Java访问远程接口的几种方式

1.原生JavaAPI获取

package com.util;

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.Map;

/**
* <pre>
* 功能：httpUrlConnection访问远程接口工具
* 日期：2015年3月17日 上午11:19:21
* </pre>
*/
public class HttpUrlConnectionUtil {

/**
* <pre>
* 方法体说明：向远程接口发起请求，返回字符串类型结果
* @param url 接口地址
* @param requestMethod 请求方式
* @param params 传递参数     重点：参数值需要用Base64进行转码
* @return String 返回结果
* </pre>
*/
public static String httpRequestToString(String url, String requestMethod,
Map<String, String> params){

String result = null;
try {
InputStream is = httpRequestToStream(url, requestMethod, params);
byte[] b = new byte[is.available()];
is.read(b);
result = new String(b);
} catch (IOException e) {
e.printStackTrace();
}
return result;
}

/**
* <pre>
* 方法体说明：向远程接口发起请求，返回字节流类型结果
* 作者：高会于
* 日期：2015年3月17日 上午11:20:25
* @param url 接口地址
* @param requestMethod 请求方式
* @param params 传递参数     重点：参数值需要用Base64进行转码
* @return InputStream 返回结果
* </pre>
*/
public static InputStream httpRequestToStream(String url, String requestMethod,
Map<String, String> params){

InputStream is = null;
try {
String parameters = "";
boolean hasParams = false;
//将参数集合拼接成特定格式，如name=zhangsan&age=24
for(String key : params.keySet()){
String value = URLEncoder.encode(params.get(key), "UTF-8");
parameters += key +"="+ value +"&";
hasParams = true;
}
if(hasParams){
parameters = parameters.substring(0, parameters.length()-1);
}

//请求方式是否为get
boolean isGet = "get".equalsIgnoreCase(requestMethod);
//请求方式是否为post
boolean isPost = "post".equalsIgnoreCase(requestMethod);
if(isGet){
url += "?"+ parameters;
}

URL u = new URL(url);
HttpURLConnection conn = (HttpURLConnection) u.openConnection();

//请求的参数类型(使用restlet框架时，为了兼容框架，必须设置Content-Type为“”空)
conn.setRequestProperty("Content-Type", "application/octet-stream");
//conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
//设置连接超时时间
conn.setConnectTimeout(50000);
//设置读取返回内容超时时间
conn.setReadTimeout(50000);
//设置向HttpURLConnection对象中输出，因为post方式将请求参数放在http正文内，因此需要设置为ture，默认false
if(isPost){
conn.setDoOutput(true);
}
//设置从HttpURLConnection对象读入，默认为true
conn.setDoInput(true);
//设置是否使用缓存，post方式不能使用缓存
if(isPost){
conn.setUseCaches(false);
}
//设置请求方式，默认为GET
conn.setRequestMethod(requestMethod);

//post方式需要将传递的参数输出到conn对象中
if(isPost){
DataOutputStream dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(parameters);
dos.flush();
dos.close();
}

//从HttpURLConnection对象中读取响应的消息
//执行该语句时才正式发起请求
is = conn.getInputStream();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return is;
}
}

2.利用httpClient访问获取

package com.util;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Map;

import org.apache.http.HttpResponse;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.util.EntityUtils;

/**
* <pre>
* 功能：httpClient访问远程接口工具类
* 日期：2015年3月17日 上午11:19:21
* </pre>
*/
@SuppressWarnings("deprecation")
public class HttpClientUtil {

/**
* <pre>
* 方法体说明：向远程接口发起请求，返回字符串类型结果
* @param url 接口地址
* @param requestMethod 请求类型
* @param params 传递参数
* @return String 返回结果
* </pre>
*/
public static String httpRequestToString(String url, String requestMethod,
Map<String, String> params, String ...auth){
//接口返回结果
String methodResult = null;
try {
String parameters = "";
boolean hasParams = false;
//将参数集合拼接成特定格式，如name=zhangsan&age=24
for(String key : params.keySet()){
String value = URLEncoder.encode(params.get(key), "UTF-8");
parameters += key +"="+ value +"&";
hasParams = true;
}
if(hasParams){
parameters = parameters.substring(0, parameters.length()-1);
}
//是否为GET方式请求
boolean isGet = "get".equalsIgnoreCase(requestMethod);
boolean isPost = "post".equalsIgnoreCase(requestMethod);
boolean isPut = "put".equalsIgnoreCase(requestMethod);
boolean isDelete = "delete".equalsIgnoreCase(requestMethod);

//创建HttpClient连接对象
DefaultHttpClient client = new DefaultHttpClient();
HttpRequestBase method = null;
if(isGet){
url += "?" + parameters;
method = new HttpGet(url);
}else if(isPost){
method = new HttpPost(url);
HttpPost postMethod = (HttpPost) method;
StringEntity entity = new StringEntity(parameters);
postMethod.setEntity(entity);
}else if(isPut){
method = new HttpPut(url);
HttpPut putMethod = (HttpPut) method;
StringEntity entity = new StringEntity(parameters);
putMethod.setEntity(entity);
}else if(isDelete){
url += "?" + parameters;
method = new HttpDelete(url);
}
method.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 6000);
//设置参数内容类型
method.addHeader("Content-Type","application/x-www-form-urlencoded");
//httpClient本地上下文
HttpClientContext context = null;
if(!(auth==null || auth.length==0)){
String username = auth[0];
String password = auth[1];
UsernamePasswordCredentials credt = new UsernamePasswordCredentials(username,password);
//凭据提供器
CredentialsProvider provider = new BasicCredentialsProvider();
//凭据的匹配范围
provider.setCredentials(AuthScope.ANY, credt);
context = HttpClientContext.create();
context.setCredentialsProvider(provider);
}
//访问接口，返回状态码
HttpResponse response = client.execute(method, context);
//返回状态码200，则访问接口成功
if(response.getStatusLine().getStatusCode()==200){
methodResult = EntityUtils.toString(response.getEntity());
}
client.close();
}catch (UnsupportedEncodingException e) {
e.printStackTrace();
}catch (IOException e) {
e.printStackTrace();
}
return methodResult;
}
}