Java字符串太长了？

Question

我有在Java中下面的代码（其工作用C就好++出于某种原因），它产生一个错误：

int a; 
System.out.println("String length: " + input.length()); 
for(a = 0; ((a + 1) * 97) < input.length(); a++) { 
    System.out.print("Substring at " + a + ": "); 
    System.out.println(input.substring(a * 97, 97)); 
    //other code here... 
} 

输出：然而

String length: 340 
Substring at 0: HelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHe 
Substring at 1: 
Exception in thread "AWT-EventQueue-0" java.lang.StringIndexOutOfBoundsException: String index out of range: -97 
//long list of "at ..." stuff 
Substring at 2: 

使用长度200的串，产生以下输出：

String length: 200 
Substring at 0: HelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHelloHe 
Substring at 1: 

就是这样;没有例外提出，只是......没有。这里发生了什么？

Answer 1

String.substring的第二个参数是上一个索引不是子串的长度。所以你想要以下（我假设）：

int a; 
System.out.println("String length: " + input.length()); 
for(a = 0; ((a + 1) * 97) < input.length(); a++) { 
    System.out.print("Substring at " + a + ": "); 
    System.out.println(input.substring(a * 97, (a + 1) * 97)); 
    //other code here... 
}