equals方法Objects.equals (对象1,对象2 );
public class demo { publicstaticvoidmain (string args [ ] ) } { qxyq=null; QXY q1=new QXY (; system.out.println (objects.equals ) q,q1 ); }结果: fasle is空方法。 判断是否为空指针
public class demo { publicstaticvoidmain (string args [ ] ) } { qxyq=null; QXY q1=new QXY (; system.out.println (objects.is null (Q1 ) ); }结果: turepublicclassqxy { privatestring name; @ overridepublicbooleanequals (objecto ) if ) this==o ) return true; if(o==null||getclass (!=o.getClass () ) return false; qxyqxy=(qxy ) o; returnobjects.equals(name,qxy.name ); } @Override public int hashCode () returnobjects.hash ) ) name ); } public void show () { System.out.println ('名称); }} requireNonNull方法
判断是否为空指针,如果是,则直接抛出异常
public class demo { publicstaticvoidmain (string args [ ] ) } { qxyq=null; QXY q1=new QXY (; system.out.println (objects.require nonnull (q ) ); }结果: publicclassqxy { privatestring name; @ overridepublicbooleanequals (objecto ) if ) this==o ) return true; if(o==null||getclass (!=o.getClass () ) return false; qxyqxy=(qxy ) o; returnobjects.equals(name,qxy.name ); } @Override public int hashCode () returnobjects.hash ) ) name ); } public void show () { System.out.println ('名称); }