Java 字符串、数组、ArrayList转换

import java.util.Arrays;

public class Test02 {
    public static void main(String[] args){
        int[] scores1 = new int[]{10,20,30,40,50};
        int[] scores2 = {10,20,30,40,50};

        // 数组转字符串
        // 1.第一种方法
        String str = Arrays.toString(scores1);
        System.out.println(str); // [10, 20, 30, 40, 50]
        // 2.第二种方法
        String str2 = "";
        for (int i = 0; i < scores1.length; i++) {
            str2 += scores1[i] + ",";
        }
        str2 = str2.substring(0, str2.length() - 1);
        System.out.println(str2); // 10,20,30,40,50
        // 3.第三种方法（相比第二种，更推荐第三种）
        StringBuilder stringBuilder = new StringBuilder();
        for (int score : scores1) {
            stringBuilder.append(score).append(",");
        }
        // String str3 = new StringBuilder(stringBuilder.substring(0, stringBuilder.length() - 1)).toString();
        String str3 = stringBuilder.toString().substring(0, stringBuilder.length() - 1);
        System.out.println(str3); // 10,20,30,40,50
　　}
}

import java.util.Arrays;

public class Test02 {
    public static void main(String[] args){
        // 字符串转数组
        String str = "10,20,30,40,50";
        String[] strArr = str.split(",");
        System.out.println(Arrays.toString(strArr)); // [10, 20, 30, 40, 50]
　　}
}