SQL注入防御的方法有哪些

public static boolean sql_inj(String str){

String inj_str = "'|and|exec|insert|select|delete|update|

count|*|%|chr|mid|master|truncate|char|declare|;|or|-|+|,";

String inj_stra[] = split(inj_str,"|");

for (int i=0 ; i < inj_stra.length ; i++ ){

if (str.indexOf(inj_stra[i])>=0){

return true;

}

}

return false;

}