目录

1、直接在Controller层方法参数上获取2、通过@Autowired注入3、通过RequestContextHolder获取

1、直接在Controller层方法参数上获取

仅仅适用在controller方法上。当Spring接收到HTTP请求时，会寻找一个合适的方法来处理该请求。如果该方法参数上标注了@RequestMapping或@Get、@Post等注解，Spring就会将HttpServletRequest对象注入到该参数中。

@RestController

public class Controller {

@RequestMapping("/test")

public String test(HttpServletRequest request,HttpServletResponse response) {

return "success";

}

}

2、通过@Autowired注入

适用于所有的bean

@Autowired

private HttpServletRequest request;

@Autowired

private HttpServletResponse response;

@RequestMapping("/test")

public String test() {

Enumeration headerNames = request.getHeaderNames();

response.setHeader("header","header_value");

return "success";

}

通过调试可以看到，注入的Reques是一个代理类，而这个被代理的目标由RequestObjectFactory.getObject() 获取 我们再看一下RequestObjectFactory.getObject() 的方法，最终还是走到了RequestContextHolder.getRequestAttributes()方法

private static class RequestObjectFactory implements ObjectFactory, Serializable {

@Override

public ServletRequest getObject() {

return currentRequestAttributes().getRequest();

}

@Override

public String toString() {

return "Current HttpServletRequest";

}

}

private static ServletRequestAttributes currentRequestAttributes() {

RequestAttributes requestAttr = RequestContextHolder.currentRequestAttributes();

if (!(requestAttr instanceof ServletRequestAttributes)) {

throw new IllegalStateException("Current request is not a servlet request");

}

return (ServletRequestAttributes) requestAttr;

}

3、通过RequestContextHolder获取

适用于所有的方法，spring会通过RequestContextHolder.setRequestAttributes方法将RequestAttributes设置到ThreadLocal中。

ServletRequestAttributes attr = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();

HttpServletRequest request = attr.getRequest();

HttpServletResponse response = attr.getResponse();

文章链接

评论可见，请评论后查看内容，谢谢！！！评论后请刷新页面。