如何将这个 Javascript 代码转换为 Java ？

一个 Javascript 代码的函数，其中替换的正则是 JS 语法，如何转换为 Java 语法代码？

function HTML2UBB(str) {
str = str.replace(/\r/g,"");
str = str.replace(/on(load|click|dbclick|mouseover|mousedown|mouseup)="[^"]+"/ig,"");
str = str.replace(/<script[^>]*?>([\w\W]*?)<\/script>/ig,"");
str = str.replace(/<p align=(.*)>(.*?)<\/p>/ig,"[$1]$2[\/$1]");
str = str.replace(/<a[^>]+href="([^"]+)"[^>]*>(.*?)<\/a>/ig,"[url=$1]$2[/url]");

str = str.replace(/<font[^>]+color=([^ >]+)[^>]*>(.*?)<\/font>/ig,"[color=$1]$2[/color]");
str = str.replace(/<img[^>]+src="([^"]+)"[^>]*>/ig,"[img]$1[/img]");

str = str.replace(/ /ig," ");
str = str.replace(/\n/g," ");
str = str.replace(/<\/p>/ig,"\n");
str = str.replace(/<br[^>]*>/ig,"\n");
str = str.replace(/<([\/]?)b>/ig,"[$1b]");
str = str.replace(/<([\/]?)strong>/ig,"[$1b]");
str = str.replace(/<([\/]?)u>/ig,"[$1u]");
str = str.replace(/<([\/]?)i>/ig,"[$1i]");
str = str.replace(/<([\/]?)em>/ig,"[$1i]");
str = str.replace(/<([\/]?)center>/ig,"[$1center]");


str = str.replace(/<([\/]?)pre>/ig, "[$1code]");
str = str.replace(/<([\/]?)blockquote>/ig, "[$1quote]");

//if the text mark as del, just remove it
str = str.replace(/<del[^>]*>.*<\/del>/ig, "");

str = str.replace(/&/g,"&");
str = str.replace(/ +/g," ");
str = str.replace(/\n /g,"\n");
str = str.replace(/ \n/g,"\n");
str = str.replace(/"/g,"\"");
str = str.replace(/</g,"<");
str = str.replace(/>/g,">");

str = str.replace(/<[^>]*?>/g,"");
str = str.replace(/\[url=([^\]]+)\]\n(\[img\]\1\[\/img\])\n\[\/url\]/g,"$2");

return str;
}