JavaCore-OOP-5-简易的【学生信息管理系统】
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话说:
每天坚持一件事情真不容易。在下前段日子找不到代码写，复杂的写不出来，简单的吧，又觉得太简单，不足以发表，所以隔了这么久才发表这篇…..
今天这篇，也是十分滴基础。实现类似上一篇【图书管理系统】的功能，不过这次不在数组中实现，加入了JDBC,连接了后台，前台通过控制台交互。至于JDBC与前台交互，在笔者前20篇JDBC系列里面总结得很详细了，不在赘述~
目标：
JDBC+控制台 实现学生信息管理系统。核心在于注册功能和JDBC的CURD操作。
开发工具：Eclipse（Oxygen 4.7.0 M7 ）
目录
一、效果图
二、实体类
三、Dao层
四、工具类
五、视图类
六、测试类
七、总结
一、效果图
整体框架如下：
这里容易出现InputMismatchException，用try{} catch() {}处理下.
注册功能，已经存在给提示（用户名）
可以修改全部，也可修改部分字段。
二、实体类
1）创建数据库及表
#1.创建数据库create database db_stuSys;use db_stuSys;#2.创建数据表create table t_stu(stu_id int primary key auto_increment comment '学生编号',stu_name varchar(10) not null comment '学生姓名',stu_sex char(2) not null comment '性别',stu_age int unsigned comment '年龄',stu_grade varchar(5) comment '所属年级',stu_addr varchar(50) comment '地址',stu_phone varchar(15) comment '联系方式',stu_email varchar(15) comment '电子邮箱')comment='学生信息表';#创建用户表create table t_user(id int primary key auto_increment comment '用户id',username varchar(15) comment '用户名',password varchar(8) comment '密码')comment='用户表';#自封为超级管理员insert into t_user (username,password) values('meice','321');后来为便于操作，把stu_sex修改为了varchar()类型.
2）实体类
Student
package com.hmc2.entity;/****2017年12月7日*User:Meice*下午2:00:55*/public class Student { private int stu_id; private String stu_name; private String stu_sex; private int stu_age; private String stu_grade; private String stu_addr; private String stu_phone; private String stu_email; public Student() {} public Student(int stu_id, String stu_name, String stu_sex, int stu_age, String stu_grade, String stu_addr, String stu_phone, String stu_email) { super(); this.stu_id = stu_id; this.stu_name = stu_name; this.stu_sex = stu_sex; this.stu_age = stu_age; this.stu_grade = stu_grade; this.stu_addr = stu_addr; this.stu_phone = stu_phone; this.stu_email = stu_email; } public Student( String stu_name, String stu_sex, int stu_age, String stu_grade, String stu_addr, String stu_phone, String stu_email) { this.stu_name = stu_name; this.stu_sex = stu_sex; this.stu_age = stu_age; this.stu_grade = stu_grade; this.stu_addr = stu_addr; this.stu_phone = stu_phone; this.stu_email = stu_email; } public int getStu_id() { return stu_id; } public void setStu_id(int stu_id) { this.stu_id = stu_id; } public String getStu_name() { return stu_name; } public void setStu_name(String stu_name) { this.stu_name = stu_name; } public String getStu_sex() { return stu_sex; } public void setStu_sex(String stu_sex) { this.stu_sex = stu_sex; } public int getStu_age() { return stu_age; } public void setStu_age(int stu_age) { this.stu_age = stu_age; } public String getStu_grade() { return stu_grade; } public void setStu_grade(String stu_grade) { this.stu_grade = stu_grade; } public String getStu_addr() { return stu_addr; } public void setStu_addr(String stu_addr) { this.stu_addr = stu_addr; } public String getStu_phone() { return stu_phone; } public void setStu_phone(String stu_phone) { this.stu_phone = stu_phone; } public String getStu_email() { return stu_email; } public void setStu_email(String stu_email) { this.stu_email = stu_email; } @Override public String toString() { return "Student [stu_id=" + stu_id + ", stu_name=" + stu_name + ", stu_sex=" + stu_sex + ", stu_age=" + stu_age + ", stu_grade=" + stu_grade + ", stu_addr=" + stu_addr + ", stu_phone=" + stu_phone + ", stu_email=" + stu_email + "]"; }}User
package com.hmc2.entity;/****2017年12月7日*User:Meice*下午2:01:03*/public class User { private int userid; private String username; private String password; public User() {} public User(String username,String password) { this.username = username; this.password = password; } public User(int userid,String username,String password) { this.userid = userid; this.username = username; this.password = password; } public int getUserid() { return userid; } public void setUserid(int userid) { this.userid = userid; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override public String toString() { return "User [userid=" + userid + ", username=" + username + ", password=" + password + "]"; }}三、Dao层
1) 接口-JdbcDao
package com.hmc2.dao;/****2017年12月7日*User:Meice*下午2:45:06*/import java.util.List;public interface JdbcDao { public int Cud(String sql,Object... params); public List<?> list(String sql,Object... params);}2）实现类-JdbcDaoImpl
package com.hmc2.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import java.util.Scanner;import com.hmc2.entity.Student;import com.hmc2.entity.User;import com.hmc2.util.JdbcUtil;import com.hmc2.util.MatcherUtil;import com.hmc2.view.ControllerView;/****2017年12月7日*User:Meice*下午2:49:47*/public class JdbcDaoImpl implements JdbcDao{ Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; //实例化验证学生信息类 MatcherUtil mu = new MatcherUtil(); //实例化ControllerView类 ControllerView cv = new ControllerView(); /** * 1.增删改 */ @Override public int Cud(String sql, Object... params) { int result =0; //1.获取连接 conn = JdbcUtil.getConnection(); try { ps = conn.prepareStatement(sql); if(params != null) { for(int i=0;i<params.length;i++) { ps.setObject((i+1), params[i]); } } //2.执行语句 result = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return result; } /** * 2.查 */ @Override public List<?> list(String sql, Object... params) { List<Student> listStu = new ArrayList<Student>(); conn = JdbcUtil.getConnection(); try { ps = conn.prepareStatement(sql); //可以带参，也可以不带参s if(params != null) { for(int i=0;i<params.length;i++) { ps.setObject((i+1), params[i]); } } rs = ps.executeQuery(); while(rs.next()) { int stu_id = rs.getInt("stu_id"); String stu_name = rs.getString("stu_name"); String stu_sex = "男"; try { stu_sex = rs.getString("stu_sex"); }catch(NullPointerException e) { stu_sex = "男"; } int stu_age = rs.getInt("stu_age"); String stu_grade = rs.getString("stu_grade"); String stu_addr = rs.getString("stu_addr"); String stu_phone = rs.getString("stu_phone"); String stu_email = rs.getString("stu_email"); Student student = new Student(stu_id, stu_name, stu_sex, stu_age, stu_grade, stu_addr, stu_phone, stu_email); listStu.add(student); //System.out.println(listStu); } } catch (SQLException e) { e.printStackTrace(); } return listStu; } /** * 3.根据CUD结果给出对应信息提示 * getResultOfCudInfo() */ public void getResultCudInfo(int result,String successInfo,String failInfo) { if(result>0) { System.out.println(successInfo); }else { System.out.println(failInfo); } } /** * 4.根据用户名判断用户是否存在 * isUserExist() * 带2个参数，灵活性增加：判断注册有效否，只用判断用户名；判断登录，则要用户名、密码一起判断 */ public boolean isUserExist(User user,String sql,String existInfo,Object... params) { conn= JdbcUtil.getConnection(); //String sql = "select * from t_user where username = ?"; try { ps = conn.prepareStatement(sql); if(params!= null) { for(int i=0;i<params.length;i++) { ps.setObject((i+1), params[i]); } } //ps.setString(1, user.getUsername()); rs = ps.executeQuery(); if(rs.next()) { System.out.println(existInfo); return true; }else { return false; } } catch (SQLException e) { e.printStackTrace(); return false; } } /** * 5.定义注册 * studentRegister() * */ public void studentRegister(User user) { //User user2 = cv.getUser("亲，输入【注册用户名】:", "输入【注册密码】:", ""); //判断用户是否已经存在 String sql1 = "select * from t_user where username = ?"; Object[] parmas = {user.getUsername()}; if(isUserExist(user, sql1,"用户【已注册】，请重新选择操作:", parmas)) { //方法内已经处理 }else { //执行添加用户方法 String sql2 = "insert into t_user (username,password) values (?,?)"; Object[] params2 = {user.getUsername(),user.getPassword()}; int result = Cud(sql2, params2); getResultCudInfo(result, "恭喜你！注册成功! *.* ", "遗憾，注册失败..."); System.out.println("请牢记已注册用户名:"+user.getUsername()+" 密码:"+user.getPassword()); } } /** * 6.查看学生列表 * studentList() */ public void studentList() { String sql = "select * from t_stu"; List<Student> list =(List<Student>)list(sql, null); System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++所有学生信息++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); //这里不要list==null来判断，对象存在当然不为null if(list.size()==0) { System.out.println("暂无学员信息！请新增后再查看~ "); }else { System.out.println("* id\t|姓名\t|性别\t|年龄\t|年级\t|家庭地址\t\t\t|电话\t\t\t|邮箱\t\t*"); for(Student stu:list) { System.out.println("* "+stu.getStu_id()+"\t|"+stu.getStu_name()+"\t|"+stu.getStu_sex()+"\t|"+stu.getStu_age()+"\t|"+stu.getStu_grade()+"\t|"+stu.getStu_addr()+"\t\t\t|"+stu.getStu_phone()+"\t\t|"+stu.getStu_email()+" *"); } } System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); } /** * 7.新增学生 * addStudent() */ public void addStudent(Student student) { //Student student = mu.getStudent(); String sql3 = "insert into t_stu (stu_name,stu_sex,stu_age,stu_grade,stu_addr,stu_phone,stu_email)" + "values (?,?,?,?,?,?,?)"; Object[] params3 = {student.getStu_name(),student.getStu_sex(),student.getStu_age(),student.getStu_grade(),student.getStu_addr(),student.getStu_phone(),student.getStu_email()}; int result = Cud(sql3, params3); getResultCudInfo(result, "恭喜亲，【新增】成功！", "遗憾,【新增】失败"); } /** * 8.删除学生 * delStudent() */ public void delStudent(int stu_id) { String sql6 = "delete from t_stu where stu_id = ? "; //int stu_id = cv.getStuId("请输入要【删除】学生的Id:"); Object[] params6 = {stu_id}; //打印删除信息 //判断Id存在，存在在删除，不存在给精确提示;这里之所以不封装，是因为要输出删除信息，不然封装会更啰嗦 String sql = "select * from t_stu where stu_id = ?"; Object[] params = {stu_id}; List<Student> list2 =(List<Student>)list(sql, params); if(list2.size()==0) { System.out.println("该ID不存在..."); }else { System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++【待删除】学生信息++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); System.out.println("* id\t|姓名\t|性别\t|年龄\t|年级\t|家庭地址\t\t\t\t|电话\t\t\t|邮箱\t\t*"); for(Student stu:list2) { System.out.println("* "+stu.getStu_id()+"\t|"+stu.getStu_name()+"\t|"+stu.getStu_sex()+"\t|"+stu.getStu_age()+"\t|"+stu.getStu_grade()+"\t|"+stu.getStu_addr()+"\t\t\t|"+stu.getStu_phone()+"\t\t|"+stu.getStu_email()+"\t*"); } System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); //删除前要确认删除信息 int result2 = 0; if(cv.isContinue("确认删除(y/n)?")) { result2 = Cud(sql6, params6); getResultCudInfo(result2, "恭喜亲，【删除】成功！", "遗憾，【删除】失败"); }else { System.out.println("未执行【删除】操作~"); } } } /** * 9.修改1——根据学生Id修改全部信息 * updateStuInfoById() * 假设Id是存在的 */ public void updateStuInfoById(int stu_id) { //用户Id存在前提下才有修改的意义 if(isStudentExistById(stu_id)) { String sql = "update t_stu set stu_name =?,stu_sex=?,stu_age=?,stu_grade=?,stu_addr=?,stu_phone=?,stu_email=? "; Student student = mu.getStudent(); Object[] params = {student.getStu_name(),student.getStu_sex(),student.getStu_age(),student.getStu_grade(),student.getStu_addr(),student.getStu_phone(),student.getStu_email()}; //打印修改 后的信息，确认是否修改 System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++【待修改】学生信息++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); System.out.println("* id\t|姓名\t|性别\t|年龄\t|年级\t|家庭地址\t\t\t\t|电话\t\t\t|邮箱\t\t*"); System.out.println("* "+stu_id+"\t|"+student.getStu_name()+"\t|"+student.getStu_sex()+"\t|"+student.getStu_age()+"\t|"+student.getStu_grade()+"\t|"+student.getStu_addr()+"\t\t\t|"+student.getStu_phone()+"\t\t|"+student.getStu_email()+"\t*"); System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); if(cv.isContinue("请核对以上【待修改】信息，确认修改(y/n)?")) { int result = Cud(sql, params); getResultCudInfo(result, "恭喜，【修改成功！】", "遗憾，【修改】失败~"); }else { System.out.println("未执行【修改】操作"); } }else { System.out.println("该ID不存在奥~"); } } /** * 10.修改2——根据学生Id修改部分属性 * updateLittleStuInfoById() */ public int updateLittleStuInfoById(int stu_id) { int result = 0; if(isStudentExistById(stu_id)) { System.out.println("亲，请输入要修改的属性："); String stuProperty = new Scanner(System.in).next(); System.out.println("亲，请输入要修改后的值："); String stuVal = new Scanner(System.in).next(); String sql = "update t_stu set "+ stuProperty+" = ? where stu_id = ?"; Object[] params = {stuVal,stu_id}; //输出修改后的信息 System.out.println("++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++【待修改】学生信息++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); System.out.println("* id\t|"+stuProperty+"\t*"); System.out.println("* "+stu_id+"\t|"+stuVal+"\t*"); System.out.println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); //询问是否执行修改 if(cv.isContinue("请核对以上【待修改】信息，确认修改(y/n)?")) { result = Cud(sql, params); }else { System.out.println("属性未修改~"); } }else { System.out.println("该用户Id不存在~"); } return result; } /** * 11.根据stu_id返回一个对象 * getStudentById */ public Student getStudentById(int stu_id) { String sql = "select * from t_stu where id = ?"; Object[] params = {stu_id}; List<Student> list =(List<Student>) list(sql, params); return list.get(0); } /** * 12.根据Id判断学生是否存在 * isStudentExistById() */ public boolean isStudentExistById(int stu_id) { String sql = "select * from t_stu where stu_id = ?"; Object[] params = {stu_id}; List<Student> list =(List<Student>) list(sql, params); if(list.size()==0) { return false; }else{ return true; } }}这里面还是有很大优化空间，比如User的查和Student的查通过泛型是可以合并的，如果再加入对用户的后台管理，那很多代码都可以复用。
四、工具类
1）把获取JDBC连接封装成对象，便于调用
2）JDBC连接优化为加载静态资源
3）获取一个Student，验证各种条件
1）把获取JDBC连接封装成对象，便于调用
JdbcUtil
package com.hmc2.util;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;/****2017年12月7日*User:Meice*下午2:20:47*/public class JdbcUtil { private JdbcUtil() {} static Connection connection = null; /** * 1.定义静态语句块，加载驱动 */ static { try { Class.forName(JdbcProperUtil.getJdbcVal().getProperty("driver")); /*connection = DriverManager.getConnection(JdbcProperUtil.getJdbcVal().getProperty("url"), JdbcProperUtil.getJdbcVal().getProperty("root"), JdbcProperUtil.getJdbcVal().getProperty("password"));*/ connection = DriverManager.getConnection(JdbcProperUtil.getJdbcVal().getProperty("url"),JdbcProperUtil.getJdbcVal().getProperty("username"),JdbcProperUtil.getJdbcVal().getProperty("password")); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } } /** * 2.定义获取驱动方法getConnection() */ public static Connection getConnection() { return connection; } /** * 3.定义关闭资源的方法 * closeJdbc() */ public void closeJdbc(ResultSet rs,PreparedStatement ps,Connection conn) { try { if(rs != null) rs.close(); if(ps != null) ps.close(); if(conn != null) conn.close(); } catch (SQLException e) { e.printStackTrace(); } }}2）JDBC连接优化为加载静态资源
JdbcProperUtil
package com.hmc2.util;import java.io.FileNotFoundException;import java.io.FileReader;import java.io.IOException;import java.io.Reader;import java.util.Properties;import org.junit.Test;/****2017年12月7日*User:Meice*下午3:01:34*/public class JdbcProperUtil { /** * 这个类用来获取JDBC静态资源 */ @Test public static Properties getJdbcVal() { Properties properties = new Properties(); Reader reader; try { reader = new FileReader("db.properties"); properties.load(reader); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return properties; }public static void main(String[] args) { //Properties properties = getJdbcVal(); //System.out.println(properties.getProperty("root"));}}3）获取一个Student，验证各种条件
MatcherUtil
package com.hmc2.util;import java.util.InputMismatchException;import java.util.Scanner;import org.junit.Test;import com.hmc2.entity.Student;/****2017年12月7日*User:Meice*下午4:54:35*/public class MatcherUtil { Scanner sc = new Scanner(System.in); /** * 这里面最核心的是正则校验（这里暂且不用正则） * 其次就是重复调用方法，思路很好 * @return */ @Test public Student getStudent() { try { stu_name = setStu_name(); stu_sex = setStu_sex(); stu_age = setStu_age(); stu_grade = setStu_grade(); stu_addr = setStu_addr(); stu_phone = setStu_phone(); stu_email = setStu_email(); }catch(InputMismatchException e) { System.out.println("输入有误，请重新输入:"); this.getStudent(); } Student student = new Student(stu_name, stu_sex, stu_age, stu_grade, stu_addr, stu_phone, stu_email); //System.out.println(student); return student; } public static void main(String[] args) { MatcherUtil mu = new MatcherUtil(); mu.getStudent(); } private int stu_id; private String stu_name; private String stu_sex; private int stu_age; private String stu_grade; private String stu_addr; private String stu_phone; private String stu_email; public MatcherUtil() {} public MatcherUtil(int stu_id, String stu_name, String stu_sex, int stu_age, String stu_grade, String stu_addr, String stu_phone, String stu_email) { super(); this.stu_id = stu_id; this.stu_name = stu_name; this.stu_sex = stu_sex; this.stu_age = stu_age; this.stu_grade = stu_grade; this.stu_addr = stu_addr; this.stu_phone = stu_phone; this.stu_email = stu_email; } public MatcherUtil( String stu_name, String stu_sex, int stu_age, String stu_grade, String stu_addr, String stu_phone, String stu_email) { this.stu_name = stu_name; this.stu_sex = stu_sex; this.stu_age = stu_age; this.stu_grade = stu_grade; this.stu_addr = stu_addr; this.stu_phone = stu_phone; this.stu_email = stu_email; } public int getStu_id() { return stu_id; } public void setStu_id(int stu_id) { this.stu_id = stu_id; } public String getStu_name() { return stu_name; } public String setStu_name() { System.out.println("姓名:"); stu_name = sc.next(); return stu_name; } public String getStu_sex() { return stu_sex; } public String setStu_sex() { System.out.println("性别:"); stu_sex = sc.next(); if("男".equals(stu_sex)||"女".equals(stu_sex)) { }else { System.out.println("性别输入有误，请输入【男】或【女】"); this.setStu_sex(); } return stu_sex; } public int getStu_age() { return stu_age; } public int setStu_age() { System.out.println("年龄:"); stu_age = sc.nextInt(); if(stu_age>=1 && stu_age<120) { }else { System.out.println("年龄有误，请重新输入:"); this.setStu_age(); } return stu_age; } public String getStu_grade() { return stu_grade; } public String setStu_grade() { System.out.println("年级【初级、中级、高级】:"); stu_grade = sc.next(); if("初级".equals(stu_grade)||"中级".equals(stu_grade)||"高级".equals(stu_grade)) { }else { System.out.println("输入有误，请选择以下三个选项之一【初级、中级、高级】"); this.setStu_grade(); } return stu_grade; } public String getStu_addr() { return stu_addr; } public String setStu_addr() { System.out.println("家庭住址:"); stu_addr = sc.next(); return stu_addr; } public String getStu_phone() { return stu_phone; } public String setStu_phone() { System.out.println("手机号码:"); stu_phone = sc.next(); if(stu_phone.length() ==11) { }else { System.out.println("手机号码输入有误，请输入11位手机号码:"); this.setStu_phone(); } return stu_phone; } public String getStu_email() { return stu_email; } public String setStu_email() { System.out.println("邮箱:"); stu_email = sc.next(); if(stu_email.contains("@")&&stu_email.contains(".com")) { }else { System.out.println("邮箱有误！必须包含@和.com奥~"); this.setStu_email(); } return stu_email; }}这里对手机号码、邮箱验证都不够精确，通过正则是最为精确的验证方式。
以下为正则方式验证，非本人所写。
package com.yijian.utils;import java.util.Scanner;import java.util.regex.Pattern;public class Matches { Scanner input = new Scanner(System.in); static String id = null; static String gender = null; static String age = null; static String grade = null; static String phone = null; static String email = null; /** * 匹配id * * @return */ public String matchesId() { id = input.next(); if (Pattern.matches("^[0-9]{1,}$", id)) { } else { System.out.println("输入错误，只能输入数字："); this.matchesId(); } return id; } /** * 匹配性别 * * @return */ public String matchesGender() { gender = input.next(); if (!(gender.equals("男") || gender.equals("女"))) { System.out.println("性别只能是男或者女:"); this.matchesGender(); } return gender; } /** * 匹配年龄 * * @return */ public int matchesAge() { age = input.next(); if (!Pattern.matches("^[0-9]{1,}$", age)) { System.out.println("以上输入不合法，只能输入1-120之内的数字："); this.matchesAge(); } else if (Integer.valueOf(age) < 1 || Integer.valueOf(age) > 120) { System.out.println("以上输入不合法，只能输入1-120之内的数字："); this.matchesAge(); } return Integer.parseInt(age); } /** * 匹配年级 * * @return */ public String matchesGrade() { grade = input.next(); if (!(grade.equals("初级") || grade.equals("中级") || grade.equals("高级"))) { System.out.println("无此年级设置，年级只能输入初级、中级或高级，请重新输入:"); this.matchesGrade(); } return grade; } /** * 匹配手机号 * * @return */ public String matchesPhone() { phone = input.next(); if (!Pattern.matches("^[0-9]{11}$", phone)) { System.out.println("输入有误，电话号码只能是11位数字,请重新输入："); this.matchesPhone(); } return phone; } /** * 匹配email * * @return */ public String matchesEmail() { email = input.next(); if (!Pattern.matches("^[0-9a-zA-Z]+@[0-9a-zA-Z]+.[0-9a-zA-Z]+$", email)) { System.out.println("邮箱格式有误，请输入正确的电子邮箱（包含@和.com）"); this.matchesEmail(); } return email; }}五、视图类
控制台在这里扮演UI的角色，委屈UI了。
ControllerView
package com.hmc2.view;import java.util.InputMismatchException;import java.util.Scanner;import com.hmc2.entity.User;/****2017年12月7日*User:Meice*下午1:42:15*/public class ControllerView { /** * 1.定义登陆界面方法 * welcomeLogin() */ public void welcomeLogin() { System.out.println("***********************欢迎【进入】学生管理系统*******************************"); System.out.println("\t1.登录\t\t2.注册\t\t3.退出"); System.out.println("************************************************************************"); } /** * 2.定义接收用户名和参数的方法 * getUser() */ public User getUser(String startUserInfo, String StartPwdInfo,String endInfo) { System.out.println(startUserInfo); String username = new Scanner(System.in).next(); System.out.println(StartPwdInfo); String password = new Scanner(System.in).next(); User user = new User(username, password); return user; } /** * 3.判断是否继续方法 * isContinue() */ public boolean isContinue(String startInfo) { System.out.println(startInfo); String choice = new Scanner(System.in).next(); if("y".equals(choice)|| "Y".equals(choice)) { return true; }else if("n".equals(choice)|| "N".equals(choice)) { return false; }else { System.out.println("输入有误，请重新输入【y/Y表示继续，n/N表示终止】:"); if(this.isContinue(startInfo)) { return true; }else { return false; } } } /** * 4.获取用户选择的选项 * getChooseNumber() */ public int getChooseNumber() { System.out.println("亲，输入【序号】选择你要的操作:"); try { int chooseNumber = new Scanner(System.in).nextInt(); return chooseNumber; }catch(InputMismatchException e) { System.out.println("输入有误奥，请重新输入【整数】序号:"); try { int chooseNumber2 = new Scanner(System.in).nextInt(); return chooseNumber2; }catch(InputMismatchException e2) { return this.getChooseNumber(); } } } /** * 5.定义登录成功后的界面 * welcomeEnter() */ public void welcomeEnter() { System.out.println("---------------------亲，按照对应【序号】选择操作---------------------------"); System.out.println("1.查看学生信息\t2.新增学生\t\t3.删除学员\t\t4.修改学生信息\t5.退出登录"); System.out.println("---------------------------------------------------------------------"); } /** * 6.定义获取学生id的方法 * getStuId() */ public int getStuId(String info ) { int stu_id =0; try { System.out.println(info); stu_id = new Scanner(System.in).nextInt(); }catch(InputMismatchException e) { this.getStuId("输入id有误，请重新输入:"); } return stu_id; } /** * 7.定义修改学生信息欢迎界面 * welcomeUpdate() */ public void welcomeUpdate() { System.out.println(":::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::"); System.out.println("* 1.根据ID修改学生全部信息\t2.根据ID修改学生部分信息\t3.返回上级目录\t4.系统退出\t*"); System.out.println(":::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::"); }}封装起来可以使后面的测试类异常简洁清晰。
六、测试类
TestStudentManagementSystem
package com.hmc2.test;import java.util.List;import com.hmc2.dao.JdbcDaoImpl;import com.hmc2.entity.Student;import com.hmc2.entity.User;import com.hmc2.util.MatcherUtil;import com.hmc2.view.ControllerView;/****2017年12月7日*User:Meice*下午1:41:53*/public class TestStudentManagementSystem { //界面层对象 static ControllerView cv = new ControllerView(); //dao层对象 static JdbcDaoImpl jdi = new JdbcDaoImpl(); //实例化MatcherUtil类；用于获取一个Student对象 static MatcherUtil mu = new MatcherUtil(); public static void main(String[] args) throws InterruptedException { boolean flag1 = true; do { cv.welcomeLogin(); switch(cv.getChooseNumber()) { case 1: //TODO Login User user = cv.getUser("亲，输入【用户名】:", "输入【密码】:", ""); String sql = "select * from t_user where username = ? and password = ?"; Object[] params = {user.getUsername(),user.getPassword()}; //用户名及密码都正确，提示登录成功 if(jdi.isUserExist(user, sql,"欢迎【"+user.getUsername()+"】！登录成功！ *.* ", params)) { boolean flag2 = true; System.out.println("正在登录......"); Thread.sleep(1000); //已处理 do { cv.welcomeEnter(); switch(cv.getChooseNumber()) { case 1: //TODO 查看学生信息 jdi.studentList(); System.out.println("系统自动返回上层目录......"); Thread.sleep(1000); break; case 2: //TODO 新增学生信息 jdi.addStudent(mu.getStudent()); System.out.println("系统自动返回上层目录......"); Thread.sleep(1000); break; case 3: //TODO 删除学生信息 jdi.studentList(); jdi.delStudent(cv.getStuId("请输入要【删除】学生的Id:")); System.out.println("系统自动返回上层目录......"); Thread.sleep(2000); break; case 4: //TODO 修改学生信息 boolean flag3 = true; do { cv.welcomeUpdate(); switch(cv.getChooseNumber()) { case 1: //TODO 根据Id修改全部信息 jdi.studentList(); jdi.updateStuInfoById(cv.getStuId("请输入【待修改学生Id】:")); flag3 = false; System.out.println("程序正在返回上一级目录......"); Thread.sleep(1000); break; case 2: //TODO 根据Id修改部分信息 jdi.studentList(); int result = jdi.updateLittleStuInfoById(cv.getStuId("请输入【待修改学生Id】:")); jdi.getResultCudInfo(result, "恭喜！【属性修改】成功！", "遗憾，属性修改失败~"); flag3 = false; System.out.println("程序正在返回上一级目录......"); Thread.sleep(1000); break; case 3: //TODO 返回上一级 flag3 = false; System.out.println("程序正在返回上一级目录......"); Thread.sleep(1000); break; case 4: //TODO 系统退出 flag3 = false; flag2 = false; break; default: //TODO Others System.out.println("输入【序号】有误，程序自动返回上一级....."); Thread.sleep(5000); break; } }while(flag3); break; case 5: //TODO 退出登录 System.out.println("您已退出，请重新进入学生管理系统~ *.* "); flag2 = false; break; default: //TODO Others System.out.println("序号不存在，请重新输入~ *.* "); break; } }while(flag2); }else { System.out.println("用户不存在，请重新选择操作:"); } break; case 2: //TODO Register jdi.studentRegister(cv.getUser("亲，输入【注册用户名】:", "输入【注册密码】:", "")); System.out.println("正在进入系统......"); Thread.sleep(3000); break; case 3: //TODO Exit System.out.println("再会！ *.* ~"); flag1 = false; break; default : //TODO Others System.out.println("该序号不存在，请重新选择!"); break; } }while(flag1); }}这是在下精简后的精简，测试类精简到这一步，算是可以了。然而，Dao的实现类还有不少优化空间。
七、总结
1.功能实现没有太多问题，细节多，特殊情况要考虑周全，比如根据Id删除和修改的前提是ID都要存在，否则操作没意义；
2.如果用户输入错误，需要让用户反复输入直至正确为止，或者限定试错次数类似的场景，采用方法自我调用；
3.java.sql.SQLException: Incorrect string value: ‘\xAC\xED\x00\x05sr…’ for column ‘stu_sex’ at row 1出现类似的编码问题，要么修改属性，要么尝试如下解决：
url=jdbc:mysql://localhost:3306/db_stusys?useUnicode=true&characterEncoding=utf84.根据Id判断对象是否存在可以通过查所有的方法来判断，就是结果集List的size()>0表示存在；否则不存在，这样比较简洁；或者重写一个方法判断ResultSet.next()，这个代码就冗余啦；
5.框架因为底层封装好，可以直接传递整个对象，这里故意不用框架，所以传参和接收参数就比较痛苦；
6.PreparedStatement对象执行语句，参数化SQL语句有讲究。
String sql = "update t_stu set stu_sex = ? where stu_id = ?";这里set 后面的属性不能为变量呢？
可以的，不能直接这样
String sql = "update t_stu set ? = ? where stu_id = ?";这样是不行的。字段名和表名一样，不可以用？表示。怎么搞定，传变量。
类似这样处理：
String stuProperty = new Scanner(System.in).next();String sql = "update t_stu set "+ stuProperty+" = ? where stu_id = ?";7.还是老话——温故而知新，不惧路途遥远，进一寸有一寸的欢喜。
好了，晚安！下次再会！~
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