10、RestTemplate方式实现远程调用Client

一、JSONObject类详解：

JSONobject是FastJson提供的对象，在API中是用一个私有的常量map进行封装的，实际就是一个map，只不过 FastJson对其进行了封装，添加了很多方便快捷的属性方法。

添加相关依赖：

<dependency>

    <groupId>com.alibaba</groupId>

    <artifactId>fastjson</artifactId>

    <version>1.2.79</version>

</dependency>

1、将Java对象转化成String：

2、将String类型转json对象，取JSON中KEY对应的VALUE：

3、将String对象转化为List类型：

public class JSONObjectDemo {

    public static void main(String[] args) {

        //创建对象

        List<JsonObjectVO> list = new ArrayList<>();

        //对象1

        JsonObjectVO vo1 = new JsonObjectVO();

        vo1.setUuid(UUID.randomUUID().toString());

        vo1.setName("1");

        //对象2

        JsonObjectVO vo2 = new JsonObjectVO();

        vo2.setUuid(UUID.randomUUID().toString());

        vo2.setName("2");

        list.add(vo1);

        list.add(vo2);

        ResponseVO responseVO = ResponseVO.builder()

                .uuid(UUID.randomUUID().toString())

                .list(list)

                .build();

        /**

         * 1、java对象转化成String

         * toPrint:{"list":[{"name":"1","uuid":"b73bb9e8-f7a3-4dcf-8d8d-51313c7f5fd7"},{"name":"2","uuid":"ef109d35-cd07-45cd-9b45-791b205c878f"}],"uuid":"dbc3b9c6-2360-4b83-9d15-b88fe7980f27"}

         * */

        String str = JSONObject.toJSONString(responseVO);

        /**

         * 2、String类型转json对象，取JSON中的KEY

         * toPrint:[{"name":"1","uuid":"b73bb9e8-f7a3-4dcf-8d8d-51313c7f5fd7"},{"name":"2","uuid":"ef109d35-cd07-45cd-9b45-791b205c878f"}]

         * */

        Object data = JSONObject.parseObject(str).get("list");

        /**

         * 3、将String对象转化为List类型

         * toPrint:[JsonObjectVO(uuid=aebd390d-f543-4410-9c3a-98f2cb057757, name=1), JsonObjectVO(uuid=d170bb12-7570-47dd-8f2d-9ec2df5573c5, name=2)]

         * */

        List<JsonObjectVO> aList = JSONObject.parseArray(JSONObject.toJSONString(data),JsonObjectVO.class);

        System.out.println(str);

        System.out.println(data);

        System.out.println(aList);

    }

}

二、RestTemplate详解：

RestTemplate是由Spring框架提供的一个可调用REST服务的类，它简化了与HTTP服务的通信方式，统一了RESTFUL的标准，封装了HTTP连接。相较于之前常用的HttpClient，RestTemplate是一种更为优雅的调用RESTFul服务的方式。

1、添加依赖：

<!--JSONObject插件-->

<dependency>

    <groupId>com.alibaba</groupId>

    <artifactId>fastjson</artifactId>

    <version>1.2.79</version>

</dependency>

<dependency>

    <groupId>org.apache.commons</groupId>

    <artifactId>commons-lang3</artifactId>

    <version>3.1</version>

</dependency>

2、声明RestTemplate配置类：

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.client.RestTemplate;

@Configuration

public class RestTemplateConfig {

    @Bean

    public RestTemplate restTemplate(){

        return new RestTemplate();

    }

}

3、自定义远程调用Client通用工具类（重）：

import com.alibaba.fastjson.JSONObject;

import lombok.extern.slf4j.Slf4j;

import org.apache.commons.lang3.StringUtils;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.http.HttpEntity;

import org.springframework.http.HttpMethod;

import org.springframework.http.ResponseEntity;

import org.springframework.stereotype.Component;

import org.springframework.util.LinkedMultiValueMap;

import org.springframework.util.MultiValueMap;

import org.springframework.web.client.RestTemplate;

import java.util.HashSet;

import java.util.Map;

import java.util.Optional;

@Slf4j

@Component

public class HttpClientUtil {

    @Autowired

    private RestTemplate restTemplate;

    /**

     * @Param basisUrl:根地址(不带请求参数)

     * @Param param:请求参数

     * @Param method:请求方式(HttpMethod.GET、HttpMethod.POST......)

     * @Param authToken:请求令牌

     */

    public String getUrlResponse(String basisUrl, Map<Object, Object> param, HttpMethod method, String authToken) {

        MultiValueMap heards = new LinkedMultiValueMap();

        if (StringUtils.isNotBlank(authToken)) {

            heards.add("Authorization", authToken);

        }

        //合成请求地址

        String url = buildUrl(basisUrl, param);

        log.info("请求地址为：" + url);

        HttpEntity<Object> httpEntity = new HttpEntity<>(heards);

        ResponseEntity<Object> response = restTemplate.exchange(url, method, httpEntity, Object.class, param);

        String jsonString = JSONObject.toJSONString(response.getBody());

        return jsonString;

    }

    /**

     * 拼接url地址:

     * 例：http://127.0.0.1:xxx/xx/xxx?xx=xx&xx=xx

     */

    private String buildUrl(String basisUrl, Map<Object, Object> param) {

        StringBuilder params = new StringBuilder(basisUrl);

        params.append("?");

        Optional.ofNullable(param.entrySet()).orElse(new HashSet<>()).stream().forEach((Map.Entry entry) -> {

            params.append(entry.getKey()).append("=").append(entry.getValue()).append("&");

        });

        return params.toString().substring(0, params.toString().length() - 1);

    }

}

三、远程调用的实现：

1、test-demo工程：

声明控制类：

@RestController

@RequestMapping("/v1")

public class DemoController {

    @Autowired

    private DemoService demoService;

    /**

     * get方式

     * 查询全量信息

     *

     * http://localhost:8081/v1/get-detail?pageNum=1&pageSize=8

     * */

    @GetMapping("/get-detail")

    public Response<List<ResponseVO>> list1(

            @RequestParam(value = "pageNum", required = false , defaultValue = "1") Integer pageNum,

            @RequestParam(value = "pageSize", required = false , defaultValue = "8") Integer pageSize) {

        return Response.success(demoService.selectDetail(pageNum , pageSize));

    }

    /**

     * post方式

     * 查询全量信息

     *

     * http://localhost:8081/v1/post-detail

     * */

    @PostMapping("/post-detail")

    public Response<List<ResponseVO>> list2() {

        return Response.success(demoService.selectList());

    }

}

2、client-demo工程：

（1）、获取test-demo工程接口返回：

@Component

@Slf4j

public class HttpClient {

    @Autowired

    private HttpClientUtil httpClientUtil;

    @Value("${url.v1.clent:http://localhost:8081/v1}")

    private String url;

    public String getGetMethodURL() {

        return url + "/get-detail";

    }

    public String list() {

        //获取根地址

        String url = getGetMethodURL();

        //放置请求参数

        Map<Object, Object> param = new HashMap<>();

        param.put("pageNum", 1);

        param.put("pageSize", 100);

        String jsonString = httpClientUtil.getUrlResponse(url, param, HttpMethod.GET, null);

        Object data = JSONObject.parseObject(jsonString).get("entity");

        if (ObjectUtils.isEmpty(data)) {

            return "数据为空";

        }

        String dataList = JSONObject.toJSONString(data);

        return dataList;

    }

}

（2）、业务类：

@Service

public class DemoServiceImpl implements DemoService {

    @Autowired

    private HttpClient httpClient;

    @Override

    public String selectList() {

        return httpClient.list();

    }

}

搜索

复制

巴特西