java实现HTTP请求的三种方式
2019-05-17 本文已影响0人
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目前JAVA实现HTTP请求的方法用的最多的有两种：一种是通过HTTPClient这种第三方的开源框架去实现。HTTPClient对HTTP的封装性比较不错，通过它基本上能够满足我们大部分的需求，HttpClient3.1 是 org.apache.commons.httpclient下操作远程 url的工具包，虽然已不再更新，但实现工作中使用httpClient3.1的代码还是很多，HttpClient4.5是org.apache.http.client下操作远程 url的工具包，最新的;另一种则是通过HttpURLConnection去实现，HttpURLConnection是JAVA的标准类，是JAVA比较原生的一种实现方式。
自己在工作中三种方式都用到过，总结一下分享给大家，也方便自己以后使用，话不多说上代码。
第一种方式：java原生HttpURLConnection
package com.powerX.httpClient;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class HttpClient {
public static String doGet(String httpurl) {
HttpURLConnection connection = null;
InputStream is = null;
BufferedReader br = null;
String result = null;
// 返回结果字符串
try {
// 创建远程url连接对象
URL url = new URL(httpurl);
// 通过远程url连接对象打开一个连接，强转成httpURLConnection类
connection = (HttpURLConnection) url.openConnection();
// 设置连接方式：get
connection.setRequestMethod("GET");
// 设置连接主机服务器的超时时间：15000毫秒
connection.setConnectTimeout(15000);
// 设置读取远程返回的数据时间：60000毫秒
connection.setReadTimeout(60000);
// 发送请求
connection.connect();
// 通过connection连接，获取输入流
if (connection.getResponseCode() == 200) {
is = connection.getInputStream();
// 封装输入流is，并指定字符集
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
// 存放数据
StringBuffer sbf = new StringBuffer();
String temp = null;
while ((temp = br.readLine()) != null) {
sbf.append(temp);
sbf.append("rn");
}
result = sbf.toString();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
connection.disconnect();// 关闭远程连接
}
return result;
}
public static String doPost(String httpUrl, String param) {
HttpURLConnection connection = null;
InputStream is = null;
OutputStream os = null;
BufferedReader br = null;
String result = null;
try {
URL url = new URL(httpUrl);
// 通过远程url连接对象打开连接
connection = (HttpURLConnection) url.openConnection();
// 设置连接请求方式
connection.setRequestMethod("POST");
// 设置连接主机服务器超时时间：15000毫秒
connection.setConnectTimeout(15000);
// 设置读取主机服务器返回数据超时时间：60000毫秒
connection.setReadTimeout(60000);
// 默认值为：false，当向远程服务器传送数据/写数据时，需要设置为true
connection.setDoOutput(true);
// 默认值为：true，当前向远程服务读取数据时，设置为true，该参数可有可无
connection.setDoInput(true);
// 设置传入参数的格式:请求参数应该是 name1=value1&name2=value2 的形式。
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
// 设置鉴权信息：Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0
connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
// 通过连接对象获取一个输出流
os = connection.getOutputStream();
// 通过输出流对象将参数写出去/传输出去,它是通过字节数组写出的
os.write(param.getBytes());
// 通过连接对象获取一个输入流，向远程读取
if (connection.getResponseCode() == 200) {
is = connection.getInputStream();
// 对输入流对象进行包装:charset根据工作项目组的要求来设置
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
String temp = null;
// 循环遍历一行一行读取数据
while ((temp = br.readLine()) != null) {
sbf.append(temp);
sbf.append("rn");
}
result = sbf.toString();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != os) {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 断开与远程地址url的连接
connection.disconnect();
}
return result;
}
}
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第二种方式：apache HttpClient3.1
package com.powerX.httpClient;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
public class HttpClient3 {
public static String doGet(String url) {
// 输入流
InputStream is = null;
BufferedReader br = null;
String result = null;
// 创建httpClient实例
HttpClient httpClient = new HttpClient();
// 设置http连接主机服务超时时间：15000毫秒
// 先获取连接管理器对象，再获取参数对象,再进行参数的赋值
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 创建一个Get方法实例对象
GetMethod getMethod = new GetMethod(url);
// 设置get请求超时为60000毫秒
getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
// 设置请求重试机制，默认重试次数：3次，参数设置为true，重试机制可用，false相反
getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));
try {
// 执行Get方法
int statusCode = httpClient.executeMethod(getMethod);
// 判断返回码
if (statusCode != HttpStatus.SC_OK) {
// 如果状态码返回的不是ok,说明失败了,打印错误信息
System.err.println("Method faild: " + getMethod.getStatusLine());
} else {
// 通过getMethod实例，获取远程的一个输入流
is = getMethod.getResponseBodyAsStream();
// 包装输入流
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
// 读取封装的输入流
String temp = null;
while ((temp = br.readLine()) != null) {
sbf.append(temp).append("rn");
}
result = sbf.toString();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 释放连接
getMethod.releaseConnection();
}
return result;
}
public static String doPost(String url, MapparamMap) {
// 获取输入流
InputStream is = null;
BufferedReader br = null;
String result = null;
// 创建httpClient实例对象
HttpClient httpClient = new HttpClient();
// 设置httpClient连接主机服务器超时时间：15000毫秒
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 创建post请求方法实例对象
PostMethod postMethod = new PostMethod(url);
// 设置post请求超时时间
postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
NameValuePair[] nvp = null;
// 判断参数map集合paramMap是否为空
if (null != paramMap && paramMap.size() > 0) {// 不为空
// 创建键值参数对象数组，大小为参数的个数
nvp = new NameValuePair[paramMap.size()];
// 循环遍历参数集合map
Set<entry> entrySet = paramMap.entrySet();
// 获取迭代器
Iterator<entry> iterator = entrySet.iterator();
int index = 0;
while (iterator.hasNext()) {
EntrymapEntry = iterator.next();
// 从mapEntry中获取key和value创建键值对象存放到数组中
try {
nvp[index] = new NameValuePair(mapEntry.getKey(),
new String(mapEntry.getValue().toString().getBytes("UTF-8"), "UTF-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
index++;
}
}
// 判断nvp数组是否为空
if (null != nvp && nvp.length > 0) {
// 将参数存放到requestBody对象中
postMethod.setRequestBody(nvp);
}
// 执行POST方法
try {
int statusCode = httpClient.executeMethod(postMethod);
// 判断是否成功
if (statusCode != HttpStatus.SC_OK) {
System.err.println("Method faild: " + postMethod.getStatusLine());
}
// 获取远程返回的数据
is = postMethod.getResponseBodyAsStream();
// 封装输入流
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
String temp = null;
while ((temp = br.readLine()) != null) {
sbf.append(temp).append("rn");
}
result = sbf.toString();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭资源
if (null != br) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (null != is) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 释放连接
postMethod.releaseConnection();
}
return result;
}
}
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第三种方式：apache httpClient4.5
package com.powerX.httpClient;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
public class HttpClient4 {
public static String doGet(String url) {
CloseableHttpClient httpClient = null;
CloseableHttpResponse response = null;
String result = "";
try {
// 通过址默认配置创建一个httpClient实例
httpClient = HttpClients.createDefault();
// 创建httpGet远程连接实例
HttpGet httpGet = new HttpGet(url);
// 设置请求头信息，鉴权
httpGet.setHeader("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
// 设置配置请求参数
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 连接主机服务超时时间
.setConnectionRequestTimeout(35000)// 请求超时时间
.setSocketTimeout(60000)// 数据读取超时时间
.build();
// 为httpGet实例设置配置
httpGet.setConfig(requestConfig);
// 执行get请求得到返回对象
response = httpClient.execute(httpGet);
// 通过返回对象获取返回数据
HttpEntity entity = response.getEntity();
// 通过EntityUtils中的toString方法将结果转换为字符串
result = EntityUtils.toString(entity);
}
catch (ClientProtocolException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
finally {
// 关闭资源
if (null != response) {
try {
response.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
if (null != httpClient) {
try {
httpClient.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
public static String doPost(String url, MapparamMap) {
CloseableHttpClient httpClient = null;
CloseableHttpResponse httpResponse = null;
String result = "";
// 创建httpClient实例
httpClient = HttpClients.createDefault();
// 创建httpPost远程连接实例
HttpPost httpPost = new HttpPost(url);
// 配置请求参数实例
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 设置连接主机服务超时时间
.setConnectionRequestTimeout(35000)// 设置连接请求超时时间
.setSocketTimeout(60000)// 设置读取数据连接超时时间
.build();
// 为httpPost实例设置配置
httpPost.setConfig(requestConfig);
// 设置请求头
httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
// 封装post请求参数
if (null != paramMap && paramMap.size() > 0) {
Listnvps = new ArrayList();
// 通过map集成entrySet方法获取entity
Set<entry> entrySet = paramMap.entrySet();
// 循环遍历，获取迭代器
Iterator<entry> iterator = entrySet.iterator();
while (iterator.hasNext()) {
EntrymapEntry = iterator.next();
nvps.add(new BasicNameValuePair(mapEntry.getKey(), mapEntry.getValue().toString()));
}
// 为httpPost设置封装好的请求参数
try {
httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
}
catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
try {
// httpClient对象执行post请求,并返回响应参数对象
httpResponse = httpClient.execute(httpPost);
// 从响应对象中获取响应内容
HttpEntity entity = httpResponse.getEntity();
result = EntityUtils.toString(entity);
}
catch (ClientProtocolException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
finally {
// 关闭资源
if (null != httpResponse) {
try {
httpResponse.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
if (null != httpClient) {
try {
httpClient.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
return result;
}
}
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实例
有时候我们在使用post请求时，可能传入的参数是json或者其他格式，此时我们则需要更改请求头及参数的设置信息，以httpClient4.5为例，更改下面两列配置：httpPost.setEntity(new StringEntity(“你的json串”)); httpPost.addHeader(“Content-Type”, “application/json”)。
import java.io.File;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.URISyntaxException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.net.ssl.SSLException;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpRequest;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpRequestRetryHandler;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.protocol.HttpClientContext;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.entity.mime.MultipartEntityBuilder;
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.message.BasicNameValuePair;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.EntityUtils;
public class HttpClientUtils {
static Log log = LogFactory.getLog(HttpClientUtils.class);
private static CloseableHttpClient httpClient;
static {
PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
cm.setMaxTotal(100);
cm.setDefaultMaxPerRoute(100);
httpClient = HttpClients.custom().setRetryHandler(createRequestRetryHandler()).setConnectionManager(cm).build();
}
private static RequestConfig getRequestConfig() {
// return
// RequestConfig.custom().setConnectTimeout(30000).setConnectionRequestTimeout(30000).setSocketTimeout(30000).build();
return RequestConfig.custom().setConnectTimeout(120000).setConnectionRequestTimeout(120000)
.setSocketTimeout(120000).build();
}
private static HttpRequestRetryHandler createRequestRetryHandler() {
return new HttpRequestRetryHandler() {
@Override
public Boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
if (executionCount > 3) {
return false;
}
if (exception instanceof InterruptedIOException || exception instanceof UnknownHostException
|| exception instanceof ConnectTimeoutException || exception instanceof SSLException) {
return false;
}
final HttpClientContext clientContext = HttpClientContext.adapt(context);
final HttpRequest request = clientContext.getRequest();
Boolean idempotent = !(request instanceof HttpEntityEnclosingRequest);
if (idempotent) {
return true;
}
return false;
}
}
;
}
/**
* 无参get请求
*
* @throws ClientProtocolException
* @throws IOException
*/
public static String doGet(String url) throws Exception {
// 创建http GET请求
HttpGet httpGet = new HttpGet(url);
httpGet.setConfig(getRequestConfig());
// 设置请求参数
CloseableHttpResponse response = null;
try {
long begin = System.currentTimeMillis();
// 执行请求郑州 不 孕 不 育 医 院:http://jbk.39.net/yiyuanzaixian/zztjyy/
response = httpClient.execute(httpGet);
long end = System.currentTimeMillis();
long timeLength = (end - begin) / 1000;
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
log.info("时长： " + timeLength + "s, URL: " + url);
return EntityUtils.toString(response.getEntity(), "UTF-8");
} else {
log.info("时长： " + timeLength + "s, 异常URL: " + url);
throw new BusinessException("查询数据为空");
}
}
catch (Exception ex) {
throw ex;
}
finally {
if (response != null) {
response.close();
}
}
}
/**
* 有参get请求
*
* @param url
* @return
* @throws URISyntaxException
* @throws IOException
* @throws ClientProtocolException
*/
public static String doGet(String url, Mapparams) throws Exception {
URIBuilder uriBuilder = new URIBuilder(url);
if (params != null) {
for (String key : params.keySet()) {
uriBuilder.setParameter(key, params.get(key));
}
}
return doGet(uriBuilder.build().toString());
}
/**
* 有参post请求
*
* @throws ClientProtocolException
* @throws IOException
*/
public static String doPost(String url, Mapparams) throws Exception {
// 创建http POST请求
HttpPost httpPost = new HttpPost(url);
httpPost.setConfig(getRequestConfig());
if (params != null) {
// 设置2个post参数，一个是scope、一个是q
Listparameters = new ArrayList(0);
for (String key : params.keySet()) {
parameters.add(new BasicNameValuePair(key, params.get(key)));
}
// 构造一个form表单式的实体
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters, "UTF-8");
// 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) {
return EntityUtils.toString(response.getEntity(), "UTF-8");
}
}
finally {
if (response != null) {
response.close();
}
}
return null;
}
/**
* 有参post请求
*
* @throws ClientProtocolException
* @throws IOException
*/
public static String doPost(String url, Mapparams, MapheaderMap)
throws Exception {
// 创建http POST请求
HttpPost httpPost = new HttpPost(url);
httpPost.setConfig(getRequestConfig());
if(headerMap != null){
for (Entryheader: headerMap.entrySet()){
httpPost.setHeader(header.getKey(), header.getValue());
}
}
if (params != null) {
// 设置2个post参数，一个是scope、一个是q
Listparameters = new ArrayList(0);
for (String key : params.keySet()) {
parameters.add(new BasicNameValuePair(key, params.get(key)));
}
// 构造一个form表单式的实体
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters, "UTF-8");
// 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) {
return EntityUtils.toString(response.getEntity(), "UTF-8");
}
}
finally {
if (response != null) {
response.close();
}
}
return null;
}
/**
* 有参post请求所传参数为文件
*
* @throws ClientProtocolException
* @throws IOException
*/
public static String doPostMultipartFile(String url, Mapparams, MapheaderMap)
throws Exception {
// 创建http POST请求
HttpPost httpPost = new HttpPost(url);
httpPost.setConfig(getRequestConfig());
if(headerMap != null){
for (Entryheader: headerMap.entrySet()){
httpPost.setHeader(header.getKey(), header.getValue());
}
}
if (params != null) {
// 构造一个form表单式的实体
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
for (String key : params.keySet()) {
builder.addBinaryBody(key, new File(params.get(key)));
}
HttpEntity reqEntity = builder.build();
// 将请求实体设置到httpPost对象中
httpPost.setEntity(reqEntity);
}
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) {
return EntityUtils.toString(response.getEntity(), "UTF-8");
}
}
finally {
if (response != null) {
response.close();
}
}
return null;
}
/**
* 有参post请求,json交互
*
* @throws ClientProtocolException
* @throws IOException
*/
public static String doPostJson(String url, String json) throws Exception {
// 创建http POST请求
HttpPost httpPost = new HttpPost(url);
httpPost.setConfig(getRequestConfig());
if (StringUtils.isNotBlank(json)) {
// 标识出传递的参数是 application/json
StringEntity stringEntity = new StringEntity(json, ContentType.APPLICATION_JSON);
httpPost.setEntity(stringEntity);
}
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) {
return EntityUtils.toString(response.getEntity(), "UTF-8");
}
}
finally {
if (response != null) {
response.close();
}
}
return null;
}
/**
* 无参post请求
*
* @throws ClientProtocolException
* @throws IOException
*/
public static String doPost(String url) throws Exception {
return doPost(url, null);
}
}
