小编Apu*_*urv的帖子

如果Java线程在其run方法中没有循环,则可以安全地假设一旦run方法完成就会销毁Thread.我们考虑以下代码,

Thread t = new Thread(){
   public void run(){
      System.out.print("Hello World!");
   }
};

t.start();

在上面的示例中,一旦run方法结束,如何将系统资源返回给系统？

我想计算使用GUI点击按钮的次数.

我做了这个代码:

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) 
 {                                         
  int clicked = 0;
  clicked++;
  System.out.println(clicked);
 }    

但它每次单击按钮时都会显示输出"1".

我希望每次单击按钮向我显示计数.

例如:如果我单击按钮两次,它应该输出"2".

我创建了一个程序并将客户对象分配给customers数组,但是当我尝试在数组中获取对象时,它返回null.我是Java的新手,请帮助我解决我的错误.

public class Customer {

    private String firstname,lastname;

    public Customer(String f,String l){
        this.firstname = f;
        this.lastname = l;
    }

    public String getFirstName(){
        return firstname;
    }

    public String getLastName(){
        return lastname;
    }   
}

public class Bank {

    private Customer [] customers;
    private int numberofCustomers;

    public Bank(){
        customers = new Customer [5];
        numberofCustomers = 0;

    }

    public void addCustomer(String f,String l){
        int i = numberofCustomers++;
        customers[i] = new Customer(f,l);
    }

    public int getNumberofCustomer(){
        return numberofCustomers;
    }

    public Customer getCustomerMethod(int index){
        return customers[index]; …

我有一个文件叫"CI.txt"

在文件内部,信息​​是:

Mr Abc;ABC;abc123;Abc Road;428428;VISA;2222111144442222
Mr Efg;EFG;efg123;Efg Road;424213;MASTERCARD;4444555566667777
Mr Lmn;LMN;lmn123;Lmn Road;492482;VISA;9999000011112222

这是我的代码,它工作得很好,但问题是..

for (Customer ci : custList){
//Compares the username and userpassword
//If correct, set new card number and card type..
if (inputUser.equals(ci.getUserName()) && inputPass.equals(ci.getPassword())) {
     ci.setCardNo(newCardNo);
     ci.setCardType(newCardType);
}

     String text = ci.getRealName() + ";" + ci.getUserName() + ";" + ci.getPassword() + ";" + ci.getContact() + ";" + ci.getcardType() + ";" + ci.getcardNo();
     try {
         File fileCI = new File("CI.txt");
         FileWriter fileWriter = new FileWriter(fileCI);
         BufferedWriter bw = new BufferedWriter(fileWriter); …

我正在尝试格式化数字DecimalFormat.但我希望它格式化一个数字,就像

input: 1234.  -->  should be formatted to: 1,234.

但我得到1,234.0或1,234.00取决于我的十进制格式规则我需要做什么才能完成这项工作？