// user 添加修改
    public static boolean updateUser(int userID, String username,
            String password, String sex, String email, String qq, String phone) {
        /*
         * update user information
         */
        Connection conn = null;
        boolean flag = false;
        try {
            conn = DB.getConnection();
            PreparedStatement ptmt = conn
                    .prepareStatement("update user "
                            + "set username=?, password=?, sex=?, email=?, qq=?, phone=?"
                            + " where userID=?");
            ptmt.setString(1, username);
            ptmt.setString(2, password);
            ptmt.setString(3, sex);
            ptmt.setString(4, email);
            ptmt.setString(5, qq);
            ptmt.setString(6, phone);
            ptmt.setInt(7, userID);
            ptmt.executeUpdate();
            flag = true;
        } catch (Exception e) {
            flag = false;
            e.printStackTrace();
        } finally {
            DB.closeConnection(conn);
        }
        return flag;
    }
//user删除
    public static boolean deleteUser(int userID) {
        boolean flag = false;
        Connection conn = null;
        try {
            conn = DB.getConnection();
            PreparedStatement ptmt = conn
                    .prepareStatement("delete from user where userID = ?");
            ptmt.setInt(1, userID);
            ptmt.executeUpdate();
            ptmt.close();
            ptmt = conn.prepareStatement("delete from reply where userID = ?");
            ptmt.setInt(1, userID);
            ptmt.executeUpdate();
            ptmt.close();
            ptmt = conn.prepareStatement("delete from user where userID = ?");
            ptmt.setInt(1, userID);
            ptmt.executeUpdate();
            flag = true;
        } catch (Exception e) {
            flag = false;
            e.printStackTrace();
        } finally {
            DB.closeConnection(conn);
        }
        return flag;
    }

------解决方案--------------------
Java code

//DB 类
package com.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DB {

    public static Connection getConnection() {
        Connection conn = null;
        try {
            String driver = "com.mysql.jdbc.Driver";
            String dbURL = "jdbc:mysql://localhost:3306/dbName?useUnicode=true&characterEncoding=UTF-8";
            String username = "root";
            String password = "";

            Class.forName(driver).newInstance();
            conn = DriverManager.getConnection(dbURL, username, password);
        } catch (SQLException e) {
            // TODO: handle exception
            e.printStackTrace();