[Java] Java catch与throw同时使用的操作

public class auctiontest
{
  private double initprice = 30.0;
  // 因为该方法中显式抛出了auctionexception异常，
  // 所以此处需要声明抛出auctionexception异常
  public void bid(string bidprice)
    throws auctionexception
  {
    double d = 0.0;
    try
    {
      d = double.parsedouble(bidprice);
    }
    catch (exception e)
    {
      // 此处完成本方法中可以对异常执行的修复处理，
      // 此处仅仅是在控制台打印异常跟踪栈信息。
      e.printstacktrace();
      // 再次抛出自定义异常
      throw new auctionexception("竞拍价必须是数值，"
        + "不能包含其他字符！");
    }
    if (initprice > d)
    {
      throw new auctionexception("竞拍价比起拍价低，"
        + "不允许竞拍！");
    }
    initprice = d;
  }
  public static void main(string[] args)
  {
    auctiontest at = new auctiontest();
    try
    {
      at.bid("df");
    }
    catch (auctionexception ae)
    {
      // 再次捕捉到bid方法中的异常。并对该异常进行处理
      system.err.println(ae.getmessage());
    }
  }
}

public class auctionexception extends exception
{
 // 无参数的构造器
 public auctionexception(){}  //①
 // 带一个字符串参数的构造器
 public auctionexception(string msg)  //②
 {
 super(msg);
 }
}

java.lang.numberformatexception: for input string: "df"
 at sun.misc.floatingdecimal.readjavaformatstring(floatingdecimal.java:1224)
 at java.lang.double.parsedouble(double.java:510)
 at auctiontest.bid(auctiontest.java:16)
 at auctiontest.main(auctiontest.java:39)

package com.exception.demo;
public class main {
  public static void main(string[] args) {
  main main = new main();
  }
  public void methodtry() {
  }
  public void methodthrow() {
  }
}

public static void main(string[] args) {
  main main = new main();
  main.methodtry();
}
public void methodtry() {
  int a=10;
  int b=0;
  int c=a/b;
}

public void methodtry() {
  try {
  int a=10;
  int b=0;
  int c=a/b;
  system.out.println(c);
  } catch (exception e) {
  system.out.println("这个方法体有问题:"+e.getmessage());
  }
  
}

public static void main(string[] args) {
  main main = new main();
  main.methodthrow();
}
public void methodthrow() {
  throw new exception("这里有异常");
}

public void methodthrow() {
  try {
  throw new exception("这里有异常");
  } catch (exception e) {
  system.out.println("methodthrow:"+e.getmessage());
  }
}

public static void main(string[] args) throws exception {
  main main = new main();
  main.methodthrow();
}
public void methodthrow() throws exception {
  throw new exception("这里有异常");
}

public static void main(string[] args){
  main main = new main();
  try {
  main.methodthrow();
  } catch (exception e) {
  system.out.println(e.getmessage());
  }
}
public void methodthrow() throws exception {
  throw new exception("这里有异常");
}