1 package com.java7; 2 // A simple automated telephone directory. 3 class Phone { 4     public static void main(String[] args) { 5         String numbers[][] = { 6                 { "Tom", "555-3322" }, 7                 { "Mary", "555-8976" }, 8                 { "Jon", "555-1037" }, 9                 { " Rachel", "555-1400"}10         };11         12         int i;13         14         if(args.length != 1) // 要使用程序，必须提供一个命令行实参15             System.out.println("Usage: java Phone <name>");16         else {17             for(i = 0; i < numbers.length; i++){18                 if(numbers[i][0].equals(args[0])) {19                     System.out.println(numbers[i][0] + ": " + numbers[i][1]);20                     break;21                 }22             }23             if(i == numbers.length)24                 System.out.println("Name not found.");25         }26     }27 }