非web项目实现文件下载，使用apache的httpmime工具进行相关的http请求操做。java
需求：实现非web项目进行文件下载或者http请求。web
一、添加相关pom依赖apache
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpmime</artifactId> <version>4.5.5</version> </dependency>
二、请求相关工具代码json
package com.lanxuewei.utils.file.deepwise; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.util.HashMap; import java.util.Map; import org.apache.http.Consts; import org.apache.http.HttpEntity; import org.apache.http.HttpStatus; import org.apache.http.client.methods.CloseableHttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.client.methods.HttpRequestBase; import org.apache.http.entity.ContentType; import org.apache.http.entity.StringEntity; import org.apache.http.entity.mime.HttpMultipartMode; import org.apache.http.entity.mime.MultipartEntityBuilder; import org.apache.http.entity.mime.content.StringBody; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.util.CharsetUtils; import org.apache.http.util.EntityUtils; import org.junit.jupiter.api.Test; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.alibaba.fastjson.JSON; import com.lanxuewei.utils.io.IOUtils; /** * @author lanxuewei Create in 2018/9/19 16:54 * Description: 本地http请求帮助类 */ public class HttpClientHelper { private static final Logger logger = LoggerFactory.getLogger(HttpClientHelper.class); /** * http post请求，json格式传输参数 * * @param map 参数对 * @param url url地址 * @return * @throws IOException */ public String postWithHttp(Map<String, Object> map, String url) { CloseableHttpClient client = HttpClients.createDefault(); HttpPost httpPost = new HttpPost(url); // 设置超时时间 RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(5000) .setConnectionRequestTimeout(5000) .setSocketTimeout(5000).build(); httpPost.setConfig(requestConfig); StringEntity stringEntity = new StringEntity(JSON.toJSONString(map), "UTF-8"); stringEntity.setContentEncoding("UTF-8"); stringEntity.setContentType("application/json"); httpPost.setEntity(stringEntity); CloseableHttpResponse response = null; try { response = client.execute(httpPost); if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { HttpEntity resEntity = response.getEntity(); return EntityUtils.toString(resEntity); } } catch (IOException e) { logger.error("", e); } return ""; } /** * 表单提交 post请求 * * @param map 参数对 * @param url url * @param token token * @return 响应流 * @throws IOException */ public String postFormWithHttp(Map<String, Object> map, String url, String token) { CloseableHttpClient client = HttpClients.createDefault(); HttpPost httpPost = new HttpPost(url); // 设置超时时间 RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(5000) .setConnectionRequestTimeout(5000) .setSocketTimeout(5000).build(); httpPost.setConfig(requestConfig); httpPost.setHeader("token", token); ContentType contentType = ContentType.create("text/plain", Consts.UTF_8); MultipartEntityBuilder builder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.BROWSER_COMPATIBLE); for (Map.Entry<String, Object> entry : map.entrySet()) { builder.addPart(entry.getKey(), new StringBody(entry.getValue().toString(), contentType)); } HttpEntity httpEntity = null; try { httpEntity = builder.setCharset(CharsetUtils.get("UTF-8")).build(); } catch (UnsupportedEncodingException e) { logger.error("", e); } httpPost.setEntity(httpEntity); return execute(client, httpPost); } /** * get请求 * * @param map 参数对 * @param url url * @param token token * @return 响应流 * @throws IOException */ public String getWithHttp(Map<String, Object> map, String url, String token) { CloseableHttpClient client = HttpClients.createDefault(); HttpGet httpGet = new HttpGet(url); // 设置超时时间 RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(5000) .setConnectionRequestTimeout(5000) .setSocketTimeout(5000).build(); httpGet.setConfig(requestConfig); httpGet.setHeader("token", token); return execute(client, httpGet); } /** * 执行请求并响应 * * @param client client * @param httpPost httpPost * @return 结果流字符串 */ private String execute(CloseableHttpClient client, HttpRequestBase httpPost) { if (client == null || httpPost == null) { return ""; } CloseableHttpResponse response = null; try { response = client.execute(httpPost); if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { HttpEntity resEntity = response.getEntity(); return EntityUtils.toString(resEntity); } } catch (Exception e) { logger.error("", e); } finally { IOUtils.safeClose(response); } return ""; } /** * 文件下载 * * @param url url * @param token token * @return 响应流 * @throws IOException */ public boolean downFileByGet(String url, String token, File targetFile) { CloseableHttpClient client = HttpClients.createDefault(); HttpGet httpGet = new HttpGet(url); // 设置超时时间 RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(5000) .setConnectionRequestTimeout(5000) .setSocketTimeout(5000).build(); httpGet.setConfig(requestConfig); httpGet.setHeader("token", token); CloseableHttpResponse response = null; try { response = client.execute(httpGet); } catch (IOException e) { logger.error("", e); } assert response != null; if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) { try { // org.apache.commons.io.IOUtils.copy(response.getEntity().getContent(), new FileOutputStream(targetFile)); response.getEntity().writeTo(new FileOutputStream(targetFile)); // 写入文件 } catch (IOException e) { logger.error("", e); } } return true; } }
说明：
一、本代码中采用的是日志是logback，json相关解析等采用的是fastjson，直接拷贝代码会有错误，因此须要引入相关依赖，因为和本文章内容关系不大，因此前排依赖中没有给出，本文最后会给出，或者不采用日志以及采用别的也行
二、有些请求函数中包含token，这是由于笔者的需求须要token认证，因此去掉或者保留看读者须要
三、url为完整的接口访问路径，例：http://localhost:8080/index
四、请求中的参数采用map传入，即 参数名-参数值 键值对
五、最后一个函数downFileByGet为文件下载函数api
三、 logback相关依赖app
<!-- httpmine --> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.1.11</version> </dependency> <!-- fastJson --> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.39</version> </dependency>
补充：以前因为没有手动设置超时时间，因此若是请求长时间无响应的话会致使一直等待阻塞问题出现，因此补充超时设置代码，以上代码已补充，下面也贴出手动设置超时代码块，代码以下：svg
// 设置超时时间
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(5000)
.setConnectionRequestTimeout(5000)
.setSocketTimeout(5000).build();
httpPost.setConfig(requestConfig);