1. WIKI教程
2. Java.io包
3. PermissionCollection newPermissionCollection()

PermissionCollection newPermissionCollection()

描述 (Description)

java.io.FileOutputStream.newPermissionCollection()返回一个存储FilePermission对象的新PermissionCollection对象。

声明 (Declaration)

以下是java.io.FilePermission.newPermissionCollection()方法的声明 -

public PermissionCollection newPermissionCollection()

参数 (Parameters)

p - 允许检查

返回值 (Return Value)

该方法返回适用于stroing FilePermissions的新PermissionCollection对象。

异常 (Exception)

NA

例子 (Example)

以下示例显示了java.io.FilePermission.newPermissionCollection（）方法的用法。

package com.iowiki;
import java.io.FilePermission;
import java.io.IOException;
import java.security.PermissionCollection;
public class FilePermissionDemo {
   static FilePermission fp = null;
   static PermissionCollection pc = null;
   public static void main(String[] args) throws IOException {
      try {
         // create new file permissions
         fp = new FilePermission("C://test.txt", "read");
         // create new permission collection
         pc = fp.newPermissionCollection();
         // add permission to the permission collection
         pc.add(fp);
         // tests if the file permission is read
         TestFileReadPermission("C://test.txt");
      } catch(Exception ex) {
         // if an error occurs
         ex.printStackTrace();
      }
   } 
   // method to test file permission
   public static void TestFileReadPermission(String path) {
      if(pc.implies(new FilePermission("C://test.txt", "read"))) {
         System.out.println("Permission for "+path+" is read");
      }
   }
}

让我们编译并运行上面的程序，这将产生以下结果 -

Permission for C://test.txt is read