Java 错误 - 预期的类接口或枚举
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Error - Class interface or enum expected
提问by sugam
I am new to java and i am writing this code in notepad which is giving me errors.In netbeans although package is already defined.How to do this in notepad?
我是 Java 新手，我正在记事本中编写这段代码，这给了我错误。在 netbeans 中，虽然已经定义了包。如何在记事本中执行此操作？
package A;
class A {
private String name;
protected String company="oracle";
A(String name) {
this.name = name;
System.out.println(name);
}
}
public class B extends A {
// A public class constant
public final static String st = "Public access modifiers";
B(String name) {
super(name);
}
void getCompany()
{
System.out.println(company);
}
}
package B;//getting class interface or enum expected
public class Application {
public static void main(String[] args) {
System.out.println(st);
B b=new B("Java");
b.getCompany();
}
}
采纳答案by ppeterka
You can not put different packages into the same source file... You have to create the appropriate folder structure, and separate Java source files for the sources in each package...
您不能将不同的包放入同一个源文件中...您必须创建适当的文件夹结构，并为每个包中的源单独的 Java 源文件...
Also, to be able to reference classes from other packages, you have to importthem appropriately, and make sure they are actually on the classpathboth for compiling and running too......
此外，为了能够从其他包中引用类，您必须import适当地引用它们，并确保它们实际上位于类路径上以进行编译和运行......
Recommended reading
推荐阅读
回答by SpringLearner
package B;//getting class interface or enum expected
remove this line
Packagedeclaration should be the first lineof the source file.
删除这一行
Package声明应该是源文件的第一行。
You can not write 2 or more different packageswith in the same source
您不能在同一个源中编写2 个或更多不同的包
回答by Suresh Atta
The PackageOrTypeName must be the canonical name (§6.7) of a package, a class type, an interface type, an enum type, or an annotation type.
PackageOrTypeName 必须是包、类类型、接口类型、枚举类型或注释类型的规范名称（第 6.7 节）。
That is what it is telling, and remove multiple declarations of package
这就是它所说的，并删除多个声明 package
And you should import the class B, When they both belongs to different packages.
并且您应该导入 class B，当它们都属于不同的包时。
import packagePath.B;
If a single-type-import declaration imports a type whose simple name is n, and the compilation unit also declares a top level type (§7.6) whose simple name is n, a compile-time error occurs.
如果单类型导入声明导入了一个简单名称为 n 的类型，并且编译单元还声明了一个简单名称为 n 的顶级类型（第 7.6 节），则会发生编译时错误。
Side note:Do not write multiple classes in a single java file. Later It's very hard to maintain the code.
旁注：不要在单个 java 文件中编写多个类。后来代码维护起来很吃力。
回答by sara
The package statement should be the first line in the source file. There can be only one package statement in each source file, and it applies to all types in the file.
package 语句应该是源文件中的第一行。每个源文件中只能有一个 package 语句，它适用于文件中的所有类型。
