java防止SQL注入的几个途径
- 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 sql
- 5 * @return
- 6 */
- 7 public static String TransactSQLInjection(String sql) {
- 8 return sql.replaceAll(".*([;]+|(--)+).*", " ");
- 9 }