Ambiguous handler methods mapped for 'xxx'的解决办法

清疚 2024-02-19 20:27 4阅读 0赞

## Ambiguous handler methods mapped for '/book/es' ##

### 一. 问题描述 ###

我们在创建Restful风格的url的时候,可以直接将参数变量值放入到url中,然后传递到后台,后台自动识别对应的方法,非常的方便.

**但是如果我们的接口方法中出现了方法重载的情况,则有可能会出现一些问题**,如下:

package com.syc.boot.web;
    
    import com.syc.boot.domain.Book;
    import com.syc.boot.service.BookService;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.data.domain.Page;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import java.util.Optional;
    
    @Slf4j
    @RestController
    public class ElasticController {
    
        @Autowired
        private BookService bookService;
    
        @RequestMapping("/book/{id}")
        public Book getBookById(@PathVariable String id) {
            Optional<Book> opt = bookService.findById(id);
            Book book = opt.get();
            log.warn(book.toString());
            return book;
        }
    
        @RequestMapping("/book/{title}")
        public Page<Book> getBookByTitleHighLight(@PathVariable("title") String title) {
            Page<Book> books = bookService.findByTitle(title, 1, 10);
            log.warn(books.toString());
            return books;
        }
    
    }

此时在浏览器地址栏访问 `http://localhost:8080/book/1` 或 `http://localhost:8080/book/es教程` 时均会出现如下错误.

java.lang.IllegalStateException: Ambiguous handler methods mapped for '/book/es': {public com.syc.boot.domain.Book com.syc.boot.web.ElasticController.getBookById(java.lang.String), public org.springframework.data.domain.Page com.syc.boot.web.ElasticController.getBookByTitleHighLight(java.lang.String)}

![Image 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70][]

**意思是说我们的Controller中,有两个模棱两可的处理方法,这两个方法有歧义,无法分清谁是谁.因为Spring无法根据传参的类型自动匹配到可以处理的方法.**

此时如果我们依然想使用Restful编程风格,就必须改变请求得url格式,保证url对应的方法不会产生歧义.

### 二. 解决办法 ###

针对上面的例子,只要保证一个类中多个方法请求的接口方法不一样就可以了,可以是请求方法,请求参数,url等不同,这样就可以匹配到不同的方法.

package com.syc.boot.web;
    
    import com.syc.boot.domain.Book;
    import com.syc.boot.service.BookService;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.data.domain.Page;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import java.util.Optional;
    
    @Slf4j
    @RestController
    public class ElasticController {
    
        @Autowired
        private BookService bookService;
    
        @RequestMapping("/book/id/{id}")
        public Book getBookById(@PathVariable String id) {
            Optional<Book> opt = bookService.findById(id);
            Book book = opt.get();
            log.warn(book.toString());
            return book;
        }
    
        @RequestMapping("/book/title/{title}")
        public Page<Book> getBookByTitleHighLight(@PathVariable("title") String title) {
            Page<Book> books = bookService.findByTitle(title, 1, 10);
            log.warn(books.toString());
            return books;
        }
    
    }

此时再到浏览器地址栏通过 `http://localhost:8080/user/id/1` 或 `http://localhost:8080/user/title/es` 来请求.

就可以可以正常访问到后台的对象内容了.  
![Image 1][]![20190707123929167.png][]

[Image 1]: 
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N5YzAwMDY2Ng_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/1b3d32733a9d49a5801cb8fd079d823f.png
[20190707123929167.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/a9660bde091648f2aad841538475bbe7.png