利用HttpURLConnection发送请求

HttpURLConnection：
每个 HttpURLConnection实例都可用于生成单个请求，但是其他实例可以透明地共享连接到 HTTP 服务器的基础网络。请求后在 HttpURLConnection 的 InputStream 或 OutputStream 上调用 close() 方法可以释放与此实例关联的网络资源，但对共享的持久连接没有任何影响。如果在调用 disconnect() 时持久连接空闲，则可能关闭基础套接字

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Web服务器与客户端三种http交互方式 

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package com.lutongnet.server;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Server_ccy
 */
@WebServlet("/Server_ccy")
public class Server_ccy extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Server_ccy() {
        super();
        // TODO Auto-generated constructor stub
    }
/**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html;charset=utf-8");  
                request.setCharacterEncoding("utf-8");  
                response.setCharacterEncoding("utf-8");  
        System.out.println("server-------doGet..start.");
        String name = request.getParameter("name");
        String password = request.getParameter("password");
        System.out.println("server-------params:"+name+":"+password);
        System.out.println("server-------doGet..end.");
        PrintWriter out = response.getWriter(); 
        out.print("{\"姓名\":\"陈昌圆\"}"); 
        out.flush();
        out.close();
        //response.getWriter().append("server_get_info:").append("Served at: ").append(request.getContextPath());
    }
/**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        //doGet(request, response);
        response.setContentType("application/json;charset=utf-8"); 
                request.setCharacterEncoding("utf-8");  
                response.setCharacterEncoding("utf-8");
        System.out.println("server-------doPost..start.");
        System.out.println("ContentType---->"+response.getContentType());
        System.out.println("queryString---->"+request.getQueryString());
        String name = request.getParameter("name");
                System.out.println("name---->"+name);
        //String password = request.getParameter("password");
        //System.out.println("server-------params:"+name+":"+password);
        StringBuffer sb = new StringBuffer("");
        String str;
        BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream()));
        if((str = br.readLine()) != null){
            sb.append(str);
        }
                System.out.println("从客户端获取的参数："+sb);
        
        System.out.println("server-------doPost..end.");
        PrintWriter out = response.getWriter(); 
        out.print("{\"姓名\":\"陈昌圆\"}"); 
        out.flush();
        out.close();
    }

}
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package com.lutongnet.HttpURLConnection;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Date;

public class HttpURLConnectionTest {

    
    public static void main(String[] args) {
        String url = "http://localhost:7373/ccy_server/ccy";
        //String params = "name=ccy&password=123";
        String params = "{\"name\":\"陈昌圆\",\"password\":\"123\"}";
        try {
            String result = httpGetOrPost("POST", url, params);
            System.out.println("client---result:"+result);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }
public static String httpGetOrPost(String type, String url, String params) throws Exception{
            //get请求通过url传参（post可以通过url传参也可以将参数写在http正文传参）
            if("GET".equals(type)){
                if(url.contains("?")){
                    url += "&" + params;
                }else{
                    url += "?" + params;
                }
            }
                        System.out.println("请求地址：" + url);
            System.out.println("请求参数：" + params);
            URL u = new URL(url);
            /*
             * 查看URL API 发现 openConnection方法返回为URLConnection
             * HttpURLConnection为URLConnection的子类，有其更多的实现方法，
             * 通常将其转型为HttpURLConnection
             * */
            HttpURLConnection httpConn = (HttpURLConnection) u.openConnection();
            //设置请求方式  默认是GET
            httpConn.setRequestMethod(type);
            //写 默认均为false，GET不需要向HttpURLConnection进行写操作
            if("POST".equals(type)){
                httpConn.setDoOutput(true);
            }
                        httpConn.setDoInput(true);//读 默认均为true，HttpURLConnection主要是用来获取服务器端数据 肯定要能读
            httpConn.setAllowUserInteraction(true);//设置是否允许用户交互  默认为false
            httpConn.setUseCaches(false);//设置是否缓存 
            httpConn.setConnectTimeout(5000);//设置连接超时时间 单位毫秒 ms
            httpConn.setReadTimeout(5000);//设置访问超时时间
            //setRequestProperty主要设置http请求头里面的相关属性
            httpConn.setRequestProperty("user-agent", "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.64 Safari/537.31");
            httpConn.setRequestProperty("accept", "*/*");
            httpConn.setRequestProperty("Content-Type", "application/json");
            //开启连接
            httpConn.connect();
            //post方式在建立连接后把头文件内容从连接的输出流中写入
            if("POST".equals(type)){
                                //在调用getInputStream()方法中会检查连接是否已经建立，如果没有建立，则会调用connect()
                OutputStreamWriter out = new OutputStreamWriter(httpConn.getOutputStream(), "utf-8");
                out.write(params);//将数据写入缓冲流
                out.flush();//将缓冲区数据发送到接收方
                out.close();
            }
            System.out.println("httpcode:"+httpConn.getResponseCode());
            //读取响应，现在开始可以读取服务器反馈的数据
            BufferedReader br = new BufferedReader(new InputStreamReader(httpConn.getInputStream(), "utf-8"));
            StringBuffer sb = new StringBuffer("");
            String str;
            while((str = br.readLine()) != null){
                sb.append(str);
            }
            System.out.println(new Date()+"---响应："+sb);
            br.close();
            httpConn.disconnect();
            return sb.toString();
}
    
}

get请求运行结果
客户端：
Image

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package com.lutongnet.HttpClient;

import java.security.cert.CertificateException;
public class HttpClientDemo {

    public static void main(String[] args) {
        HttpClientDemo hct = new HttpClientDemo();
        String url = "http://localhost:7373/ccy_server/ccy";
        Map<String, String> map = new HashMap<String, String>();
        map.put("name", "ccy");
        map.put("password", "123");
        String charset = "utf-8";
                String result = hct.doPost(url, map, charset);
        System.out.println("1.获取服务器端数据为："+result);
        String params = "{\"name\":\"陈昌圆\",\"password\":\"123\"}";
        String result2 = hct.doPost2(url, params);
        System.out.println("2.获取服务器端数据为："+result2);
    }
public String doPost2(String url, String content) {
        System.out.println("请求地址：" + url);
        System.out.println("请求参数：" + content);
        String charsetName = "utf-8";
        DefaultHttpClient httpclient = null;
        HttpPost post = null;
        try {
            httpclient = new DefaultHttpClient();
            post = new HttpPost(url);
            post.setHeader("Content-Type", "application/json;charset=" + charsetName);
            post.setEntity(new StringEntity(content, charsetName));
            HttpResponse response = httpclient.execute(post);
            HttpEntity entity = response.getEntity();
            String rsp = EntityUtils.toString(entity, charsetName);
            System.out.println("返回参数： "+rsp);
            return rsp;
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            try {
                httpclient.getConnectionManager().shutdown();
            } catch (Exception ignore) {}
        }

    }
public String doPost(String url,Map<String,String> map,String charset){  
        HttpClient httpClient = null;  
        HttpPost httpPost = null;  
        String result = null;  
        try{  
            httpClient = new SSLClient();  
            httpPost = new HttpPost(url);  
            //设置参数  
            List<NameValuePair> list = new ArrayList<NameValuePair>();  
            Iterator iterator = map.entrySet().iterator();  
            while(iterator.hasNext()){  
                Entry<String,String> elem = (Entry<String, String>) iterator.next();  
                list.add(new BasicNameValuePair(elem.getKey(),elem.getValue()));  
            }  
            if(list.size() > 0){  
                UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list,charset);  
                httpPost.setEntity(entity);  
            }  
            HttpResponse response = httpClient.execute(httpPost);  
            if(response != null){  
                HttpEntity resEntity = response.getEntity();  
                if(resEntity != null){  
                    result = EntityUtils.toString(resEntity,charset);  
                }  
            }  
        }catch(Exception ex){  
            ex.printStackTrace();  
        }  
        return result;  
    }
class SSLClient extends DefaultHttpClient{  
        public SSLClient() throws Exception{  
            super();  
            SSLContext ctx = SSLContext.getInstance("TLS");  
            X509TrustManager tm = new X509TrustManager() {  
                    @Override  
                    public void checkClientTrusted(X509Certificate[] chain,  
                            String authType) throws CertificateException {  
                    }  
                    @Override  
                    public void checkServerTrusted(X509Certificate[] chain,  
                            String authType) throws CertificateException {  
                    }  
                    @Override  
                    public X509Certificate[] getAcceptedIssuers() {  
                        return null;  
                    }  
            }; 
                ctx.init(null, new TrustManager[]{tm}, null);  
            SSLSocketFactory ssf = new SSLSocketFactory(ctx,SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);  
            ClientConnectionManager ccm = this.getConnectionManager();  
            SchemeRegistry sr = ccm.getSchemeRegistry();  
            sr.register(new Scheme("https", 443, (SchemeSocketFactory) ssf));  
        }  
    }
}

post请求运行结果
客户端：
Image

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package com.lutongnet.commonHttpclient;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;

public class CommonHttpClient {
public static void main(String[] args) {
        String url = "http://localhost:7373/ccy_server/ccy";
        List<String> params = new ArrayList<String>();
        params.add("陳昌圓");
        params.add("123");
        CommonHttpClient chc = new CommonHttpClient();
        String result = chc.getPostMethod(url, params);
        System.out.println("commonHttpClient---->从服务端获取的数据：" + result);
    }
private String getPostMethod(String url, List<String> params) {
        String result = null;
        HttpClient httpClient = new HttpClient();
        PostMethod postMethod = new PostMethod(url);
        //httpClient.getParams().setContentCharset("utf-8");
        //httpClient.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET, "utf-8");
        //postMethod.addRequestHeader("Content-type","application/x-www-form-urlencoded; charset=UTF-8");  
        //postMethod.addRequestHeader("Content-Type", PostMethod.FORM_URL_ENCODED_CONTENT_TYPE
        //        + "; charset=utf-8");
        postMethod.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET,
         "utf-8");
        postMethod.addParameter("name", params.get(0));
        postMethod.addParameter("password", params.get(1));
        try {
            httpClient.executeMethod(postMethod);
            result = postMethod.getResponseBodyAsString();
            System.out.println("result:" + result);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
/*class ccyPostMethod extends PostMethod {
        public ccyPostMethod(String url) {
            super(url);
        }

        @Override
        public String getRequestCharSet() {
            return "utf-8";
        }
    }*/

}

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redis清空缓存

进入redis命令行

首先启动redis服务

redis-server /home/redis/redis_7901.conf

redis-cli -p 7901(指定进入端口号为7901的redis数据库)

1.清空当前redis数据库缓存FLUSHDB

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NoClassDefFoundError 

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//Java对象转化json格式
    public static void toJsonByJettisonMappedXmlDriver(){
        try {
            User user = getUser();
            FileOutputStream fileOutputStream = new FileOutputStream(file);
            OutputStreamWriter ow = new OutputStreamWriter(fileOutputStream, Charset.forName("UTF-8"));
            xstream = new XStream(new JettisonMappedXmlDriver());
            xstream.setMode(XStream.NO_REFERENCES);
            xstream.alias("user", User.class);
            xstream.toXML(user,ow);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

在xstream初始化时报错

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mysql启动报错The server quit without updating PID file

Image
1.root#vim /etc/my.cnf
修改datadir=/var/lib/mysql – linux中mysql安装的默认路径
socket=/var/lib/mysql/mysql.sock
2.将之前数据库安装目录中需要的数据库（需要还原的数据库）、ib_logfile0、ib_logfile1、ibdata1（主要是这三个文件）拷贝到新的mysql目录并设置用户和用户组为mysql:mysql
root#cp -r /home/mysqlData/mysql/需要的文件或文件夹 /var/lib/mysql/
root#chown -hR mysql:mysql /var/lib/mysql
root#ps -ef|grep mysql –查看mysql的进程 如果有则kill
root#service mysql start –启动mysql
root#mysql -u root -p –进入mysql客户端
mysql>set password for ‘root‘@’%’=password(‘newpassword’);
mysql>flush privileges;
解决问题！

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tag:

    缺失模块。
    1、请确保node版本大于6.2
    2、在博客根目录（注意不是yilia根目录）执行以下命令：
    npm i hexo-generator-json-content --save

    3、在根目录_config.yml里添加配置： 

      jsonContent:
    meta: false
    pages: false
    posts:
      title: true
      date: true
      path: true
      text: false
      raw: false
      content: false
      slug: false
      updated: false
      comments: false
      link: false
      permalink: false
      excerpt: false
      categories: false
      tags: true

多看多思少搬砖