springboot 从一个系统A 调用系统B得接口并拿到返回结果

淡淡的烟草味﹌ 2024-04-22 15:13 60阅读 0赞

> 网上方案基本都是3种，我的实际应用场景比较简单，所以我选了 HttpClient

主要是将它融入到 Springboot项目里面

## 一、导入依赖 ##

<dependency>
                <groupId>org.apache.httpcomponents.client5</groupId>
                <artifactId>httpclient5</artifactId>
                <version>5.2.1</version>
     </dependency>

## 第二、post请求案例，携带json参数，获取返回结果 ##

public void doPostTestOne() {
            // 获得Http客户端(可以理解为:你得先有一个浏览器;注意:实际上HttpClient与浏览器是不一样的)
            CloseableHttpClient httpClient = HttpClientBuilder.create().build();
    
            // 创建Post请求
            HttpPost httpPost = new HttpPost("http://10.10.123.45:8008/test/add");
            //构建post参数
            JSONObject postParam= new JSONObject();
            postParam.put("content", "参数值");
            StringEntity stringEntity = new StringEntity(postParam.toString(), ContentType.APPLICATION_JSON);
            httpPost.setEntity(stringEntity);
    
            // 响应模型
            CloseableHttpResponse response = null;
            try {
                // 由客户端执行(发送)Post请求
                response = httpClient.execute(httpPost);
                // 从响应模型中获取响应实体
                HttpEntity responseEntity = response.getEntity();
                System.out.println("响应状态码:" + response.getCode());
                if (responseEntity != null) {
                    System.out.println("响应内容长度为:" + responseEntity.getContentLength());
                    String strData = EntityUtils.toString(responseEntity);
     System.out.println("响应内容"+strData);
                     //将字符串转成对象，便于取出里面属性的值
                    JSONObject jsonObject = JSONObject.parseObject(strData);
                    String data = jsonObject.getString("data");
                }
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (ParseException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    // 释放资源
                    if (httpClient != null) {
                        httpClient.close();
                    }
                    if (response != null) {
                        response.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

## 第三、注意EntityUtils.toString只能使用一次，使用两次会报错 ##

具体原因不清楚[HttpClient EntityUtils.toString(responseEntity) 转为 JSOnObject 报错 Stream already closed\_tengyuxin的博客-CSDN博客][HttpClient EntityUtils.toString_responseEntity_ _ JSOnObject _ Stream already closed_tengyuxin_-CSDN]

[HttpClient EntityUtils.toString_responseEntity_ _ JSOnObject _ Stream already closed_tengyuxin_-CSDN]: https://blog.csdn.net/tengyuxin/article/details/132397616