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这段构造块的代码啥意思啊？哪位大神帮忙解释解释？
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这段构造块的代码啥意思啊？哪位大神帮忙解释解释？
这段构造块里面代码啥意思啊，尤其 aa -> aa instanceof xxxMapper， 这个aa是个啥呢？
哪位大神帮忙解释一下这块代码的整体意思？
08/05 18:16
这是函数式编程。下面的三种写法是一个意思： public class User { private String name; private int age; public User() {} public User(String name, int age) { this.name = name; this.age = age; } public int getAge() { return age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public void setAge(int age) { this.age = age; } public static void main(String[] args) { Predicate p1 = aa -> "zhangsan".equals(aa.getName()); Predicate p2 = new Predicate() {
@Override public boolean test(User aa) { return "zhangsan".equals(aa.getName()); } }; Predicate p3 = new MyPredicate(); } } class MyPredicate implements Predicate { public boolean test(User aa) { return "zhangsan".equals(aa.getName()); } } p1、p2、p3写法是等价的。通常为了方便，我们会简写成p1的方式。结合你的代码中aa就是XXXMapper的实例，但是正如p1、p2、p3中的例子，这里只是定义了三个实例，并未传入真正的User对象呢，具体使用如p1.test(new User("lisi",18))。简单点可以理解为，这里只是定义了三个函数。
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