springboot2.0, 使用RestController + RestClient 方式通過API 傳回

1. 目的：使用RestController + RestClient 方式通過API 傳回。
2. 一句話總結：RestController + RestCliet 方式相當于輕量級 WebService。
3. 用戶端技巧
   1. 通過單一的orderId獲得傳回
   2. 構造map參數,通過map對象擷取
   3. 通過map對象擷取,并獲得HTTP封包頭判斷後有效傳回

4. 伺服器端代碼：

   package com.winter.controller;

   import com.winter.model.DeptDomain;
    import com.winter.service.user.DeptService;
    import com.winter.service.user.UserService;
    import lombok.extern.slf4j.Slf4j;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.transaction.annotation.Transactional;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
   
    import javax.servlet.http.HttpServletRequest;
   
    @org.springframework.web.bind.annotation.RestController
    @RequestMapping(value = "/api/v1")
    @Slf4j
    @Transactional
    public class RestController {
        @Autowired
        private DeptService DeptService;
   
        Logger logger = LoggerFactory.getLogger(RestController.class);
   
        //POST http://localhost:8080/api/v1/order/15
        //擷取param
        @RequestMapping(value = "/order/{orderId}", method = RequestMethod.GET)
        public DeptDomain getDeptDomain(@PathVariable int orderId) throws Exception {
    	System.out.println("orderId:>>>" + orderId);
    	DeptDomain deptDomain = DeptService.selectById(orderId);
    	System.out.println(deptDomain.getDeptName());
   
    	return deptDomain;
        }
    }
              

5. 用戶端代碼

   package com.winter.controller;

   import com.winter.model.DeptDomain;
    import lombok.extern.slf4j.Slf4j;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.boot.web.client.RestTemplateBuilder;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.http.HttpHeaders;
    import org.springframework.http.ResponseEntity;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    import org.springframework.web.client.RestTemplate;
   
    import javax.servlet.http.HttpServletRequest;
    import java.util.HashMap;
    import java.util.Map;
   
    @Controller
    @RequestMapping(value = "/test")
    @Slf4j
    @Configuration // 為了配合以下的使用 @Value("${api.order:#{'http://127.0.0.1:8080/api/v1'}}")
    public class RestClientTestController {
        @Autowired
        HttpServletRequest request;
   
    Logger logger = LoggerFactory.getLogger(RestController.class);
   
    //如要如此使用，必須加上@Configuration注釋，同時，以下文字必須使用 ' ' 包圍文字
    @Value("${api.order:#{'http://127.0.0.1:8080/api/v1'}}")
    String base;
   
    @Autowired
    RestTemplateBuilder restTemplateBuilder;
   
    @GetMapping("/get/{orderId}")
    public @ResponseBody DeptDomain testGetDeptDomain(@PathVariable String orderId)
    throws Exception {
    	RestTemplate restClient = restTemplateBuilder.build();
   
    	//Step 1 構造uri
    	String uri = base + "/order/{orderId}";
    	System.out.println("uri>>>" + uri);
   
    	//Step 2.1 通過單一的orderId獲得傳回
    	DeptDomain deptDomain1 = restClient.getForObject(uri,DeptDomain.class, orderId);
   
    	//Step 2.2 構造map參數,通過map對象擷取
    	Map mapParam = new HashMap();
    	mapParam.put("orderId",orderId);
   
    	DeptDomain deptDomain2 = restClient.getForObject(uri,DeptDomain.class, mapParam);
   
    	//Step 2.2 通過map對象擷取,并獲得HTTP封包頭判斷後有效傳回
    	ResponseEntity<DeptDomain> responseEntity = restClient.getForEntity(uri,DeptDomain.class, mapParam);
    	System.out.println(responseEntity.getStatusCode());
   
    	if (responseEntity.getStatusCode().is2xxSuccessful()) {
    	    DeptDomain deptDomain3 = responseEntity.getBody();
    	    HttpHeaders headers = responseEntity.getHeaders();
    	    return deptDomain3;
    	} else {
    	    return null;
    	}
    }
              

   }