java中求几个字符串的最大公共子串 使用了比较器Comparator

package com.swift;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

public class Max_Substring_Test {

    public static void main(String[] args) {

        /*

         * 几个字符串的最大公共子字符串

         */

        String str1 = "eriousdfndnfdlk";

        String str2 = "dkgfdkgkdjgdjgjksjgksgjsdkjsdierioe";

        String str3 = "ldskfjdskierundsnfjerioejrejrheruer3j43j4hj3";

        String sub;

        List<String> list=new ArrayList<String>();

        for (int i = 0; i < str1.length(); i++) {

            sub = str1.substring(0, i);

            if(str2.indexOf(sub)!=-1&&str3.indexOf(sub)!=-1) {

//                System.out.println(sub);

                list.add(sub);

            }

        }

        Collections.sort(list, new Comparator<String>() {

            @Override

            public int compare(String arg0, String arg1) {

                int i=arg1.length()-arg0.length();

                return i;

            }

        });

            System.out.println("The max subString is "+list.get(0));

    }

}

上面方法中测试的子串都是从第一个字母开始的，所以并不完全，子串还有很多，还有从第二个字母开始，从第三个字母开始，等等的子字符串

所以，还应该再加一层循环，把substring(开始参数，结束参数)中开始和结束参数都设置为变量，开始参数从0开始到最后一个字母下标，结束参数起始位置要根据开始参数而定，否则会出现下标异常

package com.swift;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

public class Max_Substring_Test {

    public static void main(String[] args) {

        /*

         * 几个字符串的最大公共子字符串

         */

        String str1 = "eriousdfndnfdlk";

        String str2 = "dkgfdkgkdjgdjgjksjgksgjsdkjsdierioe";

        String str3 = "ldskfjdskierundsnfjerioejrejrheruer3j43j4hj3";

        String sub;

        List<String> list = new ArrayList<String>();

        for (int i = 0; i < str1.length(); i++) {

            for (int j = i; j < str1.length(); j++) {

                System.out.println(sub = str1.substring(i, j+1));

                if (str2.contains(sub)&& str3.contains(sub)) {

                    System.out.println(sub);

                    list.add(sub);

                }

            }

        }

        Collections.sort(list, new Comparator<String>() {

            @Override

            public int compare(String arg0, String arg1) {

                int i = arg1.length() - arg0.length();

                return i;

            }

        });

        System.out.println("The max subString is " + list.get(0));

    }

}