Controller

示例：

HelloController

package com.example;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @Value("${age}")
    private Integer age;//@value可以获取application.yml配置的值

    @RequestMapping(value = "/hello")
    public String sayHello() {
        return "hello world age:" + age;
    }
}

application.yml

age: 18

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常用注解

@RestController = @Controller + @ResponseBody
@Controller需要返回 template 模版，类似于 Django 的模板。
建议使用：@RestController

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映射多个路径

• 单个映射：@RequestMapping(value = "/hello")

@RequestMapping(value = "/hello")
public String sayHello() {
   return "hello world name:" + person.getName() + " , age:" + person.getAge();
}

• 多个映射：@RequestMapping(value = {"hello", "hi"})

@RequestMapping(value = {"hello", "hi"})
public String sayHello() {
   return "hello world name:" + person.getName() + " , age:" + person.getAge();
}

• 整个 controller 增加映射，在类上增加：@RequestMapping(value = "/demo")

@RestController
@RequestMapping(value = "/demo")
public class HelloController {

    @Autowired
    private Person person;

    @RequestMapping(value = {"hello", "hi"})
    public String sayHello() {
        return "hello world name:" + person.getName() + " , age:" + person.getAge();
    }
}

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访问方式：

• method = RequestMethod.GET
• method = RequestMethod.POST
• ...
• 简便方式：
  • @GetMapping(value = "hello")
  • @PostMapping(value = "hello")

@RestController
@RequestMapping(value = "/demo")
public class HelloController {

    @Autowired
    private Person person;

    @RequestMapping(value = {"hello", "hi"}, method = RequestMethod.GET)
    //@GetMapping(value = "hello")
    public String sayHello() {
        return "hello world name:" + person.getName() + " , age:" + person.getAge();
    }
}

注意：什么都不写，默认是 get 和 post 都可以访问，但是不建议这样做，需要明确指定访问方式。

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获取访问参数

• 获取 GET 的 URL 的参数和 POST 的 请求 body 参数

  • 字段field映射

  @RequestMapping(value = "hello", method = RequestMethod.GET)
  public String sayHello(@RequestParam(value = "id", required = false, defaultValue = "0") Integer id) {
     return "id:" + id;
  }
  

  • 实体 model 映射

  @PostMapping(value = "/addPerson")
  public Person addPerson(Person person) {
     return personRespository.save(person);
  }
  

• 获取 restfully 参数

@RequestMapping(value = "hello/{id}", method = RequestMethod.GET)
public String sayHello(@PathVariable("id") Integer id) {
   return "id:" + id;
}

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