SpringBoot2.X基础HTTP接口GET请求实战【GET请求】

讲解springboot接口，http的get请求，各个注解使用

1、单一参数@RequestMapping(path = "/{id}", method = RequestMethod.GET)
   1) public String getUser(@PathVariable String id ) {}
                
   2）@RequestMapping(path = "/{depid}/{userid}", method = RequestMethod.GET) 可以同时指定多个提交方法
                getUser(@PathVariable("depid") String departmentID,@PathVariable("userid") String userid)

  3）一个顶俩
   @GetMapping = @RequestMapping(method = RequestMethod.GET)
   @PostMapping = @RequestMapping(method = RequestMethod.POST)
   @PutMapping = @RequestMapping(method = RequestMethod.PUT)
    @DeleteMapping = @RequestMapping(method = RequestMethod.DELETE)

 4）@RequestParam(value = "name", required = true)
                    可以设置默认值，比如分页 

5)@RequestBody 请求体映射实体类
                    需要指定http头为 content-type为application/json charset=utf-8

6）@RequestHeader 请求头，比如鉴权
                    @RequestHeader("access_token") String accessToken

 7）HttpServletRequest request自动注入获取参数

代码：

package net.xdclass.demo.controller;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import net.xdclass.demo.domain.TestUser;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

//@RestController返回json格式
@RestController
//定义控制器对应法URL
@RequestMapping("/testGet")
public class GetController {

	
	private Map params = new HashMap<>();

	//++++++++++++++++++++
	/***
	 * 第一类：GET请求路径参数
	 * 1、@PathVariable
	 * 获取路径参数。即url/{id}这种形式。
	 *
	 * 2、@RequestParam
	 * 获取查询参数。即url?name=这种形式
	 * @param id
	 * @param name
	 */
	@GetMapping("/demo/{id}")
	public Object demo(@PathVariable(name = "id") String id,
					   @RequestParam(name = "name") String name,
					   @RequestParam(name = "age") int age) {

		params.clear();
		params.put("id",id);
		params.put("name",name);
		params.put("age",age);
		return params;
	}
	//++++++++++++++++++++


	/**
	 * 通过request获取参数【重点】
	 * HttpServletRequest request
	 * @param request
	 * @return
	 */
	@GetMapping("test_request")
	public Object testRequest(HttpServletRequest request){
		params.clear();
		String id = request.getParameter("id");
		params.put("id", id);
		String name = request.getParameter("name");
		params.put("name",name);
		return params;
	}



	/**
	 * 功能描述：测试restful协议，从路径中获取字段
	 * 定义接口协议：小写字母 + 下划线，防止有些语言不支持驼峰
	 * 或者这样：但是赋值变量名必须与参数一致
	 * path = "/{city_id}/{user_id}"
	 * findUser(@PathVariable String city_id,
	 *          @PathVariable String user_id )
	 * @param cityId
	 * @param userId
	 * @return
	 */
	@RequestMapping(path = "/{city_id}/{user_id}", method = RequestMethod.GET)
	public Object findUser(@PathVariable("city_id") String cityId,
			@PathVariable("user_id") String userId ){
		params.clear();
		params.put("cityId", cityId);
		params.put("userId", userId);
		return params;
	}


	/**
	 * 功能描述：测试GetMapping
	 * @param from
	 * @param size
	 * @return
	 */
	@GetMapping(value="page_user1")
	public Object pageUser(int  from, int size ){
		params.clear();
		params.put("from", from);
		params.put("size", size);
		
		return params;
		
	}
	
	
	
	/**
	 * 功能描述：默认值，是否必须的参数
	 * /testGet/page_user2?size=10&page=1
	 * @param from
	 * @param size
	 * @return
	 * @RequestParam 传递默认值 ,required=true为必须参数
	 * (@RequestParam(defaultValue="0",name="page",required = true)
	 */
	@GetMapping(value="page_user2")
	public Object pageUserV2(@RequestParam(defaultValue="0",name="page") int  from, int size ){
		
		params.clear();
		params.put("from", from);
		params.put("size", size);
		
		return params;
		
	}
	

	/**
	 * 功能描述：bean对象传参
	 * 注意：1、注意需要指定http头为 content-type为application/json
	 * 		2、使用body传输数据
	 * @param user
	 * @return
	 */
	@RequestMapping("save_user")
	public Object saveUser(@RequestBody TestUser user){
		params.clear();
		params.put("user", user);
		return params;	
	}
	
	
	
	
	/**
	 * 功能描述：测试获取http头信息
	 * @param accessToken
	 * @param id
	 * @return
	 */
	@GetMapping("get_header")
	public Object getHeader(@RequestHeader("access_token") String accessToken, String id){
		params.clear();
		params.put("access_token", accessToken);
		params.put("id", id);
		return params;	
	}

}