计算l两个句子之间的余弦相似度

package cn.edu.image;

import java.util.HashMap;

import java.util.Map;

import java.util.Set;

/**

 * 字符串相似性匹配算法

 * Created by panther on 15-7-20.

 */  

public class Similarity {  

    Map<Character, int[]> vectorMap = new HashMap<Character, int[]>();  

 

    int[] tempArray = null;  

 

    public Similarity(String string1, String string2) {  

 

        for (Character character1 : string1.toCharArray()) {  

            if (vectorMap.containsKey(character1)) {  

                vectorMap.get(character1)[0]++;  

            } else {  

                tempArray = new int[2];  

                tempArray[0] = 1;  

                tempArray[1] = 0;  

                vectorMap.put(character1, tempArray);  

            }  

        }  

        for (Character character2 : string2.toCharArray()) {  

            if (vectorMap.containsKey(character2)) {  

                vectorMap.get(character2)[1]++;  

            } else {  

                tempArray = new int[2];  

                tempArray[0] = 0;  

                tempArray[1] = 1;  

                vectorMap.put(character2, tempArray);  

            }  

        }  

    }  

 

    // 计算相似度

    public double sim() {  

        double result = 0;  

        result = pointMulti(vectorMap) / sqrtMulti(vectorMap);  

        return result;  

    }  

 

    private double sqrtMulti(Map<Character, int[]> paramMap) {  

        double result = 0;  

        result = squares(paramMap);  

        result = Math.sqrt(result);  

        return result;  

    }  

 

    // 求平方和

    private double squares(Map<Character, int[]> paramMap) {  

        double result1 = 0;  

        double result2 = 0;    

        Set<Character> keySet = paramMap.keySet();  

        for (Character character : keySet) {  

            int temp[] = paramMap.get(character);  

            result1 += (temp[0] * temp[0]);  

            result2 += (temp[1] * temp[1]);  

        }  

        return result1 * result2;  

    }  

 

    // 点乘

    private double pointMulti(Map<Character, int[]> paramMap) {  

        double result = 0;  

        Set<Character> keySet = paramMap.keySet();  

        for (Character character : keySet) {  

            int temp[] = paramMap.get(character);  

            result += (temp[0] * temp[1]);  

        }  

        return result;  

    }  

 

    public static void main(String[] args) {  

        String s1 = "你妈妈是个美国人";  

        String s2 = "你是个小样儿";

        String s3 = "";

        String s4 = "";

        String s5 = "";

        String s6 = "";

        

        Similarity similarity = new Similarity(s1, s2);  

        System.out.println(similarity.sim());  

    }  

 

}