Java中http请求的三种方式

这是第一种方式：

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("\r\n");
        }
        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("\r\n");
        }
        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;
  }
}

这是第二种方式

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("\r\n");
        }

        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, Map<String, Object> paramMap) {
    // 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<String, Object>> entrySet = paramMap.entrySet();
      // 获取迭代器
      Iterator<Entry<String, Object>> iterator = entrySet.iterator();

      int index = 0;
      while (iterator.hasNext()) {
        Entry<String, Object> mapEntry = 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("\r\n");
      }

      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;
  }
}

这是第三种方式

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("\r\n");
        }

        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, Map<String, Object> paramMap) {
    // 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<String, Object>> entrySet = paramMap.entrySet();
      // 获取迭代器
      Iterator<Entry<String, Object>> iterator = entrySet.iterator();

      int index = 0;
      while (iterator.hasNext()) {
        Entry<String, Object> mapEntry = 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("\r\n");
      }

      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;
  }
}

Java中http请求的三种方式

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