JAVA JDBC

List<Student> students = new ArrayList<>();
//加try 是为了释放链接
try( Connection  conn = DriverManager.getConnection(jdbcUrl,jdbcUname,jdbcPwd)) {
try( PreparedStatement ps = conn.preparedStatement("select * from table where field=? and field2 >= ?)) {
ps.setInt(1,9);
ps.setInt(2,90);
try ( ResultSet  rs = ps.executeQuery() ) {//相当于 select * from table where field = 9 and field2 >= 90;
while( rs.next()) {
students.add(extractRow(rs));
}
}
}
}
return students;

try (Connection conn = DriverManager.getConnection(JDBC_URL, JDBC_USER, JDBC_PASSWORD)) {
    try (PreparedStatement ps = conn.prepareStatement(
            "INSERT INTO students (grade, name, gender) VALUES (?,?,?)",
            Statement.RETURN_GENERATED_KEYS)) {
      ps.setObject(1, 1); // grade
        ps.setObject(2, "Bob"); // name
        ps.setObject(3, "M"); // gender
        int n = ps.executeUpdate(); // 1
      
              try (ResultSet rs = ps.getGeneratedKeys()) {
            if (rs.next()) {
                long id = rs.getLong(1); // 注意：索引从1开始
            }
        }
    }
}
   

try (PreparedStatement ps = conn.prepareStatement("INSERT INTO students (name, gender, grade, score) VALUES (?, ?, ?, ?)")) {
    // 对同一个PreparedStatement反复设置参数并调用addBatch():
    for (Student s : students) {
        ps.setString(1, s.name);
        ps.setBoolean(2, s.gender);
        ps.setInt(3, s.grade);
        ps.setInt(4, s.score);
        ps.addBatch(); // 添加到batch
    }
    // 执行batch:
    int[] ns = ps.executeBatch();
    for (int n : ns) {
        System.out.println(n + " inserted."); // batch中每个SQL执行的结果数量
    }
}