• 注解用法详解——@SuppressWarnings


    一、前言                                  

      编码时我们总会发现如下变量未被使用的警告提示:

      上述代码编译通过且可以运行,但每行前面的“感叹号”就严重阻碍了我们判断该行是否设置的断点了。这时我们可以在方法前添加 @SuppressWarnings("unused") 去除这些“感叹号”。

    二、 @SuppressWarings注解                            

      作用:用于抑制编译器产生警告信息。

      示例1——抑制单类型的警告:

    @SuppressWarnings("unchecked")
    public void addItems(String item){
      @SuppressWarnings("rawtypes")
       List items = new ArrayList();
       items.add(item);
    }

      示例2——抑制多类型的警告:

    @SuppressWarnings(value={"unchecked", "rawtypes"})
    public void addItems(String item){
       List items = new ArrayList();
       items.add(item);
    }

      示例3——抑制所有类型的警告:

    @SuppressWarnings("all")
    public void addItems(String item){
       List items = new ArrayList();
       items.add(item);
    }

    三、注解目标                                

     通过 @SuppressWarnings 的源码可知,其注解目标为类、字段、函数、函数入参、构造函数和函数的局部变量。

     而家建议注解应声明在最接近警告发生的位置。

    四、抑制警告的关键字                                

    关键字 用途
    all to suppress all warnings
    boxing  to suppress warnings relative to boxing/unboxing operations
    cast to suppress warnings relative to cast operations
    dep-ann to suppress warnings relative to deprecated annotation
    deprecation to suppress warnings relative to deprecation
    fallthrough  to suppress warnings relative to missing breaks in switch statements
    finally  to suppress warnings relative to finally block that don’t return
    hiding to suppress warnings relative to locals that hide variable
    incomplete-switch  to suppress warnings relative to missing entries in a switch statement (enum case)
    nls  to suppress warnings relative to non-nls string literals
    null to suppress warnings relative to null analysis
    rawtypes to suppress warnings relative to un-specific types when using generics on class params
    restriction to suppress warnings relative to usage of discouraged or forbidden references
    serial to suppress warnings relative to missing serialVersionUID field for a serializable class
    static-access o suppress warnings relative to incorrect static access
    synthetic-access   to suppress warnings relative to unoptimized access from inner classes
    unchecked  to suppress warnings relative to unchecked operations
    unqualified-field-access to suppress warnings relative to field access unqualified
    unused to suppress warnings relative to unused code

    链接https://www.cnblogs.com/fsjohnhuang/p/4040785.html

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  • 原文地址:https://www.cnblogs.com/mike-mei/p/9963022.html
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