PreparedStatement\u7684\u7528\u6cd5
\njdbc(java database connectivity\uff0cjava\u6570\u636e\u5e93\u8fde\u63a5)\u7684api\u4e2d\u7684\u4e3b\u8981\u7684\u56db\u4e2a\u7c7b\u4e4b\u4e00\u7684java.sql.statement\u8981\u6c42\u5f00\u53d1\u8005\u4ed8\u51fa\u5927\u91cf\u7684\u65f6\u95f4\u548c\u7cbe\u529b\u3002\u5728\u4f7f\u7528statement\u83b7\u53d6jdbc\u8bbf\u95ee\u65f6\u6240\u5177\u6709\u7684\u4e00\u4e2a\u5171\u901a\u7684\u95ee\u9898\u662f\u8f93\u5165\u9002\u5f53\u683c\u5f0f\u7684\u65e5\u671f\u548c\u65f6\u95f4\u6233\uff1a2002-02-05 20:56 \u6216\u8005 02\/05\/02 8:56 pm\u3002
\n\u901a\u8fc7\u4f7f\u7528java.sql.preparedstatement\uff0c\u8fd9\u4e2a\u95ee\u9898\u53ef\u4ee5\u81ea\u52a8\u89e3\u51b3\u3002\u4e00\u4e2apreparedstatement\u662f\u4ecejava.sql.connection\u5bf9\u8c61\u548c\u6240\u63d0\u4f9b\u7684sql\u5b57\u7b26\u4e32\u5f97\u5230\u7684\uff0csql\u5b57\u7b26\u4e32\u4e2d\u5305\u542b\u95ee\u53f7\uff08?\uff09\uff0c\u8fd9\u4e9b\u95ee\u53f7\u6807\u660e\u53d8\u91cf\u7684\u4f4d\u7f6e\uff0c\u7136\u540e\u63d0\u4f9b\u53d8\u91cf\u7684\u503c\uff0c\u6700\u540e\u6267\u884c\u8bed\u53e5\uff0c\u4f8b\u5982\uff1a<\/p>\n
stringsql = \"select * from people p where p.id = ? and p.name = ?\";\npreparedstatement ps = connection.preparestatement(sql);\nps.setint(1,id);\nps.setstring(2,name);\nresultset rs = ps.executequery(); \n<\/code><\/pre>\n\u4f7f\u7528preparedstatement\u7684\u53e6\u4e00\u4e2a\u4f18\u70b9\u662f\u5b57\u7b26\u4e32\u4e0d\u662f\u52a8\u6001\u521b\u5efa\u7684\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u52a8\u6001\u521b\u5efa\u5b57\u7b26\u4e32\u7684\u4f8b\u5b50\uff1a<\/p>\n
stringsql = \"select * from people p where p.i = \"+id; \n<\/code><\/pre>\n\u8fd9\u5141\u8bb8jvm\uff08javavirtual machine\uff0cjava\u865a\u62df\u673a\uff09\u548c\u9a71\u52a8\/\u6570\u636e\u5e93\u7f13\u5b58\u8bed\u53e5\u548c\u5b57\u7b26\u4e32\u5e76\u63d0\u9ad8\u6027\u80fd\u3002
\npreparedstatement\u4e5f\u63d0\u4f9b\u6570\u636e\u5e93\u65e0\u5173\u6027\u3002\u5f53\u663e\u793a\u58f0\u660e\u7684sql\u8d8a\u5c11\uff0c\u90a3\u4e48\u6f5c\u5728\u7684sql\u8bed\u53e5\u7684\u6570\u636e\u5e93\u4f9d\u8d56\u6027\u5c31\u8d8a\u5c0f\u3002
\n\u7531\u4e8epreparedstatement\u5177\u5907\u5f88\u591a\u4f18\u70b9\uff0c\u5f00\u53d1\u8005\u53ef\u80fd\u901a\u5e38\u90fd\u4f7f\u7528\u5b83\uff0c\u53ea\u6709\u5728\u5b8c\u5168\u662f\u56e0\u4e3a\u6027\u80fd\u539f\u56e0\u6216\u8005\u662f\u5728\u4e00\u884csql\u8bed\u53e5\u4e2d\u6ca1\u6709\u53d8\u91cf\u7684\u65f6\u5019\u624d\u4f7f\u7528\u901a\u5e38\u7684statement\u3002
\n\u4e00\u4e2a\u5b8c\u6574\u7684preparedstatement\u7684\u4f8b\u5b50\uff1a<\/p>\n
package jstarproject;\nimport java.sql.*;\npublic class mypreparedstatement {\nprivate final string db_driver=\"com.microsoft.jdbc.sqlserver.sqlserverdriver\";\nprivate final string url = \"jdbc:microsoft:sqlserver:\/\/127.0.0.1:1433;databasename=pubs\";\npublic mypreparedstatement() \n{\n}\npublic void query() throws sqlexception{\nconnection conn = this.getconnection();\nstring strsql = \"select emp_id from employee where emp_id = ?\";\npreparedstatement pstmt = conn.preparestatement(strsql);\npstmt.setstring(1,\"pma42628m\");\nresultset rs = pstmt.executequery();\n\nwhile(rs.next()){\nstring fname = rs.getstring(\"emp_id\");\nsystem.out.println(\"the fname is \" + fname);\n}\nrs.close();\npstmt.close();\nconn.close();\n}\nprivate connection getconnection() throws sqlexception{\n\/\/ class.\nconnection conn = null;\ntry {\nclass.forname(db_driver);\nconn = drivermanager.getconnection(url,\"sa\",\"sa\");\n}\ncatch (classnotfoundexception ex) {}\nreturn conn;\n}\n\/\/main\npublic static void main(string[] args) throws sqlexception {\nmypreparedstatement jdbctest1 = new mypreparedstatement();\njdbctest1.query();\n}\n}\n<\/code><\/pre>\n\u4e3a\u4ec0\u4e48\u8981\u59cb\u7ec8\u4f7f\u7528PreparedStatement\u4ee3\u66ffStatement?\u4e3a\u4ec0\u4e48\u8981\u59cb\u7ec8\u4f7f\u7528PreparedStatement\u4ee3\u66ffStatement?<\/p>\n
\u5728JDBC\u5e94\u7528\u4e2d,\u5982\u679c\u4f60\u5df2\u7ecf\u662f\u7a0d\u6709\u6c34\u5e73\u5f00\u53d1\u8005,\u4f60\u5c31\u5e94\u8be5\u59cb\u7ec8\u4ee5PreparedStatement\u4ee3\u66ffStatement.\u4e5f\u5c31\u662f\u8bf4,\u5728\u4efb\u4f55\u65f6\u5019\u90fd\u4e0d\u8981\u4f7f\u7528Statement.
\n\u57fa\u4e8e\u4ee5\u4e0b\u7684\u539f\u56e0:
\n\u4e00.\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u53ef\u7ef4\u62a4\u6027.
\n\u867d\u7136\u7528PreparedStatement\u6765\u4ee3\u66ffStatement\u4f1a\u4f7f\u4ee3\u7801\u591a\u51fa\u51e0\u884c,\u4f46\u8fd9\u6837\u7684\u4ee3\u7801\u65e0\u8bba\u4ece\u53ef\u8bfb\u6027\u8fd8\u662f\u53ef\u7ef4\u62a4\u6027\u4e0a\u6765\u8bf4.\u90fd\u6bd4\u76f4\u63a5\u7528Statement\u7684\u4ee3\u7801\u9ad8\u5f88\u591a\u6863\u6b21:<\/p>\n
stmt.executeUpdate(\"insert into tb_name (col1,col2,col2,col4) values ('\"+var1+\"','\"+var2+\"',\"+var3+\",'\"+var4+\"')\");\n\nperstmt = con.prepareStatement(\"insert into tb_name (col1,col2,col2,col4) values (?,?,?,?)\");\nperstmt.setString(1,var1);\nperstmt.setString(2,var2);\nperstmt.setString(3,var3);\nperstmt.setString(4,var4);\nperstmt.executeUpdate();\n\n<\/code><\/pre>\n\u4e0d\u7528\u6211\u591a\u8bf4,\u5bf9\u4e8e\u7b2c\u4e00\u79cd\u65b9\u6cd5.\u522b\u8bf4\u5176\u4ed6\u4eba\u53bb\u8bfb\u4f60\u7684\u4ee3\u7801,\u5c31\u662f\u4f60\u81ea\u5df1\u8fc7\u4e00\u6bb5\u65f6\u95f4\u518d\u53bb\u8bfb,\u90fd\u4f1a\u89c9\u5f97\u4f24\u5fc3.<\/p>\n
\u4e8c.PreparedStatement\u5c3d\u6700\u5927\u53ef\u80fd\u63d0\u9ad8\u6027\u80fd.
\n\u6bcf\u4e00\u79cd\u6570\u636e\u5e93\u90fd\u4f1a\u5c3d\u6700\u5927\u52aa\u529b\u5bf9\u9884\u7f16\u8bd1\u8bed\u53e5\u63d0\u4f9b\u6700\u5927\u7684\u6027\u80fd\u4f18\u5316.\u56e0\u4e3a\u9884\u7f16\u8bd1\u8bed\u53e5\u6709\u53ef\u80fd\u88ab\u91cd\u590d\u8c03\u7528.\u6240\u4ee5\u8bed\u53e5\u5728\u88abDB\u7684\u7f16\u8bd1\u5668\u7f16\u8bd1\u540e\u7684\u6267\u884c\u4ee3\u7801\u88ab\u7f13\u5b58\u4e0b\u6765,\u90a3\u4e48\u4e0b\u6b21\u8c03\u7528\u65f6\u53ea\u8981\u662f\u76f8\u540c\u7684\u9884\u7f16\u8bd1\u8bed\u53e5\u5c31\u4e0d\u9700\u8981\u7f16\u8bd1,\u53ea\u8981\u5c06\u53c2\u6570\u76f4\u63a5\u4f20\u5165\u7f16\u8bd1\u8fc7\u7684\u8bed\u53e5\u6267\u884c\u4ee3\u7801\u4e2d(\u76f8\u5f53\u4e8e\u4e00\u4e2a\u6db5\u6570)\u5c31\u4f1a\u5f97\u5230\u6267\u884c.\u8fd9\u5e76\u4e0d\u662f\u8bf4\u53ea\u6709\u4e00\u4e2aConnection\u4e2d\u591a\u6b21\u6267\u884c\u7684\u9884\u7f16\u8bd1\u8bed\u53e5\u88ab\u7f13\u5b58,\u800c\u662f\u5bf9\u4e8e\u6574\u4e2aDB\u4e2d,\u53ea\u8981\u9884\u7f16\u8bd1\u7684\u8bed\u53e5\u8bed\u6cd5\u548c\u7f13\u5b58\u4e2d\u5339\u914d.\u90a3\u4e48\u5728\u4efb\u4f55\u65f6\u5019\u5c31\u53ef\u4ee5\u4e0d\u9700\u8981\u518d\u6b21\u7f16\u8bd1\u800c\u53ef\u4ee5\u76f4\u63a5\u6267\u884c.\u800cstatement\u7684\u8bed\u53e5\u4e2d,\u5373\u4f7f\u662f\u76f8\u540c\u4e00\u64cd\u4f5c,\u800c\u7531\u4e8e\u6bcf\u6b21\u64cd\u4f5c\u7684\u6570\u636e\u4e0d\u540c\u6240\u4ee5\u4f7f\u6574\u4e2a\u8bed\u53e5\u76f8\u5339\u914d\u7684\u673a\u4f1a\u6781\u5c0f,\u51e0\u4e4e\u4e0d\u592a\u53ef\u80fd\u5339\u914d.\u6bd4\u5982:<\/p>\n
insert into tb_name (col1,col2) values ('11','22');\ninsert into tb_name (col1,col2) values ('11','23');\n<\/code><\/pre>\n\u5373\u4f7f\u662f\u76f8\u540c\u64cd\u4f5c\u4f46\u56e0\u4e3a\u6570\u636e\u5185\u5bb9\u4e0d\u4e00\u6837,\u6240\u4ee5\u6574\u4e2a\u4e2a\u8bed\u53e5\u672c\u8eab\u4e0d\u80fd\u5339\u914d,\u6ca1\u6709\u7f13\u5b58\u8bed\u53e5\u7684\u610f\u4e49.\u4e8b\u5b9e\u662f\u6ca1\u6709\u6570\u636e\u5e93\u4f1a\u5bf9\u666e\u901a\u8bed\u53e5\u7f16\u8bd1\u540e\u7684\u6267\u884c\u4ee3\u7801\u7f13\u5b58.<\/p>\n
\u5f53\u7136\u5e76\u4e0d\u662f\u6240\u4ee5\u9884\u7f16\u8bd1\u8bed\u53e5\u90fd\u4e00\u5b9a\u4f1a\u88ab\u7f13\u5b58,\u6570\u636e\u5e93\u672c\u8eab\u4f1a\u7528\u4e00\u79cd\u7b56\u7565,\u6bd4\u5982\u4f7f\u7528\u9891\u5ea6\u7b49\u56e0\u7d20\u6765\u51b3\u5b9a\u4ec0\u4e48\u65f6\u5019\u4e0d\u518d\u7f13\u5b58\u5df2\u6709\u7684\u9884\u7f16\u8bd1\u7ed3\u679c.\u4ee5\u4fdd\u5b58\u6709\u66f4\u591a\u7684\u7a7a\u95f4\u5b58\u50a8\u65b0\u7684\u9884\u7f16\u8bd1\u8bed\u53e5.<\/p>\n
\u4e09.\u6700\u91cd\u8981\u7684\u4e00\u70b9\u662f\u6781\u5927\u5730\u63d0\u9ad8\u4e86\u5b89\u5168\u6027.<\/p>\n
\u5373\u4f7f\u5230\u76ee\u524d\u4e3a\u6b62,\u4ecd\u6709\u4e00\u4e9b\u4eba\u8fde\u57fa\u672c\u7684\u6076\u4e49SQL\u8bed\u6cd5\u90fd\u4e0d\u77e5\u9053.<\/p>\n
String sql = \"select * from tb_name where name= '\"+varname+\"' and passwd='\"+varpasswd+\"'\";\n<\/code><\/pre>\n\u5982\u679c\u6211\u4eec\u628a[‘ or ‘1’ = ‘1]\u4f5c\u4e3avarpasswd\u4f20\u5165\u8fdb\u6765.\u7528\u6237\u540d\u968f\u610f,\u770b\u770b\u4f1a\u6210\u4e3a\u4ec0\u4e48?<\/p>\n
select * from tb_name = '\u968f\u610f' and passwd = '' or '1' = '1';\n<\/code><\/pre>\n\u56e0\u4e3a’1’=’1’\u80af\u5b9a\u6210\u7acb,\u6240\u4ee5\u53ef\u4ee5\u4efb\u4f55\u901a\u8fc7\u9a8c\u8bc1.\u66f4\u6709\u751a\u8005:
\n\u628a[‘;drop table tb_name;]\u4f5c\u4e3avarpasswd\u4f20\u5165\u8fdb\u6765,\u5219:<\/p>\n
select * from tb_name = ‘\u968f\u610f’ and passwd = ”;drop table tb_name;\u6709\u4e9b\u6570\u636e\u5e93\u662f\u4e0d\u4f1a\u8ba9\u4f60\u6210\u529f\u7684,\u4f46\u4e5f\u6709\u5f88\u591a\u6570\u636e\u5e93\u5c31\u53ef\u4ee5\u4f7f\u8fd9\u4e9b\u8bed\u53e5\u5f97\u5230\u6267\u884c.<\/p>\n
\u800c\u5982\u679c\u4f60\u4f7f\u7528\u9884\u7f16\u8bd1\u8bed\u53e5.\u4f60\u4f20\u5165\u7684\u4efb\u4f55\u5185\u5bb9\u5c31\u4e0d\u4f1a\u548c\u539f\u6765\u7684\u8bed\u53e5\u53d1\u751f\u4efb\u4f55\u5339\u914d\u7684\u5173\u7cfb.\u53ea\u8981\u5168\u4f7f\u7528\u9884\u7f16\u8bd1\u8bed\u53e5,\u4f60\u5c31\u7528\u4e0d\u7740\u5bf9\u4f20\u5165\u7684\u6570\u636e\u505a\u4efb\u4f55\u8fc7\u8651.\u800c\u5982\u679c\u4f7f\u7528\u666e\u901a\u7684statement,\u6709\u53ef\u80fd\u8981\u5bf9drop,;\u7b49\u505a\u8d39\u5c3d\u5fc3\u673a\u7684\u5224\u65ad\u548c\u8fc7\u8651.<\/p>\n","protected":false},"excerpt":{"rendered":"
PreparedStatement\u7684\u7528\u6cd5 jdbc(java database connectivity\uff0cja […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"aside","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[3],"tags":[10,11],"class_list":["post-85","post","type-post","status-publish","format-aside","hentry","category-tech","tag-preparedstatement","tag-sql","post_format-post-format-aside"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.espandy.com\/index.php?rest_route=\/wp\/v2\/posts\/85","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.espandy.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.espandy.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.espandy.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.espandy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=85"}],"version-history":[{"count":3,"href":"https:\/\/www.espandy.com\/index.php?rest_route=\/wp\/v2\/posts\/85\/revisions"}],"predecessor-version":[{"id":88,"href":"https:\/\/www.espandy.com\/index.php?rest_route=\/wp\/v2\/posts\/85\/revisions\/88"}],"wp:attachment":[{"href":"https:\/\/www.espandy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=85"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.espandy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=85"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.espandy.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=85"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}