Java获取http和https网址对应html数据实例

　　由于之前在公司一直用的c#做的软件开发，近些天有同学需要用java做一个从指定网址获取信息的java程序。正好不是很难，顺便复习了一下java的知识。

　　要求如下，在https://www.marinetraffic.com/en/ais/details/ships/shipid:650235/mmsi:414726000/vessel:yu%20ming网址中得到如下图框中标记的数据。

　　程序如下：getwebposition类是主要程序类

package yinhang.wang;

import java.io.bufferedreader;
import java.io.ioexception;
import java.io.inputstream;
import java.io.inputstreamreader;
import java.net.url;
import java.util.regex.matcher;
import java.util.regex.pattern;

import javax.net.ssl.httpsurlconnection;
import javax.net.ssl.sslcontext;
import javax.net.ssl.sslsocketfactory;
import javax.net.ssl.trustmanager;
public class getwebposition {

    /**
     * @param args
     */
    public static void main(string[] args) {
        // todo auto-generated method stub
        string info = getdatabytwo();
        system.out.println(info);
    }

    // 从指定的url中获取数据
    //https://www.marinetraffic.com/en/ais/details/ships/shipid:650235/mmsi:414726000/vessel:yu%20ming
        private static string httprequest(string requesturl) {
   
            stringbuffer buffer = null;
            bufferedreader bufferedreader = null;
            inputstreamreader inputstreamreader = null;
            inputstream inputstream = null;
            httpsurlconnection httpurlconn = null;
            // 建立并向网页发送请求
            try {
                trustmanager[] tm = { new myx509trustmanager() };
                sslcontext sslcontext = sslcontext.getinstance("ssl", "sunjsse");
                sslcontext.init(null, tm, new java.security.securerandom());
                // 从上述sslcontext对象中得到sslsocketfactory对象
                sslsocketfactory ssf = sslcontext.getsocketfactory();

                url url = new url(requesturl);
                // 描述状态
                httpurlconn = (httpsurlconnection) url.openconnection();
                httpurlconn.setsslsocketfactory(ssf);
                httpurlconn
                .setrequestproperty("user-agent", "mozilla/5.0 (windows nt 6.1; win64; x64) applewebkit/537.36 (khtml, like gecko) chrome/61.0.3163.100 safari/537.36)");
                //防止报403错误。
                httpurlconn.setdooutput(true);
                httpurlconn.setdoinput(true);
                httpurlconn.setusecaches(false);
                // 请求的类型
                httpurlconn.setrequestmethod("get");
                // 获取输入流
                inputstream = httpurlconn.getinputstream();
                inputstreamreader = new inputstreamreader(inputstream, "utf-8");
                bufferedreader = new bufferedreader(inputstreamreader);
                // 从输入流读取结果
                buffer = new stringbuffer();
                string str = null;
                while ((str = bufferedreader.readline()) != null) {
                    buffer.append(str);
                }
            } catch (exception e) {
                e.printstacktrace();
            } finally {
                // 释放资源
                if (bufferedreader != null) {
                    try {
                        bufferedreader.close();
                    } catch (ioexception e) {
                        e.printstacktrace();
                    }
                }
                if (inputstreamreader != null) {
                    try {
                        inputstreamreader.close();
                    } catch (ioexception e) {
                        e.printstacktrace();
                    }
                }
                if (inputstream != null) {
                    try {
                        inputstream.close();
                    } catch (ioexception e) {
                        e.printstacktrace();
                    }
                }
                if (httpurlconn != null) {
                    httpurlconn.disconnect();
                }
            }
            return buffer.tostring();
        }　
    private static string htmlfiter(string html) {

        stringbuffer buffer = new stringbuffer();
        string str1 = "";
        string str2 = "";
        //取出所用的范围,
        //pattern p = pattern.compile("(.*)(<div class=\"panel panel-primary no-border vertical-offset-20\">)(.*)(</div>)(.*)");
        pattern p = pattern.compile("(.*)(</script>)(.*)(<div class=\"wind_icon wind_low\")(.*)");
        matcher m = p.matcher(html);
        if (m.matches()) {
            str1 = m.group(3);
            //取得时间：vessel's local time:
            p = pattern.compile("(.*)(time datetime=\")(.*)(\">)(.*)(</time>)(.*)(</span></strong>)(.*)");
            m = p.matcher(str1);
            if (m.matches()) {
                str2 = m.group(5);
                string str3 = m.group(7);
                buffer.append("\nvessel's local time: ");
                buffer.append(str2);
                buffer.append(str3);
                }
            // <a href="/en/ais/home/centerx:120.3903/centery:32.02979/zoom:10/mmsi:414726000/shipid:650235"
            // class="details_data_link">32.02979° / 120.3903°</a>
            //取得当前经纬度：latitude / longitude:
            p = pattern.compile("(.*)(class=\"details_data_link\">)(.*)(</a></strong></span>)(.*)");
            m = p.matcher(str1);
            if (m.matches()) {
                str2 = m.group(3);
                buffer.append("\nlatitude / longitude: ");
                buffer.append(str2);
            }
            //取得当前速度航线speed/course:
            p = pattern.compile("(.*)(<span><strong>)(.*)(</strong></span>)(.*)");
            m = p.matcher(str1);
            if (m.matches()) {
                str2 = m.group(3);
                buffer.append("\nspeed/course: ");
                buffer.append(str2);
            }
            }
        return buffer.tostring();
    }

        //封裝上述两个方法
        public static string getdatabytwo(){
            //调用第一个方法,获得html字符串
            string html = httprequest("https://www.marinetraffic.com/en/ais/details/ships/shipid:650235/mmsi:414726000/vessel:yu%20ming");
            //调用第二个方法,过滤掉无用的信息
            string result = htmlfiter(html);
            return result;
        }
}

 

myx509trustmanager这个类的作用是提供安全证书去访问https类型 的网站

package yinhang.wang;
 
import java.security.cert.certificateexception;
import java.security.cert.x509certificate;
 
import javax.net.ssl.x509trustmanager;
 
public class myx509trustmanager implements x509trustmanager {
    public void checkclienttrusted(x509certificate[] chain, string authtype)
            throws certificateexception
          {
          }
 
          public void checkservertrusted(x509certificate[] chain, string authtype)
            throws certificateexception
          {
          }
 
          public x509certificate[] getacceptedissuers()
          {
            return null;
          }
}

希望初步学习正则表达式和爬数据的小伙伴们能够用到。