Java list foreach修改元素方式

        List<O> oList = new ArrayList<O>();
        for (int i = 0; i < 10; i++) {
            oList.add(new O());
        }
        for (O o : oList) {
            o.setI(2);
        }
        System.out.println(oList);
        for (O o : oList) {
            o = new O();
        }
        System.out.println(oList);

//         引用类型数组
        Person[] p = new Person[2];
        Person student1 = new Person();
        student1.setId("1");
        student1.setName("牛千千");
 
        Person student2 =new Person();
        student2.setId("2");
        student2.setName("大千");
 
        p[0]=student1;
        p[1]=student2;
        for (Person per:p
             ) {
            per.setName("引用类型数组");
        }
        for (int i=0 ;i<2;i++){
            System.out.println(p[i].getName());
        }
 
// String类型数组
        String[] s = {"牛千千","大千"};
        for (String per:s
        ) {
            per ="String类型";
        }
        for (int i=0 ;i<2;i++){
            System.out.println(s[i]);
        }
 
    }
// 引用类型数组
// 引用类型数组
// 牛千千
// 大千

 import java.util .*;
 
    public class Test1 {
        public static void main(String[] args) {
            int[] a = new int[]{1, 2, 3, 4, 5, 6, 7, 8}; //定义数组
            for (int b : a)                           //foreach遍历数组a
            {
                if (b == 3)                        //如果找到b=3
                {
                    b = 4;                    //把b改成4
                }
            }
            System.out.println("---------输出数组");
            for (int b : a)                            //再次遍历数组a，看看改变有没有影响a
            {
                System.out.println(b);          //输出a中的全部值
            }
        }
    }
 
输出结果：
---------输出数组
1
2
3
4
5
6
7

public class Test_1 {
    public static void main(String[] args) {
     int a=1;
     int b=a;
     b=2;
     System.out.println("a="+a);
    }
}
 
输出结果: a=1

    
import java.util .*;    //导包  
 
    public class Test1 {
        public static void main(String[] args) {
            ArrayList<Clerk> al = new ArrayList<>();    //创建Clerk类型的ArrayList
            al.add(new Clerk("牛千千", 30, 50000));       //添加几个Clerk类型对象
            al.add(new Clerk("李云龙", 30, 5000));
            al.add(new Clerk("诸葛亮", 30, 5000));
            al.add(new Clerk("张小凡", 30, 5000));
          
            System.out.println("---------遍历集合");
            for (Clerk x : al)                           //foreach遍历集合
            {
                if (x.getName().equals("李云龙"))  //如果找到名字等于李云龙的对象
                {
                    x.setSalary(10000);      //修改对象的薪资
                }
            }
            System.out.println("---------输出集合");
            for (Clerk x : al)                          //foreach遍历
            {
                System.out.println(x.getName() + " " + x.getAge() + " " + x.getSalary());    //输出信息
            }
        }
    }
 
    class Clerk                                                   //定义员工类
    {
        private String name;
        private int age;
        private double salary;
        Clerk(String name, int age, double salary) {
            this.name = name;
            this.age = age;
            this.salary = salary;
        }
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        public int getAge() {
            return age;
        }
        public void setAge(int age) {
            this.age = age;
        }
        public double getSalary() {
            return salary;
        }
        public void setSalary(double salary) {
            this.salary = salary;
        }
    }
 
输出结果：
---------遍历集合
---------输出集合
周卫国 30 5000.0
李云龙 30 10000.0
诸葛亮 30 5000.0
张小凡 30 5000.0

 public class Test_1 {
        public static void main(String[] args) {
            Clerk c1 = new Clerk("周华剑", 30, 5000);    //创建一个员工
            Clerk temp = c1;                          //把c1交给temp
            temp.setSalary(10000);                  //改变temp的薪资
            System.out.println(c1.getSalary());     //输出c1的薪资
        }
    }
 
输出结果：
c1的薪资：10000.0