java - 如何在运行选择查询时使用 java 并发

Question

我有三个查询要运行，所有查询都类似于“select * from table”，它们花费了很多时间。 我想使用java并发并行运行所有查询，我如何实现这一点。

Answer 1

您可以将数据库调用包装在 Callable 中，如下所示:

public class SqlTask implements Callable<ResultSet> {

    private String sql;

    public SqlTask(final String sql) {
        this.sql = sql;
    }

    @Override
    public ResultSet call() throws Exception {
        Connection connection = ...; // get connection
        Statement stmt = connection.createStatement();
        return stmt.executeQuery(this.sql);
    }
}

然后使用 ExecutorService 并行执行它们，例如:

    final ExecutorService executor = Executors.newCachedThreadPool();
    final Future<ResultSet> futureResult1 = executor.submit (new SqlTask("SELECT * FROM table1"));
    final Future<ResultSet> futureResult2 = executor.submit(new SqlTask("SELECT * FROM table2"));
    final Future<ResultSet> futureResult3 = executor.submit(new SqlTask("SELECT * FROM table3"));
    final ResultSet result1 = futureResult1.get();
    final ResultSet result2 = futureResult2.get();
    final ResultSet result3 = futureResult3.get();