javaclient

❶ 用java 寫出一個Server 和Client 能實現Client發送的消息顯示在服務端上，Server發送的信息顯示在客戶端上

你好！
我寫的很簡單，你可以在此基礎上完善，好了，廢話不多說，直入正題。
首先，建立一個項目名為TestChat，然後建兩個包，分別為server和client。
server包下建立一個類為Server，一個類為ServerListen。
client包建立一個類Client，一個類為ClentListen。
由於我時間倉促，你自行參考哈。

***********************************************************************

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

/*
* Server.java
*
* Created on 2011-5-8, 16:37:13
*/

package server;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
*
* @author Study
*/
public class Server extends javax.swing.JFrame {

/** Creates new form Server */
public Server() {
initComponents();
try {
ss = new ServerSocket(8888);
s = ss.accept();
in = new ObjectInputStream(getS().getInputStream());
out = new ObjectOutputStream(getS().getOutputStream());
this.startListen();
} catch (IOException ex) {
Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, ex);
}
}

/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

jScrollPane1 = new javax.swing.JScrollPane();
messageShow = new javax.swing.JTextArea();
messageInput = new javax.swing.JTextField();
sendBtn = new javax.swing.JButton();

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("伺服器");

messageShow.setColumns(20);
messageShow.setEditable(false);
messageShow.setRows(5);
jScrollPane1.setViewportView(messageShow);

sendBtn.setText("發送");
sendBtn.addMouseListener(new java.awt.event.MouseAdapter() {
public void mousePressed(java.awt.event.MouseEvent evt) {
sendBtnMousePressed(evt);
}
});

javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
.addComponent(messageInput, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(333, Short.MAX_VALUE)
.addComponent(sendBtn)
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 300, Short.MAX_VALUE)
.addGroup(layout.createSequentialGroup()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 201, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(messageInput, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(sendBtn)
.addContainerGap(19, Short.MAX_VALUE))
);

pack();
}// </editor-fold>

private void sendBtnMousePressed(java.awt.event.MouseEvent evt) {
this.sendMessage();
this.messageInput.setText("");
}

/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Server().setVisible(true);
}
});
}

// Variables declaration - do not modify
protected javax.swing.JScrollPane jScrollPane1;
protected javax.swing.JTextField messageInput;
protected javax.swing.JTextArea messageShow;
protected javax.swing.JButton sendBtn;
// End of variables declaration

private ServerSocket ss;
private Socket s;
private ObjectOutputStream out;
private ObjectInputStream in;

private void startListen() {
ServerListen listen = new ServerListen(this);
Thread t = new Thread(listen);
t.start();
}

/**
* @return the s
*/
public Socket getS() {
return s;
}

/**
* @return the out
*/
public ObjectOutputStream getOut() {
return out;
}

/**
* @return the in
*/
public ObjectInputStream getIn() {
return in;
}

/**
* @return the messageShow
*/
public javax.swing.JTextArea getMessageShow() {
return messageShow;
}

private void sendMessage() {
try {
out.writeObject("伺服器說");
out.flush();
out.writeObject(this.messageInput.getText().trim());
out.flush();
} catch (IOException ex) {
Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, ex);
}
}

}

❷ java怎麼創建hivemetastoreclient

下面就來解釋下系統是如何生成meta client的！

先來看幾段代碼！

publicvoidcreateDatabase(Databasedb,booleanifNotExist)throwsAlreadyExistsException,HiveException{

try{

getMSC().createDatabase(db);

}catch(AlreadyExistsExceptione){

if(!ifNotExist){

throwe;

}

}catch(Exceptione){

thrownewHiveException(e);

}

}

=========

privateIMetaStoreClientgetMSC()throwsMetaException{

if(metaStoreClient==null){

metaStoreClient=createMetaStoreClient();

}

returnmetaStoreClient;

}

=========

()throwsMetaException{

HiveMetaHookLoaderhookLoader=newHiveMetaHookLoader(){

publicHiveMetaHookgetHook(org.apache.hadoop.hive.metastore.api.Tabletbl)throwsMetaException{

try{

if(tbl==null){

returnnull;

}

=HiveUtils.getStorageHandler(conf,

tbl.getParameters().get(META_TABLE_STORAGE));

if(storageHandler==null){

returnnull;

}

returnstorageHandler.getMetaHook();

}catch(HiveExceptionex){

LOG.error(StringUtils.stringifyException(ex));

thrownewMetaException("Failedtoloadstoragehandler:"+ex.getMessage());

}

}

};

returnnewHiveMetaStoreClient(conf,hookLoader);

}

=========

publicHiveMetaStoreClient(HiveConfconf,HiveMetaHookLoaderhookLoader)

throwsMetaException{

this.hookLoader=hookLoader;

if(conf==null){

conf=newHiveConf(HiveMetaStoreClient.class);

}

this.conf=conf;

localMetaStore=conf.getBoolVar(ConfVars.METASTORE_MODE);

if(localMetaStore){

//

//throughthenetwork

client=newHiveMetaStore.HMSHandler("hiveclient",conf);

isConnected=true;

return;

}

//getthenumberretries

retries=HiveConf.getIntVar(conf,HiveConf.ConfVars.METASTORETHRIFTRETRIES);

retryDelaySeconds=conf.getIntVar(ConfVars.METASTORE_CLIENT_CONNECT_RETRY_DELAY);

//

if(conf.getVar(HiveConf.ConfVars.METASTOREURIS)!=null){

StringmetastoreUrisString[]=conf.getVar(

HiveConf.ConfVars.METASTOREURIS).split(",");

metastoreUris=newURI[metastoreUrisString.length];

try{

inti=0;

for(Strings:metastoreUrisString){

URItmpUri=newURI(s);

if(tmpUri.getScheme()==null){

("URI:"+s

+"doesnothaveascheme");

}

metastoreUris[i++]=tmpUri;

}

}catch(IllegalArgumentExceptione){

throw(e);

}catch(Exceptione){

MetaStoreUtils.logAndThrowMetaException(e);

}

}elseif(conf.getVar(HiveConf.ConfVars.METASTOREDIRECTORY)!=null){

metastoreUris=newURI[1];

try{

metastoreUris[0]=newURI(conf

.getVar(HiveConf.ConfVars.METASTOREDIRECTORY));

}catch(URISyntaxExceptione){

MetaStoreUtils.logAndThrowMetaException(e);

}

}else{

LOG.error("NOTgettingurisfromconf");

thrownewMetaException("");

}

//finallyopenthestore

open();

}

下面要認真分析下上面的這段代碼，因為關聯到一些參數的配置，對於理解生產環境的部署參數有幫助！先看下面這段代碼

localMetaStore=conf.getBoolVar(ConfVars.METASTORE_MODE);

if(localMetaStore){

//

//connecting

//throughthenetwork

client=newHiveMetaStore.HMSHandler("hiveclient",conf);

isConnected=true;

return;

}

PS:ConfVars.METASTORE_MODE---METASTORE_MODE("hive.metastore.local",true),

❸ 有關java client——server 間傳送文件的問題，本想通過server把client1 發來的信息傳送給client2

client必須保持長連接，
簡單說，你的client和server之間的連接是不能斷開的，你每次啟動client都是內直接嘗試讀取然後斷掉鏈接容的話，
c1在傳輸文件的時候，c2的連接已經斷掉了，server還如何和c2之間通訊呢？

❹ 求問 java中 client 和 implementer分別是什麼 區別是什麼謝謝

client? 這不是客戶端嗎？

在java中基於b/s架構的 client是瀏覽器
而基於 c/s 和三層 c/s 的 client是由程序員自己專門開發的一個軟體，用於支持業務的顯示(給用戶用的界面，他可以用別的語言來編寫 如 java ， c,c++等)

implementer?沒見過
implement 介面
介面就是定義了一系列的方法，介面不能直接實例化，只能被實現
介面我舉個例子，就像電腦 有 usb介面 你可以插 USB鍵盤，然後通過鍵盤來控制電腦

如:

public interface EmployeeDAO

{//這個是介面的定義，你懂的
public List<Employee> findAll() throws Exception;
public void delete(int id) throws Exception ;
public void save(Employee e) throws Exception ;
public Employee findById(int id) throws Exception;
public void modify(Employee e) throws Exception;
}

public class EmployeeJDBCImpl implements EmployeeDAO

{//這是實現介面，裡面要不介面中定義的方法全都寫出來，這里我就寫一個啊throws 這是拋出異常，你可以不寫的，前提是定義介面時的方法別寫throws Exception
public List<Employee> findAll() throws Exception
{
return null;

}

public class ActionServlet extends HttpServlet {
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException

{
// EmployeeDAO = (EmployeeDAO) Factor.getInstance("EmployeeDAO"); 這個不用管
EmployeeDAO = (EmployeeDAO) new EmployeeJDBCImpl();//這個你懂的
List<Employee> employees = .findAll();
}//這個方法可以不寫的，我這是把我自己的工程拷貝過來的

}