Java JDBC executeBatch

Question

我试图在数据库中执行很多INSERT命令。

try{
    int Records[];
    Statement title = write.getConnection().createStatement();
    Title titleFilter = application.Title.getTitle();
    ResultSet rs = titleFilter.getTitleData();

    while(rs.next()){;
        String add = ("INSERT INTO title VALUES ("
                + "'" + rs.getInt(1) + "'"+","
                + "'" +rs.getString(2)+ "'" +","
                + "'" +rs.getString(3) + "'"+","
                + "'" +rs.getInt(4)+ "'" +","
                + "'" +rs.getInt(5)+ "'" +","
                + "'" +rs.getInt(6) + "'"+","
                + "'" +rs.getString(7)+ "'" +","
                + "'" +rs.getInt(8) + "'"+","
                +"'" + rs.getInt(9)+ "'" +","
                + "'" +rs.getInt(10)+ "'" +","
                + "'" +rs.getString(11)+ "'" +","
                +"'" + rs.getString(12) + "'"+")"
        );
        title.addBatch(add);
        System.out.println(add);
        title.executeBatch();
    }

我知道添加表达式后立即执行批处理有点愚蠢。 我更改它以查找错误。

每次我尝试运行该程序时，此代码部分仅插入六个表达式。 我做了很多事情来发现自己的错误，但我想我永远找不到。 而且我得到这个例外

org.postgresql.util.PSQLException: ERROR: syntax error at or near ")"
  Position: 48
    at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2310)
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2023)
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:217)
    at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:421)
    at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:318)....

Answer 1

首先，您应该使用PreparedStatement ； 这将帮助您避免语法错误（在连接Java String时很难看到）。 其次，您在每个循环中执行批处理，这违反了使用批处理的目的。

这是使用PreparedStatement的示例：

String sql = "INSERT INTO title VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
try (PreparedStatement title = write.getConnection().prepareStatement(sql);
     ResultSet rs = titleFilter.getTitleData()) {

    while (rs.next()) {
        title.setInt(1, rs.getInt(1));
        title.setString(2, rs.getString(2));
        // ... do this for all the parameters ...

        title.addBatch(); // add to batch and move to next loop (if rs.next() returns true)
    }

    title.executeBatch(); // executed after loop

} catch (SQLException ex) {
    ex.printStackTrace(); // or do what you need to when an error occurs
}

此示例还使用try-with-resources 。

编辑：

如Ivan的评论中所述，在每条X记录之后执行批处理可能更好。 我将其代码保留为“读者练习”。