Android开发中经常用到HttpUrlConnection和HttpClient两种网络请求框架，HttpUrlConnection是基于Java的网络请求的，原理是IO流流机制，Httpclient是Android开发平台封装的网络请求框架，也是基于HttpUrlCollection的封装的，HttpClient封装的相当丰富和完善，用起来十分方便，但是如用到比较特别的网络请求情况，用起来反而不方便，从效率上讲HttpClient没有HttpUrlConnection高，下面就简单介绍两种请求的方式（代码）.
1，HttpUrlConnection的get请求方法:
package com.qf.demo;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
/**
* GET请求示例
*
* @author 小明
*
*/
public class GetDemo {
public static void main(String[] args) {
try {
// 1. 得到访问地址的URL
URL url = new URL(
"http://localhost:8080/Servlet/do_login.do?username=test&password=123456");
//注：设置字符的编码格式是： URLEncoder.encode("username=test", "utf-8");
// 2. 得到网络访问对象java.net.HttpURLConnection
HttpURLConnection connection = (HttpURLConnection) url
.openConnection();
/* 3. 设置请求参数（过期时间，输入、输出流、访问方式），以流的形式进行连接 */
// 设置是否向HttpURLConnection输出
connection.setDoOutput(false);
// 设置是否从httpUrlConnection读入
connection.setDoInput(true);
// 设置请求方式
connection.setRequestMethod("GET");
// 设置是否使用缓存
connection.setUseCaches(true);
// 设置此 HttpURLConnection 实例是否应该自动执行 HTTP 重定向
connection.setInstanceFollowRedirects(true);
// 设置超时时间
connection.setConnectTimeout(3000);
// 连接
connection.connect();
//注：如果没有调用.connect()方法连接，则下面调用connection.getResponseCode()或者connection.getInputStream()会自动连接；
// 4. 得到响应状态码的返回值 responseCode
int code = connection.getResponseCode();
// 5. 如果返回值正常，数据在网络中是以流的形式得到服务端返回的数据
String msg = "";
if (code == 200) { // 正常响应
// 从流中读取响应信息
BufferedReader reader = new BufferedReader(
new InputStreamReader(connection.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) { // 循环从流中读取
msg += line + "\n";
}
reader.close(); // 关闭流
}
// 6. 断开连接，释放资源
connection.disconnect();
// 显示响应结果
System.out.println(msg);
} catch (IOException e) {
e.printStackTrace();
}
}
}
2，HttpUrlConnection的Post请求：
package com.qf.demo;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
/**
* POST请求示例
*
* @author 小明
*
*/
public class PostDemo {
public static void main(String[] args) {
try {
// 1. 获取访问地址URL
URL url = new URL("http://localhost:8080/Servlet/do_login.do");
// 2. 创建HttpURLConnection对象
HttpURLConnection connection = (HttpURLConnection) url
.openConnection();
/* 3. 设置请求参数等 */
// 请求方式
connection.setRequestMethod("POST");
// 超时时间
connection.setConnectTimeout(3000);
// 设置是否输出
connection.setDoOutput(true);
// 设置是否读入
connection.setDoInput(true);
// 设置是否使用缓存
connection.setUseCaches(false);
// 设置此 HttpURLConnection 实例是否应该自动执行 HTTP 重定向
connection.setInstanceFollowRedirects(true);
// 设置使用标准编码格式编码参数的名-值对
connection.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded");
// 连接
connection.connect();
/* 4. 处理输入输出 */
// 写入参数到请求中
String params = "username=test&password=123456";
// 注：转为UTF-8格式的字符：String params = URLEncoder.encode("username=test&password=123456", "UTF-8");
OutputStream out = connection.getOutputStream();
out.write(params.getBytes());
out.flush();
out.close();
// 从连接中读取响应信息
String msg = "";
int code = connection.getResponseCode();
if (code == 200) {
BufferedReader reader = new BufferedReader(
new InputStreamReader(connection.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
msg += line + "\n";
}
reader.close();
}
// 5. 断开连接
connection.disconnect();
// 处理结果
System.out.println(msg);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
3,HttpClient的get请求：
package com.qf.client;
import java.io.IOException;
import org.apache.http.HttpEntity;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
/**
* GET请求示例
*
* @author 小明
*
*/
public class GetDemo {
public static void main(String[] args) {
// 1. 创建HttpClient对象
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
// 2. 创建HttpGet对象
HttpGet httpGet = new HttpGet(
"http://localhost:8080/Servlet/do_login.do?username=test&password=123456");
CloseableHttpResponse response = null;
try {
// 3. 执行GET请求
response = httpClient.execute(httpGet);
System.out.println(response.getStatusLine());
// 4. 获取响应实体
HttpEntity entity = response.getEntity();
// 5. 处理响应实体
if (entity != null) {
System.out.println("长度：" + entity.getContentLength());
System.out.println("内容：" + EntityUtils.toString(entity));
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 6. 释放资源
try {
response.close();
httpClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
4,HttpClient的post请求：
package com.qf.client;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
/**
* POST请求测试
*
* @author 小明
*
*/
public class PostDemo {
public static void main(String[] args) {
// 1. 创建HttpClient对象
CloseableHttpClient httpClient = HttpClientBuilder.create().build();
// 2. 创建HttpPost对象
HttpPost post = new HttpPost(
"http://localhost:8080/Servlet/do_login.do");
// 3. 设置POST请求传递参数
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("username", "test"));
params.add(new BasicNameValuePair("password", "12356"));
try {
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params);
post.setEntity(entity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
// 4. 执行请求并处理响应
try {
CloseableHttpResponse response = httpClient.execute(post);
HttpEntity entity = response.getEntity();
if (entity != null){
System.out.println("响应内容：");
System.out.println(EntityUtils.toString(entity));
}
response.close();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 释放资源
try {
httpClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
转自(https://www.cnblogs.com/sharpest/p/7831350.html)
https://blog.csdn.net/u012838207/article/details/82867701
HttpURLConnection与HttpClient浅析
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