吴裕雄--天生自然 JAVA开发学习：String 类

public class StringDemo{

   public static void main(String args[]){

      char[] helloArray = { 'r', 'u', 'n', 'o', 'o', 'b'};

      String helloString = new String(helloArray);

      System.out.println( helloString );

   }

}

public class StringDemo {

    public static void main(String args[]) {

        String site = "www.runoob.com";

        int len = site.length();

        System.out.println( "菜鸟教程网址长度 : " + len );

   }

}

public class StringDemo {

    public static void main(String args[]) {

        String string1 = "菜鸟教程网址：";

        System.out.println("1、" + string1 + "www.runoob.com");

    }

}

System.out.printf("浮点型变量的值为 " +

                  "%f, 整型变量的值为 " +

                  " %d, 字符串变量的值为 " +

                  "is %s", floatVar, intVar, stringVar);

String fs;

fs = String.format("浮点型变量的值为 " +

                   "%f, 整型变量的值为 " +

                   " %d, 字符串变量的值为 " +

                   " %s", floatVar, intVar, stringVar);

public class Test {

    public static void main(String args[]) {

        String s = "www.runoob.com";

        char result = s.charAt(8);

        System.out.println(result);

    }

}

public class Test {

    public static void main(String args[]) {

        String str1 = "Strings";

        String str2 = "Strings";

        String str3 = "Strings123";

        int result = str1.compareTo( str2 );

        System.out.println(result);

        result = str2.compareTo( str3 );

        System.out.println(result);

        result = str3.compareTo( str1 );

        System.out.println(result);

    }

}

public class Test {

    public static void main(String args[]) {

        String str1 = "STRINGS";

        String str2 = "Strings";

        String str3 = "Strings123";

        int result = str1.compareToIgnoreCase( str2 );

        System.out.println(result);

        result = str2.compareToIgnoreCase( str3 );

        System.out.println(result);

        result = str3.compareToIgnoreCase( str1 );

        System.out.println(result);

    }

}

public class Test {

    public static void main(String args[]) {

        String s = "菜鸟教程：";

        s = s.concat("www.runoob.com");

        System.out.println(s);

    }

}

public class Test {

    public static void main(String args[]) {

        String str1 = "String1";

        String str2 = "String2";

        StringBuffer str3 = new StringBuffer( "String1");

        boolean  result = str1.contentEquals( str3 );

        System.out.println(result);

        result = str2.contentEquals( str3 );

        System.out.println(result);

    }

}

public class Test {

    public static void main(String args[]) {

        char[] Str1 = {'h', 'e', 'l', 'l', 'o', ' ', 'r', 'u', 'n', 'o', 'o', 'b'};

        String Str2 = "";

        Str2 = Str2.copyValueOf( Str1 );

        System.out.println("返回结果：" + Str2);

        Str2 = Str2.copyValueOf( Str1, 2, 6 );

        System.out.println("返回结果：" + Str2);

    }

}

public class Test {

    public static void main(String args[]) {

        String Str = new String("菜鸟教程：www.runoob.com");

        boolean retVal;

        retVal = Str.endsWith( "runoob" );

        System.out.println("返回值 = " + retVal );

        retVal = Str.endsWith( "com" );

        System.out.println("返回值 = " + retVal );

    }

public class Test {

    public static void main(String args[]) {

        String Str1 = new String("runoob");

        String Str2 = Str1;

        String Str3 = new String("runoob");

        boolean retVal;

        retVal = Str1.equals( Str2 );

        System.out.println("返回值 = " + retVal );

        retVal = Str1.equals( Str3 );

        System.out.println("返回值 = " + retVal );

    }

}

public class Test {

    public static void main(String args[]) {

        String Str1 = new String("runoob");

        String Str2 = Str1;

        String Str3 = new String("runoob");

        String Str4 = new String("RUNOOB");

        boolean retVal;

        retVal = Str1.equals( Str2 );

        System.out.println("返回值 = " + retVal );

        retVal = Str3.equals( Str4);

        System.out.println("返回值 = " + retVal );

        retVal = Str1.equalsIgnoreCase( Str4 );

        System.out.println("返回值 = " + retVal );

    }

}

import java.io.*;

public class Test {

    public static void main(String args[]) {

        String Str1 = new String("runoob");

        try{

            byte[] Str2 = Str1.getBytes();

            System.out.println("返回值：" + Str2 );

            Str2 = Str1.getBytes( "UTF-8" );

            System.out.println("返回值：" + Str2 );

            Str2 = Str1.getBytes( "ISO-8859-1" );

            System.out.println("返回值：" + Str2 );

        } catch ( UnsupportedEncodingException e){

            System.out.println("不支持的字符集");

        }

    }

}

public class Test {

    public static void main(String args[]) {

        String Str1 = new String("www.runoob.com");

        char[] Str2 = new char[6];

        try {

            Str1.getChars(4, 10, Str2, 0);

            System.out.print("拷贝的字符串为：" );

            System.out.println(Str2 );

        } catch( Exception ex) {

            System.out.println("触发异常...");

        }

    }

}

public class Test {

    public static void main(String args[]) {

        String Str = new String("www.runoob.com");

        System.out.println("字符串的哈希码为 :" + Str.hashCode() );

    }

}

public class Main {

    public static void main(String args[]) {

        String string = "aaa456ac";

        //查找指定字符是在字符串中的下标。在则返回所在字符串下标；不在则返回-1.

        System.out.println(string.indexOf("b")); // indexOf(String str); 返回结果：-1，"b"不存在

        // 从第四个字符位置开始往后继续查找，包含当前位置

        System.out.println(string.indexOf("a",3));//indexOf(String str, int fromIndex); 返回结果：6

        //（与之前的差别：上面的参数是 String 类型，下面的参数是 int 类型）参考数据：a-97,b-98,c-99

        // 从头开始查找是否存在指定的字符

        System.out.println(string.indexOf(99));//indexOf(int ch)；返回结果：7

        System.out.println(string.indexOf('c'));//indexOf(int ch)；返回结果：7

        //从fromIndex查找ch，这个是字符型变量，不是字符串。字符a对应的数字就是97。

        System.out.println(string.indexOf(97,3));//indexOf(int ch, int fromIndex); 返回结果：6

        System.out.println(string.indexOf('a',3));//indexOf(int ch, int fromIndex); 返回结果：6

    }

}

public class Test {

    public static void main(String args[]) {

        String Str = new String("菜鸟教程:www.runoob.com");

        String SubStr1 = new String("runoob");

        String SubStr2 = new String("com");

        System.out.print("查找字符 o 第一次出现的位置 :" );

        System.out.println(Str.indexOf( 'o' ));

        System.out.print("从第14个位置查找字符 o 第一次出现的位置 :" );

        System.out.println(Str.indexOf( 'o', 14 ));

        System.out.print("子字符串 SubStr1 第一次出现的位置:" );

        System.out.println( Str.indexOf( SubStr1 ));

        System.out.print("从第十五个位置开始搜索子字符串 SubStr1 第一次出现的位置 :" );

        System.out.println( Str.indexOf( SubStr1, 15 ));

        System.out.print("子字符串 SubStr2 第一次出现的位置 :" );

        System.out.println(Str.indexOf( SubStr2 ));

    }

}