Java - 将记录插入数据库时​​，executebatch 不起作用

Question

在从文件中提取单词并将它们存储在哈希集中后，我试图将记录插入到我在 MYSQL 中的表中。

我尝试在获得 500 条记录后使用 executeBatch() 插入我的数据库，但是当执行完成时，我检查了我的表，根本没有插入任何记录。

注意:当我使用 ExecuteUpdate() 时，记录将显示在我的表中。但不是 ExecuteBatch() 因为我想批量插入，而不是一个一个地插入。我可以知道我做错了什么吗？

代码:

public void readDataBase(String path,String word) throws Exception {
        try {

            // Result set get the result of the SQL query

            int i=0;
            // This will load the MySQL driver, each DB has its own driver
            Class.forName("com.mysql.jdbc.Driver");
            // Setup the connection with the DB
            connect = DriverManager
                    .getConnection("jdbc:mysql://126.32.3.20/fulltext_ltat?"
                            + "user=root&password=root");

            // Statements allow to issue SQL queries to the database
          //  statement = connect.createStatement();
            System.out.print("Connected");
            // Result set get the result of the SQL query

            preparedStatement = connect
                    .prepareStatement("insert IGNORE into  fulltext_ltat.indextable values (default,?, ?) ");

            preparedStatement.setString(  1, path);
            preparedStatement.setString(2, word);
            preparedStatement.addBatch();
            i++;
           // preparedStatement.executeUpdate();

            if(i%500==0){
                preparedStatement.executeBatch();

            }




         preparedStatement.close();



            //  writeResultSet(resultSet);
        } catch (Exception e) {
            throw e;
        } finally {
            close();
        }

    }

这是我调用该方法的循环(words 只是一个包含要插入到表中的单词的数组):

 for(int i = 1 ; i <= words.length - 1 ; i++ ) {

                    connection.readDataBase(path, words[i].toString());

                }

我的主要方法:

public static void main(String[] args) throws Exception {

        StopWatch stopwatch = new StopWatch();
        stopwatch.start();



        File folder = new File("D:\\PDF1");
        File[] listOfFiles = folder.listFiles();

        for (File file : listOfFiles) {
            if (file.isFile()) {
                HashSet<String> uniqueWords = new HashSet<>();
                String path = "D:\\PDF1\\" + file.getName();
                try (PDDocument document = PDDocument.load(new File(path))) {

                    if (!document.isEncrypted()) {

                        PDFTextStripper tStripper = new PDFTextStripper();
                        String pdfFileInText = tStripper.getText(document);
                        String lines[] = pdfFileInText.split("\\r?\\n");
                        for (String line : lines) {
                            String[] words = line.split(" ");

                            for (String word : words) {
                                uniqueWords.add(word)
                                ;

                            }

                        }
                        // System.out.println(uniqueWords);

                    }
                } catch (IOException e) {
                    System.err.println("Exception while trying to read pdf document - " + e);
                }
                Object[] words = uniqueWords.toArray();



                MysqlAccessIndex connection = new MysqlAccessIndex();

                for(int i = 1 ; i <= words.length - 1 ; i++ ) {

                    connection.readDataBase(path, words[i].toString());

                }

                System.out.println("Completed");

            }
        }

Answer 1

您执行批量更新的模式已关闭。您应该只打开连接并准备语句一次。然后，迭代多次，绑定(bind)参数，并将该语句添加到批处理中。

// define a collection of paths and words somewhere
List<String> paths = new ArrayList<>();
List<String> words = new ArrayList<>();

try {
    // presumably you only want to insert so many records
    int LIMIT = 10000;
    Class.forName("com.mysql.jdbc.Driver");
    connect = DriverManager
            .getConnection("jdbc:mysql://126.32.3.20/fulltext_ltat?"
                + "user=root&password=root");

    String sql = "INSERT IGNORE INTO fulltext_ltat.indextable VALUES (default, ?, ?);";
    preparedStatement = connect.prepareStatement(sql);

    for (int i=0; i < LIMIT; ++i) {
        preparedStatement.setString(1, paths.get(i));
        preparedStatement.setString(2, word.get(i));
        preparedStatement.addBatch();
        if (i % 500 == 0) {
            preparedStatement.executeBatch();
        }
    }

    // execute remaining batches
    preparedStatement.executeBatch();
}
catch (SQLException e) {
    e.printStackTrace();
}
finally {
    try {
        preparedStatement.close();
        connect.close();
    }
    catch (SQLException e) {
        e.printStackTrace();
    }
}

我在这里所做的一个关键更改是添加了何时应该停止插入的逻辑。目前，您的代码看起来有一个无限循环，这意味着它将永远运行。这可能不是您打算做的。