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)}

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.
