1.Array类

package bilibili.chapter14;

import java.util.Arrays;

public class test {
    public static void main(String []args){
        int []arr = {3,4,5,2,1};
        System.out.println(Arrays.toString(arr));

        Arrays.sort(arr);
        System.out.println(Arrays.toString(arr));
        System.out.println(Arrays.binarySearch(arr,4));

    }

}

2.包装类

package bilibili.chapter14;

import java.util.Arrays;

public class test {
    public static void main(String []args){
        Integer i = Integer.valueOf("10");
        //System.out.println(i);
        String ii = Integer.toString(i);
        int num = i.intValue();
        System.out.println(num);
    }

}

javabean里一般将基本数据类型变成包装类型属性,表中uid是自增的，默认值是null，使用包装类型的话，插入语句可以是insert into user(uid,username,password) values (NULL,’金莲’,‘36666’);