import org.junit.Test;import java.util.Arrays;/** * @author CH * @create 2021 上午 10:42 */public class StringDemo2 {    /*    获取两个字符串中最大相同子串。比如：   str1 = "abcwerthelloyuiodefabcdef";str2 = "cvhellobnm"   提示：将短的那个串进行长度依次递减的子串与较长的串比较。     */    //前提：两个字符串中只有一个最大相同子串    public String getMaxSameString(String str1,String str2){        if(str1 != null && str2 != null){            String maxStr = (str1.length() >= str2.length())? str1 : str2;            String minStr = (str1.length() < str2.length())? str1 : str2;            int length = minStr.length();            for(int i = 0;i < length;i++){//外层有多少大轮（小字符串的长度）                for(int x = 0,y = length - i;y <= length;x++,y++){//内层循环相当于一个方框从左移动到右边（动态规划）                    String subStr = minStr.substring(x,y);//substring切片要比较的字符串                    if(maxStr.contains(subStr)){                        return subStr;                    }                }            }        }        return null;    }    // 如果存在多个长度相同的最大相同子串    // 此时先返回String[]，后面可以用集合中的ArrayList替换，较方便    public String[] getMaxSameString1(String str1, String str2) {        if (str1 != null && str2 != null) {            StringBuffer sBuffer = new StringBuffer();            String maxString = (str1.length() > str2.length()) ? str1 : str2;            String minString = (str1.length() > str2.length()) ? str2 : str1;            int len = minString.length();            for (int i = 0; i < len; i++) {                for (int x = 0, y = len - i; y <= len; x++, y++) {                    String subString = minString.substring(x, y);                    if (maxString.contains(subString)) {                        sBuffer.append(subString + ",");                    }                }//                System.out.println(sBuffer);                if (sBuffer.length() != 0) {//如果找到了该长度的字串，则要中止最外层循环                    break;                }            }            String[] split = sBuffer.toString().replaceAll(",$", "").split("\\,");            return split;        }        return null;    }    @Test    public void testGetMaxSameString(){        String str1 = "abcwerthello1yuiodefabcdef";        String str2 = "cvhello1bnmabcdef";        String[] maxSameStrings = getMaxSameString1(str1, str2);        System.out.println(Arrays.toString(maxSameStrings));    }}