Spring 注解面面通 之 @RequestBody
@RequestBody
用于将完整请求正文映射到控制器处理方法的参数中,请求正文通过HttpMessageConverter进行转换。
注解解析
① required
:
请求正文是否必须有值,默认值为true
。
required
为true
时,如果请求正文没有值,则会抛出异常。
required
为false
时,如果请求正文没有值,则会返回null
。
注解示例
1) 建Controller
,用来演示@RequestBody
使用方法。
package com.arhorchin.securitit.webannotations;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import com.alibaba.fastjson.JSON;
/**
* @author Securitit.
* @note 演示@RequestBody使用方法.
*/
@Controller
@RequestMapping("/WebAnnotations")
public class RequestBodyController {
/**
* logger.
*/
private Logger logger = LoggerFactory.getLogger(RequestBodyController.class);
/**
* 从请求报文以Map解析方法参数.
*/
@ResponseBody
@RequestMapping(
value = "/RequestBodyMap.do",
method = RequestMethod.POST)
public String requestParamMap(@RequestBody Map<String, String> requestBodyMap) throws Exception {
logger.info("Current value of RequestBody is " + JSON.toJSONString(requestBodyMap));
return "Current value of RequestBody is " + JSON.toJSONString(requestBodyMap);
}
/**
* 从请求报文以Map解析方法参数.
*/
@ResponseBody
@RequestMapping(
value = "/RequestBodyMapRequiredTrue.do",
method = RequestMethod.POST)
public String requestParamMapRequiredTrue(@RequestBody(
required = true) Map<String, String> requestBodyMap) throws Exception {
logger.info("Current value of RequestBody [required is true] is " + JSON.toJSONString(requestBodyMap));
return "Current value of RequestBody [required is true] is " + JSON.toJSONString(requestBodyMap);
}
/**
* 从请求报文以Map解析方法参数.
*/
@ResponseBody
@RequestMapping(
value = "/RequestBodyMapRequiredFalse.do",
method = RequestMethod.POST)
public String requestParamMapRequiredFalse(@RequestBody(
required = false) Map<String, String> requestBodyMap) throws Exception {
logger.info("Current value of RequestBody [required is false] is " + JSON.toJSONString(requestBodyMap));
return "Current value of RequestBody [required is false] is " + JSON.toJSONString(requestBodyMap);
}
}
2) 使用《Spring 注解面面通 之 Http测试工具》提供的Http测试工具进行测试。
① 测试http://localhost:9199/spring-annotations/WebAnnotations/RequestBodyMap.do
。
② 测试http://localhost:9199/spring-annotations/WebAnnotations/RequestBodyMapRequiredTrue.do
。
可以看到请求返回400
和Bad Request
,查看后端控制台可以看到:
2020-12-05 13:46:10 WARN [org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver] Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing: public java.lang.String com.arhorchin.securitit.webannotations.RequestBodyController.requestParamMapRequiredTrue(java.util.Map<java.lang.String, java.lang.String>) throws java.lang.Exception
③ 测试http://localhost:9199/spring-annotations/WebAnnotations/RequestBodyMapRequiredFalse.do
。
可以看到虽然和②中请求一直,但确正常返回数据,原因在于后端设置了@RequestBody(required = false)
所致。
总结
@RequestBody
注解在当下的应用开发中使用非常频繁,掌握它可以让我们开发更加顺畅。
若文中存在错误和不足,欢迎指正!
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