代码

//反序列化，从流中的二进制转换成IntPair  public void readFields(DataInput in) throws IOException          //序列化，将IntPair转化成使用流传送的二进制  public void write(DataOutput out)  //key的比较  public int compareTo(IntPair o)          //另外新定义的类应该重写的两个方法  //The hashCode() method is used by the HashPartitioner (the default partitioner in MapReduce)  public int hashCode()   public boolean equals(Object right)