西宁做网站君博领先,php网站开发打不开,网站建设代码编译的问题及解决方案,云服务器搭建文章目录 一、数据库准备二、导入依赖 与 JDBC工具类三、pojo包处理四、daodao包工具类 五、service六、controllerservlet 基类 反射 七、加密工具类 MD5八、页面文件九、业务代码9.1 注册业务处理9.2 登录业务处理 总结 一、数据库准备 创建数据库#xff1a; SET NAMES … 文章目录 一、数据库准备二、导入依赖 与 JDBC工具类三、pojo包处理四、daodao包工具类 五、service六、controllerservlet 基类 反射 七、加密工具类 MD5八、页面文件九、业务代码9.1 注册业务处理9.2 登录业务处理 总结 一、数据库准备 创建数据库 SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS 0;-- ---------------------------- -- 创建日程表 -- ---------------------------- DROP TABLE IF EXISTS sys_schedule; CREATE TABLE sys_schedule (sid int NOT NULL AUTO_INCREMENT,uid int NULL DEFAULT NULL,title varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,completed int(1) NULL DEFAULT NULL,PRIMARY KEY (sid) USING BTREE ) ENGINE InnoDB AUTO_INCREMENT 1 CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci ROW_FORMAT Dynamic;-- ---------------------------- -- 插入日程数据 -- ------------------------------ ---------------------------- -- 创建用户表 -- ---------------------------- DROP TABLE IF EXISTS sys_user; CREATE TABLE sys_user (uid int NOT NULL AUTO_INCREMENT,username varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,user_pwd varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,PRIMARY KEY (uid) USING BTREE,UNIQUE INDEX username(username) USING BTREE ) ENGINE InnoDB CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci ROW_FORMAT Dynamic;-- ---------------------------- -- 插入用户数据 -- ---------------------------- INSERT INTO sys_user VALUES (1, zhangsan, e10adc3949ba59abbe56e057f20f883e); INSERT INTO sys_user VALUES (2, lisi, e10adc3949ba59abbe56e057f20f883e);SET FOREIGN_KEY_CHECKS 1;二、导入依赖 与 JDBC工具类 使用lombok处理 getter setter equals hashcode 构造器 导入JDBCUtil连接池工具类并准备jdbc.properties配置文件 package com.doug.wake.util;import com.alibaba.druid.pool.DruidDataSourceFactory;import javax.sql.DataSource; import java.io.IOException; import java.io.InputStream; import java.sql.Connection; import java.sql.SQLException; import java.util.Properties;/*** Description: JDBCUtil连接池工具类*/ public class JDBCUtil {private static ThreadLocalConnection threadLocal new ThreadLocal();private static DataSource dataSource;// 初始化连接池static{// 可以帮助我们读取.properties配置文件Properties properties new Properties();InputStream resourceAsStream JDBCUtil.class.getClassLoader().getResourceAsStream(jdbc.properties);try {properties.load(resourceAsStream);} catch (IOException e) {throw new RuntimeException(e);}try {dataSource DruidDataSourceFactory.createDataSource(properties);} catch (Exception e) {throw new RuntimeException(e);}}/*1 向外提供连接池的方法*/public static DataSource getDataSource(){return dataSource;}/*2 向外提供连接的方法*/public static Connection getConnection(){Connection connection threadLocal.get();if (null connection) {try {connection dataSource.getConnection();} catch (SQLException e) {throw new RuntimeException(e);}threadLocal.set(connection);}return connection;}/*定义一个归还连接的方法 (解除和ThreadLocal之间的关联关系) */public static void releaseConnection(){Connection connection threadLocal.get();if (null ! connection) {threadLocal.remove();// 把连接设置回自动提交的连接try {connection.setAutoCommit(true);// 自动归还到连接池connection.close();} catch (SQLException e) {throw new RuntimeException(e);}}} }driverClassNamecom.mysql.cj.jdbc.Driver urljdbc:mysql://localhost:3306/schedule_system usernameroot passwordroot initialSize5 maxActive10 maxWait1000三、pojo包处理 实体类 使用lombok处理getter setter equals hashcode 构造器 implements Serializable : 习惯上要实现序列化接口与缓存、分布式项目数据传递有关 将对象序列化 防止报错 AllArgsConstructor // 全参构造 NoArgsConstructor // 添加无参构造 Data //getter setter equals hashcode toString public class SysUser implements Serializable {private int uid;private String username;private String userPwd; }AllArgsConstructor NoArgsConstructor Data public class SysSchedule {private int sid;private int uid;private String title;private int completed; }四、dao Data access Object 数据访问对象 该类中用于定义针对数据库表格的CRUD的方法 DAO层一般需要定义接口和实现类 dao包工具类 package com.doug.wake.dao;import com.doug.wake.util.JDBCUtil;import java.lang.reflect.Field; import java.sql.*; import java.time.LocalDateTime; import java.util.ArrayList; import java.util.List;/*** Description: Dao工具类*/ public class BaseDao {// 公共的查询方法 返回的是单个对象public T T baseQueryObject(ClassT clazz, String sql, Object ... args) {T t null;Connection connection JDBCUtil.getConnection();PreparedStatement preparedStatement null;ResultSet resultSet null;int rows 0;try {// 准备语句对象preparedStatement connection.prepareStatement(sql);// 设置语句上的参数for (int i 0; i args.length; i) {preparedStatement.setObject(i 1, args[i]);}// 执行 查询resultSet preparedStatement.executeQuery();if (resultSet.next()) {t (T) resultSet.getObject(1);}} catch (Exception e) {e.printStackTrace();} finally {if (null ! resultSet) {try {resultSet.close();} catch (SQLException e) {e.printStackTrace();}}if (null ! preparedStatement) {try {preparedStatement.close();} catch (SQLException e) {e.printStackTrace();}}JDBCUtil.releaseConnection();}return t;}// 公共的查询方法 返回的是对象的集合public T ListT baseQuery(Class clazz, String sql, Object ... args){ListT list new ArrayList();Connection connection JDBCUtil.getConnection();PreparedStatement preparedStatementnull;ResultSet resultSet null;int rows 0;try {// 准备语句对象preparedStatement connection.prepareStatement(sql);// 设置语句上的参数for (int i 0; i args.length; i) {preparedStatement.setObject(i1,args[i]);}// 执行 查询resultSet preparedStatement.executeQuery();ResultSetMetaData metaData resultSet.getMetaData();int columnCount metaData.getColumnCount();// 将结果集通过反射封装成实体类对象while (resultSet.next()) {// 使用反射实例化对象Object obj clazz.getDeclaredConstructor().newInstance();for (int i 1; i columnCount; i) {String columnName metaData.getColumnLabel(i);Object value resultSet.getObject(columnName);// 处理datetime类型字段和java.util.Data转换问题if(value.getClass().equals(LocalDateTime.class)){value Timestamp.valueOf((LocalDateTime) value);}Field field clazz.getDeclaredField(columnName);field.setAccessible(true);field.set(obj,value);}list.add((T)obj);}} catch (Exception e) {e.printStackTrace();} finally {if (null !resultSet) {try {resultSet.close();} catch (SQLException e) {throw new RuntimeException(e);}}if (null ! preparedStatement) {try {preparedStatement.close();} catch (SQLException e) {throw new RuntimeException(e);}}JDBCUtil.releaseConnection();}return list;}// 通用的增删改方法public int baseUpdate(String sql,Object ... args) {// 获取连接Connection connection JDBCUtil.getConnection();PreparedStatement preparedStatementnull;int rows 0;try {// 准备语句对象preparedStatement connection.prepareStatement(sql);// 设置语句上的参数for (int i 0; i args.length; i) {preparedStatement.setObject(i1,args[i]);}// 执行 增删改 executeUpdaterows preparedStatement.executeUpdate();// 释放资源(可选)} catch (SQLException e) {e.printStackTrace();} finally {if (null ! preparedStatement) {try {preparedStatement.close();} catch (SQLException e) {throw new RuntimeException(e);}}JDBCUtil.releaseConnection();}// 返回的是影响数据库记录数return rows;} }基本按照这样写 Dao 接口 /*** Description: 日程表CRUD*/ public interface SysScheduleDao {/*** 用于向数据中增加一条日程记录* param schedule 日程数据以SysSchedule实体类对象形式入参* return 返回影响数据库记录的行数行数为0增加失败行数大于0增加成功*/int addSchedule(SysSchedule schedule);/*** 查找所有的日程信息* return 返回全部日程数据*/ListSysSchedule findSchedule(); }public interface SysUserDao {/*** 向数据库表sys_user增加一条用户记录的方法* param sysUser 要增加记录的username和usePwd 以SysUser对象的形式接收* return 增加 成功返回 1 失败0*/int addUser(SysUser sysUser); }Dao实现类 public class SysScheduleDaoImpl extends BaseDao implements SysScheduleDao {Overridepublic int addSchedule(SysSchedule schedule) {String sql insert into sys_schedule values(DEFAULT,?,?,?);int rows baseUpdate(sql, schedule.getUid(),schedule.getTitle(), schedule.getCompleted());return rows;}Overridepublic ListSysSchedule findSchedule() {String sql select sid,uid,title,completed from sys_schedule;ListSysSchedule scheduleList baseQuery(SysSchedule.class, sql);return scheduleList;} }public class SysUserDaoImpl extends BaseDao implements SysUserDao {Overridepublic int addUser(SysUser sysUser) {String sql insert into sys_user values(DEFAULT,?,?);;int rows baseUpdate(sql, sysUser.getUsername(), sysUser.getUserPwd());return rows;} }五、service 这样写 写注释 /*** 该接口定义了以 sys_user 表 为核心的业务处理功能*/ public interface SysUserService {/*** 用户注册方法* param sysUser 要注册的用户名和明文密码 以SysUser对象的形式接收* return 注册 成功返回1 失败返回0*/int regist(SysUser sysUser); } public class SysUserServiceImpl implements SysUserService {private SysUserDao userDao new SysUserDaoImpl();Overridepublic int regist(SysUser sysUser) {//密码加密sysUser.setUserPwd(MD5Util.encrypt(sysUser.getUserPwd()));return userDao.addUser(sysUser);} }六、controller 前端 action 格式 servlet 的名字 方法名 user/add user/remove … 接收前端传来的URI【 /user/add 】截取后面的add 再定义同名方法这样就自动invoke执行相同名字的方法不用自己手动去写ifelse( 加一个方法就得写一个 servlet 基类 反射 /*** Description: Controller servlet基类 使用反射调用方法*/ public class BaseController extends HttpServlet {Overrideprotected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//拿到方法的URI 格式项目上下文Context 加上 后缀名 //举例项目Context设置为空时 /schedule/addString requestURI req.getRequestURI();//拿到最后的 add 方法名String[] split requestURI.split(/);String methodName split[split.length - 1];//使用反射 获取所有的方法Class aClass this.getClass();try {Method declaredMethod aClass.getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);//取消访问检查 防止方法为私有导致不能执行declaredMethod.setAccessible(true);//执行方法 传入参数declaredMethod.invoke(this, req, resp);} catch (Exception e) {e.printStackTrace();}} }这样只要 继承基类 定义 方法即可 WebServlet(/schedule/*) public class SysScheduleController extends BaseController{protected void add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {System.out.println(add);} }WebServlet(/user/*) public class SysUserController extends BaseController{private SysUserService userService new SysUserServiceImpl();/*** 接收用户注册的业务请求 处理方法* param req* param resp* throws ServletException* throws IOException*/protected void regist(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String username req.getParameter(username);String userPwd req.getParameter(userPwd);SysUser sysUser new SysUser(null, username, userPwd);int rows userService.regist(sysUser);if (rows 0){resp.sendRedirect(/registSuccess.html);}else{resp.sendRedirect(/registFail.html);}} }七、加密工具类 MD5 public class MD5Util {public static String encrypt(String strSrc) {try {char hexChars[] { 0, 1, 2, 3, 4, 5, 6, 7, 8,9, a, b, c, d, e, f };byte[] bytes strSrc.getBytes();MessageDigest md MessageDigest.getInstance(MD5);md.update(bytes);bytes md.digest();int j bytes.length;char[] chars new char[j * 2];int k 0;for (int i 0; i bytes.length; i) {byte b bytes[i];chars[k] hexChars[b 4 0xf];chars[k] hexChars[b 0xf];}return new String(chars);} catch (NoSuchAlgorithmException e) {e.printStackTrace();throw new RuntimeException(MD5加密出错!!!);}} }八、页面文件 注册页面 登录页面 九、业务代码 9.1 注册业务处理 controller servlet WebServlet(/user/*) public class SysUserController extends BaseController{private SysUserService userService new SysUserServiceImpl();/*** 接收用户注册的业务请求 处理方法* param req* param resp* throws ServletException* throws IOException*/protected void regist(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String username req.getParameter(username);String userPwd req.getParameter(userPwd);SysUser sysUser new SysUser(null, username, userPwd);int rows userService.regist(sysUser);if (rows 0){resp.sendRedirect(/registSuccess.html);}else{resp.sendRedirect(/registFail.html);}} }service 业务代码 /*** 该接口定义了以 sys_user 表 为核心的业务处理功能*/ public interface SysUserService {/*** 用户注册方法* param sysUser 要注册的用户名和明文密码 以SysUser对象的形式接收* return 注册 成功返回1 失败返回0*/int regist(SysUser sysUser); } public class SysUserServiceImpl implements SysUserService {private SysUserDao userDao new SysUserDaoImpl();Overridepublic int regist(SysUser sysUser) {//密码加密sysUser.setUserPwd(MD5Util.encrypt(sysUser.getUserPwd()));return userDao.addUser(sysUser);} }dao 数据库 /*** Description: 用户CRUD*/ public interface SysUserDao {/*** 向数据库表sys_user增加一条用户记录的方法* param sysUser 要增加记录的username和usePwd 以SysUser对象的形式接收* return 增加 成功返回 1 失败0*/int addUser(SysUser sysUser); }public class SysUserDaoImpl extends BaseDao implements SysUserDao {Overridepublic int addUser(SysUser sysUser) {String sql insert into sys_user values(DEFAULT,?,?);;int rows baseUpdate(sql, sysUser.getUsername(), sysUser.getUserPwd());return rows;} }9.2 登录业务处理 controller : /*** 接收用户登录请求完成登录业务接口* param req* param resp* throws ServletException* throws IOException*/protected void login(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String username req.getParameter(username);String userPwd req.getParameter(userPwd);//通过用户名查找对象SysUser loginUser userService.findUserByUsername(username);//用户为Null不存在if(null loginUser){resp.sendRedirect(/loginUsernameError.html);//密码不匹配} else if (!MD5Util.encrypt(userPwd).equals(loginUser.getUserPwd())) {resp.sendRedirect(/loginUserPwdError.html);}else{resp.sendRedirect(/showSchedule.html);}}service /*** 根据用户名查找完整的user对象* param username 要查找的用户名* return 查到返回SysUser对象找不到返回Null*/SysUser findUserByUsername(String username);Overridepublic SysUser findUserByUsername(String username) {return userDao.findUserByUsername(username);}dao /*** 根据用户名查找完整的user对象* param username 要查找的用户名* return 查到返回SysUser对象找不到返回Null*/SysUser findUserByUsername(String username);Overridepublic SysUser findUserByUsername(String username) {String sql select uid,username,user_pwd as userPwd from sys_user where username?;;ListSysUser sysUserList baseQuery(SysUser.class, sql, username);return sysUserList ! null sysUserList.size() 0 ? sysUserList.get(0) : null;}总结 开启注解处理 测试类 测试日程表的CRUD 调用DAO层方法 public class TestSysScheduleDao {private static SysScheduleDao sysScheduleDao;BeforeClasspublic static void initSysScheduleDaoImpl(){sysScheduleDao new SysScheduleDaoImpl();}Testpublic void testAddSchedule(){int rows sysScheduleDao.addSchedule(new SysSchedule(null, 2, 学习后端, 0));System.out.println(rows);}Testpublic void testFindSchedule(){ListSysSchedule scheduleList sysScheduleDao.findSchedule();scheduleList.forEach(System.out::println);} }测试BaseDao工具类 private static BaseDao baseDao;BeforeClasspublic static void initBaseDao(){baseDao new BaseDao();}Testpublic void testBaseUpdate(){String sql insert into sys_schedule values(DEFAULT,?,?,?);int rows baseDao.baseUpdate(sql, 1, 学习JS, 1);System.out.println(rows);}Testpublic void testBaseQuery(){String sql select sid,uid,title,completed from sys_schedule;ListSysSchedule listSchedules baseDao.baseQuery(SysSchedule.class, sql);listSchedules.forEach(System.out::println);}Testpublic void testBaseSingleQuery(){String sql select count(1) from sys_schedule;Long aLong baseDao.baseQueryObject(Long.class, sql);System.out.println(aLong);}