在jsp中作HTTP认证的方法-JSP教程,Jsp/Servlet-IDC资讯中心

最近研究了jsp中作http认证的问题，它的工作方式如下： 

 

1、server发送一个要求认证代码401和一个头信息www-authenticate，激发browser弹出一个认证窗口 

 

2、server取得browser送来的认证头"authorization",它是加密的了，要用base64方法解密，取得明文的用户名和密码 

 

3、检查用户名和密码，根据结果传送不同的页面 

 

 

以下是jsp的片断，你也可以把它做成include文件。和base64的加解密的class源码。 

如有兴趣可与我联系：unixboy@yeah.net 

 

<jsp:usebean id="base64" scope="page" class="base64"/> 

<% 

if(request.getheader("authorization")==null){ 

   response.setstatus(401); 

   response.setheader("www-authenticate", "basic realm=\"unixboy.com\""); 

}else{ 

   string encoded=(request.getheader("authorization")); 

   string tmp=encoded.substring(6); 

   string up=base64.decode(tmp); 

   string user=""; 

   string password=""; 

   if(up!=null){ 

        user=up.substring(0,up.indexof(":")); 

    password=up.substring(up.indexof(":")+1); 

   } 

   if(user.equals("unixboy")&&password.equals("123456")){ 

        //认证成功 

   }else{ 

        //认证失败 

   } 

} 

%> 

 

 

//消息加解密class 

public class base64 

{ 

        /** decode a base 64 encoded string. 

          * <h4>string to byte conversion</h4> 

          * this method uses a naive string to byte interpretation, it simply gets each 

          * char of the string and calls it a byte. 

          * since we should be dealing with base64 encoded strings that is a reasonable 

          * assumption. 

          * <h4>end of data</h4> 

          * we dont try to stop the converion when we find the "=" end of data padding char. 

          * we simply add zero bytes to the unencode buffer. 

        */ 

        public static string decode(string encoded) 

        { 

                stringbuffer sb=new stringbuffer(); 

                int maxturns; 

                //work out how long to loop for. 

                if(encoded.length()%3==0) 

                maxturns=encoded.length(); 

                else 

                maxturns=encoded.length()+(3-(encoded.length()%3)); 

                //tells us whether to include the char in the unencode 

                boolean skip; 

                //the unencode buffer 

                byte[] unenc=new byte[4]; 

                byte b; 

                for(int i=0,j=0; i<maxturns; i++) 

                { 

                        skip=false; 

                        //get the byte to convert or 0 

                        if(i<encoded.length()) 

                        b=(byte)encoded.charat(i); 

                        else 

                        b=0; 

                        //test and convert first capital letters, lowercase, digits then + and / 

                        if(b>=65 && b<91) 

                        unenc[j]=(byte)(b-65); 

                        else if(b>=97 && b<123) 

                        unenc[j]=(byte)(b-71); 

                        else if(b>=48 && b<58) 

                        unenc[j]=(byte)(b+4); 

                        else if(b==+) 

                        unenc[j]=62; 

                        else if(b==/) 

                        unenc[j]=63; 

                        //if we find "=" then data has finished, were not really dealing with this now 

                        else if(b===) 

                        unenc[j]=0; 

                        else 

                        { 

                                char c=(char)b; 

                                if(c==\n || c==\r || c== || c==\t) 

                                skip=true; 

                                else 

                                //could throw an exception here? its input we dont understand. 

                                ; 

                        } 

                        //once the array has boiled convert the bytes back into chars 

                        if(!skip && ++j==4) 

                        { 

                                //shift the 6 bit bytes into a single 4 octet word 

                                int res=(unenc[0] << 18)+(unenc[1] << 12)+(unenc[2] << 6)+unenc[3]; 

                                byte c; 

                                int k=16; 

                                //shift each octet down to read it as char and add to stringbuffer 

                                while(k>=0) 

                                { 

                                        c=(byte)(res >> k); 

                                        if ( c > 0 ) 

                                        sb.append((char)c); 

                                        k-=8; 

                                } 

                                //reset j and the unencode buffer 

                                j=0; 

                                unenc[0]=0;unenc[1]=0;unenc[2]=0;unenc[3]=0; 

                        } 

                } 

                return sb.tostring(); 

        } 

         

        /** encode plaintext data to a base 64 string 

          * @param plain the text to convert. if plain is longer than 76 characters this method 

          *             returns null (see rfc2045). 

          * @return the encoded text (or null if string was longer than 76 chars). 

        */ 

        public static string encode(string plain) 

        { 

                if(plain.length()>76) 

                return null; 

                int maxturns; 

                stringbuffer sb=new stringbuffer(); 

                //the encode buffer 

                byte[] enc=new byte[3]; 

                boolean end=false; 

                for(int i=0,j=0; !end; i++) 

                { 

                        char _ch=plain.charat(i); 

                        if(i==plain.length()-1) 

                        end=true; 

                        enc[j++]=(byte)plain.charat(i); 

                        if(j==3 || end) 

                        { 

                                int res; 

                                //this is a bit inefficient at the end point 

                                //worth it for the small decrease in code size? 

                                res=(enc[0] << 16)+(enc[1] << 8)+enc[2]; 

                                int b; 

                                int lowestbit=18-(j*6); 

                                for(int toshift=18; toshift>=lowestbit; toshift-=6) 

                                { 

                                        b=res >>> toshift; 

                                        b&=63; 

                                        if(b>=0 && b<26) 

                                        sb.append((char)(b+65)); 

                                        if(b>=26 && b<52) 

                                        sb.append((char)(b+71)); 

                                        if(b>=52 && b<62) 

                                        sb.append((char)(b-4)); 

                                        if(b==62) 

                                        sb.append(+); 

                                        if(b==63) 

                                        sb.append(/); 

                                        if(sb.length()%76==0) 

                                        sb.append(\n); 

                                } 

                                //now set the end chars to be pad character if there 

                                //was less than integral input (ie: less than 24 bits) 

                                if(end) 

                                { 

                                        if(j==1) 

                                        sb.append("=="); 

                                        if(j==2) 

                                        sb.append(=); 

                                } 

                                enc[0]=0; enc[1]=0; enc[2]=0; 

                                j=0; 

                        } 

                } 

                return sb.tostring(); 

        } 

}

在jsp中作HTTP认证的方法-JSP教程,Jsp/Servlet

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