两个字符串对比显示差异

public static String getcompareStr(String char1, String char2) {
    String bcolor = "<font color=;'>";
    String ecolor = "</font>";
    StringBuffer sb = new StringBuffer();
    char[] a = new char[char1.length()];
    for (int i = 0; i < char1.length(); i++) {
        a[i] = char1.charAt(i);
    }
    char[] b = new char[char2.length()];
    for (int i = 0; i < char2.length(); i++) {
        b[i] = char2.charAt(i);
    }
    // 不同字符集合
    Map<Object, Object> map1 = new HashMap<Object, Object>();
    // 包含字符集合
    Map<Object, Object> map2 = new HashMap<Object, Object>();
    for (int i = 0; i < a.length; i++) {
        if (i == a.length - 1) {
            if (i > 1) {
                if (String.valueOf(b).contains(String.valueOf(a[i - 1]) + String.valueOf(a[i]))) {
                    map2.put(i - 1, a[i - 1]);
                    map2.put(i, a[i]);
                }else{
                    map1.put(i, a[i]);
                }
            } else {
                map2.put(i, a[i]);
            }
        } else {
            if (String.valueOf(b).contains(String.valueOf(a[i]) + String.valueOf(a[i + 1]))) {
                if (i > 1) {
                    if (String.valueOf(b).contains(String.valueOf(a[i - 1]) + String.valueOf(a[i]))) {
                        map2.put(i - 1, a[i - 1]);
                        map2.put(i, a[i]);
                    }
                } else {
                    map2.put(i, a[i]);
                }
            } else {
                if (i > 0) {
                    if (String.valueOf(b).contains(String.valueOf(a[i - 1]) + String.valueOf(a[i]))) {
                        map2.put(i - 1, a[i - 1]);
                        map2.put(i, a[i]);
                    } else {
                        map1.put(i, a[i]);
                    }
                } else {
                    map1.put(i, a[i]);
                }
            }
        }
    }
    for (int i = 0; i < a.length; i++) {
        if (map1.get(i) != null) {
            sb.append(bcolor).append(map1.get(i)).append(ecolor);
        } else if (map2.get(i) != null) {
            sb.append(map2.get(i));
        }
    }
    return sb.toString();
}


使用中发现如果两个字符串重复出现的字符差异显示不了。存在问题，还是用距离算法才能解决字符串比较找出差异问题。
新方法看下面随笔。
http://www.cnblogs.com/chenjb-0218/p/8086892.html