【初级】String str=" ac,42,123,sd Fa,c df,4,acdf,5ewRRre ";1．把字符串按,进行分割

第7题做的不好...

package HomeWork;import java.util.Arrays;/*3.String str="  ac,42,123,sd  Fa,c  df,4,acdf,5ewRRre  ";1．把字符串按,进行分割2．把里面的大写转化成小写3．把里面的小写转化成大写4．统计字符串的长度5．把字符串前后的空格去掉6．把字符串中所有空格去掉7. 找出字符串中所有a出现的位置,没有返回-1*/public class HomeWork_03 {public static void main(String[] args) {String str = "  ac,42,123,sd  Fa,c  df,4,acdf,5ewRRre  ";char[] key = str.toCharArray();show1(str, ",");show2(str);show3(str);show4(str);show5(str);show6(str, " ");show7(str, "x");show7(str, "a");}public static void show1(String str, String key) {// (1)String[] s1 = str.split(key);// 分割后-存到数组-在输出sop("割掉,:");for (int i = 0; i < s1.length; i++) {sop(s1[i]);}sop("\n");}public static void show2(String str) {// (2)sop("转小写:" + str.toLowerCase() + "\n");}public static void show3(String str) {// (3)sop("转大写:" + str.toUpperCase() + "\n");}public static void show4(String str) {char[] key = str.toCharArray();// (4)存到数组在遍历(定义个计数器)int sum = 0;for (int i = 0; i < key.length; i++) {sum++;}sop("长度:" + sum + "\n");}public static void show5(String str) {sop("去前后空格:"+str.trim() + "\n");}public static void show6(String str, String key) {// 截取后重新组合的新串String[] sc = str.split(key);// 先割掉for (int i = 0; i < sc.length; i++) {// 在循环输出(组合)sop(sc[i]);}sop("\n");}public static void show7(String str, String key) {int index = 0;index = str.indexOf(key, index);if (index != -1) {while ((index = str.indexOf(key, index)) != -1) {sop("位置码:"+index + "\n");index = index + key.length();}} else {sop("位置码: -1\n");}}public static void sop(Object obj) {System.out.print(obj);}}