java中文分词算法

package com.huawei.cloud.phone.platform.app.api.web.controller;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class analyzer {

/**
 * 最大匹配分词算法
 *
 * @author JYC506
 */
private Set set = new HashSet();
private int positiveOver = 0;
private int reverseOver = 0;

/**
 * 正向最大匹配
 *
 * @param str     要分词的句子
 * @param maxSize 词的最大长度
 * @return
 */
public String[] positiveSplit(String str, int maxSize) {
    int tem = 0;
    int length = str.length();
    String[] ss = new String[length];
    char[] cc = str.toCharArray();
    for (int i = 0; i < length; i++) {
        positiveOver = 0;
        String sb = this.toStr(cc, i, maxSize);
        ss[tem++] = sb;
        i = i + positiveOver;
    }
    String[] ss2 = new String[tem];
    System.arraycopy(ss, 0, ss2, 0, tem);
    return ss2;
}

/**
 * 添加词库
 *
 * @param words
 */
public void addWord(String[] words) {
    for (String st : words) {
        this.set.add(st);
    }
}

/**
 * 逆向最大匹配
 *
 * @param str
 * @param num
 * @return
 */
public String[] reverseSplit(String str, int num) {
    int tem = 0;
    int length = str.length();
    String[] ss = new String[length];
    char[] cc = str.toCharArray();
    for (int i = str.length() - 1; i > -1; i--) {
        reverseOver = 0;
        String sb = this.toStr2(cc, i, num);
        tem++;
        ss[--length] = sb;
        i = i - reverseOver;
    }
    String[] ss2 = new String[tem];
    System.arraycopy(ss, str.length() - tem, ss2, 0, tem);
    return ss2;
}

private String toStr(char[] cs, int start, int num) {
    int num2 = num;
    out:
    for (int j = 0; j < num; j++) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < num2; i++) {
            if (start + i < cs.length) {
                sb.append(cs[start + i]);
            } else {
                num2--;
                j--;
                continue out;
            }
        }
        if (set.contains(sb.toString())) {
            positiveOver = num2 - 1;
            return sb.toString();
        }
        num2--;
    }
    return String.valueOf(cs[start]);
}

private String toStr2(char[] cs, int start, int num) {
    int num2 = num;
    for (int j = 0; j < num; j++) {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < num2; i++) {
            int index = start - num2 + i + 1;
            if (index > -1) {
                sb.append(cs[index]);
            } else {
                num2--;
            }
        }
        if (set.contains(sb.toString())) {
            reverseOver = num2 - 1;
            return sb.toString();
        }
        num2--;
    }
    return String.valueOf(cs[start]);
}

public static void main(String[] args) {
    String[] words = new String[]{"我们", "我们五人", "五人一组", "一组"};
    analyzer ss = new analyzer();
    /*添加词到词库*/
    ss.addWord(words);
    String st = "我们五人一组";
    System.out.println("脚本之家测试结果：");
    System.out.println("要分词的句子：" + st);
    /*使用两种方式分词，下面我指定最大词长度为4*/
    String[] ss2 = ss.reverseSplit(st, 4);
    String[] ss1 = ss.positiveSplit(st, 4);
    System.out.println("正向最大匹配分词算法分词结果：" + Arrays.toString(ss1));
    System.out.println("逆向最大匹配分词算法分词结果：" + Arrays.toString(ss2));
}

}