138
、
Java
的通信編程，編程題
(
或問答
)
，用
JAVA SOCKET
編程，讀服務器幾個字符，再寫入本地顯示？
答
:
Server
端程序
:
package test;
import java.net.*;
import java.io.*;
public class Server
{
?private ServerSocket ss;
?private Socket socket;
?private BufferedReader in;
?private PrintWriter out;
?public Server()
?{
??try
??{
???ss=new ServerSocket(10000);
???while(true)
???{
????socket = ss.accept();
????String RemoteIP = socket.getInetAddress().getHostAddress();
????String RemotePort = ":"+socket.getLocalPort();
????System.out.println("A client come in!IP:"+RemoteIP+RemotePort);
????in = new BufferedReader(new
InputStreamReader(socket.getInputStream()));
????String line = in.readLine();
????System.out.println("Cleint send is :" + line);
????out = new PrintWriter(socket.getOutputStream(),true);
????out.println("Your Message Received!");
????out.close();
????in.close();
????socket.close();
???}
??}catch (IOException e)
??{
???out.println("wrong");
??}
?}
?public static void main(String[] args)
?{
??new Server();
?}
};
Client
端程序
:
package test;
import java.io.*;
import java.net.*;
public class Client
{
?Socket socket;
?BufferedReader in;
?PrintWriter out;
?public Client()
?{
??try
??{
???System.out.println("Try to Connect to 127.0.0.1:10000");
???socket = new Socket("127.0.0.1",10000);
???System.out.println("The Server Connected!");
???System.out.println("Please enter some Character:");
???BufferedReader line = new BufferedReader(new
InputStreamReader(System.in));
???out = new PrintWriter(socket.getOutputStream(),true);
???out.println(line.readLine());
???in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
???System.out.println(in.readLine());
???out.close();
???in.close();
???socket.close();
??}catch(IOException e)
??{
???out.println("Wrong");
??}
?}
?public static void main(String[] args)
?{
??new Client();
?}
};
139
、用
JAVA
實現一種排序，
JAVA
類實現序列化的方法
(
二種
)
？
如在
COLLECTION
框架中，實現比較要實現什么樣的接口？
答
:
用插入法進行排序代碼如下
package test;
import java.util.*;
class? InsertSort
{
?ArrayList al;
?public InsertSort(int num,int mod)
?{
??al = new ArrayList(num);
??Random rand = new Random();
??System.out.println("The ArrayList Sort Before:");
??for (int i=0;i<num ;i++ )
??{
???al.add(new Integer(Math.abs(rand.nextInt()) % mod + 1));
???System.out.println("al["+i+"]="+al.get(i));
??}
?}
?public void SortIt()
?{
??Integer tempInt;
??int MaxSize=1;
??for(int i=1;i<al.size();i++)
??{
?????? tempInt = (Integer)al.remove(i);
????if(tempInt.intValue()>=((Integer)al.get(MaxSize-1)).intValue())
????{
?????al.add(MaxSize,tempInt);
?????MaxSize++;
?????System.out.println(al.toString());
????} else {
?????for (int j=0;j<MaxSize ;j++ )
?????{
??????if
(((Integer)al.get(j)).intValue()>=tempInt.intValue())
??????{
???????al.add(j,tempInt);
???????MaxSize++;
???????System.out.println(al.toString());
???????break;
??????}
?????}
????}
??}
??System.out.println("The ArrayList Sort After:");
??for(int i=0;i<al.size();i++)
??{
???System.out.println("al["+i+"]="+al.get(i));
??}
?}
?public static void main(String[] args)
?{
??InsertSort is = new InsertSort(10,100);
??is.SortIt();
?}
}
140
、編程：編寫一個截取字符串的函數，輸入為一個字符串和字節數，輸出為按字節截取的字符串。
但是要保證漢字不被截半個，如
“
我
ABC”4
，應該截為
“
我
AB”
，輸入
“
我
ABC
漢
DEF”
，
6
，應該輸出為
“
我
ABC”
而不是
“
我
ABC+
漢的半個
”
。
答：
代碼如下：
package test;
class? SplitString
{
?String SplitStr;
?int SplitByte;
?public SplitString(String str,int bytes)
?{
??SplitStr=str;
??SplitByte=bytes;
??System.out.println("The String is:'"+SplitStr+"';SplitBytes="+SplitByte);
?}
?public void SplitIt()
?{
??int loopCount;
??
loopCount=(SplitStr.length()%SplitByte==0)?(SplitStr.length()/SplitByte):(SplitStr.length()/Split
Byte+1);
??System.out.println("Will Split into "+loopCount);
??for (int i=1;i<=loopCount ;i++ )
??{
???if (i==loopCount){
????
System.out.println(SplitStr.substring((i-1)*SplitByte,SplitStr.length()));
???} else {
????
System.out.println(SplitStr.substring((i-1)*SplitByte,(i*SplitByte)));
???}
??}
?}
?public static void main(String[] args)
?{
??SplitString ss = new SplitString("test
中
dd
文
dsaf
中男大
3443n
中國
43
中國人
0ewldfls=103",4);
??ss.SplitIt();
?}
}
141
、
JAVA
多線程編程。
用
JAVA
寫一個多線程程序，如寫四個線程，二個加
1
，二個對一個變量減一，輸出。
希望大家補上，謝謝
142
、可能會讓你寫一段
Jdbc
連
Oracle
的程序
,
并實現數據查詢
.
答
:
程序如下：
package hello.ant;
import java.sql.*;
public class? jdbc
{
?String dbUrl="jdbc:oracle:thin:@127.0.0.1:1521:orcl";
?String theUser="admin";
?String thePw="manager";
?Connection c=null;
?Statement conn;
?ResultSet rs=null;
?public jdbc()
?{
??try{
??? Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();
????????? c = DriverManager.getConnection(dbUrl,theUser,thePw);
??? conn=c.createStatement();
??}catch(Exception e){
???e.printStackTrace();
??}
?}
?public boolean executeUpdate(String sql)
?{
???try
???{
?????conn.executeUpdate(sql);
?????return true;
???}
???catch (SQLException e)
???{
?????e.printStackTrace();
?????return false;
???}
?}
?public ResultSet executeQuery(String sql)
?{
???rs=null;
???try
???{
?????rs=conn.executeQuery(sql);
???}
???catch (SQLException e)
???{
?????e.printStackTrace();
???}
???return rs;
?}
?public void close()
?{
???try
???{
?????conn.close();
?????c.close();
???}
???catch (Exception e)
???{
?????e.printStackTrace();
???}
?}
?public static void main(String[] args)
?{
??ResultSet rs;
??jdbc conn = new jdbc();
??rs=conn.executeQuery("select * from test");
??try{
??while (rs.next())
??{
???System.out.println(rs.getString("id"));
???System.out.println(rs.getString("name"));
??}
??}catch(Exception e)
??{
???e.printStackTrace();
??}
?}
}
143
、
ORACLE
大數據量下的分頁解決方法。一般用截取
ID
方法，還有是三層嵌套方法。
答
:
一種分頁方法
<%
? int i=1;
? int numPages=14;
? String pages = request.getParameter("page") ;
? int currentPage = 1;
? currentPage=(pages==null)?(1):{Integer.parseInt(pages)}
? sql = "select count(*) from tables";
? ResultSet rs = DBLink.executeQuery(sql) ;
? while(rs.next()) i = rs.getInt(1) ;
? int intPageCount=1;
? intPageCount=(i%numPages==0)?(i/numPages):(i/numPages+1);
? int nextPage ;
? int upPage;
? nextPage = currentPage+1;
? if (nextPage>=intPageCount) nextPage=intPageCount;
? upPage = currentPage-1;
? if (upPage<=1) upPage=1;
? rs.close();
? sql="select * from tables";
? rs=DBLink.executeQuery(sql);
? i=0;
? while((i<numPages*(currentPage-1))&&rs.next()){i++;}
%>
//
輸出內容
//
輸出翻頁連接
合計
:<%=currentPage%>/<%=intPageCount%><a href="List.jsp?page=1">
第一頁
</a><a
href="List.jsp?page=<%=upPage%>">
上一頁
</a>
<%
? for(int j=1;j<=intPageCount;j++){
? if(currentPage!=j){
%>
? <a href="list.jsp?page=<%=j%>">[<%=j%>]</a>
<%
? }else{
? out.println(j);
? }
? }
%>
<a href="List.jsp?page=<%=nextPage%>">
下一頁
</a><a href="List.jsp?page=<%=intPageCount%>">
最后頁
</a>
144
、用
jdom
解析
xml
文件時如何解決中文問題
?
如何解析
?
答
:
看如下代碼
,
用編碼方式加以解決
package test;
import java.io.*;
public class DOMTest
{
?private String inFile = "c:\\people.xml";
?private String outFile = "c:\\people.xml";?
?public static void main(String args[])
?{
??? ?new DOMTest();
??? }
?public DOMTest()
?{
??try
???? {?
???? ?javax.xml.parsers.DocumentBuilder builder =
???? ??
javax.xml.parsers.DocumentBuilderFactory.newInstance().newDocumentBuilder();
???? ?org.w3c.dom.Document doc = builder.newDocument();
???? ?org.w3c.dom.Element root = doc.createElement("
老師
");
???? ?org.w3c.dom.Element wang = doc.createElement("
王
");
???org.w3c.dom.Element liu = doc.createElement("
劉
");
???? ?wang.appendChild(doc.createTextNode("
我是王老師
"));
???? ?root.appendChild(wang);
???? ?doc.appendChild(root);
???? ?javax.xml.transform.Transformer transformer =
???? ??javax.xml.transform.TransformerFactory.newInstance().newTransformer();
???? ?transformer.setOutputProperty(javax.xml.transform.OutputKeys.ENCODING, "gb2312");
???? ?transformer.setOutputProperty(javax.xml.transform.OutputKeys.INDENT, "yes");??
? ?
???? ?transformer.transform(new javax.xml.transform.dom.DOMSource(doc),
???? ???????new
javax.xml.transform.stream.StreamResult(outFile));
???? }
???? catch (Exception e)
???? {
???? ?System.out.println (e.getMessage());
???? }
??? }
}
145
、編程用
JAVA
解析
XML
的方式
.
答
:
用
SAX
方式解析
XML
，
XML
文件如下：
<?xml version="1.0" encoding="gb2312"?>
<person>
? <name>
王小明
</name>
? <college>
信息學院
</college>??
? <telephone>6258113</telephone>
? <notes>
男
,1955
年生
,
博士，
95
年調入海南大學
</notes>
?</person>
?
事件回調類
SAXHandler.java
?import java.io.*;
import java.util.Hashtable;
import org.xml.sax.*;
public class SAXHandler extends HandlerBase
? {
? private Hashtable table = new Hashtable();
? private String currentElement = null;
? private String currentValue = null;
? public void setTable(Hashtable table)
??? {
??? this.table = table;
??? }
? public Hashtable getTable()
??? {
??? return table;
??? }
? public void startElement(String tag, AttributeList attrs)
? throws SAXException
??? {
??? currentElement = tag;
??? }
? public void characters(char[] ch, int start, int length)
? throws SAXException
??? {
??? currentValue = new String(ch, start, length);
??? }
? public void endElement(String name) throws SAXException
??? {
??? if (currentElement.equals(name))
????? table.put(currentElement, currentValue);
??? }
? }
JSP
內容顯示源碼
,SaxXml.jsp:
<HTML>
<HEAD>
<TITLE>
剖析
XML
文件
people.xml</TITLE>
</HEAD>
<BODY>
<%@ page errorPage="ErrPage.jsp"
contentType="text/html;charset=GB2312" %>
<%@ page import="java.io.*" %>
<%@ page import="java.util.Hashtable" %>
<%@ page import="org.w3c.dom.*" %>
<%@ page import="org.xml.sax.*" %>
<%@ page import="javax.xml.parsers.SAXParserFactory" %>
<%@ page import="javax.xml.parsers.SAXParser" %>
<%@ page import="SAXHandler" %>
<%
File file = new File("c:\\people.xml");
FileReader reader = new FileReader(file);
Parser parser;
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
SAXHandler handler = new SAXHandler();
sp.parse(new InputSource(reader), handler);
Hashtable hashTable = handler.getTable();
out.println("<TABLE BORDER=2><CAPTION>
教師信息表
</CAPTION>");
out.println("<TR><TD>
姓名
</TD>" + "<TD>" +
? (String)hashTable.get(new String("name")) + "</TD></TR>");
out.println("<TR><TD>
學院
</TD>" + "<TD>" +
? (String)hashTable.get(new String("college"))+"</TD></TR>");
out.println("<TR><TD>
電話
</TD>" + "<TD>" +
? (String)hashTable.get(new String("telephone")) + "</TD></TR>");
out.println("<TR><TD>
備注
</TD>" + "<TD>" +
? (String)hashTable.get(new String("notes")) + "</TD></TR>");
out.println("</TABLE>");
%>
</BODY>
</HTML>