1.需求是调用远程的服务器来返回数据,开始想用前端来发送请求采用 jsonp或者cors,发现这两种都需要远程服务器代码有所改变,无奈用后台了。
代码:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
//postData参数,//postUrl 远程链接地址
public static String JsonSMS(String postData, String postUrl) {
try {
// 发送POST请求 建立连接
URL url = new URL(postUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//设置连接属性
conn.setRequestMethod("POST");// 设置URL请求方法
conn.setRequestProperty("Content-Type", "application/json");//发送请求参数类型
conn.setRequestProperty("Connection", "Keep-Alive");// 维持长连接
conn.setUseCaches(false);// 忽略缓存
conn.setDoOutput(true);//使用 URL 连接进行输出
conn.setRequestProperty("Content-Length", "" + postData.length());
OutputStreamWriter out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
out.write(postData);
out.flush();
out.close();
// 获取响应状态
if (conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
System.out.println("connect failed!");
return "";
}
// 获取响应内容体
String line, result = "";
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "utf-8"));
while ((line = in.readLine()) != null) {
result += line + "\n";
}
in.close();
return result;
} catch (IOException e) {
e.printStackTrace(System.out);
}
return "";
}