的值时我知道MySQLSyntaxErrorException错误中已经有无数条目了,但是我还没有阅读任何已解决我的问题的帖子,而且我真的可以使用额外的一组眼睛尝试指出我出错的地方。MySQLSyntaxErrorException尝试插入包含'
我正在创建一个简单的网络抓取工具,它将维基百科页面上列出的啤酒厂名称存储在使用WAMP本地存储的基本MySQL表格中。我现有的代码似乎正常工作,直到我遇到名称中包含''的啤酒厂名称。这也是我第一次使用JSoup进行HTML解析。
这里是我当前的代码:
import java.io.IOException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
public class Main {
public static DB db = new DB();
public static void main(String[] args) throws SQLException, IOException {
db.runSql2("TRUNCATE Brewery;");
processPage("myBrew");
System.out.println("done parsing");
}
// recursive method to find brewery names by adding db entry for all <li><a>
// values on site. Might not need recursion for this.
public static void processPage(String bName) throws SQLException,
IOException {
// check if the given URL is already in database
String sql = "select * from Brewery where name = '" + bName + "'";
ResultSet rs = db.runSql(sql);
if (rs.next()) {
// do nothing because already exists
} else {
// store the brewery to database to avoid parsing again
sql = "INSERT INTO `Crawler`.`Brewery` " + "(`name`) VALUES "
+ "(?);";
PreparedStatement stmt = db.conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
stmt.setString(1, bName);
//stmt.execute();
stmt.executeUpdate();
// get useful information
//research this further to better understand what it's doing
Document doc = Jsoup.connect("https://en.wikipedia.org/wiki/List_of_microbreweries").get();
//case-senstive
if (doc.text().contains("Brewery")) {
System.out.println(bName);
}
// get all links and recursively call the processPage method
Elements breweries = doc.select("a[href]");
for (Element link : breweries) {
//System.out.println("element class: " + link.nodeName());
//System.out.println("parent class: " + link.parent().nodeName());
System.out.println("element title: " + link.attr("title"));
//assumes that all brewery names will be listed in <li><a> html format
if (link.nodeName() == "a" && link.parent().nodeName() == "li") {
System.out.println("recursive call tripped");
String tmp = link.attr("title");
//String first = tmp.charAt(0) + "";
if(tmp.contains("'")){
String brew = tmp.replaceAll("'", "\\\'");
/*System.out.println("new string: '" + brew +"'");
processPage("'" + brew + "'");*/
System.out.println("new string: " + brew);
processPage(brew);
}
else {
if (tmp.contains(" (page does not exist)")) {
String brew = tmp.replaceAll(" (page does not exist)", "");
System.out.println("shortened string: " + brew);
processPage(brew);
}
else {
//no ' exists in the name
processPage(tmp);
}
}
}
}
}
}
}
当使用这种语法,我得到以下错误:
Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 's All Natural Brewing Company'' at line 1
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:939)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2547)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2505)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1370)
at DB.runSql(DB.java:26)
at Main.processPage(Main.java:57)
at Main.processPage(Main.java:95)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.main(Main.java:17)
有了这个代码,包含啤酒厂的名字“是没有得到存储在我的MySQL表。但是,如果我替换下面的行
String brew = tmp.replaceAll("'", "\\\'");
与
String brew = tmp.replaceAll("'", "\\\\'");
然后啤酒厂的名字被打存储到我的MySQL表,我得到以下错误的下一个啤酒厂的名字被刮掉前:
Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry 'Beau\'s All Natural Brewing Company' for key 'brewery_name'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:932)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2551)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2073)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2009)
at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5094)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1994)
at Main.processPage(Main.java:67)
at Main.processPage(Main.java:95)
at Main.processPage(Main.java:95)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:101)
at Main.processPage(Main.java:105)
at Main.processPage(Main.java:105)
at Main.main(Main.java:17)
使用
String brew = tmp.replaceAll("'", "''");
而不是
String brew = tmp.replaceAll("'", "\\\\'");
导致同样的问题。从我的DB类
我runSql方法:
public ResultSet runSql(String sql) throws SQLException {
Statement sta = conn.createStatement();
return sta.executeQuery(sql);
}
如果任何人有任何想法,请让我知道。我花了几个小时尝试不同的转义字符等,但我找不到解决这个问题的任何东西。另一双眼睛看着我的代码可能只是我需要的东西。在此先感谢您的帮助。
编辑: 我目前不使用Spring或Hibernate。
感谢@Andreas,我能够解决这个问题。如果有人遇到类似的问题,我改变了String sql =“select * from Brewery where name ='”+ bName +“'”; \t \t ResultSet rs = db.runSql(sql); to String sql =“select * from Brewery where name =?;”; \t \t PreparedStatement ps = db.conn.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS); \t \t ps.setString(1,bName); \t \t ResultSet rs = ps.executeQuery(); – jeffkempf
去除'prepareStatement()'的第二个参数。 'RETURN_GENERATED_KEYS'只能用于自动生成主键的'INSERT'语句,例如, 'IDENTITY','SERIAL','AUTO_INCREMENT','SEQUENCE',... – Andreas
@Andreas驱动程序应该忽略选择语句的Statement.RETURN_GENERATED_KEYS(如:它应该可以正常工作)。 –