails(@RequestParam String msg){
    System.out.println("message is " + msg);
    return "success";
}

2. Adjust redirect to use path variables (if you need @PathVariable) #

If you really want to stick with @PathVariable, update both the redirect URL and the @RequestMapping of getPaymentDetails to include the path variable:

@RequestMapping(value="/getDonationDetails" , method={RequestMethod.GET,RequestMethod.POST})
public String getDonationDetails() throws IOException {
    // Pass msg as a path segment in the redirect URL
    return "redirect:/getPaymentDetails/hello";
}

// Update the mapping to include the {msg} path variable
@RequestMapping(value="/getPaymentDetails/{msg}", method={RequestMethod.GET, RequestMethod.POST})
public String getPaymentDetails(@PathVariable String msg){
    System.out.println("message is " + msg);
    return "success";
}

3. Direct method call (no redirect, better for same-controller logic) #

Since both methods live in the same controller, you don't need a redirect at all—just call the method directly. Use Model or ModelMap to pass data between methods instead of URL parameters:

@RequestMapping(value="/getDonationDetails" , method={RequestMethod.GET,RequestMethod.POST})
public String getDonationDetails(Model model) throws IOException {
    // Add data to the model to pass to the target method
    model.addAttribute("msg", "hello");
    // Call getPaymentDetails directly
    return getPaymentDetails(model);
}

@RequestMapping(value="/getPaymentDetails", method={RequestMethod.GET, RequestMethod.POST})
public String getPaymentDetails(@RequestParam(required = false) String msg, Model model){
    // Handle both direct calls (get from model) and URL requests (get from param)
    String message = msg != null ? msg : (String) model.getAttribute("msg");
    System.out.println("message is " + message);
    return "success";
}

Note: If your methods rely on request-specific objects like HttpServletRequest or HttpServletResponse, make sure to pass those along when calling the method directly.

内容的提问来源于stack exchange，提问作者Sachin HR