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源码版本

commons-lang3-3.1.jar

function

Provides extra functionality for Java Number classes.

源码介绍

字符串转化成int

/** * 
Convert a String to an int,  * returning zero if the conversion fails.
 * * 
If the string is null, zero is  * returned.
 * 
 *   NumberUtils.toInt(null) = 0 *   NumberUtils.toInt("")   = 0 *   NumberUtils.toInt("1")  = 1 * 
 * @since 2.1 */public static int toInt(String str) {    return toInt(str, 0);}/** * 
Convert a String to an int,  * returning a default value if the conversion fails.
 * * 
If the string is null, the default value is  * returned.
 * 
 *   NumberUtils.toInt(null, 1) = 1 *   NumberUtils.toInt("", 1)   = 1 *   NumberUtils.toInt("1", 0)  = 1 * 
 * @since 2.1 */public static int toInt(String str, int defaultValue) {    if(str == null) {        return defaultValue;    }    try {        return Integer.parseInt(str);    } catch (NumberFormatException nfe) {        return defaultValue;    }}

字符串转化成long

public static long toLong(String str) {    return toLong(str, 0L);}public static long toLong(String str, long defaultValue) {    if (str == null) {        return defaultValue;    }    try {        return Long.parseLong(str);    } catch (NumberFormatException nfe) {        return defaultValue;    }}

类似的还有toFloat、toDouble、toByte、toShort

字符串转成Integer

public static Integer createInteger(String str) {    if (str == null) {        return null;    }    // decode() handles 0xAABD and 0777 (hex and octal) as well.    return Integer.decode(str);}

Min in array

/**     * 
Returns the minimum value in an array.
     *      */public static long min(long[] array) {    // Validates input    if (array == null) {        throw new IllegalArgumentException("The Array must not be          null");    } else if (array.length == 0) {        throw new IllegalArgumentException("Array cannot be         empty.");    }    // Finds and returns min    long min = array[0];    for (int i = 1; i < array.length; i++) {        if (array[i] < min) {            min = array[i];        }    }    return min;}

Max in array

/** * 
Returns the maximum value in an array.
 */public static long max(long[] array) {    // Validates input    if (array == null) {        throw new IllegalArgumentException("The Array must not be null");    } else if (array.length == 0) {        throw new IllegalArgumentException("Array cannot be empty.");    }    // Finds and returns max    long max = array[0];    for (int j = 1; j < array.length; j++) {        if (array[j] > max) {            max = array[j];        }    }    return max;}

Gets the maximum of three int

public static int max(int a, int b, int c) {    if (b > a) {        a = b;    }    if (c > a) {        a = c;    }    return a;}

Gets the minimum of three int

public static int min(int a, int b, int c) {    if (b < a) {        a = b;    }    if (c < a) {        a = c;    }    return a;}

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