验证用户名是否正确
2018-08-19 本文已影响0人
神坛下的我
StringUtil.java
public class StringUtil {
public StringUtil(){}
private String str;//要判断的字符串
private boolean valid;//是否有效
private String cue;//提示信息
public String getStr() {
return str;
}
public void setStr(String str) {
this.str = str;
}
public boolean isValid() {
char cArr[]=str.toCharArray();
int firstChar=(int)cArr[0];//第一个字符的ASCII码
StringBuffer sb=new StringBuffer("");
/*判断首字母是否为字母*/
if((firstChar>=65&&firstChar<=90)||(firstChar>=97&&firstChar<=122)){
for (int i = 1; i < cArr.length; i++) {
int ascii = cArr[i];
/*判断字符是否为字母，数字或下划线*/
if ((ascii>=48&&ascii<=57)||(ascii>=65&&ascii<=90)||(ascii>=97&&ascii<=122)||(ascii==95)) {
sb.append(cArr[i]);
}
}
int length=cArr.length-sb.toString().length();
if(length==1){
/*如果被判断字符串的长度与sb字符串的长度差1*/
this.setCue("用户名格式正确！");
valid=true;
return valid;
}else {
this.setCue("用户名格式错误，只能由字母，下划线，数字组成！");
valid=false;
return valid;
}
}else {
this.setCue("首字符必须为字母！");
valid=false;
return valid;
}
}
public void setValid(boolean valid) {
this.valid = valid;
}
public String getCue() {
return cue;
}
public void setCue(String cue) {
this.cue = cue;
}
}
index.jsp
<body>
<form action="result.jsp" method="post">
<table>
<tr>
<td align="right">请输入用户名：</td>
<td><input type="text" name="name" /><font>只能由字母，数字，下划线组成</font></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="验证"/></td>
</tr>
</table>
</form>
</body>
result.jsp
<body>
<%
request.setCharacterEncoding("utf-8");
String name= request.getParameter("name");
%>
<jsp:useBean id="strBean" class="com.count.StringUtil"></jsp:useBean>
<jsp:setProperty property="str" name="strBean" value="<%=name %>"/>
<table>
<tr>
<td>输入的用户名是：</td>
<td align="left">
<jsp:getProperty property="str" name="strBean"/>
</td>
</tr>
<tr>
<td>是否有效：</td>
<td align="center">
<jsp:getProperty property="valid" name="strBean"/>
</td>
</tr>
<tr>
<td>提示信息：</td>
<td align="right">
<jsp:getProperty property="cue" name="strBean"/>
</td>
</tr>
</table>
</body>
10.PNG
