摘要：前言在開發(fā)應(yīng)用中，作為聲明式調(diào)用的事實(shí)標(biāo)準(zhǔn)極大的簡化了遠(yuǎn)程調(diào)用，提供了類本地化的調(diào)用方式。本文介紹一種通過動(dòng)態(tài)代理的方式無需直接暴露接口。后語關(guān)于這個(gè)框架的介紹，后續(xù)詳細(xì)的給大家進(jìn)行介紹。

在開發(fā)SpringCloud應(yīng)用中，F(xiàn)eign作為聲明式調(diào)用的事實(shí)標(biāo)準(zhǔn)極大的簡化了Rest遠(yuǎn)程調(diào)用，提供了類本地化的調(diào)用方式。服務(wù)提供方的接口暴露方式是通過Controller暴露Restful，而在這個(gè)Controller的代碼現(xiàn)實(shí)中大部分都是處理請求然后再調(diào)用Service中的方法，是一個(gè)比較模板化的功能，但是工作量確不少。本文介紹一種通過動(dòng)態(tài)代理的方式無需Controller直接暴露Restful接口。
本文中使用筆者在Github開源的框架來實(shí)現(xiàn)，本文的講解也在這個(gè)框架基礎(chǔ)之上來說明
Git路徑：https://github.com/leecho/spr...

     
        com.github.leecho
        spring-cloud-starter-feign-proxy
        {last-version}
    

首先定義服務(wù)接口，使用@FeignClient標(biāo)示是一個(gè)Feign接口，在這個(gè)示例Sevice中定義了CURD和文件上傳方法，并使用了一些常用參數(shù)注解

@Api(tags = "DemoService", description = "Demo Feign Client")
@FeignClient("demo-service")
public interface DemoService {

    /**
     * create demo
     *
     * @param demo
     * @return
     */
    @ApiOperation(value = "Create demo")
    @PostMapping(value = "/demo")
    Demo create(@RequestBody @Valid @ApiParam Demo demo);

    /**
     * update demo
     *
     * @param demo
     * @return
     */
    @PutMapping(value = "/demo")
    Demo update(@RequestBody @Valid Demo demo);

    /**
     * delete demo
     *
     * @param id
     * @return
     */
    @DeleteMapping(value = "/demo/{id}")
    Demo delete(@PathVariable(name = "id") String id);

    /**
     * list demo
     *
     * @param id
     * @param headerValue test header value
     * @return
     */
    @GetMapping(value = "/demo/{id}")
    Demo get(@PathVariable(name = "id") String id, @RequestHeader(name = "header") String headerValue);

    /**
     * list demos
     *
     * @return
     */
    @GetMapping(value = "/demos")
    List list();

    /**
     * upload file
     *
     * @param file
     * @return
     */
    @PostMapping(value = "/demo/upload")
    String upload(@RequestPart(name = "file") MultipartFile file);
}

在實(shí)現(xiàn)類中簡單的實(shí)現(xiàn)了CURD和上傳文件的方法

@Slf4j
@Primary
@Service
public class DemoServiceImpl implements DemoService {

    @Override
    public Demo create(Demo demo) {
        log.info("Create executed : " + demo);
        return demo;
    }

    @Override
    public Demo update(Demo demo) {
        log.info("Update execute :" + demo);
        return demo;
    }

    @Override
    public Demo delete(String id) {
        log.info("Delete execute : " + id);
        return Demo.builder().name("demo-" + id).data("data-" + id).build();
    }

    @Override
    public Demo get(String id, String header) {
        Demo demo = Demo.builder()
                .name(header)
                .data(header).build();
        System.out.println("Get execute : " + id + "," + header);
        return demo;
    }

    @Override
    public List list() {
        System.out.println("List execute");
        List demos = new ArrayList<>();
        for (int i = 0; i < 5; i++) {
            Demo demo = Demo.builder()
                    .name("demo-" + i)
                    .data("data" + i).build();
            demos.add(demo);
        }
        return demos;
    }

    @Override
    public String upload(MultipartFile file) {
        return file.getOriginalFilename();
    }
}

動(dòng)態(tài)生成Restful接口的原理是動(dòng)態(tài)生成Controller類實(shí)現(xiàn)ServiceInterface，如果真正的實(shí)現(xiàn)類會(huì)被其他BEAN依賴，需要通過注解@Primary來方式來防止依賴沖突

在應(yīng)用中通過@EnableFeignProxies來標(biāo)示應(yīng)用在啟動(dòng)的過程中會(huì)掃描所有的FeignClients并暴露Restful接口

@EnableFeignProxies(basePackages = "com.github.leecho")
@ComponentScan("com.github.leecho")
@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

在測試用例中對Service的接口進(jìn)行測試

@SpringBootTest
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
public class DemoApplicationTest {
    @Autowired
    private WebApplicationContext context;

    private MockMvc mvc;

    @Before
    public void setUp() {
        mvc = MockMvcBuilders.webAppContextSetup(context).build();
    }

    @Test
    public void create() throws Exception {
        mvc.perform(MockMvcRequestBuilders.post("/demo")
                .contentType(MediaType.APPLICATION_JSON_UTF8)
                .content(new ObjectMapper().writeValueAsString(Demo.builder().name("create").data("data").build()))
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andDo(MockMvcResultHandlers.print());

    }

    @Test
    public void update() throws Exception {
        mvc.perform(MockMvcRequestBuilders.put("/demo")
                .contentType(MediaType.APPLICATION_JSON_UTF8)
                .content(new ObjectMapper().writeValueAsString(Demo.builder().name("update").data("data").build()))
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andDo(MockMvcResultHandlers.print());

    }

    @Test
    public void delete() throws Exception {
        mvc.perform(MockMvcRequestBuilders.delete("/demo/{id}", "1")
                .contentType(MediaType.APPLICATION_JSON_UTF8)
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andDo(MockMvcResultHandlers.print());

    }

    @Test
    public void get() throws Exception {
        mvc.perform(MockMvcRequestBuilders.get("/demo/{id}", "1")
                .contentType(MediaType.APPLICATION_JSON_UTF8)
                .header("header", "header-value")
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andDo(MockMvcResultHandlers.print());

    }

    @Test
    public void list() throws Exception {
        mvc.perform(MockMvcRequestBuilders.get("/demos")
                .contentType(MediaType.APPLICATION_JSON_UTF8)
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andDo(MockMvcResultHandlers.print());

    }

    @Test
    public void upload() throws Exception {
        mvc.perform(MockMvcRequestBuilders.multipart("/demo/upload").file(new MockMultipartFile("file", "test.txt", ",multipart/form-data", "upload test".getBytes()))
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(MockMvcResultMatchers.status().isOk())
                .andDo(MockMvcResultHandlers.print());

    }
}

在啟動(dòng)日志中也可以看到Restful接口已經(jīng)暴露成功。

關(guān)于這個(gè)框架的介紹，后續(xù)詳細(xì)的給大家進(jìn)行介紹。文中所涉及到的代碼也在Git中：spring-cloud-feign-proxy-sample