بناء السلاسل باستخدام StringBuilder

منشئ سلاسل نصية قابل للتغيير

إنشاء StringBuilder

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        StringBuilder named = new StringBuilder("Hello");
        System.out.println("empty length: " + sb.length());
        System.out.println("named: " + named);
    }
}

إلحاق النص

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append("Count: ");
        sb.append(5);
        sb.append(' ');
        sb.append(true);
        System.out.println(sb);
    }
}

تسلسل استدعاءات الأساليب

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append("a").append("b").append("c").append(123);
        System.out.println(sb);
    }
}

البناء داخل حلقة

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        for (int i = 1; i <= 10; i++) {
            sb.append(i).append(' ');
        }
        System.out.println(sb.toString().trim());
    }
}

التحويل إلى String

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder("result");
        String finalText = sb.toString();
        System.out.println(finalText.toUpperCase());
    }
}

الدمج باستخدام فاصل

public class Main {
    public static void main(String[] args) {
        String[] names = {"Ann", "Ben", "Cara"};
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < names.length; i++) {
            sb.append(names[i]);
            if (i < names.length - 1) {
                sb.append(", ");
            }
        }
        System.out.println(sb);
    }
}

قراءة الطول

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append("12345");
        System.out.println("Length: " + sb.length());
    }
}

الوصول إلى المحارف

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder("Coddy");
        System.out.println("First: " + sb.charAt(0));
        System.out.println("Last: " + sb.charAt(sb.length() - 1));
    }
}

السعة مقابل الطول

public class Main {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder(100);
        sb.append("short");
        System.out.println("Length: " + sb.length());
        System.out.println("Capacity at least: " + (sb.capacity() >= 100));
    }
}

منشئ عملي

public class Main {
    public static void main(String[] args) {
        int[] sales = {100, 250, 75};
        StringBuilder report = new StringBuilder("Sales Report\n");
        int total = 0;
        for (int i = 0; i < sales.length; i++) {
            report.append("Day ").append(i + 1).append(": ").append(sales[i]).append('\n');
            total += sales[i];
        }
        report.append("Total: ").append(total);
        System.out.println(report);
    }
}

تحقق سريع

خلاصة