java防SQL注入,最简单的办法是杜绝SQL拼接,SQL注入攻击能得逞是因为在原有SQL语句中加入了新的逻辑，如果使用PreparedStatement来代替Statement来执行SQL语句，其后只是输入参数，SQL注入攻击手段将无效，这是因为PreparedStatement不允许在不同的插入时间改变查询的逻辑结构 ,大部分的SQL注入已经挡住了, 在WEB层我们可以过滤用户的输入来防止SQL注入比如用Filter来过滤全局的表单参数01 import java.io.IOException;02 import java.util.Iterator;03 import javax.servlet.Filter;04 import javax.servlet.FilterChain;05 import javax.servlet.FilterConfig;06 import javax.servlet.ServletException;07 import javax.servlet.ServletRequest;08 import javax.servlet.ServletResponse;09 import javax.servlet.http.HttpServletRequest;10 import javax.servlet.http.HttpServletResponse;11 /**12 * 通过Filter过滤器来防SQL注入攻击13 *
14 */15 public class SQLFilter implements Filter {16 private String inj_str = "\’|and|exec|insert|select|delete|update|count|*|%|chr|mid|master|truncate|char|declare|; |or|-|+|,";17 protected FilterConfig filterConfig = null;18 /**19 * Should a character encoding specified by the client be ignored?20 */21 protected boolean ignore = true;22 public void init(FilterConfig config) throws ServletException {23 this.filterConfig = config;24 this.inj_str = filterConfig.getInitParameter("keywords");25 }26 public void doFilter(ServletRequest request, ServletResponse response,27 FilterChain chain) throws IOException, ServletException {28 HttpServletRequest req = (HttpServletRequest)request;29 HttpServletResponse res = (HttpServletResponse)response;30 Iterator values = req.getParameterMap().values().iterator();//获取所有的表单参数31 while(values.hasNext()){32 String[] value = (String[])values.next();33 for(int i = 0;i < value.length;i++){34 if(sql_inj(value[i])){35 //TODO这里发现sql注入代码的业务逻辑代码36 return;37 }38 }39 }40 chain.doFilter(request, response);41 }42 public boolean sql_inj(String str)43 {44 String[] inj_stra=inj_str.split("\\\\|");45 for (int i=0 ; i < inj_stra.length ; i++ )46 {47 if (str.indexOf(" "+inj_stra[i]+" ")>=0)48 {49 return true;50 }51 }52 return false;53 }54 }也可以单独在需要防范SQL注入的JavaBean的字段上过滤：1 /**2 * 防止sql注入3 *4 * @param sql5 * @return6 */7 public static String TransactSQLInjection(String sql) {8 return sql.replaceAll(".*([\’;]+|(–)+).*", " ");9 }
