Java中String类的常用方法示例

 1 package dg;
 2 
 3 
 4 /**
 5  *
 6  * @author DUGANG
 7  */
 8 public class StringMethod {
 9     public static void main(String[] args){
10         String str = "Hello World!!!";
11         System.out.println("示例字符串为：" + str);
12         //public char charAt(int index)方法
13         System.out.println(str + "中第四个字符为：" + str.charAt(4));
14         //public int length()方法
15         System.out.println(str + "的字符长度为：" + str.length());
16         //public int indexOf(String str)方法
17         System.out.println(str + "中第一个“l”出现在字符串的第" + str.indexOf("l") + "位");
18         //public boolean equalsIgnoreCase(String another)方法
19         System.out.println(str + "与hello world!!!相同:" + str.equalsIgnoreCase("hello world!!!"));
20         //public String replace(char oldChar, char newChar)方法
21         System.out.println(str + "用‘L’替换‘l’后为：" + str.replace("l", "L"));
22         //public boolean startsWith(String prefix)方法
23         System.out.println(str + "以字母‘H’开头：" + str.startsWith("H"));
24         //public boolean endsWith(String suffix)方法
25         System.out.println(str + "以‘！’结尾:" + str.endsWith("!"));
26         //public String toUpperCase()方法
27         System.out.println(str + "转换为大写：" + str.toUpperCase());
28         //public String toLowerCase()fangfa
29         System.out.println("JAVA转换为小写：" + "JAVA".toLowerCase());
30         //public String substring(int beginIndex)
31         System.out.println(str + "从第六个字符开始截取子串为：" + str.substring(6));
32         //public String trim()方法
33         System.out.println("       hello      " + "去掉开头和结尾的空格为:" + "       hello      ".trim());
34     }
35 
36 }

package dg;


/**
 *
 * @author DUGANG
 */
public class StringMethod {
    public static void main(String[] args){
        String str = "Hello World!!!";
        System.out.println("示例字符串为：" + str);
        //public char charAt(int index)方法
        System.out.println(str + "中第四个字符为：" + str.charAt(4));
        //public int length()方法
        System.out.println(str + "的字符长度为：" + str.length());
        //public int indexOf(String str)方法
        System.out.println(str + "中第一个“l”出现在字符串的第" + str.indexOf("l") + "位");
        //public boolean equalsIgnoreCase(String another)方法
        System.out.println(str + "与hello world!!!相同:" + str.equalsIgnoreCase("hello world!!!"));
        //public String replace(char oldChar, char newChar)方法
        System.out.println(str + "用‘L’替换‘l’后为：" + str.replace("l", "L"));
        //public boolean startsWith(String prefix)方法
        System.out.println(str + "以字母‘H’开头：" + str.startsWith("H"));
        //public boolean endsWith(String suffix)方法
        System.out.println(str + "以‘！’结尾:" + str.endsWith("!"));
        //public String toUpperCase()方法
        System.out.println(str + "转换为大写：" + str.toUpperCase());
        //public String toLowerCase()fangfa
        System.out.println("JAVA转换为小写：" + "JAVA".toLowerCase());
        //public String substring(int beginIndex)
        System.out.println(str + "从第六个字符开始截取子串为：" + str.substring(6));
        //public String trim()方法
        System.out.println("       hello      " + "去掉开头和结尾的空格为:" + "       hello      ".trim());
    }

}