Java访问远程接口的几种方式

迷南。 2022-09-13 04:28 201阅读 0赞

## 一.Java访问远程url接口并获取结果 ##

**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：itar * 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;
        }
    }