Java基础（一）字符串之如何删除指定的字符

需求说明：

　　在Java中，如何删除字符串中指定位置的字符？

解决方式：

　　在Java中并没有提供一个直接删除字符串中字符的方法，想要删除字符需要自己封装一个方法实现

方法一：通过从前往后循环每一个字符，如果不是要删除的字符进行拼接处理。

package com.de.test;

public class test {
    public static void main(String[] args) {
        String str = "How does Java remove the characters specified in the string?";
        char delChar = 'a';
        System.out.println(deleteString2(str,delChar));
    }

    /**
     * 删除方法一
     * @param str
     * @param delChar
     * @return
     */
    public static String deleteString0(String str, char delChar){
        String delStr = "";
        for (int i = 0; i < str.length(); i++) {
            if(str.charAt(i) != delChar){
                delStr += str.charAt(i);
            }
        }
        return delStr;
    }

    /**
     * 删除方法一
     * @param str
     * @param delChar
     * @return
     */
    public static String deleteString2(String str, char delChar) {
        StringBuffer stringBuffer = new StringBuffer("");
        for (int i = 0; i < str.length(); i++) {
            if (str.charAt(i) != delChar) {
                stringBuffer.append(str.charAt(i));
            }
        }
        return stringBuffer.toString();
    }
}

运行结果：

How does Jv remove the chrcters specified in the string?

方法二：通过采用正则的方式和replaceAll函数，本种方法要注意特殊字符，例如正则中的 “.”字符，需要对特殊字符进行转义

package com.de.test;

public class test {
    public static void main(String[] args) {
        String str = "How does Java remove the characters specified in the string?";
        char delChar = 'i';
        System.out.println(deleteString1(str,delChar));
    }

    /**
     *删除方法二
     * @return
     */
    public static String deleteString1(String str, char delChar){
        String delStr = "";
        final String strTable = "|^$*+?.(){}\\";
        String tmpRegex = "[";
        for (int i = 0; i < strTable.length(); i++) {
            if (strTable.charAt(i) == delChar) {
                tmpRegex += "//";
                break;
            }
        }
        tmpRegex += delChar + "]";
        delStr = str.replaceAll(tmpRegex, "");
        return delStr;
    }
}

运行结果：

How does Java remove the characters specfed n the strng?

 方法三：把原字符串转化为字符数组，然后原理与直接插入排序原理类似

package com.de.test;

public class test {
    public static void main(String[] args) {
        String str = "How does Java remove the characters specified in the string?";
        char delChar = 'e';
        System.out.println(deleteString3(str,delChar));
    }

    /**
     *  删除方法三
     * @param str
     * @param delChar
     * @return
     */
    public static String deleteString3(String str, char delChar) {
        String delStr = "";
        char[] Bytes = str.toCharArray();
        int iSize = Bytes.length;
        for (int i = Bytes.length - 1; i >= 0; i--) {
            if (Bytes[i] == delChar) {
                for (int j = i; j < iSize - 1; j++) {
                    Bytes[j] = Bytes[j + 1];
                }
                iSize--;
            }
        }
        for (int i = 0; i < iSize; i++) {
            delStr += Bytes[i];
        }
        return delStr;
    }
}

运行结果：

How dos Java rmov th charactrs spcifid in th string?

方法四： 通过循环确定要删除字符的位置索引，然后通过分割字符串的形式，将子字符串拼接，注意最后一段子字符串和源字符串中没有要删除字符的情况

package com.de.test;

public class test {
    public static void main(String[] args) {
        String str = "How does Java remove the characters specified in the string?";
        char delChar = 's';
        System.out.println(deleteString4(str,delChar));
    }

    /**
     * 删除方法四
     * @param str
     * @param delChar
     * @return
     */
    public static String deleteString4(String str, char delChar) {
        String delStr = "";
        int iIndex = 0;
        for (int i = 0; i < str.length(); i++) {
            if (str.charAt(i) == delChar) {
                if (i > 0) {
                    delStr += str.substring(iIndex, i);
                }
                iIndex = i + 1;
            }
        }
        if (iIndex <= str.length()) {
            delStr += str.substring(iIndex, str.length());
        }
        return delStr;
    }
}

运行结果：

How doe Java remove the character pecified in the tring?

 总结：上面的方法参考了http://blog.csdn.net/li767517488/article/details/64919194