Spring MVC Controller：“return forward”，“return redirect”和“return return”之间的区别是什么？和“返回jsp文件” [英] Spring MVC Controller: what is the difference between "return forward", "return redirect" and "return jsp file"

问题描述

我不明白我应该使用什么。
我有两个页面--intro.jsp（1）和booksList.jsp（2）。对于每个页面，我创建了一个Controller类。
第一页有按钮打开第二页：

I don't understand what I should use. I have two pages - intro.jsp(1) and booksList.jsp(2). For each page I created one Controller Class. The first page has button which opens second page:

<form method="GET" action="/request-list">
        <input type="submit"/>
</form>

第一个问题是：我不确定这个按钮的正确性。它运作良好，但按下此按钮后我有问号。

The first question is: I am not sure about correctness this button. It works well, but I have question mark after press this button.

第二个问题是：当我按下该按钮时，方法有下一个调用注释（第二页的控制器）：

The second question is: When I press that button, method with next annotation is called (Controller for the second page):

@RequestMapping(value = "/books")
@Controller
public class BooksListController {

   @RequestMapping
   public String booksList() {
      return "jsp/books/booksList";
   }
}

此方法应该返回什么？换句话说，我如何从第一页跳到第二页？

What should I return by this method? In other words how can I jump from first page to second one?

1. returnredirect：/ books;返回http：// localhost：8080 / books？


2. returnjsp / books / booksList;返回http：// localhost：8080 / request-list？


3. returnforward：/ books;返回http：// localhost：8080 / request-list？

1. return "redirect:/books"; returns http://localhost:8080/books?
2. return "jsp/books/booksList"; returns http://localhost:8080/request-list?
3. return "forward:/books"; returns http://localhost:8080/request-list?

我看到结果是一样的：所有这些字符串给了我相同的页面（第2页打开）。
在哪些情况下我应该使用redirect，forward，page.jsp？

I see that result is the same: all these Strings gave me the same page (page 2 was opened). In which cases I should use "redirect", "forward", "page.jsp"?

我还读过发布/重定向/获取文章。在POST方法处理后我是否必须使用重定向？

Also I've read Post/Redirect/Get article. Do I have to use "redirect" after POST method handling??

推荐答案

第一个问题是：我不确定这个按钮的正确性。
效果很好，但按下此按钮后我有问号。

The first question is: I am not sure about correctness this button. It works well, but I have question mark after press this button.

好的，它会插入一个问号，因为你使用GET http方法。您需要使用POST方法传递请求有效负载中的数据。

Ok, it's insert a question mark because you use GET http method. You need to use POST method to pass the data in the request payload.

return "redirect:/books";

它返回客户端（浏览器），解释http响应并自动调用重定向URL

It returns to the client (browser) which interprets the http response and automatically calls the redirect URL

return "jsp/books/booksList";

它处理JSP并将HTML发送到客户端

It process the JSP and send the HTML to the client

return "forward:/books";

它传输请求并直接在服务器端调用URL。

It transfer the request and calls the URL direct in the server side.

要决定使用哪一种，你必须考虑每种方法的某些方面：

To decide which one to use you have to consider some aspects of each approach:

转发：速度更快，客户端浏览器不参与，浏览器显示原始URL，转发请求转发URL。

Forward: is faster, the client browser is not involved, the browser displays the original URL, the request is transfered do the forwarded URL.

重定向：速度慢，客户端涉及浏览器，浏览器显示重定向的URL，它会向重定向的URL创建新请求。

Redirect: is slower, the client browser is involved, the browser displays the redirected URL, it creates a new request to the redirected URL.

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