JAVA中@SuppressWarnings注解的作用

eclipse中开发JAVA代码时，经常会出现编译告警符号，影响代码可读性，也影响调试的断点符号正常显示，可以使用@SuppressWarnings注解来抑制这些告警符号的再现。
1.抑制单个类型的告警：

@SuppressWarnings("unused")

public void test1() {

    String s = "test";

}

2.抑制多个类型的告警：

@SuppressWarnings({"unused", "rawtypes"})

public void test2() {

    List list = new ArrayList();

}

3.抑制所有类型的告警：

@SuppressWarnings("all")

public void test3() {

    String s = "test";

}

以下是@SuppressWarnings注解中各个可选值含义描述：

all	抑制所有警告	to suppress all warnings
boxing	抑制装箱、拆箱操作时候的警告	to suppress warnings relative to boxing/unboxing operations
cast	抑制映射相关的警告	to suppress warnings relative to cast operations
dep-ann	抑制启用注释的警告	to suppress warnings relative to deprecated annotation
deprecation	抑制过期方法警告	to suppress warnings relative to deprecation
fallthrough	抑制在switch中缺失break的警告	to suppress warnings relative to missing breaks in switch statements
finally	抑制finally模块没有返回的警告	to suppress warnings relative to finally block that don’t return
hiding	抑制隐藏的本地变量相对应的警告	to suppress warnings relative to locals that hide variable
incomplete-switch	忽略没有完整的switch语句	to suppress warnings relative to missing entries in a switch statement (enum case)
nls	忽略非nls格式的字符	to suppress warnings relative to non-nls string literals
null	忽略对null的操作	to suppress warnings relative to null analysis
rawtypes	使用generics时忽略没有指定相应的类型	to suppress warnings relative to un-specific types when using generics on class params
restriction	抑制使用劝阻或禁止引用的警告	to suppress warnings relative to usage of discouraged or forbidden references
serial	忽略在serializable类中没有声明serialVersionUID变量	to suppress warnings relative to missing serialVersionUID field for a serializable class
static-access	抑制不正确的静态访问方式警告	to suppress warnings relative to incorrect static access
synthetic-access	抑制子类没有按最优方法访问内部类的警告	to suppress warnings relative to unoptimized access from inner classes
unchecked	抑制没有进行类型检查操作的警告	to suppress warnings relative to unchecked operations
unqualified-field-access	抑制没有权限访问的域的警告	to suppress warnings relative to field access unqualified
unused	抑制没被使用过的代码的警告	to suppress warnings relative to unused code