java Java 中的 StringBuffer setLength()，示例

Java 中的 StringBuffer setLength()，示例

原文:https://www . geeksforgeeks . org/stringbuffer-setlength-in-Java-with-examples/

StringBuffer 类的 setLength(int newLength) 方法是用于将字符序列的长度设置为等于 newLength 的内置方法。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 . stringbuffer . setlength()方法: 示例 1:

// Java program to demonstrate
// the setLength() Method.

class GFG {

    public static void main(String[] args)
    {
        // create a StringBuffer object
        // with a String pass as parameter
        StringBuffer str
            = new StringBuffer("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 StringBuffer object
        // with a String pass as parameter
        StringBuffer str
            = new StringBuffer("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 StringBuffer object
        // with a String pass as parameter
        StringBuffer str
            = new StringBuffer("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.AbstractStringBuffer.setLength(AbstractStringBuffer.java:207)
    at java.lang.StringBuffer.setLength(StringBuffer.java:76)
    at GFG.main(File.java:15)