BM实现字符串匹配问题，java

昨天在博客园看到一道关于字符串匹配的题，用BM算法实现了一下，有不足之处望大家多提意见！题目是这样的，找出一个字符串中某子串出现的次数，直接上代码：

import java.util.Scanner;
public class BM_Test {

	public static void main(String args[]){
		
		Scanner s=new Scanner(System.in);
		System.out.println("请输入文本串");
		String str1=s.next();
		System.out.println("请输入要查找的字符串");
		String str2=s.next();
		int length=str2.length();
		int[] matchJump=new int[length];
		char[] p=str2.toCharArray();
		int count=0;
		
		computeMatchJumps(p,length,matchJump);
		int start1=0;
		int start2=0;
		for(int i=start1;i<str1.length();i++){
			int num=i;
			for(int j=0;j<str2.length();j++){
				if(str1.substring(num,num+1).equals(str2.substring(j,j+1))){
					num++;
					if(j==str2.length()-1){
						start1+=str2.length();
						count++;
						continue;
					}
					else
						continue;
				}
				if(!str1.substring(num,num+1).equals(str2.substring(j,j+1))){
					start1+=matchJump[j];
					break;
				}
				
			}
		}
		System.out.println(count);
	}
	public static void computeMatchJumps(char[] p,int m,int[] matchJump){
		int low;
		int shift;
		int[] sufx = new int[m+1];
		for(int k=0;k<m;k++){
			matchJump[k]=m+1;
		}
		sufx[m]=m+1;
		for(int k=m-1;k>=0;k--){
			int s=sufx[k+1];
			while(s<=m){
				if(p[k]==p[s-1]){
					break;
				}
				matchJump[s-1] = min(matchJump[s-1],s-k-1);
				s=sufx[s];
			}
			sufx[k]=s-1;
		}
		low=1;
		shift=sufx[0];
		while(shift<=m){
			for(int k=low;k<=shift;k++){
				matchJump[k-1]=min(matchJump[k-1],shift);
			}
			low=shift+1;
			shift=sufx[shift];
		}
		for(int k=0;k<m;k++){
			matchJump[k]+=m-k;
		}
	}

	private static int min(int i, int j) {
		// TODO Auto-generated method stub
		int minNum=i<j?i:j;
		return minNum;
	}
	
	
}