使用PreparedStatement对象完成记录的条件查询和删除。
SQL/Demo.java

package cn.antraces.SQL;
import java.sql.*;
public class Demo {
/**
 * 查询
 * @param statement
 * @throws SQLException
 */
public static void select (Statement statement) throws SQLException {
    ResultSet resultSet = statement.executeQuery("select * from course");
    while (resultSet.next()) {
        System.out.print(resultSet.getString("cno"));
        System.out.println("\t" + resultSet.getString("cname"));
    }
}

/**
 * 增加
 * @param connection
 * @param statement
 * @return
 * @throws SQLException
 */
public static int insert (Connection connection, Statement statement) throws SQLException {
    PreparedStatement preparedStatement = connection.prepareStatement("insert into course value(?, ?)");
    preparedStatement.setString(1, "a0");
    preparedStatement.setString(2, "我丢");
    return preparedStatement.executeUpdate();
}

/**
 * 修改
 * @param connection
 * @param statement
 * @return
 * @throws SQLException
 */
public static int update (Connection connection, Statement statement) throws SQLException {
    PreparedStatement preparedStatement = connection.prepareStatement("update course set cno=? where cname=?");
    preparedStatement.setString(1, "a00 ");
    preparedStatement.setString(2, "我丢");
    return preparedStatement.executeUpdate();
}

/**
 * 删除
 * @param connection
 * @return
 * @throws SQLException
 */
public static int delete (Connection connection) throws SQLException {
    PreparedStatement preparedStatement = connection.prepareCall("delete from course where cno=?");
    preparedStatement.setString(1, "a00 ");
    return preparedStatement.executeUpdate();
}

/**
 * 条件查询
 * @param connection
 * @return
 * @throws SQLException
 */
public static String select1 (Connection connection) throws SQLException {
    PreparedStatement preparedStatement = connection.prepareStatement("select * from course where cno= ? and cname=?");
    preparedStatement.setString(1, "a00 ");
    preparedStatement.setString(2, "我丢");
    ResultSet resultSet = preparedStatement.executeQuery();
    if (resultSet.next()) {
        System.out.print(resultSet.getString("cno") + " " + resultSet.getString("cname"));
        return "true";
    } else {
        return "false";
    }
}

public static void main (String[] args) throws ClassNotFoundException, SQLException {
    Class.forName("com.mysql.cj.jdbc.Driver");
    Connection connection = DriverManager.getConnection(
            "jdbc:mysql://127.0.0.1:3306/student?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT", "root", "wodiu");

    Statement statement = connection.createStatement();

    select(statement);

    /*
    System.out.println("\ninsert : " + insert(connection, statement));
    select(statement);

    System.out.println("\nupdate : " + update(connection, statement));
    select(statement);
     */

    System.out.println("\nselect1_1 : " + select1(connection));

    System.out.println("\ndelete : " + delete(connection));
    select(statement);

    System.out.println("\nselect1_2 : " + select1(connection));
}

}

在前俩次的基础上增加了delete 和 select1 俩个方法
至此, 本学期的Java课程就到此结束了, 但是学习之路并没有结束