参考自：http://blog.csdn.net/daydayupzzc/article/details/38866489



import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

public class Url {

    public static void main(String[] args) throws Exception {
        String url="http://flash.weather.com.cn/wmaps/xml/chengdu.xml";
        getData(url);
    }

    public static String getData(String urlString) throws Exception {
        String res = "";
        BufferedReader reader = null;
        try {
            URL url = new URL(urlString);
            URLConnection conn = (URLConnection)url.openConnection();
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));
            System.out.println("创建url!");
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println("分别获取每行内容！："+line);
                res += line;
            }
            reader.close();
        } catch (Exception e) {
            e.getMessage();
        }
        System.out.println(res);
        return res;
    }
}

返回结果： 


原网页内容： 


接下来就可以解析其中自己需要的内容了（上面例子中返回的数据是xml格式的字符串，如果需要返回数据流请参考上面原教程）

public void downloadExcelFile() throws Exception {

        URL url = new URL(strURL);

        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        conn.connect();

        // 打印HTTP header

        Map headers = conn.getHeaderFields();

        Set<String> keys = headers.keySet();

        // 转换编码

        String contentDisposition = URLDecoder.decode(

                conn.getHeaderField("content-Disposition"), "UTF-8");

        System.out.println(contentDisposition);

        // 匹配文件名

        Pattern pattern = Pattern.compile(".*fileName=(.*)");

        Matcher matcher = pattern.matcher(contentDisposition);

        System.out.println(matcher.groupCount());

        System.out.println(matcher.matches());

        String filename = contentDisposition.split("=")[1];

        // 写盘

        File vfile = new File(path);

        if (!vfile.exists()) {

            vfile.mkdirs();

        }

        RandomAccessFile file = new RandomAccessFile(path + PreFileName, "rw");

        InputStream stream = conn.getInputStream();

        byte buffer[] = new byte[1024];

        while (true) {

            int len = stream.read(buffer);

            if (len == -1) {

                break;

            }

            file.write(buffer, 0, len);

        }

        if (file != null) {

            file.close();

        }

        if (stream != null) {

            stream.close();

        }

    }

需求:

testCase 访问本地的 url,获得返回 url 的 json 数据
1,url 路径 比如访问 http://localhost:8080/spb/result

Controller如下

@RestController
@RequestMapping("/spb")
public class JsonController extends MainController {

    private static final Logger logger = LoggerFactory.getLogger(JsonController.class);

    @RequestMapping("/result")
    public String resultJson() {
        return "{\"name\": \"小明\",\"age\": 14,\"gender\": true,\"height\": 1.65,\"grade\": null,\"middle-school\": \"\\\"W3C\\\" Middle School\",\"skills\": [\"JavaScript\",\"Java\",\"Python\",\"Lisp\"]}";
    }

运行项目访问url如下



那我们在testCase中如何访问这个url路径来获取json数据呢?如下

 

    @Test
    public void testJsonResult() throws IOException {
        URL connect = isConnect("http://localhost:8080/spb/result");
        if (null != connect){
            String json = loadJson(connect.toString());
            System.out.println(json);
        }
    }


    public synchronized URL isConnect(String urlStr) {
        URL url = null;
        HttpURLConnection connection = null;
        int counts = 0;
        if (urlStr == null || urlStr.length() <= 0) {
            return null;
        }
        while (counts < 5) {
            try {
                url = new URL(urlStr);
                connection = (HttpURLConnection) url.openConnection();
                int code = connection.getResponseCode();
                System.out.println(counts +" = "+code);
                if (code == 200) {
                    System.out.println("URL可用！");
                }
                break;
            } catch (Exception ex) {
                counts++;
                System.out.println("URL不可用，连接第 " + counts +"次");
                urlStr = null;
                continue;
            }
        }
        return url;
    }


    public static String loadJson(String url) {
        StringBuilder json = new StringBuilder();
        try {
            URL urlObject = new URL(url);
            URLConnection uc = urlObject.openConnection();
            // 设置为utf-8的编码 才不会中文乱码
            BufferedReader in = new BufferedReader(new InputStreamReader(uc
                .getInputStream(), "utf-8"));
            String inputLine = null;
            while ((inputLine = in.readLine()) != null) {
                json.append(inputLine);
            }
            in.close();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return json.toString();
    }

运行效果为

 

易错点注意

在运行testCase之前需要确认服务器是否启动(tomcat是否启动),如果没有启动获取不到json数据
	
如果连接不上url,请确认访问的端口是否与你tomcat的端口相同
 

 

URL url = new URL(surl); 
URLConnection rulConnection   = url.openConnection();
HttpURLConnection httpUrlConnection  =  (HttpURLConnection) rulConnection;
httpUrlConnection.setConnectTimeout(300000);
httpUrlConnection.setReadTimeout(300000);
httpUrlConnection.setInstanceFollowRedirects(false);//禁止重定向
httpUrlConnection.connect();
String code = new Integer(httpUrlConnection.getResponseCode()).toString();//code
返回code: 
1xx ：请求已被接受，需要继续处理
2xx：代表请求已成功被服务器接收、理解、并接受
3xx：代表客户端采取进一步的操作才能完成请求。通常，这些状态码用来重定向
4xx：代表客户端发生了错误
5xx：代表了服务器在处理请求的过程中有错误或者异常状态发生