Java 实例 - 连接字符串

以下实例演示了通过 "+" 操作符和StringBuffer.append() 方法来连接字符串，并比较其性能：

StringConcatenate.java 文件

public   class   StringConcatenate   {
     public   static   void   main ( String [ ]   args ) {
         long   startTime  =  System . currentTimeMillis ( ) ;
         for ( int   i = 0 ; i < 5000 ; i ++ ) {
             String   result  =  " This is "
            +  " testing the "
            +  " difference " +  " between "
            +  " String " +  " and " +  " StringBuffer " ;
         }
         long   endTime  =  System . currentTimeMillis ( ) ;
         System . out . println ( " 字符串连接 "
        +  "  - 使用 + 操作符 :  "
        +  ( endTime  -  startTime ) +  "  ms " ) ;
         long   startTime1  =  System . currentTimeMillis ( ) ;
         for ( int   i = 0 ; i < 5000 ; i ++ ) {
             StringBuffer   result  =  new   StringBuffer ( ) ;
             result . append ( " This is " ) ;
             result . append ( " testing the " ) ;
             result . append ( " difference " ) ;
             result . append ( " between " ) ;
             result . append ( " String " ) ;
             result . append ( " and " ) ;
             result . append ( " StringBuffer " ) ;
         }
         long   endTime1  =  System . currentTimeMillis ( ) ;
         System . out . println ( " 字符串连接 "
        +  "  - 使用 StringBuffer :  "
        +  ( endTime1  -  startTime1 ) +  "  ms " ) ;
     }
}

以上代码实例输出结果为：

字符串连接 - 使用 + 操作符 : 0 ms

字符串连接 - 使用 StringBuffer : 6 ms

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[这个贴子最后由 flybird 在 2020-01-26 21:03:55 重新编辑]

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