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This article mainly explains "the use scenario of @ RequestParam and @ RequestBody in postman". The content of the explanation in this article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "the use scenario of @ RequestParam and @ RequestBody in postman".

I. Preface

There has always been a question: when using the postman tool to test the api interface, how to use json strings to pass values instead of using x-www-form-urlencoded types, after all, passing values through key-value is limited. If I were to test the interface for bulk inserting data, using the x-www-form-urlencoded method would not be suitable for this scenario at all.

So how to use the json string to pass values through the postman tool? here are two annotations of spring:

@ RequestParam

@ RequestBody

All in all, both annotations can receive parameters in the background, but the usage scenarios are different. Keep looking down, ↓.

2. @ RequestParam

Let's first introduce the usage scenario of @ RequestParam:

Note @ RequestParam receives parameters from requestHeader, the request header. It is usually used for GET requests, such as the common url: http://localhost:8081/spring-boot-study/novel/findByAuthorAndType?author= Tang Jia San Shao & type= has been completed, which is written in the Controller layer as shown below:

@ RequestParam has three configuration parameters:

Required indicates whether it is required. The default is true. It must be.

DefaultValue sets the default values for request parameters.

Value is the parameter name that receives the url (equivalent to the key value).

@ RequestParam is used to process content encoded by Content-Type for application/x-www-form-urlencoded, and Content-Type defaults to this attribute.

@ RequestParam can also be used for other types of requests, such as POST, DELETE, and so on. For example, if you insert a single piece of data into a table, the Controller layer is written as follows:

Since @ RequestParam is used to handle content encoded by Content-Type for application/x-www-form-urlencoded, in postman, select the type of body as x-www-form-urlencoded, which automatically changes to the Content-Type: application/x-www-form-urlencoded encoding format in headers. As shown in the following figure:

But this does not support batch insertion of data, ah, if you use json string to pass the value, the type is set to application/json, and if you click to send, it will report an error, and the backend will not receive the value, which is null.

At this point, the annotation @ RequestBody comes in handy. Keep looking down, ↓.

3. @ RequestBody

Let's first introduce the usage scenario of @ RequestBody:

Note @ RequestBody receives parameters from requestBody, that is, the request body. It is generally used to deal with data in non-Content-Type: application/x-www-form-urlencoded encoding format, such as application/json, application/xml and other types of data.

For data of type application/json, you can use the annotation @ RequestBody to transfer all the json data in body to the backend, and then parse it.

3.1 insert data in bulk into the table

For example, to insert data in bulk, the Controller layer is written as follows:

Since @ RequestBody can be used to process content encoded by Content-Type for application/json, in postman, select the type of body as row-> JSON (application/json), which will automatically change to Content-Type: application/json encoding in Headers. The data in body is shown in the figure below:

Insert two pieces of data into the table in batches, and the saveBatchNovel () method here encapsulates the saveAll () method of JPA. The key value of the json statement in body corresponds to the attributes of the backend entity class one by one.

Note: if the front end uses $. Ajax, be sure to specify contentType: "application/json;charset=utf-8;", which defaults to application/x-www-form-urlencoded.

3.2 the backend parses json data

The above example is the specific writing passed to the entity class, so how do you parse the json data in body if you pass it to a non-entity class? Let's take a look at the following example:

In body, we still enter the above json data. According to the analysis, the above json data is a List array with map objects nested within it, so the receiving form in the background can be written as List. The specific code is shown below:

Postman request:

Console output:

It is concluded that the data in json format in Body can be parsed through @ RequestBody.

IV. Summary

Note @ RequestParam receives parameters from requestHeader, the request header. It is usually used for GET requests, but other types of requests such as POST, DELETE, and so on can also be used.

Note @ RequestBody receives parameters from requestBody, that is, the request body. It is generally used to deal with data in non-Content-Type: application/x-www-form-urlencoded encoding format, such as application/json, application/xml and other types of data. It is usually used to receive request data of POST, DELETE, and other types, and the GET type can also be applied.

Thank you for your reading. The above is the content of @ RequestParam and @ RequestBody usage scenarios in postman. After the study of this article, I believe you have a deeper understanding of the use scenarios of @ RequestParam and @ RequestBody in postman, and the specific usage needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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