String格式化工具类-StringFormatUtil

============================================================================String格式化工具类：

import java.util.Arrays;

public class StringFormatUtil {
    
    /**
     * 打印异常信息 等同于 exception.printStackTrace();
     * @param exception
     * @return
     */
    public static synchronized String getStackTrace(Exception exception) {
        StringBuffer sb = new StringBuffer();
        sb.append(exception.getClass()).append(": ");
        sb.append(exception.getMessage());
        sb.append("\r\n");
        for (StackTraceElement stackTraceElement : exception.getStackTrace()) {
            sb.append("        ");
            sb.append(stackTraceElement.toString());
            sb.append("\r\n");
        }
        return sb.toString();
    }
    
    /**  驼峰命名法工具 
     * @return
     *         camelCase("hello_world") == "helloWorld" 
     *         capCamelCase("hello_world") == "HelloWorld"
     *         uncamelCase("helloWorld") = "hello_world"
     */
    public static String camelCase(String s) {
        if (s == null) {
            return null;
        }
        s = s.toLowerCase();
        StringBuilder sb = new StringBuilder(s.length());
        boolean upperCase = false;
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '_') {
                upperCase = true;
            } else if (upperCase) {
                sb.append(Character.toUpperCase(c));
                upperCase = false;
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }
 
    /** 驼峰命名法工具
     * @return
     *         camelCase("hello_world") == "helloWorld" 
     *         capCamelCase("hello_world") == "HelloWorld"
     *         uncamelCase("helloWorld") = "hello_world"
     */
    public static String capCamelCase(String s) {
        if (s == null) {
            return null;
        }
        s = camelCase(s);
        return s.substring(0, 1).toUpperCase() + s.substring(1);
    }
    
    /**  驼峰命名法工具
     * @return
     *         camelCase("hello_world") == "helloWorld" 
     *         capCamelCase("hello_world") == "HelloWorld"
     *         uncamelCase("helloWorld") = "hello_world"
     */
    public static String uncamelCase(String s) {
        if (s == null) {
            return null;
        }
        StringBuilder sb = new StringBuilder();
        boolean upperCase = false;
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            boolean nextUpperCase = true;
            if (i < (s.length() - 1)) {
                nextUpperCase = Character.isUpperCase(s.charAt(i + 1));
            }
            if ((i > 0) && Character.isUpperCase(c)) {
                if (!upperCase || !nextUpperCase) {
                    sb.append('_');
                }
                upperCase = true;
            } else {
                upperCase = false;
            }
 
            sb.append(Character.toLowerCase(c));
        }
        return sb.toString();
    }
    
    /**  字符串右补空格
     * @see 该方法默认采用空格(其ASCII码为32)来右补字符
     */
    public static String rightPadForBlank(String str, int size){
        return rightPadForByte(str, size, 32);
    }
    /** 字符串右补0
     * @param str
     * @param size
     */
    public static String rightPadForZero(String str, int size){
        return rightPadForByte(str, size, 48);
    }
    
    /** 字符串右补字符
     * @see 若str对应的byte[]长度不小于size,则按照size截取str对应的byte[],而非原样返回str
     * @see 若对普通字符串进行右补字符,建议org.apache.commons.lang.StringUtils.rightPad(...)
     * @param size
     * @param padStrByASCII 该值为所补字符的ASCII码,如
     *         32表示空格,
     *         48表示0,
     *         64表示@等
     */
    public static String rightPadForByte(String str, int size, int padStrByASCII){
        byte[] srcByte = str.getBytes();
        byte[] destByte = null;
        if(srcByte.length >= size){
            //由于size不大于原数组长度,故该方法此时会按照size自动截取,它会在数组右侧填充'(byte)0'以使其具有指定的长度
            destByte = Arrays.copyOf(srcByte, size);
        }else{
            destByte = Arrays.copyOf(srcByte, size);
            Arrays.fill(destByte, srcByte.length, size, (byte)padStrByASCII);
        }
        return new String(destByte);
    }
    
    
    /** 字符串左补空格
     * @see 该方法默认采用空格(其ASCII码为32)来左补字符
     */
    public static String leftPadForBlank(String str, int size){
        return leftPadForByte(str, size, 32);
    }
    /** 字符串左补0
     * @param str
     * @param size
     * @return
     */
    public static String leftPadForZero(String str, int size){
        return leftPadForByte(str, size, 48);
    }
    
    /** 字符串左补字符
     * @see 若str对应的byte[]长度不小于size,则按照size截取str对应的byte[],而非原样返回str
     * @param padStrByASCII 该值为所补字符的ASCII码,如
     *     32表示空格,
     *     48表示0,
     *     64表示@等
     */
    public static String leftPadForByte(String str, int size, int padStrByASCII){
        byte[] srcByte = str.getBytes();
        byte[] destByte = new byte[size];
        Arrays.fill(destByte, (byte)padStrByASCII);
        if(srcByte.length >= size){
            System.arraycopy(srcByte, 0, destByte, 0, size);
        }else{
            System.arraycopy(srcByte, 0, destByte, size-srcByte.length, srcByte.length);
        }
        return new String(destByte);
    }
}

============================================================================String格式化工具测试类：

    /**
     * 打印异常信息
     */
    @Test
    public void test_getStackTrace() {
        Exception exception = new Exception("空指针异常");
        System.out.println(StringFormatUtil.getStackTrace(exception));
    }
    
    /**
     * 驼峰式命名工具
     */
    @Test
    public void test_camelCase() {
        System.out.println(StringFormatUtil.camelCase("hello_world"));
        System.out.println(StringFormatUtil.capCamelCase("hello_world"));
        System.out.println(StringFormatUtil.uncamelCase("helloWorld"));
    }
    
    
    /** 字符串填充 */
    @Test
    public void test_PadForBlank() {
        String leftPadForBlank = StringFormatUtil.leftPadForBlank("helloWorld", 10);
        System.out.println(leftPadForBlank);
        String rigthPadForBlank = StringFormatUtil.rightPadForBlank("helloWorld", 10);
        System.out.println(rigthPadForBlank);
    }
    
    /** 字符串填充 */
    @Test
    public void test_PadForZero() {
        String leftPadForZero = StringFormatUtil.leftPadForZero("helloWorld", 10);
        System.out.println(leftPadForZero);
        String rigthPadForZero = StringFormatUtil.rightPadForZero("helloWorld", 10);
        System.out.println(rigthPadForZero);
    }