一、写出java处理异常的基本语法格式
try{ }catch(exception e){ }finally{};
二、写出读出相对路径”deppondepponIT.txt”文件的流,在必要的地方做捕获异常的处理
fileInputStream fis;
Public void readTXT(){
Try{
Fis= new FileInputStream(“deppondepponIT.txt”);
}catch(IOException e){
/异常处理
}
}
三、写程序建立map集合,并在map中建立IT部,编辑部,人力资源部与德邦物流的对应关系。并写出判断语句,如果map中包含IT部,则输出字符串“good department”。
答案
Map map= new Map();
map.put(“人力资源部”,“德邦物流”);
map.put(“IT部”,“德邦物流”);
map.put(“编辑部”,“德邦物流”);
if(map.contans(“IT部”)){
system.out.print(“good department”);
}
四、有一个class A ,它有一个默认的构造方法,请写一端代码实现 A 的动态加载?(4分)
可以利用反射实现类的动态加载:
因为类A的构造器是无参的,所以实现A的动态的加载的代码如下:
public class B{
public static void main(String[] args){
try{
A a = (A)Class.forName(“A”).newInstance();
}catch(Exception e){
e.printStackTrace();
}
}
}
五、请写一个(单例)Singleton的例子,有效代码不得超过10行。(5分)
class Husband{
private static Husband instance=new Husband();
public static Husband newInstance(){
return instance;
}
private Husband(){}
}
六 发扑克牌:有52张扑克牌(从1到52),要随机分发到数组Card[52]中,请写一段程序
表达。(6分)
import java.util.*;
public class E{
public static void main(String[] args){
int Card[] = new int[52];
boolean ishave = true;
Set s = new HashSet();
for(int j = 0;j<52;j++){
Integer in = new Integer(j);
s.add(in);
}
int k = 0;
while(ishave){
if(!s.isEmpty()){
int ra = Math.round((float)Math.random()*100);
Integer rai = new Integer(ra);
if(s.contains(rai)){
s.remove(rai);
Card[k] = ra;
k++;
}
}else{ishave = false;}
}
for(int m =0;m<52;m++){
System.out.println(Card[m]);
}
}
}
七、 请完成程序,查询table1表中field1字段的值是1的纪录,并将查询结果定位到查询结果中的第三行并打印第三行的vcField的值,field1字段类型是number(用java代码实现)。 (5)
Connection con = … ;
String sql = “select vcField from table1 where field1 = ?”;
Connection con = null;
String sql = “select vcField from table1 where field1 = ?”;
PreparedStatement ps = con.prepareStatement(sql);
ps.setInt(1,1);
ResultSet rs = ps.executeQuery();
rs.next();
rs.next();
rs.next();
String vcField = rs.getString(“vcField”);
System.out.println(vcField);
八、拷贝c:temp.txt文件为c:temp2.txt文件
import java.io.*;
public class FileCopyTest {
public static void main(String[] args) {
try{
FileReader fr = new FileReader(“c:\temp.txt”);
BufferedReader br = new BufferedReader(fr);
FileWriter fw = new FileWriter(“c:\temp2.txt”);
PrintWriter pw = new PrintWriter(fw,true);
String line ;
while ((line = br.readLine()) != null){
pw.println(line);
}
}catch(Exception e) {e.printStackTrace();}
}
}
九.请完成程序,查询table1表中field1字段的值是1的纪录,并将查询结果定位到查询结果中的
第三行并打印第三行的vcField的值,field1字段类型是number.
Connection con = … ;
String sql = “select vcField from table1 where field1 = ?”;
Connection con = null;
String sql = “select vcField from table1 where field1 = ?”;
PreparedStatement ps = con.prepareStatement(sql);
ps.setInt(1,1);
ResultSet rs = ps.executeQuery();
rs.next();
rs.next();
rs.next();
String vcField = rs.getString(“vcField”);
System.out.println(vcField);
十、内部类的实现方式?
示例代码如下:
package test;
public class OuterClass
{
private class InterClass
{
public InterClass()
{
System.out.println(“InterClass Create”);
}
}
public OuterClass()
{
InterClass ic = new InterClass();
System.out.println(“OuterClass Create”);
}
public static void main(String[] args)
{
OuterClass oc = new OuterClass();
}
}
输出结果:
C:>java test/OuterClass
InterClass Create
OuterClass Create
十一、你写一段Jdbc连Oracle的程序,并实现数据查询.
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();
}
}
}
2.12 JDBC中Statement和PreparedStatement有什么不同?简要说明PreparedStatement对性能的影响(5)
2.13 请完成程序,查询table1表中field1字段的值是1的纪录,并将查询结果定位到查询结果中的第三行并打印第三行的vcField的值,field1字段类型是number(用java代码实现)。 (5)
2.14 线程有哪两种实现方法? (5)