解决axios发送post请求，springMVC接收不到数据问题

今天发现一个问题：

vue组件中无法正确接收并处理axios请求

这个问题已经困扰我好久了，在电脑面前坐了两天只能确定前端应该是正确的发送了请求，但发送请求后无法正确接受后端返回的数据。

问题：vue组件无法接受后端数据

错误代码如下：

javascript">axios.post("/simple_query",{
},this.simple_query_input).then(res=>{    console.log(res);
}).catch(err=>{console.log(err);
})

java">@RequestMapping(value = "/simple_query",method = RequestMethod.POST)
public cheName handleSimpleQuery(@RequestParam("simple_query_input") String simpleQueryInput) throws Exception {}

网上找到也有类似未解决的：

Spring MVC的Controller里面使用了@RequestParam注解来接收参数，但是只在GET请求的时候才能正常访问，在使用POST请求的时候会产生找不到参数的异常。原本好好的POST请求开始报400错误，找不到REST服务，一般情况下报这种错误多是由于POST请求时传递的参数不一致，但是这次不存在这种问题，百思不得其解啊。。。

还有这个：axios发送post请求，springMVC接收不到数据问题

java">@RequestMapping(method = RequestMethod.POST, value = "/test")
@ResponseBody
public ResponseEntity testDelete(@RequestParam("id") Integer id)throws Exception {return ResponseEntity.ok();
}

代码中是规定了请求方式POST，使用@RequestParam接收id参数。

然后前台请求参数也对,是这个形式的{id:111}，看起来没错啊，参数名完全一样，但是后台报错Required String parameter 'id' is not present,说id参数必须传过来。分析问题
虽然前端传递的参数形式为{id: 111}，看起来id的参数名确实是一样的，但是这个参数是作为请求的body而非作为普通参数或query parameter传递的。因此无法直接使用@RequestParam注释接收它。

今天就俩解决一下吧：

SpringMVC 中 @PathVariable、@RequestBody、@RequestParam的使用场景以及对应的前端axios写法是什么呢？

一、@PathVariable

axios代码：

javascript">axios.post('http://localhost:8080/endpoint3/' + this.firstName + '/' + this.lastName)
.then(response => {console.log(response.data);
})
.catch(error => {console.error(error);
});

SpringMvc的controller代码：

java">@PostMapping("/endpoint3/{firstName}/{lastName}")
@ResponseBody
public String endpoint2(@PathVariable("firstName") String firstName,  @PathVariable("lastName") String lastName) {// 处理请求逻辑return "Hello, " + firstName + " " + lastName;
}

二、@RequestBody

axios代码：

javascript">axios.post('http://localhost:8080/endpoint2', {firstName: this.firstName, lastName: this.lastName})
.then(response => {console.log(response.data);
})
.catch(error => {console.error(error);
});

SpringMvc的controller代码：

java">@PostMapping("/endpoint2")
@ResponseBody
public String endpoint2(@RequestBody Map<String, Object> requestBody) {String firstName = Objects.toString(requestBody.get("firstName"));String lastName = Objects.toString(requestBody.get("lastName"));// 处理请求逻辑return "Hello, " + firstName + " " + lastName;
}

三、@RequestParam

axios代码：

javascript">const formData = new FormData();
formData.append('firstName', this.firstName);
formData.append('lastName', this.lastName);
axios.post('http://localhost:8080/endpoint1', formData)
.then(response => {console.log(response.data);
})
.catch(error => {console.error(error);
});

SpringMvc的controller代码：

java">@PostMapping("/endpoint1")
public String handlePostRequest(@RequestParam("firstName") String firstName,@RequestParam("lastName") String lastName) {// 处理请求逻辑return "Hello, " + firstName + " " + lastName;
}

前台完整代码：

<!DOCTYPE html>
<html>
<head><script src="https://cdn.bootcdn.net/ajax/libs/vue/2.7.0/vue.min.js"></script><script src="https://cdn.bootcdn.net/ajax/libs/axios/1.6.8/axios.min.js"></script>
</head>
<body><div id="app"></div><script>new Vue({el: '#app',data () {return {firstName: "John",lastName: "Doe"}},mounted () {const formData = new FormData();formData.append('firstName', this.firstName);formData.append('lastName', this.lastName);axios.post('http://localhost:8080/endpoint1', formData).then(response => {console.log(response.data);}).catch(error => {console.error(error);});	axios.post('http://localhost:8080/endpoint2', {firstName: this.firstName, lastName: this.lastName}).then(response => {console.log(response.data);}).catch(error => {console.error(error);});	axios.post('http://localhost:8080/endpoint3/' + this.firstName + '/' + this.lastName).then(response => {console.log(response.data);}).catch(error => {console.error(error);});	}})</script></body>

后台核心代码：

java">@RestController
@CrossOrigin
public class MySpringMvcController {@PostMapping("/endpoint1")public String handlePostRequest(@RequestParam("firstName") String firstName,@RequestParam("lastName") String lastName) {// 处理请求逻辑return "Hello, " + firstName + " " + lastName;}@PostMapping("/endpoint2")@ResponseBodypublic String endpoint2(@RequestBody Map<String, Object> requestBody) {String firstName = Objects.toString(requestBody.get("firstName"));String lastName = Objects.toString(requestBody.get("lastName"));// 处理请求逻辑return "Hello, " + firstName + " " + lastName;}@PostMapping("/endpoint3/{firstName}/{lastName}")@ResponseBodypublic String endpoint2(@PathVariable("firstName") String firstName,  @PathVariable("lastName") String lastName) {// 处理请求逻辑return "Hello, " + firstName + " " + lastName;}}

问题来源：

vue组件中无法正确接收并处理axios请求_前端-CSDN问答