Java防止SQL注入的几个途径_JAVA_编程开发_程序员俱乐部

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	}