中科软面试题

中科软面试题

1. java写一个随机生成四位数的程序 每位数字不重复

 2. 写一个Servlet 使用JNDI =“jdbc/db2 DataSource” 获得数据库连接 执行SQL 把执行结果输出到文本
  文件 out.txt 中 将请求发送到/application/test.jsp

1.

Java code

Random r=new Random();

int[]tag={0,0,0,0,0,0,0,0,0,0};

String four="";

inttemp=0;

while(four.length()!=4){           

    temp=r.nextInt(10);//取出0-9的数字

    if(tag[temp]==0){

        four+=temp;

        tag[temp]=1;

    }

}

System.out.println(four);

 

2.
public class ActionServlet extends HttpServlet {

public ActionServlet() {
super();
}


public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

this.doPost(request, response);
}

/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
* 
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html");
Connection con=null;
FileOutputStream fos = null;
try {
Context ctm=new InitialContext();//初始化
DataSource src=(DataSource)ctm.lookup("java:comp/env/jdbc/db2DataSource");
con=src.getConnection();//获取连接
PreparedStatement ps=con.prepareStatement("select * from A");
ResultSet rs=ps.executeQuery();

fos = new FileOutputStream("d:\\out.txt");
OutputStreamWriter osw = new OutputStreamWriter(fos);
BufferedWriter bw = new BufferedWriter(osw);
while(rs.next()){
bw.write(rs.getString(1));
bw.newLine();
bw.write(rs.getString(2));
bw.newLine();
bw.write(rs.getString(3));
bw.newLine();
}
bw.close();
osw.close();
fos.close();
rs.close();
ps.close();
con.close();
} catch (Exception e) {
// TODO: handle exception
} 
}


public void init() throws ServletException {
// Put your code here
}

}

 

 

 仅供参考

1、用String的方法将数据类型转换为String。

2、有一个不定长度的String，其中前面是字母，后边是数字,例如："abcd123.456",

要求写一个方法得到其中的数字以String的形式返回,数字保留小数点后两位，不四舍五入，截去多余小

数,例如："abcd123.456"，得到"123.45"

如果数字没有小数点,要得到两位为0的小数，例如："abcd123"，得到"123.00".

答案如下:

1、String.valueOf(1.23)

2、 public String getString(String str){

 String getNumber;

 getNumber = str.replaceAll("[a-z|A-Z]", "");

 if(getNumber.indexOf(".") == -1){

  getNumber = getNumber+".00";

  }else {

  if(getNumber.indexOf(".")== getNumber.length()-1){

    getNumber= getNumber+"00";

   }else if (getNumber.indexOf(".")== getNumber.length()-2){

   getNumber = getNumber+"0";

   }else {

   getNumber = getNumber.substring(0, getNumber.indexOf(".")+3);

   }

  }

 return getNumber;

 }