http通信示例Httpclient和HttpServer

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本示例源于为朋友解决一个小问题,数据库到服务器的数据传输,由于本人能力有限,暂时将它理解为从数据库中获取数取表数据,实际上有可能是文件或者其他形式的数据,不过原理都得用流传输,

首先httpclient

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import netscape.javascript.JSObject;import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;/**
* Created by jisen on 2018/5/24.
*/
public class Httpclient {
public static void main(String[] args) throws SQLException, ClassNotFoundException, IOException {
String dataByJDBC = getDataByJDBC();
//如果不从数据库取直接发送字符串
//String dataByJDBC="hello httpserver";
String backData = httpPost(dataByJDBC); System.out.println(backData);
} //获取数据库的数据并封装成json字符串
public static String getDataByJDBC() throws ClassNotFoundException, SQLException { String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/admin?useSSL=false";
String username = "root";
String password = "root";
Class.forName(driver);
Connection connection = DriverManager.getConnection(url, username, password); //从数据库中获取数据
String sql = "select * from menu";
PreparedStatement preparedStatement = connection.prepareStatement(sql);//预处理说起来 ResultSet resultSet = preparedStatement.executeQuery();
int columnCount = resultSet.getMetaData().getColumnCount();
ResultSetMetaData metaData = resultSet.getMetaData();
Map<String,Object> dataMap = new HashMap<String,Object>();
List<Map<String,Object>> list = new ArrayList<>();
while (resultSet.next()){
for(int i=1 ; i<=columnCount;i++){
String columnName = metaData.getColumnName(i);
Object object = resultSet.getObject(i);
dataMap.put(columnName,object);
}
list.add(dataMap);
} String jsonString = JSON.toJSONString(list);
System.out.println(jsonString);
return jsonString;
} public static String httpGet() throws IOException {
URL url = new URL("http://localhost:8080/httpServer?param1=jisen&param2=jisen2");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.connect();
//接收反馈
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuffer sBuffer = new StringBuffer();
String line = "";
while ((line = reader.readLine())!=null){
sBuffer.append(line).append("\r\n");
}
reader.close();
return sBuffer.toString();
} public static String httpPost(String data) throws IOException {
URL url = new URL("http://localhost:8080/httpServer");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
//HttpURLConnection中的doInput默认为true,而doOutput默认为false,所以如果需要些内容到流,需要设置为true
conn.setDoOutput(true);
conn.connect();
//写入流,发送Http请求
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(
conn.getOutputStream()));
writer.write(data);
writer.flush(); //接收反馈
BufferedReader reader = new BufferedReader(new InputStreamReader(
conn.getInputStream(),"utf8"));
StringBuffer sBuffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null) {
sBuffer.append(line).append("\r\n");
}
reader.close();
return sBuffer.toString();
}
}其次httpserver

import com.sun.net.httpserver.HttpContext;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;
import java.io.*;
import java.net.InetSocketAddress;
import java.net.URI;
import java.util.HashMap;
import java.util.Map;/**
* Created by jisen on 2018/5/24.
*/
public class MyHttpServer { public static void main(String[] args) throws IOException {
HttpServer httpServer = HttpServer.create(new InetSocketAddress(8080),10);
httpServer.createContext("/httpServer", new MyHandler());
httpServer.setExecutor(null);
httpServer.start();
}
static class MyHandler implements HttpHandler {
public void handle(HttpExchange he) throws IOException { InputStream is = he.getRequestBody();
//接收反馈
BufferedReader reader = new BufferedReader(new InputStreamReader(
is,"utf8")); StringBuffer sBuffer = new StringBuffer(); String line = "";
while ((line = reader.readLine()) != null) {
sBuffer.append(line).append("\r\n");
}
reader.close();
is.close();
System.out.println("接收到来自数据库的数据");
System.out.println(sBuffer);
//服务器收到
String response = "the data is receive";
he.sendResponseHeaders(200, response.length());
OutputStream os = he.getResponseBody();
os.write(response.getBytes());
os.close();
}
}
}