包和导入之间有什么区别? [英] What's the difference between a package and an import?

问题描述

包和导入之间有什么区别?请举个例子.

What's the difference between a package and an import? Please give an example.

为什么我们不能只使用 import java.util.*; ?
它不是自动授予所有其他访问权限吗?

Why can't we just use import java.util.*;?
Doesn't it give access to all the others automatically?

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegexMatches
{
public static void main( String args[] ){

  // String to be scanned to find the pattern.
  String line = "This order was placed for QT3000! OK?";
  String pattern = "(.*)(\\d+)(.*)";

  // Create a Pattern object
  Pattern r = Pattern.compile(pattern);

  // Now create matcher object.
  Matcher m = r.matcher(line);
  if (m.find( )) {
     System.out.println("Found value: " + m.group(0) );
     System.out.println("Found value: " + m.group(1) );
     System.out.println("Found value: " + m.group(2) );
  } else {
     System.out.println("NO MATCH");
  }
 }
}

推荐答案

程序包名称是用户定义的，它是您提供的，

package name is user defined its what you give,

例如:包装测试；

import软件包用于获取Java中已经预定义的软件包，以在您当前的软件包中使用

import package is used to get already predefined packages in java to be used in your current package

例如:如果您想在测试包中使用"util"包，

Ex: if you want to use "util" package in your test package,

包装测试；

java.util.Scanner;

java.util.Scanner;

此处util是java预定义的程序包，而Scanner是util程序包中的类.

Here util is java predefined package and Scanner is the class present in util package.

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