一、介绍
最近在工作中需要在后台调用各种上传、下载、以及第三方服务接口，经过研究决定使用 HttpClient，自己封装了一个 HttpClient 工具类，简单轻松的实现get、post、put、delete 以及上传、下载请求，在此分享给大家。
二、实践应用
本文基于 HttpClient4.5.5 版本进行开发，也是现在最新的版本，之所以要提供版本说明，是因为 HttpClient 3 版本和 HttpClient 4 版本 API 差别还是很多大的，你把 HttpClient 3 版本的代码拿到 HttpClient 4 上面运行不起来，会报错的。所以在使用之前，一定要注意 HtppClient 的版本问题。
话不多说，直接上代码！
2.1、引用 HttpClient 依赖包
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.6</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpcore</artifactId>
<version>4.4.10</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
<version>4.5.6</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.68</version>
</dependency>
2.2、编写工具类（重点）
本次采用单利模式来初始化客户端，并用线程池来管理，同时支持http和https协议，项目启动之后，无需手动关闭httpClient客户端！
import com.alibaba.fastjson.JSONObject;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.exception.ExceptionUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.*;
import org.apache.http.client.utils.HttpClientUtils;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustStrategy;
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.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.ssl.SSLContexts;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.net.ssl.SSLContext;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.util.Map;
import java.util.Objects;
public class HttpUtils {
private static final Logger log = LoggerFactory.getLogger(HttpUtils.class);
private HttpUtils() {}
//多线程共享实例
private static CloseableHttpClient httpClient;
static {
SSLContext sslContext = createSSLContext();
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext, NoopHostnameVerifier.INSTANCE);
// 注册http套接字工厂和https套接字工厂
Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory> create()
.register("http", PlainConnectionSocketFactory.INSTANCE)
.register("https", sslsf)
.build();
// 连接池管理器
PoolingHttpClientConnectionManager connMgr = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
connMgr.setMaxTotal(300);//连接池最大连接数
connMgr.setDefaultMaxPerRoute(300);//每个路由最大连接数，设置的过小，无法支持大并发
connMgr.setValidateAfterInactivity(5 * 1000); //在从连接池获取连接时，连接不活跃多长时间后需要进行一次验证
// 请求参数配置管理器
RequestConfig requestConfig = RequestConfig.custom()
.setConnectTimeout(60000)
.setSocketTimeout(60000)
.setConnectionRequestTimeout(60000)
.build();
// 获取httpClient客户端
httpClient = HttpClients.custom()
.setConnectionManager(connMgr)
.setDefaultRequestConfig(requestConfig)
.build();
}
/**
* GET请求
* @param url
* @return
*/
public static String getUrl(String url) {
return sendHttp(HttpMethod.GET, url, null, null);
}
/**
* GET请求/带头部的信息
* @param url
* @param header
* @return
*/
public static String getUrl(String url, Map<String, String> header) {
return sendHttp(HttpMethod.GET, url, header, null);
}
/**
* POST请求/无参数
* @param url
* @return
*/
public static String postJson(String url) {
return postJson(url, null, null);
}
/**
* POST请求/有参数
* @param url
* @param param
* @return
*/
public static String postJson(String url, String param) {
return postJson(url, null, param);
}
/**
* POST请求/无参数带头部
* @param url
* @param header
* @return
*/
public static String postJson(String url, Map<String, String> header) {
return postJson(url, header, null);
}
/**
* POST请求/有参数带头部
* @param url
* @param header
* @param params
* @return
*/
public static String postJson(String url, Map<String, String> header, String params) {
return sendHttp(HttpMethod.POST, url, header, params);
}
/**
* 上传文件流
* @param url
* @param header
* @param param
* @param fileName
* @param inputStream
* @return
*/
public static RequestResult postUploadFileStream(String url, Map<String, String> header, Map<String, String> param, String fileName, InputStream inputStream) {
byte[] stream = inputStream2byte(inputStream);
return postUploadFileStream(url, header, param, fileName, stream);
}
/**
* 上传文件
* @param url 上传地址
* @param header 请求头部
* @param param 请求表单
* @param fileName 文件名称
* @param stream 文件流
* @return
*/
public static RequestResult postUploadFileStream(String url, Map<String, String> header, Map<String, String> param, String fileName, byte[] stream) {
String infoMessage = new StringBuilder().append("request postUploadFileStream，url:").append(url).append("，header:").append(header.toString()).append("，param:").append(JSONObject.toJSONString(param)).append("，fileName:").append(fileName).toString();
log.info(infoMessage);
RequestResult result = new RequestResult();
if(StringUtils.isBlank(fileName)){
log.warn("上传文件名称为空");
throw new RuntimeException("上传文件名称为空");
}
if(Objects.isNull(stream)){
log.warn("上传文件流为空");
throw new RuntimeException("上传文件流为空");
}
CloseableHttpResponse response = null;
try {
ContentType contentType = ContentType.MULTIPART_FORM_DATA.withCharset("UTF-8");
HttpPost httpPost = new HttpPost(url);
if (Objects.nonNull(header) && !header.isEmpty()) {
for (Map.Entry<String, String> entry : header.entrySet()) {
httpPost.setHeader(entry.getKey(), entry.getValue());
if(log.isDebugEnabled()){
log.debug(entry.getKey() + ":" + entry.getValue());
}
}
}
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.setCharset(Charset.forName("UTF-8"));//使用UTF-8
builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);//设置浏览器兼容模式
if (Objects.nonNull(param) && !param.isEmpty()) {
for (Map.Entry<String, String> entry : param.entrySet()) {
if (log.isDebugEnabled()) {
log.debug(entry.getKey() + ":" + entry.getValue());
}
builder.addPart(entry.getKey(), new StringBody(entry.getValue(), contentType));
}
}
builder.addBinaryBody("file", stream, contentType, fileName);//封装上传文件
httpPost.setEntity(builder.build());
//请求执行，获取返回对象
response = httpClient.execute(httpPost);
log.info("postUploadFileStream response status:{}", response.getStatusLine());
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode == HttpStatus.SC_OK || statusCode == HttpStatus.SC_NO_CONTENT) {
result.setSuccess(true);
}
HttpEntity httpEntity = response.getEntity();
if (Objects.nonNull(httpEntity)) {
String content = EntityUtils.toString(httpEntity, "UTF-8");
log.info("postUploadFileStream response body:{}", content);
result.setMsg(content);
}
} catch (Exception e) {
log.error(infoMessage + " failure", e);
result.setMsg("请求异常");
} finally {
HttpClientUtils.closeQuietly(response);
}
return result;
}
/**
* 从下载地址获取文件流(如果链接出现双斜杠，请用OKHttp)
* @param url
* @return
*/
public static ByteArrayOutputStream getDownloadFileStream(String url) {
String infoMessage = new StringBuilder().append("request getDownloadFileStream，url:").append(url).toString();
log.info(infoMessage);
ByteArrayOutputStream byteOutStream = null;
CloseableHttpResponse response = null;
try {
response = httpClient.execute(new HttpGet(url));
log.info("getDownloadFileStream response status:{}", response.getStatusLine());
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode == HttpStatus.SC_OK) {
//请求成功
HttpEntity entity = response.getEntity();
if (entity != null && entity.getContent() != null) {
//复制输入流
byteOutStream = cloneInputStream(entity.getContent());
}
}
} catch (Exception e) {
log.error(infoMessage + " failure", e);
} finally {
HttpClientUtils.closeQuietly(response);
}
return byteOutStream;
}
/**
* 表单请求
* @param url 地址
* @param header 请求头部
* @param param 请求表单
* @return
*/
public static RequestResult sendPostForm(String url, Map<String, String> header, Map<String, String> param) {
String infoMessage = new StringBuilder().append("request postForm，url:").append(url).append("，header:").append(JacksonUtils.toJson(header)).append("，param:").append(JacksonUtils.toJson(param)).toString();
if(log.isDebugEnabled()){
log.debug(infoMessage);
}
RequestResult result = new RequestResult();
CloseableHttpResponse response = null;
try {
HttpPost httpPost = new HttpPost(url);
httpPost.addHeader("Content-type", "application/x-www-form-urlencoded");
if (Objects.nonNull(header) && !header.isEmpty()) {
for (Map.Entry<String, String> entry : header.entrySet()) {
httpPost.setHeader(entry.getKey(), entry.getValue());
if(log.isDebugEnabled()){
log.debug(entry.getKey() + ":" + entry.getValue());
}
}
}
List<NameValuePair> nameValuePairs = new ArrayList<>();
if (Objects.nonNull(param) && !param.isEmpty()) {
for (Map.Entry<String, String> entry : param.entrySet()) {
if (log.isDebugEnabled()) {
log.debug(entry.getKey() + ":" + entry.getValue());
}
nameValuePairs.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
}
}
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs, Charset.forName("UTF-8")));
//请求执行，获取返回对象
response = httpClient.execute(httpPost);
if(log.isDebugEnabled()){
log.debug("postForm response status:{}", response.getStatusLine());
}
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode == HttpStatus.SC_OK || statusCode == HttpStatus.SC_NO_CONTENT) {
result.setSuccess(true);
}
HttpEntity httpEntity = response.getEntity();
if (Objects.nonNull(httpEntity)) {
String content = EntityUtils.toString(httpEntity, "UTF-8");
if(log.isDebugEnabled()){
log.debug("postForm response body:{}", content);
}
result.setMsg(content);
}
} catch (Exception e) {
log.error(infoMessage + " failure", e);
result.setMsg("请求异常");
} finally {
HttpClientUtils.closeQuietly(response);
}
return result;
}
/**
* 发送http请求(通用方法)
* @param httpMethod 请求方式（GET、POST、PUT、DELETE）
* @param url 请求路径
* @param header 请求头
* @param params 请求body（json数据）
* @return 响应文本
*/
public static String sendHttp(HttpMethod httpMethod, String url, Map<String, String> header, String params) {
String infoMessage = new StringBuilder().append("request sendHttp，url:").append(url).append("，method:").append(httpMethod.name()).append("，header:").append(JSONObject.toJSONString(header)).append("，param:").append(params).toString();
log.info(infoMessage);
//返回结果
String result = null;
CloseableHttpResponse response = null;
long beginTime = System.currentTimeMillis();
try {
ContentType contentType = ContentType.APPLICATION_JSON.withCharset("UTF-8");
HttpRequestBase request = buildHttpMethod(httpMethod, url);
if (Objects.nonNull(header) && !header.isEmpty()) {
for (Map.Entry<String, String> entry : header.entrySet()) {
//打印头部信息
if(log.isDebugEnabled()){
log.debug(entry.getKey() + ":" + entry.getValue());
}
request.setHeader(entry.getKey(), entry.getValue());
}
}
if (StringUtils.isNotEmpty(params)) {
if(HttpMethod.POST.equals(httpMethod) || HttpMethod.PUT.equals(httpMethod)){
((HttpEntityEnclosingRequest) request).setEntity(new StringEntity(params, contentType));
}
}
response = httpClient.execute(request);
HttpEntity httpEntity = response.getEntity();
log.info("sendHttp response status:{}", response.getStatusLine());
if (Objects.nonNull(httpEntity)) {
result = EntityUtils.toString(httpEntity, "UTF-8");
log.info("sendHttp response body:{}", result);
}
} catch (Exception e) {
log.error(infoMessage + " failure", e);
} finally {
HttpClientUtils.closeQuietly(response);//关闭返回对象
}
long endTime = System.currentTimeMillis();
log.info("request sendHttp response time cost:" + (endTime - beginTime) + " ms");
return result;
}
/**
* 请求方法（全大些）
*/
public enum HttpMethod {
GET, POST, PUT, DELETE
}
/**
* 上传返回结果封装
*/
public static class RequestResult{
private boolean isSuccess;//是否成功
private String msg;//消息
public boolean isSuccess() {
return isSuccess;
}
public RequestResult setSuccess(boolean success) {
isSuccess = success;
return this;
}
public String getMsg() {
return msg;
}
public RequestResult setMsg(String msg) {
this.msg = msg;
return this;
}
public RequestResult() {
this.isSuccess = false;
}
}
/**
* 构建请求方法
* @param method
* @param url
* @return
*/
private static HttpRequestBase buildHttpMethod(HttpMethod method, String url) {
if (HttpMethod.GET.equals(method)) {
return new HttpGet(url);
} else if (HttpMethod.POST.equals(method)) {
return new HttpPost(url);
} else if (HttpMethod.PUT.equals(method)) {
return new HttpPut(url);
} else if (HttpMethod.DELETE.equals(method)) {
return new HttpDelete(url);
} else {
return null;
}
}
/**
* 配置证书
* @return
*/
private static SSLContext createSSLContext(){
try {
//信任所有,支持导入ssl证书
TrustStrategy acceptingTrustStrategy = (cert, authType) -> true;
SSLContext sslContext = SSLContexts.custom().loadTrustMaterial(null, acceptingTrustStrategy).build();
return sslContext;
} catch (Exception e) {
log.error("初始化ssl配置失败", e);
throw new RuntimeException("初始化ssl配置失败");
}
}
/**
* 复制文件流
* @param input
* @return
*/
private static ByteArrayOutputStream cloneInputStream(InputStream input) {
try {
ByteArrayOutputStream byteOutStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len;
while ((len = input.read(buffer)) > -1) {
byteOutStream.write(buffer, 0, len);
}
byteOutStream.flush();
return byteOutStream;
} catch (IOException e) {
log.warn("copy InputStream error，{}", ExceptionUtils.getStackTrace(e));
}
return null;
}
/**
* 输入流转字节流
* @param in
* @return
*/
private static byte[] inputStream2byte(InputStream in) {
ByteArrayOutputStream bos = null;
try {
bos = new ByteArrayOutputStream();
byte[] b = new byte[1024];
int n;
while ((n = in.read(b)) != -1) {
bos.write(b, 0, n);
}
in.close();
bos.close();
byte[] buffer = bos.toByteArray();
return buffer;
} catch (IOException e) {
log.warn("inputStream transfer byte error，{}", ExceptionUtils.getStackTrace(e));
} finally {
try {
if (in != null) {
in.close();
}
} catch (IOException e) {
log.error("clone inputStream error", e);
}
try {
if (bos != null) {
bos.close();
}
} catch (IOException e) {
log.error("clone outputStream error", e);
}
}
return null;
}
public static void main(String[] args) {
String url = "https://101.231.204.80:5000/gateway/api/queryTrans.do";
String result = postJson(url);
System.out.println(result);
}
}
除了上传、下载请求之外，默认封装的请求参数格式都是application/json，如果不够，可以根据自己的业务场景进行封装处理！
其中sendHttp是一个支持GET、POST、PUT、DELETE请求的通用方法，上面介绍的getUrl、postJosn等方法，最终都会调用到这个方法！
2.3、接口请求示例
工具包封装完成之后，在代码中使用起来也非常简单，直接采用工具类方法就可以直接使用，例如下面以post方式请求某个接口！
public static void main(String[] args) throws Exception {
String url = "https://101.231.204.80:5000/gateway/api/queryTrans.do";
String result= HttpUtils.postJson(url);
System.out.println(result);
}
三、小结
在编写工具类的时候，需要注意的地方是，尽可能保证httpClient客户端全局唯一，也就是采用单利模式，如果我们每次请求都初始化一个客户端，结束之后又将其关闭，在高并发的接口请求场景下，性能效率急剧下降！
HttpClients客户端的初始化参数配置非常丰富，本文默认初始化的线程池为300，在实际的业务开发中，大家还可以结合自己的业务场景进行调优，具体的配置可以参考官网文档，地址：Apache HttpComponents。
