有时候,我们为了使得对象不为空,可以使用Objects.requireNonNull()方法对对象进行判断。
Objects.requireNonNull(T obj);
Objects.requireNonNull(T obj, String message);
Objects.requireNonNull(T obj, Supplier<String> messageSupplier);
//来自 时 代 Java - nowjava.com
import java.util.Objects;
import java.util.function.Supplier;
public class Main {
public static void main(String[] args) {
// Testing requireNonNull(T obj, String message)
try {
printName("test");
printName(null);
} catch (NullPointerException e) {
System.out.println(e.getMessage());
}
// requireNonNull(T obj, Supplier<String> messageSupplier)
try {
Supplier<String> messageSupplier = () -> "Name is required. ";/*时代Java公众号*/
printNameWithSuplier("aaa", messageSupplier);
printNameWithSuplier(null, messageSupplier);
} catch (NullPointerException e) {
System.out.println(e.getMessage());
}
}
public static void printName(String name) {
// Test name for not null. Generate a NullPointerException if it is null.
Objects.requireNonNull(name, "Name is required.");
// Print the name if the above statement dod not throw an exception
System.out.println("Name is " + name);
}
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