如何从一个 Arraylist 复制到另一个

Question

如何从一个 Arraylist 复制到另一个，如下所示。 我有 Arraylist 下面的 class 喜欢

List<A> aClass =...; // has some data

List<B> bClass =...; //empty

//imports Class X
public class A {
    private String p;
    private String q;
    private<ClassX> x
}


//imports Class Y
public class B {
    private String p;
    private String q;
    private<ClassY> y
}

public class X {
    private String r;
    private String s;
}

 public Class Y {

     private String r;
     private String s;

}

我如何从bClass复制到aClass ； 像下面一样 //bClass=aClass;

Answer 1

您可以为此使用for循环：

for(A a : aClass) {
    bClass.add(new B(a.getP(), a.getQ())); // creating new instance of B by passing params to its constructor.
}

public class A {
    private String p;
    private String q;
    
    public String getP() {
        return p;
    }

    public String getQ() {
        return q;
    }
}

public class B {
    private String p;
    private String q;

    public B(String p, String q) {
        this.p = p;
        this.q = q;
    }
}