Java 中的 StringBuilder setLength(),示例
原文:https://www . geeksforgeeks . org/stringbuilder-setlength-in-Java-with-examples/
字符串生成器的设置长度(int newLength) 方法用于将字符序列的长度设置为等于 newLength 。对于大于 0 且小于新长度的每个索引 k。如果作为参数传递的新长度小于旧长度,旧长度将更改为新长度。如果作为参数传递的新长度大于或等于旧长度,则在旧序列的末尾追加空字符(' \u0000 '),这样长度就成为新长度参数。
语法:
public void setLength(int newLength)
参数: 该方法接受一个参数新长度,该参数为整型值,指的是要设置的新序列长度。 返回: 此方法不返回任何内容。 异常: 如果新长度为负,则indexout of boundsexception。
下面的程序说明了 Java . lang . stringbuilder . setlength()方法: 示例 1:
// Java program to demonstrate
// the setLength() Method.
class GFG {
public static void main(String[] args)
{
// create a StringBuilder object
// with a String pass as parameter
StringBuilder str
= new StringBuilder("WelcomeGeeks");
// print string
System.out.println("String length = "
+ str.length() +
" and contains = " + str);
// set length equal to 10
str.setLength(10);
// print string
System.out.println("After setLength() String = "
+ str.toString());
}
}
输出:
String length = 12 and contains = WelcomeGeeks
After setLength() String = WelcomeGee
例 2:
// Java program to demonstrate
// the setLength() Method.
class GFG {
public static void main(String[] args)
{
// create a StringBuilder object
// with a String pass as parameter
StringBuilder str
= new StringBuilder("Tony Stark will die");
// print string
System.out.println("String length = "
+ str.length() +
" and contains = \"" + str + "\"");
// set length equal to 25
str.setLength(25);
// print string
System.out.println("After setLength() String = \""
+ str.toString() + "\"");
}
}
输出:
String length = 19 and contains = "Tony Stark will die"
After setLength() String = "Tony Stark will die "
示例 3: 当传递负的新长度时:
// Java program to demonstrate
// Exception thrown by the setLength() Method.
class GFG {
public static void main(String[] args)
{
// create a StringBuilder object
// with a String pass as parameter
StringBuilder str
= new StringBuilder("Tony Stark");
try {
// pass length -15
str.setLength(-15);
}
catch (Exception e) {
e.printStackTrace();
}
}
}
输出:
java.lang.StringIndexOutOfBoundsException: String index out of range: -15
at java.lang.AbstractStringBuilder.setLength(AbstractStringBuilder.java:207)
at java.lang.StringBuilder.setLength(StringBuilder.java:76)
at GFG.main(File.java:15)
参考文献: https://docs . Oracle . com/javase/10/docs/API/Java/lang/stringbuilder . html # setLength(int)
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