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这是我的代码。问题是它根据循环中的行数插入数据库，而不是只插入一次。如代码所示，它从文件中获取行数，并尝试提取一些信息以存储在数据库中。例如，如果该行有 5 行，则它将该信息在数据库中存储 5 次。

import java.io.File;
import java.io.IOException;
import java.sql.*;
import java.util.List;
import org.apache.commons.io.FileUtils;

public class Movie_Info {

    private static String user = "root";
    private static String pw = "";
    private static String dbUrl = "jdbc:mysql://127.0.0.1/NLD";
    private static String dbClass = "com.mysql.jdbc.Driver";

    public static String scraped_commentsInsert 
        = "INSERT INTO scraped_comments (id, movie_title,user_comments) VALUES (?,?,?)";

    private Connection con;
    private Statement st;
    private PreparedStatement multiInsert; 

    public Movie_Info(String id, String movie) throws IOException, SQLException{

        try {
            Class.forName(dbClass);
            con = DriverManager.getConnection(dbUrl, user, pw);
            //con.setAutoCommit(false);
            st=con.createStatement();
        } catch (Exception e) {
            System.out.println(e.getMessage());
            return;
        }

        List lines = null;

        try{
            lines = FileUtils.readLines(new File(movie+"_S1.txt"), "UTF-8");
        } catch(Exception ex) {
            System.out.println("movie file does not exist: " + movie + " id: " + id);
            return;
        }


        for (Object line : lines) {
            String Synopsis = line.toString();
            String Released = line.toString();
            String Runtime = line.toString();
            String Genre = line.toString();
            String Director = line.toString();
            String Actors = line.toString();

            if (String.valueOf(line).startsWith("Synopsis ") ) {
                // for quotes
                Synopsis = Synopsis.replace(":", " storyline goes like this. ");
                Synopsis = Synopsis.replace("'", "  ");
                // remove comment
                Synopsis = Synopsis.replace("Synopsis  ", "");
                System.out.println(Synopsis);
            }

            if ( String.valueOf(line).startsWith("Released: ") ) {
                Released = Released.replace("'", "''");
                Released = Released.replace("Released:  ", "");
                System.out.println(Released);
            }

            if (String.valueOf(line).startsWith("Runtime: ")) { 
                Runtime = Runtime.replace("'", "''");
                Runtime = Runtime.replace("Runtime:  ", "");
                System.out.println(Runtime);
            }

            if (String.valueOf(line).startsWith("Genres: ") ) { 
                Genre = Genre.replace("'", "''");
                Genre = Genre.replace("Genre:  ", "");
                System.out.println(Genre);
            }

            if (String.valueOf(line).startsWith("Director: ") ) { 
                Director = Director.replace("'", "''");
                Director = Director.replace("Director:  ", "");
                System.out.println(Director);
            }

            if (String.valueOf(line).startsWith("Actors: ") ) { 
                Actors = Actors.replace("'", " ");
                Actors = Actors.replace("Actors:  ", "");
                System.out.println(Actors);
            } // end if

            // int k= st.executeUpdate("INSERT INTO Movie_Infor ( Release_Date,movie_title,Synopsis, Runtime, Genres, Director, Actors) values('"+Released+"','"+movie+"','"+Synopsis+"','"+Runtime+"','"+Genre+"','"+Director+"','"+Actors+"')");
        } // end for

        con.close();
    }
}
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1 回答 1

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首先，请尝试发布一个简洁的代码示例......整个课程真的没有必要。

问题在于您的 for 循环：

for (Object line : lines) {
    String Synopsis = line.toString();
    String Released = line.toString();
    String Runtime = line.toString();
    String Genre = line.toString();
    String Director = line.toString();
    String Actors = line.toString();
    ...
}

在这里，您将同一行的字符串值分配给每个变量 Synopsis、Release 等。由于您似乎是从文件中读取这些行，因此不知道您的数据是什么样的——例如。字符串是什么line样子的——我无法建议一种从中提取您想要的信息的方法。

您将同一事物多次插入数据库的原因是因为这一行：

st.executeUpdate("INSERT INTO Movie_Infor ( Release_Date,movie_title,Synopsis, Runtime, Genres, Director, Actors) values('"+Released+"','"+movie+"','"+Synopsis+"','"+Runtime+"','"+Genre+"','"+Director+"','"+Actors+"')");

包含在您的 for 循环中。（我假设你在你的真实程序中没有注释掉它；如果它实际上被注释掉了，那么我不知道任何东西是如何插入你的数据库的。）无论如何，如果你把这条线移出的for循环，那么你应该只插入一次。

最后，根据 Java 编码风格约定，您应该以小写字母开头命名变量。所以不是 a String Synopsis，你应该有String synopsis，等等。

于 2012-07-05T01:53:33.250 回答