程序一：（红色处出现异常）
package test;
import java.util.Scanner;
public class Test {
    /*int[] array=new int[]{2,3,1,5,4};*/
    int[] array=new int[5];
    public void input() {
        Scanner scan=new Scanner(System.in);
        for(int i=0;i<array.length;i++)
            array[i]=scan.nextInt();
        scan.close();
    }
    public void insertSort(){
        for(int i=1; i<array.length; i++){
            if(array[i]<array[i-1]){
                int temp=array[i];
                array[i]=array[i-1];
                int j=i-1;
                for (; j>=0 && temp<array[j]; --j)
                    array[j+1] = array[j];
                array[j+1] = temp;
            }
        }
    }
    public int search(int key){
        int low=0,high=array.length-1;
        while(low<high){
            int mid=(low+high)/2;
            if(array[mid]<key) low=mid+1;
            else if(array[mid]>key) high=mid-1;
            else return mid;
        }
        return -1;
    }
    public void print(){
        for(int i=0; i<array.length; i++)
            System.out.print(array[i]+" ");
        System.out.println();
    }
    public int scan(){
        System.out.println("输入查找的元素，返回在排序后该元素的数组下标");
        Scanner s=new Scanner(System.in);
        int key=s.nextInt();
        s.close();
        return key;
    }
    public static void main(String[] args){
        try{
            Test test=new Test();
            test.input();  //可选
            test.insertSort();
            test.print();
            int key=test.scan(); //可选
            int index=test.search(key); //可选            /*System.out.println(test.search(2);*/
            if(index<0)
                System.out.println("未找到！");
            else System.out.println(index);
        }catch(Exception e){
            System.out.println("出现异常！");
        }finally{
            System.out.println("结束！");
        }
    }
}

程序二：(已解决)
package test;
import java.util.*;
public class Student implements Comparable<Student>{
    private String name;
    private int age;
    public Student (String name, int age)
    {  this.name=name;   this.age=age;  }
  
    public boolean equals(Object o) {
          if(this==o)  return true;
          if(!(o instanceof Student))  return false;
          Student other=(Student)o;
          return (other.name==this.name && other.age==this.age) ? true :  false;
    }   
    public int hasCode(){
        int result;
        result=(name==null  ? 0 : name.hashCode());
        return result*124+age*23;
    }
    public int compareTo(Student stu) {
          if((stu.name)>0)  return 1;
          if((stu.name)<0)  return -1;
          if(age>stu.age)  return 1;
          if(age<stu.age)  return -1;
          return 0;
    }
    public static void main(String[] args) {           
        Set<Student> set=new TreeSet<Student>();
        set.add(new Student("Tom",12));
        set.add(new Student("Jack",18));
        Iterator<Student>  iter=set.iterator();
        while(iter.hasNext()){
              Student stu=(Student)(iter.next());
              System.out.println("Student’s name:"+stu.name+"age:"+stu.age);
        }
}

}
Exception in thread "main" java.lang.ClassCastException: test.Student cannot be cast to java.
    at java.util.TreeMap.put(Unknown Source)
    at java.util.TreeSet.add(Unknown Source)
    at test.Student.main(Student.java:30)

[[it] 本帖最后由 c_acceleration 于 2008-6-14 17:58 编辑 [/it]]

[[it] 本帖最后由 c_acceleration 于 2008-6-15 13:12 编辑 [/it]]

不是这错，是Scanner在此处出现这个问题