springboot：整合retrofit实现本地接口调用远程服务

一、简介

okhttp是一款由square公司开源的java版本http客户端工具。square公司还开源了基于okhttp进一步封装的retrofit工具，用来支持通过接口的方式发起http请求。 retrofit-spring-boot-starter实现了Retrofit与SpringBoot框架快速整合，并且支持了部分功能增强，从而极大的简化spring-boot项目下http接口调用开发

二、springboot整合retrofit

1.导入依赖

<dependency>
            <groupId>com.github.lianjiatech</groupId>
            <artifactId>retrofit-spring-boot-starter</artifactId>
            <version>2.2.22</version>
        </dependency>

2.编写远程测试接口

package com.hl.springbootmybatis.controller;

import cn.hutool.core.collection.ListUtil;
import cn.hutool.json.JSONUtil;
import lombok.Data;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import java.util.List;
import java.util.Map;

/**
 *  测试远程被调用的retrofit接口
 */
@RestController
@RequestMapping("/test/retrofit/remote")
public class RemoteRetrofitController {
    
    @GetMapping("/t1")
    public List<String> t1(@RequestParam("name") String name) {
        return ListUtil.of(name);
    }

    @DeleteMapping("/t2/{name}")
    public List<String> t2(@PathVariable("name") String name) {
        return ListUtil.of(name);
    }

    @PostMapping("/t3")
    public Map<String, Object> t3(@RequestBody Map<String, Object> params) {
        return params;
    }

    @PutMapping("/t4")
    public Map<String, Object> t4(@RequestBody Map<String, Object> params) {
        return params;
    }

    @PostMapping("/t5")
    public Map<String, Object> t5(@RequestParam Map<String, Object> params) {
        return params;
    }

    @PostMapping("/t6")
    public String t6(RetrofitTestModel model) {
        return JSONUtil.toJsonStr(model);
    }

    @PostMapping("/t7")
    public String t7(String name) {
        return name;
    }

    @PostMapping("/t8")
    public String t8(@RequestHeader("name") String name) {
        return name;
    }

    @PostMapping("/t9")
    public String t9(@RequestHeader("name") String name, @RequestHeader("token") String token) {
        return name + ";" + token;
    }

	@GetMapping("/t10/{name}")
    public List<String> t10(@PathVariable("name") String name) {
        return ListUtil.of(name);
    }

    @Data
    public static class RetrofitTestModel {
        private String name;
    }

}

3.编写本地测试接口

3.1 retrofit的配置信息

###############retrofit配置###############
#连接池相关配置
retrofit.global-connect-timeout-ms= 5000
retrofit.pool.test.max-idle-connection=3
retrofit.pool.test.keep-alive-second=100
#日志打印拦截器配置，可以继承BaseLoggingInterceptor实现自己的日志记录方式
retrofit.logging-interceptor=com.github.lianjiatech.retrofit.spring.boot.interceptor.DefaultLoggingInterceptor
#异常格式化处理，可以继承BaseHttpExceptionMessageFormatter，实现自己的异常格式化
retrofit。http-exception-message-formatter=com.github.lianjiatech.retrofit.spring.boot.interceptor.DefaultHttpExceptionMessageFormatter

3.2 本地和测试接口

新建接口，添加@RetrofitClient注解，配置baseUrl和poolName，poolName对应上一步的配置

package com.yolo.springbootretrofit.config;

import com.github.lianjiatech.retrofit.spring.boot.annotation.RetrofitClient;
import retrofit2.http.*;
import java.util.List;
import java.util.Map;

@RetrofitClient(baseUrl = "http://localhost:9093/",poolName = "test")
public interface HttpClient {

    @GET("test/retrofit/remote/t1")
    List<String> t1(@Query("name") String name);

    /**路径中传参 /{}*/
    @DELETE("test/retrofit/remote/t2/{name}")
    String t2(@Path("name") String name);

    /**使用请求体传送json*/
    @POST("test/retrofit/remote/t3")
    Map<String, Object> t3(@Body Map<String, Object> params);

    /**put请求使用请求体传送json*/
    @PUT("test/retrofit/remote/t4")
    Map<String, Object> t4(@Body Map<String, Object> params);

    /**多个url参数使用map传递*/
    @POST("test/retrofit/remote/t5")
    Map<String, Object> t5(@QueryMap Map<String, Object> params);

    /**form表单传送数据，多个参数使用map传递*/
    @FormUrlEncoded
    @POST("test/retrofit/remote/t6")
    Map<String, Object> t6(@FieldMap Map<String, Object> model);

    /**form表单传送数据，多个参数一个一个传递*/
    @FormUrlEncoded
    @POST("test/retrofit/remote/t7")
    String t7(@Field("name") String name);

    /**header传送数据，多个参数一个一个传递*/
    @POST("test/retrofit/remote/t8")
    String t8(@Header("name") String name);

    /**header传送数据，多个参数一起传递*/
    @POST("test/retrofit/remote/t9")
    @Headers({"name:zhangsan", "token:lisi"})
    String t9();

	/**自定义全路径，避免重新写一个HttpClient **/
    @GET()
    List<String> t10(@Url String url) ;

}

3.3 测试

package com.yolo.springbootretrofit.controller;

import com.yolo.springbootretrofit.config.HttpClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/test/retrofit")
public class RetrofitTestController {

    @Resource
    private HttpClient httpClient;

    @GetMapping("/t1")
    public List<String> t1() {
        return httpClient.t1("zhangsan");
    }

    @GetMapping("t2")
    public String t2() {
        return httpClient.t2("zhangsan");
    }

    @GetMapping("t3")
    public Map<String, Object> t3() {
        Map<String, Object> map = new HashMap<>();
        map.put("name", "zhangsan");
        return httpClient.t3(map);
    }

    @GetMapping("t4")
    public Map<String, Object> t4() {
        Map<String, Object> map = new HashMap<>();
        map.put("name", "zhangsan");
        return httpClient.t4(map);
    }

    @GetMapping("t5")
    public Map<String, Object> t5() {
        Map<String, Object> map = new HashMap<>();
        map.put("name", "zhangsan");
        return httpClient.t5(map);
    }

    @GetMapping("t6")
    public Map<String, Object> t6() {
        Map<String, Object> map = new HashMap<>();
        map.put("name", "zhangsan");
        return httpClient.t6(map);
    }

    @GetMapping("t7")
    public String t7() {
        return httpClient.t7("zhangsan");
    }

    @GetMapping("t8")
    public String t8() {
        return httpClient.t8("zhangsan");
    }

    @GetMapping("t9")
    public String t9() {
        return httpClient.t9();
    }

	@GetMapping("t10")
    public List<String> t10() {
        String s = "http://localhost:9093/test/retrofit/remote/t10/lisi";
        return httpClient.t10(s);
    }
}

4.编写拦截器

可是通过编写拦截器来拦截retrofit的请求，在请求中添加一些统一的处理，拦截器需要继承BasePathMatchInterceptor并重写doIntercept方法

接口上使用@Intercept进行标注

package com.yolo.springbootretrofit.config;

import com.github.lianjiatech.retrofit.spring.boot.interceptor.BasePathMatchInterceptor;
import okhttp3.Headers;
import okhttp3.HttpUrl;
import okhttp3.Request;
import okhttp3.Response;
import org.springframework.stereotype.Component;
import java.io.IOException;

@Component
public class SimpleInterceptor extends BasePathMatchInterceptor {
    @Override
    protected Response doIntercept(Chain chain) throws IOException {
        Request request = chain.request();
        HttpUrl url = request.url();
        url = url.newBuilder().addQueryParameter("time", String.valueOf(System.currentTimeMillis()))
                .build();
        Headers headers = request.headers();
        headers = headers.newBuilder().add("add-header", "lalala").build();
        request = request.newBuilder().headers(headers)
                .url(url).build();
        return chain.proceed(request);
    }
}

在接口类中添加@Interceptor注解，handler属性为上面定义的拦截器，include属性为拦截的URL，exclude为不拦截的URL

@Intercept(handler = SimpleInterceptor.class, include = {"/demo/test/**"}) //添加拦截器

5.自定义注解拦截器

注意必须添加@InterceptMark

package com.yolo.springbootretrofit.config;

import com.github.lianjiatech.retrofit.spring.boot.annotation.InterceptMark;
import com.github.lianjiatech.retrofit.spring.boot.interceptor.BasePathMatchInterceptor;
import java.lang.annotation.*;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Documented
@InterceptMark //必须加这个注解
public @interface Sign {
    /**
     * 密钥key
     * 支持占位符形式配置。
     *
     * @return
     */
    String accessKeyId();

    /**
     * 密钥
     * 支持占位符形式配置。
     *
     * @return
     */
    String accessKeySecret();

    /**
     * 拦截器匹配路径
     *
     * @return
     */
    String[] include() default {"/**"};

    /**
     * 拦截器排除匹配，排除指定路径拦截
     *
     * @return
     */
    String[] exclude() default {};

    /**
     * 处理该注解的拦截器类
     * 优先从spring容器获取对应的Bean，如果获取不到，则使用反射创建一个！
     *
     * @return
     */
    Class<? extends BasePathMatchInterceptor> handler() default SignInterceptor.class;
}

accessKeyId和accessKeySecret字段值会依据@Sign注解的accessKeyId()和accessKeySecret()值自动注入，如果@Sign指定的是占位符形式的字符串，则会取配置属性值进行注入。另外，accessKeyId和accessKeySecret字段必须提供setter方法

package com.yolo.springbootretrofit.config;

import com.github.lianjiatech.retrofit.spring.boot.interceptor.BasePathMatchInterceptor;
import okhttp3.Request;
import okhttp3.Response;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
public class SignInterceptor extends BasePathMatchInterceptor {

    private String accessKeyId;

    private String accessKeySecret;

    public void setAccessKeyId(String accessKeyId) {
        this.accessKeyId = accessKeyId;
    }

    public void setAccessKeySecret(String accessKeySecret) {
        this.accessKeySecret = accessKeySecret;
    }

    @Override
    public Response doIntercept(Chain chain) throws IOException {
        Request request = chain.request();
        Request newReq = request.newBuilder()
                .addHeader("accessKeyId", accessKeyId)
                .addHeader("accessKeySecret", accessKeySecret)
                .build();
        return chain.proceed(newReq);
    }
}

接口上使用@Sign

@RetrofitClient(baseUrl = "${test.baseUrl}")
@Sign(accessKeyId = "${test.accessKeyId}", accessKeySecret = "${test.accessKeySecret}", exclude = {"/api/test/person"})
public interface HttpApi {

    @GET("person")
    Result<Person> getPerson(@Query("id") Long id);

    @POST("savePerson")
    Result<Person> savePerson(@Body Person person);
}

三、连接池管理

默认情况下，所有通过Retrofit发送的http请求都会使用max-idle-connections=5 keep-alive-second=300的默认连接池。当然，我们也可以在配置文件中配置多个自定义的连接池，然后通过@RetrofitClient的poolName属性来指定使用。比如我们要让某个接口下的请求全部使用poolName=test1的连接池

1.配置连接池

retrofit:
    # 连接池配置
    pool:
        test1:
        max-idle-connections: 3
        keep-alive-second: 100
        test2:
        max-idle-connections: 5
        keep-alive-second: 50

2.通过@RetrofitClient的poolName属性来指定使用的连接池

@RetrofitClient(baseUrl = "${test.baseUrl}", poolName="test1")
public interface HttpApi {
    @GET("person")
    Result<Person> getPerson(@Query("id") Long id);
}

四、日志打印

很多情况下，我们希望将http请求日志记录下来。通过@RetrofitClient的logLevel和logStrategy属性，您可以指定每个接口的日志打印级别以及日志打印策略。retrofit-spring-boot-starter支持了5种日志打印级别(ERROR, WARN, INFO, DEBUG, TRACE)，默认INFO；支持了4种日志打印策略（NONE, BASIC, HEADERS, BODY），默认BASIC。4种日志打印策略含义如下：

1. NONE：No logs.
2. BASIC：Logs request and response lines.
3. HEADERS：Logs request and response lines and their respective headers.
4. BODY：Logs request and response lines and their respective headers and bodies (if present)

retrofit-spring-boot-starter默认使用了DefaultLoggingInterceptor执行真正的日志打印功能，其底层就是okhttp原生的HttpLoggingInterceptor。当然，你也可以自定义实现自己的日志打印拦截器，只需要继承BaseLoggingInterceptor（具体可以参考DefaultLoggingInterceptor的实现），然后在配置文件中进行相关配置即可。

retrofit:
  # 日志打印拦截器
  logging-interceptor: com.github.lianjiatech.retrofit.spring.boot.interceptor.DefaultLoggingInterceptor

五、HTTP异常信息格式化器

当出现http请求异常时，原始的异常信息可能阅读起来并不友好，因此retrofit-spring-boot-starter提供了HTTP异常信息格式化器，用来美化输出http请求参数，默认使用DefaultHttpExceptionMessageFormatter进行请求数据格式化。你也可以进行自定义，只需要继承BaseHttpExceptionMessageFormatter，再进行相关配置即可

retrofit:
  # Http异常信息格式化器
  http-exception-message-formatter: com.github.lianjiatech.retrofit.spring.boot.interceptor.DefaultHttpExceptionMessageFormatter

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