java实现HTTP请求的三种方式分析

虾米哥 阅读:161 2021-11-01 17:12:12 评论:0
本文章主要介绍了java实现HTTP请求的三种方式,具有不错的的参考价值,希望对您有所帮助,如解说有误或未考虑完全的地方,请您留言指出,谢谢!

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

  

复制代码
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; 
    } 
}
复制代码

  第二种方式:apache HttpClient3.1

复制代码
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; 
    } 
}
复制代码

  第三种方式:apache  httpClient4.5

复制代码
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, Map<String, Object> paramMap) { 
        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) { 
            List<NameValuePair> nvps = new ArrayList<NameValuePair>(); 
            // 通过map集成entrySet方法获取entity 
            Set<Entry<String, Object>> entrySet = paramMap.entrySet(); 
            // 循环遍历,获取迭代器 
            Iterator<Entry<String, Object>> iterator = entrySet.iterator(); 
            while (iterator.hasNext()) { 
                Entry<String, Object> mapEntry = 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; 
    } 
}
复制代码

  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")。


标签:java
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