类型推断表示Java编译器查看方法调用以及其相应的声明来检查和确定类型的参数，如果可用，则返回分配的类型。
如果未使用类型推断，则编译器会生成未经检查的转换警告。
Type inference - 语法
Box<Integer> integerBox=new Box<>();
Box - Box是一个通用类。
<> - 运算符表示类型推断。
使用您选择的任何编辑器创建以下Java程序。
package com.learnfk;
public class GenericsTester {
public static void main(String[] args) {
//类型推断
Box<Integer> integerBox=new Box<>();
//指定string类型
Box<String> stringBox=new Box<String>();
integerBox</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Integer</span><span class="pun">(</span><span class="lit">10</span><span class="pun">));</span><span class="pln">
stringBox</span><span class="pun">.</span><span class="kwd">add</span><span class="pun">(</span><span class="kwd">new</span><span class="pln"> </span><span class="typ">String</span><span class="pun">(</span><span class="str">"Hello World"</span><span class="pun">));</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">printf</span><span class="pun">(</span><span class="str">"Integer Value :%d\n"</span><span class="pun">,</span><span class="pln"> integerBox</span><span class="pun">.</span><span class="kwd">get</span><span class="pun">());</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">printf</span><span class="pun">(</span><span class="str">"String Value :%s\n"</span><span class="pun">,</span><span class="pln"> stringBox</span><span class="pun">.</span><span class="kwd">get</span><span class="pun">());</span><span class="pln">
}
}
class Box<T> {
private T t;
public void add(T t) {
this.t=t;
}
public T get() {
return t;
}
}
这将产生以下输出。
Integer Value :10 String Value :Hello World
