fanxing.md

---
title: java 泛型 test
date: 2019-03-16 13:56:01
tags:
  - 泛型
  - Java
categories:
  - Java
---

> - 泛型方法，它在修饰符后，返回值类型前增加了类型参数 (<>)
> - 类型通配符一般使用问号`?`代替具体的类型`实`参，注意不是类型形参。

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## 代码

```java
package code0507;

public class WildCardTest {

  public static void main(String[] args) {
    Box<String>name=new Box<String>("hello");
    Box<Integer>age=new Box<Integer>(12);
    Box<Double>number=new Box<Double>(210.50);
    Box<Integer>point=new Box<Integer>();
    getData(name);
    getData(age);
    getData(number);
    point.printpoint(520, 1314);
    point.printpoint("me", "too");
  }

  public static void getData(Box<?>data){//类型通配符
    System.out.println("data:"+data.getData());
  }
}
class Box<T>{
  private T data;
  public Box() {}//构造方法重载
  public Box(T data) {
    setData(data);
  }
  public T getData() {
    return data;
  }
  public void setData(T data) {
    this.data = data;
  }
  //定义泛型方法
  public<T1,T2>void printpoint(T1 x,T2 y){
    T1 m=x;
    T2 n=y;
    System.out.println("This point is:"+m+","+n);
  }
}
```

## 运行结果

```java
data:hello
data:12
data:210.5
This point is:520,1314
This point is:me,too
```