Read HttpServletRequest object from Spring Boot controller method

Question

Below is my controller method definition

@Autowired
private HttpServletRequest request;

@PostMapping(path = "/abc")
public String createAbc(@RequestBody HttpServletRequest request)
        throws IOException {

    logger.info("Request body: "+request.getInputStream());

    return "abc";

}

All i want to do is print contents to request body. But when i make a POST request i see below error:

Type definition error: [simple type, class javax.servlet.http.HttpServletRequest]; nested exception is com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of javax.servlet.http.HttpServletRequest (no Creators, like default construct, exist): abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information\n at [Source: (PushbackInputStream); line: 1, column: 2]",

I'm using Spring boot 2.x version.Any idea what's wrong in my code?

You already have autowired your request. Where did you get @RequestBody HttpServletRequest request from ? — Scary Wombat
– Scary Wombat, Commented Sep 12, 2019 at 1:18

Andreas · Accepted Answer · 2019-09-12 01:34:04Z

18

First, remove the @Autowired field. It's wrong and you're not using it anyway.

Now you have two choices:

Let Spring process the request body for you, by using the @RequestBody annotation:

@PostMapping(path = "/abc")
public String createAbc(@RequestBody String requestBody) throws IOException {
    logger.info("Request body: " + requestBody);
    return "abc";
}

Process it yourself, i.e. don't use the @RequestBody annotation:

@PostMapping(path = "/abc")
public String createAbc(HttpServletRequest request) throws IOException {
    StringBuilder builder = new StringBuilder();
    try (BufferedReader in = request.getReader()) {
        char[] buf = new char[4096];
        for (int len; (len = in.read(buf)) > 0; )
            builder.append(buf, 0, len);
    }
    String requestBody = builder.toString();
    logger.info("Request body: " + requestBody);
    return "abc";
}

Don't know why you'd use option 2, but you can if you want.

answered Sep 12, 2019 at 1:34

Andreas

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7 Comments

Scary Wombat Over a year ago

remove the @Autowired field. It's wrong - can you please explain why it is wrong ? Seen in stackoverflow.com/questions/3320674/…

Andreas Over a year ago

@ScaryWombat Well, true, it is wrong for a singleton bean. It is not wrong in that link you provided, since it explicitly says that it is a request-scoped bean. Since this question didn't specify that, the default type of bean is singleton, so it would be wrong. Besides, why create a request-scoped bean, when a singleton bean will suffice? Anyway, it is surely wrong to have HttpServletRequest as both an autowired field and as a parameter.

Scary Wombat Over a year ago

the default type of bean is singleton, so it would be wrong - Thanks

Andreas Over a year ago

@ScaryWombat Yeah, you have to add another annotation to change the scope, e.g. @Scope(WebApplicationContext.SCOPE_REQUEST). Without a @Scope annotation, the bean is singleton.

0x4ndy Over a year ago

@Andreas one of the reasons you'd like to go for option 2 is when you don't receive the post as plain text but something like a gzip, that is sent by the client. You of course would not use the string builder to unzip the data but something like GZIPInputStream and dump it to a normal String, but that's one of the reasons why you would need to have access to HttpServletRequest. So, thanks for the answer mate, very helpful!

|

aniran mohammadpour · Accepted Answer · 2022-01-23 14:52:40Z

1

if you want to take it out easily:

private ObjectMapper objectMapper;

byte[] bytes = request.getInputStream().readAllBytes();

User u = objectMapper.readValue(bytes, User.class);

answered Jan 23, 2022 at 14:52

aniran mohammadpour

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