一、具体作用

调用其他厂商提供的服务API

二、对应示例

1、get

public static void main(String[] args) { String result = "";
	BufferedReader in = null; try { String urlName = url;
		URL realUrl = new URL(urlName);
		URLConnection conn = realUrl.openConnection();// 打开和URL之间的连接 conn.setRequestProperty("accept", "*/*");// 设置通用的请求属性 conn.setRequestProperty("connection", "Keep-Alive");
		conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
		conn.setConnectTimeout(4000);
		conn.connect();// 建立实际的连接 in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));// 定义BufferedReader输入流来读取URL的响应 String line; while ((line = in.readLine()) != null) {
			result += line;
		}
	} catch (Exception e) {
		System.out.println("发送GET请求出现异常！" + e);
	} finally {// 使用finally块来关闭输入流 try { if (in != null) { in.close();
			}
		} catch (IOException ex) {
			System.out.println("关闭流异常");
		}
	}
	System.out.println(result);
}

2、post

public static void main(String[] args) {
	PrintWriter out = null;
	BufferedReader in = null;
	String result = ""; try {
		URL realUrl = new URL(url); // 打开和URL之间的连接 URLConnection conn = realUrl.openConnection(); // 设置通用的请求属性 conn.setRequestProperty("accept", "*/*");
		conn.setRequestProperty("connection", "Keep-Alive");
		conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)"); // 发送POST请求必须设置如下两行 conn.setDoOutput(true);
		conn.setDoInput(true); // 获取URLConnection对象对应的输出流 out = new PrintWriter(conn.getOutputStream()); // 发送请求参数 out.print(param); // flush输出流的缓冲 out.flush(); // 定义BufferedReader输入流来读取URL的响应 in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
		String line; while ((line = in.readLine()) != null) {
			result += line;
		}
	} catch (Exception e) {
		System.out.println("[POST请求]向地址：" + url + " 发送数据：" + param + " 发生错误!");
	} finally {// 使用finally块来关闭输出流、输入流 try { if (out != null) { in.close();
			} if (in != null) { in.close();
			}
		} catch (IOException ex) {
			System.out.println("关闭流异常");
		}
	}
	System.out.println(result);
}