HttpClient远程调用(Spring Boot)

清疚 2022-05-14 15:11 239阅读 0赞

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<dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.6</version>
            </dependency>

# 1 .案例代码 #

## 1.1 get请求 ##

public class DoGET { 
    
        public static void main(String[] args) throws Exception { 
            // 创建Httpclient对象,相当于打开了浏览器
            CloseableHttpClient httpclient = HttpClients.createDefault();
    
            // 创建HttpGet请求，相当于在浏览器输入地址
            HttpGet httpGet = new HttpGet("http://www.baidu.com/");
    
            CloseableHttpResponse response = null;
            try { 
                // 执行请求，相当于敲完地址后按下回车。获取响应
                response = httpclient.execute(httpGet);
                // 判断返回状态是否为200
                if (response.getStatusLine().getStatusCode() == 200) { 
                    // 解析响应，获取数据
                    String content = EntityUtils.toString(response.getEntity(), "UTF-8");
                    System.out.println(content);
                }
            } finally { 
                if (response != null) { 
                    // 关闭资源
                    response.close();
                }
                // 关闭浏览器
                httpclient.close();
            }
    
        }
    }

## 1.2 带参数的get请求 ##

public class DoGETParam { 
    
        public static void main(String[] args) throws Exception { 
            // 创建Httpclient对象
            CloseableHttpClient httpclient = HttpClients.createDefault();
            // 创建URI对象，并且设置请求参数
            URI uri = new URIBuilder("http://www.baidu.com/s").setParameter("wd", "java").build();
            // 创建http GET请求
            HttpGet httpGet = new HttpGet(uri);
    
            CloseableHttpResponse response = null;
            try { 
                // 执行请求
                response = httpclient.execute(httpGet);
                // 判断返回状态是否为200
                if (response.getStatusLine().getStatusCode() == 200) { 
                    // 解析响应数据
                    String content = EntityUtils.toString(response.getEntity(), "UTF-8");
                    System.out.println(content);
                }
            } finally { 
                if (response != null) { 
                    response.close();
                }
                httpclient.close();
            }
        }
    }

## 1.3 POST请求 ##

/* * 演示：使用HttpClient发起POST请求 */
    public class DoPOST { 
        public static void main(String[] args) throws Exception { 
            // 创建Httpclient对象
            CloseableHttpClient httpclient = HttpClients.createDefault();
            // 创建http POST请求
            HttpPost httpPost = new HttpPost("http://www.oschina.net/");
            // 把自己伪装成浏览器。否则开源中国会拦截访问
            httpPost.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36");
    
            CloseableHttpResponse response = null;
            try { 
                // 执行请求
                response = httpclient.execute(httpPost);
                // 判断返回状态是否为200
                if (response.getStatusLine().getStatusCode() == 200) { 
                    // 解析响应数据
                    String content = EntityUtils.toString(response.getEntity(), "UTF-8");
                    System.out.println(content);
                }
            } finally { 
                if (response != null) { 
                    response.close();
                }
                // 关闭浏览器
                httpclient.close();
            }
    
        }
    }

## 1.4 带参数的POST请求 ##

/* * 演示：使用HttpClient发起带有参数的POST请求 */
    public class DoPOSTParam { 
    
        public static void main(String[] args) throws Exception { 
            // 创建Httpclient对象
            CloseableHttpClient httpclient = HttpClients.createDefault();
            // 创建http POST请求，访问开源中国
            HttpPost httpPost = new HttpPost("http://www.oschina.net/search");
    
            // 根据开源中国的请求需要，设置post请求参数
            List<NameValuePair> parameters = new ArrayList<NameValuePair>(0);
            parameters.add(new BasicNameValuePair("scope", "project"));
            parameters.add(new BasicNameValuePair("q", "java"));
            parameters.add(new BasicNameValuePair("fromerr", "8bDnUWwC"));
            // 构造一个form表单式的实体
            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters);
            // 将请求实体设置到httpPost对象中
            httpPost.setEntity(formEntity);
    
            CloseableHttpResponse response = null;
            try { 
                // 执行请求
                response = httpclient.execute(httpPost);
                // 判断返回状态是否为200
                if (response.getStatusLine().getStatusCode() == 200) { 
                    // 解析响应体
                    String content = EntityUtils.toString(response.getEntity(), "UTF-8");
                    System.out.println(content);
                }
            } finally { 
                if (response != null) { 
                    response.close();
                }
                // 关闭浏览器
                httpclient.close();
            }
        }
    }

# 2.整合项目 #

<dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
    </dependency>

## 2.1 在application.properties添加如下配置: ##

#The config for HttpClient 
    http.maxTotal=300
    http.defaultMaxPerRoute=50
    http.connectTimeout=1000
    http.connectionRequestTimeout=500
    http.socketTimeout=5000
    http.staleConnectionCheckEnabled=true

## 2.2 config 配置类 ##

package com.czxy.config;
    
    import org.apache.http.client.HttpClient;
    import org.apache.http.client.config.RequestConfig;
    import org.apache.http.conn.HttpClientConnectionManager;
    import org.apache.http.impl.client.HttpClientBuilder;
    import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.http.client.ClientHttpRequestFactory;
    import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
    import org.springframework.http.converter.HttpMessageConverter;
    import org.springframework.http.converter.StringHttpMessageConverter;
    import org.springframework.web.client.RestTemplate;
    
    import java.nio.charset.Charset;
    import java.util.List;
    
    /** * HttpClient的配置类---类似工具类 * Configuration:标明这是一个配置类 * ConfigurationProperties：加载application.properties属性文件 * prefix：前缀 * ignoreUnknownFields：忽略找不到的属性 * 自动将属性文件中的值赋值该类中的属性 * * 最终需要知道： * 1 SpringBoot推荐使用RestTemplate操作RestFul API * 2 RestTemplate底层需要借助HttpClient创建 * * */
    @Configuration
    @ConfigurationProperties(prefix = "http", ignoreUnknownFields = true)
    public class HttpClientConfig { 
    
        private Integer maxTotal;// 最大连接
    
        private Integer defaultMaxPerRoute;// 每个host的最大连接
    
        private Integer connectTimeout;// 连接超时时间
    
        private Integer connectionRequestTimeout;// 请求超时时间
    
        private Integer socketTimeout;// 响应超时时间
    
        /** * HttpClient连接池 * @return */
        @Bean
        public HttpClientConnectionManager httpClientConnectionManager() { 
            PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
            connectionManager.setMaxTotal(maxTotal);
            connectionManager.setDefaultMaxPerRoute(defaultMaxPerRoute);
            return connectionManager;
        }
    
        /** * 注册RequestConfig * @return */
        @Bean
        public RequestConfig requestConfig() { 
            return RequestConfig.custom().setConnectTimeout(connectTimeout)
                .setConnectionRequestTimeout(connectionRequestTimeout).setSocketTimeout(socketTimeout)
                .build();
        }
    
        /** * 注册HttpClient * @param manager * @param config * @return */
        @Bean
        public HttpClient httpClient(HttpClientConnectionManager manager, RequestConfig config) { 
            return HttpClientBuilder.create().setConnectionManager(manager).setDefaultRequestConfig(config)
                .build();
        }
       /** * 使用连接池管理连接 * @param httpClient * @return */
        @Bean
        public ClientHttpRequestFactory requestFactory(HttpClient httpClient) { 
            return new HttpComponentsClientHttpRequestFactory(httpClient);
        }
        /** * 使用HttpClient来初始化一个RestTemplate * @param requestFactory * @return */
        @Bean
        public RestTemplate restTemplate(ClientHttpRequestFactory requestFactory) { 
            RestTemplate template = new RestTemplate(requestFactory);
    
            List<HttpMessageConverter<?>> list = template.getMessageConverters();
            for (HttpMessageConverter<?> mc : list) { 
                if (mc instanceof StringHttpMessageConverter) { 
                    ((StringHttpMessageConverter) mc).setDefaultCharset(Charset.forName("UTF-8"));
                }
            }
            return template;
        }
    
        public Integer getMaxTotal() { 
            return maxTotal;
        }
    
        public void setMaxTotal(Integer maxTotal) { 
            this.maxTotal = maxTotal;
        }
    
        public Integer getDefaultMaxPerRoute() { 
            return defaultMaxPerRoute;
        }
    
        public void setDefaultMaxPerRoute(Integer defaultMaxPerRoute) { 
            this.defaultMaxPerRoute = defaultMaxPerRoute;
        }
    
        public Integer getConnectTimeout() { 
            return connectTimeout;
        }
    
        public void setConnectTimeout(Integer connectTimeout) { 
            this.connectTimeout = connectTimeout;
        }
    
        public Integer getConnectionRequestTimeout() { 
            return connectionRequestTimeout;
        }
    
        public void setConnectionRequestTimeout(Integer connectionRequestTimeout) { 
            this.connectionRequestTimeout = connectionRequestTimeout;
        }
    
        public Integer getSocketTimeout() { 
            return socketTimeout;
        }
    
        public void setSocketTimeout(Integer socketTimeout) { 
            this.socketTimeout = socketTimeout;
        }
    }

#### 还有一种写法 借助HttpClient生成RestTemplate，RestTemplate是spring提供的一个远程调用类 ####

package com.czxy.config;
    
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import org.springframework.web.client.RestTemplate;
    
    /** * @author Fang * @create 2018-12-03 20:51 * @desc httplient config **/
    @Configuration
    @ConfigurationProperties(prefix = "http", ignoreUnknownFields = true)
    public class HttpclientConfig { 
        @Bean
        public RestTemplate getRestTemplate(){ 
            return new RestTemplate();
        }
    }

## 2.3.1 前端页面方法 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYzMzEzMQ_size_27_color_FFFFFF_t_70]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYzMzEzMQ_size_27_color_FFFFFF_t_70 1]

## 2.3.2 调用（controller） ##

package com.czxy.web.product;
    import com.alibaba.fastjson.JSON;
    import com.czxy.pojo.DatagridResult;
    import com.czxy.pojo.Product;
    import org.apache.http.client.HttpClient;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.http.HttpMethod;
    import org.springframework.http.HttpStatus;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.*;
    import org.springframework.web.client.RestTemplate;
    
    import java.util.LinkedHashMap;
    import java.util.Map;
    
    /** * @author Fang * @create 2018-10-25 16:20 * @desc 商品 **/
    @RestController
    @RequestMapping("/product")
    public class ProductController { 
    
        @Autowired
        private RestTemplate restTemplate;
       /** *@author Fang *@create 2018/10/26 21:52 *@desc datagrid 分页查询 **/
        @GetMapping("/findAll")
        public ResponseEntity<DatagridResult> findAll(Integer page, Integer rows) { 
    
            String url = "http://127.0.0.1:8090/product02/findAll02?page=" + page + "&rows=" + rows;
    
            ResponseEntity<String> entity = restTemplate.getForEntity(url, String.class);
            String body = entity.getBody();
    
            DatagridResult datagridResult = JSON.parseObject(body, DatagridResult.class);
    
            return new ResponseEntity<DatagridResult>(datagridResult, HttpStatus.OK);
        }
    
        /** * @author Fang * @create 2018/10/25 18:10 * @desc 修改 **/
    
        @PutMapping("/update")
        public ResponseEntity<Void> update(Product product) { 
            String url = "http://127.0.0.1:8090/product02/update02";
    
            restTemplate.put(url, product);
    
            return new ResponseEntity(HttpStatus.OK);
        }
    
      
        /** *@author Fang *@create 2018/10/25 19:49 *@desc 删除 **/
        @DeleteMapping("/deleteProduct/{ids}")
        public ResponseEntity<Void>  delete(@PathVariable("ids") String ids){ 
            String url="http://127.0.0.1:8090/product02/deleteProduct02/"+ids;
            restTemplate.delete(url);
            return new ResponseEntity(HttpStatus.OK);
        }
    
    }

## 2.4 接收请求的（controller） ##

package com.czxy.web.product02;
    
    import com.czxy.pojo.DatagridResult;
    import com.czxy.pojo.Product;
    import com.czxy.service.product.ProductService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.http.HttpStatus;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.*;
    
    import java.util.LinkedHashMap;
    
    /** * @author Fang * @create 2018-10-25 16:20 * @desc 商品 **/
    @RestController
    @RequestMapping("/product02")
    public class ProductController02 { 
    
        @Autowired
        private ProductService productService;
      
        /** *@author Fang *@create 2018/10/26 21:52 *@desc datagrid 分页查询 **/
        @GetMapping("/findAll02")
        public ResponseEntity<DatagridResult> findAll(Integer page, Integer rows) { 
    
            DatagridResult result = productService.findAll(page, rows);
    
            return new ResponseEntity<DatagridResult>(result, HttpStatus.OK);
        }
    
        /** * @author Fang * @create 2018/10/25 18:10 * @desc 修改 **/
    
        @PutMapping("/update02")
        public ResponseEntity<Void> update(@RequestBody Product product) { 
    
            productService.update(product);
            return new ResponseEntity(HttpStatus.OK);
        }
    
    
       /** *@author Fang *@create 2018/10/25 19:49 *@desc 删除 **/
        @DeleteMapping("/deleteProduct02/{ids}")
        public ResponseEntity<Void>  delete(@PathVariable("ids") String ids){ 
    
    
            productService.deleteProduct(ids);
    
            return new ResponseEntity(HttpStatus.OK);
        }
    
    
    
    }

## 3 注意 ##

#### 发送post请求时 接受调用的方法要在参数上加一个@RequestBody注解 ####

如图所示：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYzMzEzMQ_size_27_color_FFFFFF_t_70 2]

#### delete请求 注意参数注解 ####

如图所示：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjYzMzEzMQ_size_27_color_FFFFFF_t_70 3]

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