Spring Boot注解 之 @RequestX

本文的示例代码参考RequestX

目录

• 开始

• @RequestMapping

  • GET

  • POST

  • 小重构

• @RequestHeader

• @RequestBody

  • application/x-www-form-urlencoded

  • application/json

• @RequestParam

• @PathVariable

开始

spring init -dweb --build gradle RequestX

@RequestMapping

GET

# cd RequestX
vim src/main/java/com/example/RequestX/UserController.java

package com.example.RequestX;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {
    @RequestMapping(path = "/users", method = RequestMethod.GET)
    public String getUsers() {
        return "getUsers";
    }
}

• 测试

./gradlew bootrun

curl localhost:8080/users # 返回"getUsers"

@RequestMapping(method = RequestMethod.GET)等价于@GetMapping

POST

vim src/main/java/com/example/RequestX/UserController.java

# 省略了包名和导入文件

@RestController
public class UserController {
    @RequestMapping(path = "/users", method = RequestMethod.GET)
    public String getUsers() {
        return "getUsers";
    }

    @RequestMapping(path = "/users", method = RequestMethod.POST)
    public String addUser() {
        return "addUser";
    }
}

• 测试

./gradlew bootrun

curl -X POST localhost:8080/users # 返回"addUser"

@RequestMapping(method = RequestMethod.POST)等价于@PostMapping

小重构

vim src/main/java/com/example/RequestX/UserController.java

# 省略了包名和导入文件

@RestController
@RequestMapping("/users")
public class UserController {
    @GetMapping
    public String getUsers() {
        return "getUsers";
    }

    @PostMapping
    public String addUser() {
        return "addUser";
    }
}

• 测试

./gradlew bootrun

curl localhost:8080/users # 返回"getUsers"

curl -X POST localhost:8080/users # 返回"addUser"

@RequestHeader

vim src/main/java/com/example/RequestX/UserController.java

# 省略了包名和导入文件

@RestController
@RequestMapping("/users")
public class UserController {
    @GetMapping
    public String getUsers(@RequestHeader("Custom-Header") String customHeader) {
        System.out.println("Custom-Header: " + customHeader);
        return "getUsers";
    }

    # 省略了未修改代码
}

• 测试

./gradlew bootrun

curl -H 'Custom-Header: kevin' localhost:8080/users # 打印"Custom-Header: kevin" + 返回"getUsers"

@RequestBody

vim src/main/java/com/example/RequestX/UserController.java

# 省略了包名和导入文件

@RestController
@RequestMapping("/users")
public class UserController {
    # 省略了未修改代码

    @PostMapping
    public String addUser(@RequestBody String requestBody) {
        System.out.println("requestBody: " + requestBody);
        return "addUser";
    }
}

• 测试

./gradlew bootrun

curl -X POST -d 'kevin' localhost:8080/users # 打印"requestBody: kevin=" + 返回"addUser"

application/x-www-form-urlencoded

curl -X POST -d 'name=kevin' -x 127.0.0.1:8888 localhost:8080/users
# 打印"requestBody: name=kevin" + 返回"addUser"

此时 HTTP请求的抓包信息如下

image.png

注意 Content-Type: application/x-www-form-urlencoded

它是浏览器原生

表单提交数据的编码方式 也是很多API和工具POST请求默认的编码方式 形如

key1=val1&key2=val2

这里使用Charles抓包工具 更多参考 Charles 从入门到精通

application/json

curl -X POST -H "Content-type: application/json" -d '{"name":"kevin"}' -x 127.0.0.1:8888 http://localhost:8080/users
# 打印"requestBody: {"name":"kevin"}" + 返回"addUser"

此时 HTTP请求的抓包信息如下

image.png

注意 Content-Type: application/json

关于HTTP请求Body的这两种编码方式的比较 更多参考为什么接口设计都不用普通 POST ？

@RequestParam

vim src/main/java/com/example/RequestX/UserController.java

# 省略了包名和导入文件

@RestController
@RequestMapping("/users")
public class UserController {
    @GetMapping
    public String getUsers(@RequestParam(value = "name", required = false, defaultValue = "jason") String name) {
        System.out.println("name: " + name);
        return "getUsers";
    }

    # 省略了未修改代码
}

• 测试

./gradlew bootrun

curl localhost:8080/users?name=kevin # 打印"name: kevin" + 返回"getUsers"

@PathVariable

vim src/main/java/com/example/RequestX/UserController.java

# 省略了包名和导入文件

@RestController
@RequestMapping("/users")
public class UserController {
    # 省略了未修改代码

    @GetMapping("/{userId}")
    public String getUser(@PathVariable("userId") String userId) {
        System.out.println("userId: " + userId);
        return "getUser";
    }

    # 省略了未修改代码
}

• 测试

./gradlew bootrun

curl localhost:8080/users/123 # 打印"userId: 123" + 返回"getUsers"

参考

• Spring实战（第4版）

• 四种常见的 POST 提交数据方式

• A Guide to Spring Framework Annotations