三层架构 数据访问层 业务逻辑层 表示层

三层架构

  数据访问层

  业务逻辑层

  表示层

方便团队开发，代码复用

不属于三层，但跟三层息息相关——实体类（跟数据库表对应的类）

数据访问层

连接数据库，执行sql语句

cn.edu.xcu.sims.dao

BaseDao

//增删改的封装
	public int executeUpdate(String sql,Object ...args) {
		try {
			Connection conn=this.getConnection();
			PreparedStatement ps=conn.prepareStatement(sql);
			if(args!=null) {
				for(int i=0;i

StudentDao

接口

//数据访问对象
public interface StudentDao {
	public boolean insertStudent(Students stu);
	public boolean deleteStudent(int stuid);
	public boolean updateStudent(Students stu);
	public Students findStudent(int stuid);
	public List queryStudentByGrade(int gradeid);
	public List queryStudentByName(String stuname);
	public List queryAllStudent();
	public List queryAllStudentBykeyword(String stunameKeyword);
	
	public default Students parseResultSet(ResultSet rs) {
		
		try {
			Students stu=new Students();
			stu.setStuid(rs.getInt("stuid"));
			stu.setStuname(rs.getString("stuname"));
			stu.setGender(rs.getString("gender"));
			stu.setPhone(rs.getString("phone"));
			stu.setAddress(rs.getString("address"));
			Grade grade=new Grade(rs.getInt("gradeId"),rs.getString("gradeName"));
			stu.setGrade(grade);
			return stu;
		} catch (SQLException e) {
			throw new RuntimeException(e);
		}		
	}

cn.edu.xcu.sims.dao.impl

StudentDaoImpl

实现类

public class StudentDaoImpl extends BaseDao1 implements StudentDao{
	Scanner input=new Scanner(System.in);
	@Override
	public boolean insertStudent(Students stu) {
		BaseDao1 bd=new BaseDao1();
		String sql="insert into students values(sql_students_stuid.nextval,?,?,?,?,?)";
			return bd.executeUpdate(sql,stu.getStuname(),stu.getGender(),stu.getGrade().getGradeId(),stu.getPhone(),stu.getAddress())>0;
		   	
	}
	@Override
	public boolean deleteStudent(int stuid) {
		String sql="delete from students where stuid=?";
		return super.executeUpdate(sql, stuid)>0;
	}
	@Override
	public boolean updateStudent(Students stu) {
		System.out.println("请选择要修改的信息：修改姓名请输入1，修改性别请输入2，修改年级请输入3，修改电话请输入4，修改地址请输入5");
		String sql="update students set stuname=?,gender=?,gradeid=?,phone=?,address=? where students.stuid=?";
		switch (input.nextInt()) {
		case 1:
			System.out.println("请输入姓名：");
			String stuname=input.next();
			int rows1=super.executeUpdate(sql, stuname,stu.getGender(),stu.getGrade().getGradeId(),stu.getPhone(),stu.getAddress(),stu.getStuid());
			return rows1>0;
		case 2:
			System.out.println("请输入性别：");
			String gender=input.next();
			int rows2=super.executeUpdate(sql, stu.getStuname(),gender,stu.getGrade().getGradeId(),stu.getPhone(),stu.getAddress(),stu.getStuid());
			return rows2>0;
		case 3:
			System.out.println("请输入年级号：");
			String gradeid=input.next();
			int rows3=super.executeUpdate(sql, stu.getStuname(),stu.getGender(),gradeid,stu.getPhone(),stu.getAddress(),stu.getStuid());
			return rows3>0;
		case 4:
			System.out.println("请输入性别：");
			String phone=input.next();
			int rows4=super.executeUpdate(sql, stu.getStuname(),stu.getGender(),stu.getGrade().getGradeId(),phone,stu.getAddress(),stu.getStuid());
			return rows4>0;
		case 5:
			System.out.println("请输入性别：");
			String address=input.next();
			int rows5=super.executeUpdate(sql, stu.getStuname(),stu.getGender(),stu.getGrade().getGradeId(),stu.getPhone(),address,stu.getStuid());
			return rows5>0;
		default:
			break;
		}
		return false;
	}
	@Override
	public Students findStudent(int stuid) {
		String sql="select students.*,gradeName from students inner join grade on students.gradeid=grade.gradeId where stuid=?";
		Students stu=new Students();
		ResultSet rs=super.executeQuery(sql, stuid);
		try {
			if(rs.next()) {			stu.setStuid(rs.getInt("stuid"));			stu.setStuname(rs.getString("stuname"));
				stu.setGender(rs.getString("gender"));
				stu.setPhone(rs.getString("phone"));
				stu.setAddress(rs.getString("address"));
				Grade grade=new Grade(rs.getInt("gradeId"),rs.getString("gradeName"));
				stu.setGrade(grade);
			}
		} catch (SQLException e) {
			throw new RuntimeException(e);
		}
		return stu;
	}
	@Override
	public List queryStudentByGrade(int gradeid) {
		String sql="select students.*,grade.gradeName from students inner join grade on students.gradeid=grade.gradeId where students.gradeid=?";
		List list=new ArrayList();
		try {
			ResultSet rs=super.executeQuery(sql,gradeid);
			while(rs.next()) {
				Students stu=this.parseResultSet(rs);
				list.add(stu);
				list.add(stu);
			}
			return list;
		} catch (SQLException e) {
			throw new RuntimeException(e);
		}	
	}
//模糊查询
	@Override
	public List queryStudentByName(String stuname) {
		String sql="select students.*,grade.gradeName from students inner join grade on students.gradeid=grade.gradeId where students.stuname=?";
		List list=new ArrayList();
		ResultSet rs=super.executeQuery(sql,stuname);
		try {
			//将游标的一行数据转换成学生对象
			while(rs.next()) {		
				Students stu=this.parseResultSet(rs);
				list.add(stu);
			}
			return list;
		} catch (SQLException e) {
			throw new RuntimeException(e);
		}	
	}
	public List queryAllStudent(){
		String sql="select students.*,grade.gradename from students inner join grade on students.gradeid=grade.gradeId";
		try {
			ResultSet rs=super.executeQuery(sql);
			List list=new ArrayList();
			while(rs.next()) {
				Students stu=this.parseResultSet(rs);
				list.add(stu);
			}
			return list;
		} catch (SQLException e) {
			throw new RuntimeException(e);
		}
	}

	@Override
	public List queryAllStudentBykeyword(String stunameKeyword) {
		String sql="select students.*,grade.gradeName from students inner join grade on students.gradeid=grade.gradeId where students.stuname like ?";
		List list=new ArrayList();
		ResultSet rs=super.executeQuery(sql,"%"+stunameKeyword+"%");
		try {
			while(rs.next()) {
				Students stu=this.parseResultSet(rs);
				list.add(stu);
			}
			return list;
		} catch (SQLException e) {
			throw new RuntimeException(e);
		}
			}

封装接口和实现类

封装对表的操作方法

业务逻辑层

封装对象的，业务方法，需要什么方法，封装什么方法

封装业务逻辑

执行多个sql语句才能完成的业务

转账、商品折扣等都属于业务

业务接口

cn.edu.xcu.sims.biz

StudentBiz    StudentService    StudentManager

StudentBiz

public interface StudentBiz {
	public List getAllStudent();
	public List getAllStudentByName(String stuname);
	public Students getStudentById(int stuid);
	public boolean addStudent(Students stu);
	public boolean removeStudent(int stuid);
	public boolean modifyStudent(int stuid);
	public List getAllStudentByKeyword(String stunameKeyword);
}

业务实现类

cn.edu.xcu.sims.biz.impl

StudentBizImpl

 封装业务方法

public class StudentBizImpl implements StudentBiz {
	StudentDao dao=new StudentDaoImpl();
	@Override
	public List getAllStudent() {
		List list=dao.queryAllStudent();
		return list;
	}
	@Override
	public List getAllStudentByName(String stuname) {
		List list=dao.queryStudentByName(stuname);
		return list;	
	}
//数据访问层不允许写输出，测试可以，不能显示在ui界面,可以抛出异常
	//输入输出只存在于表示层
	@Override
	public boolean addStudent(Students stu) {
		List list=dao.queryStudentByName(stu.getStuname());
		boolean exists=false;
		for(Students s:list) {
			if(s.getStuname().equals(stu.getStuname())) {
				exists=true;
				break;
			}
		}
		if(exists) {
			throw new StudentNameExistsException(stu.getStuname()+"已经存在，不能添加");
		}
		else {
			return dao.insertStudent(stu);
		}
	}
	@Override
	public boolean removeStudent(int stuid) {
		return dao.deleteStudent(stuid);
	}
	@Override
	public boolean modifyStudent(int stuid) {
		Students stu=dao.findStudent(stuid);
		if(stu==null) {
			throw new RuntimeException("学号不存在");
		}
		else {		
			return dao.updateStudent(stu);
		}	
	}
	@Override
	public Students getStudentById(int stuid) {
		return dao.findStudent(stuid);
	}
	@Override
	public List getAllStudentByKeyword(String stunameKeyword) {
		List list=dao.queryAllStudentBykeyword(stunameKeyword);
		return list;
	}

表示层

程序运行出来可看到的部分

UI

包名 cn.edu.xcu.sims.web（网页）/ui(控制台)

cn.edu.xcu.sims.ui

Menu

public class Menu {
	Scanner input=new Scanner(System.in);
	public void MainMenu() {
		System.out.println("***********************");
		System.out.println("1--查询所有学生信息");
		System.out.println("2--从姓名获得学生信息");
		System.out.println("3--从学号获得学生信息");
		System.out.println("4--添加学生信息");
		System.out.println("5--删除学生信息");
		System.out.println("6--修改学生信息");
		System.out.println("7--输入姓名关键字模糊查询");
		System.out.println("请选择你将要执行的业务：");
		System.out.println("***********************");
		switch(input.nextInt()) {
		case 1:
			showStudent();
			break;
		case 2:
			showStudentByname();
			break;
		case 3:
			showStudentById();
			break;
		case 4:
			addStudent();
			break;
		case 5:
			deleteStudent();
			break;
		case 6:
			modifyStudent();
			break;
		case 7:
			selectnameBykeyword();
			break;
		}
		System.out.println("是否继续");
		if(input.next().equalsIgnoreCase("y")) {
			MainMenu();
		}
		else {
			System.exit(0);
		}
	}
	public void selectnameBykeyword() {
		System.out.println("请输入要查询的学生姓名：");
		StudentBiz biz=new StudentBizImpl();
		List list=biz.getAllStudentByKeyword(input.next());
		if(list.size()>0) {
		System.out.println("学号\t姓名\t性别\t年级\t电话\t地址\t");
		for(Students stu:list) {
			System.out.println(stu.getStuid()+"\t"+stu.getStuname()+"\t"+stu.getGender()+"\t"+stu.getGrade().getGradeId()+"\t"+stu.getPhone()+"\t"+stu.getAddress());			
	    }
		}
		else {
			System.out.println("查无此人");
		}	
	}
	public void modifyStudent() {
		try {
			System.out.println("请输入学生学号：");
			int stuid=input.nextInt();
			StudentBiz biz=new StudentBizImpl();
			if(biz.modifyStudent(stuid)) {
				System.out.println("修改成功");
			}
		} catch (Exception e) {
			System.out.println("程序故障，删除失败"+e.getMessage());
		}	
	}
	public void deleteStudent() {
		System.out.println("请输入要删除的学生的学号：");
		StudentBiz biz=new StudentBizImpl();
		int stuid=input.nextInt();
		Students stu=biz.getStudentById(stuid);
		if(stu==null) {
			System.out.println("查无此人");
		}
		else {
			System.out.println("你确定要删除学号是"+stuid+" 姓名是"+stu.getStuname()+"的学生吗");
			{
				if(input.next().equalsIgnoreCase("y")) {
					if(biz.removeStudent(stuid)) {
					System.out.println("删除成功");
					}
					else {
						System.out.println("删除失败");
					}
				}
			}
		}	
	}
	public void showStudentById() {
		System.out.println("请输入要查询的学生学号：");
		StudentBiz biz=new StudentBizImpl();
		Students stu=biz.getStudentById(input.nextInt());
		if(stu!=null) {
		System.out.println("学号\t姓名\t性别\t年级\t电话\t地址\t");
		System.out.println(stu.getStuid()+"\t"+stu.getStuname()+"\t"+stu.getGender()+"\t"+stu.getGrade().getGradeId()+"\t"+stu.getPhone()+"\t"+stu.getAddress());			    
		}
		else {
			System.out.println("查无此人");
		}
	}
	public void showStudent() {
		StudentBiz biz=new StudentBizImpl();
		List list=biz.getAllStudent();
		System.out.println("学号\t姓名\t性别\t年级\t电话\t地址\t");
		for(Students stu:list) {
			System.out.println(stu.getStuid()+"\t"+stu.getStuname()+"\t"+stu.getGender()+"\t"+stu.getGrade().getGradeId()+"\t"+stu.getPhone()+"\t"+stu.getAddress());			
		}
	}
	public void showStudentByname() {
		System.out.println("请输入要查询的学生姓名：");
		StudentBiz biz=new StudentBizImpl();
		List list=biz.getAllStudentByName(input.next());
		if(list.size()>0) {
		System.out.println("学号\t姓名\t性别\t年级\t电话\t地址\t");
		for(Students stu:list) {			System.out.println(stu.getStuid()+"\t"+stu.getStuname()+"\t"+stu.getGender()+"\t"+stu.getGrade().getGradeId()+"\t"+stu.getPhone()+"\t"+stu.getAddress());			
	    }
		}
		else {
			System.out.println("查无此人");
		}
	}
	public void addStudent() {
		Students stu=new Students();
		System.out.println("请输入学生姓名");
		stu.setStuname(input.next());
		System.out.println("请输入学生性别");
		stu.setGender(input.next());
		System.out.println("请输入学生年级编号");
		Grade grade=new Grade();
		grade.setGradeId(input.nextInt());
		stu.setGrade(grade);
		System.out.println("请输入学生电话");
		stu.setPhone(input.next());
		System.out.println("请输入学生地址");
		stu.setAddress(input.next());
		StudentBiz biz=new StudentBizImpl();
		try {
			biz.addStudent(stu);
			System.out.println("添加成功");
		} catch (StudentNameExistsException e) {			System.out.println(e.getMessage());
		} catch (Exception e) {
			System.out.println("添加失败"+e.getMessage());
		}		
	}

Start

public class Start {
	public static void main(String[] args) {
		Menu menu=new Menu();
		menu.MainMenu();
	}
}

关系

表示层通过——业务逻辑层——数据访问层——访问数据库——封装成对象——返回业务逻辑层——表示层

实体类——封装数据 每层都要用

实体类

cn.edu.xcu.sims.entity

Students

public class Students implements Serializable{
	private int stuid;
	private String stuname;
	private String gender;
	private Grade grade;
	private String phone;
	private String address;
	public int getStuid() {
		return stuid;
	}
	public void setStuid(int stuid) {
		this.stuid = stuid;
	}
	public String getStuname() {
		return stuname;
	}
	public void setStuname(String stuname) {
		this.stuname = stuname;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}
	public Grade getGrade() {
		return grade;
	}
	public void setGrade(Grade grade) {
		this.grade = grade;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public Students() {
		super();
		// TODO Auto-generated constructor stub
	}
	public Students(int stuid, String stuname, String gender, Grade grade, String phone, String address) {
		super();
		this.stuid = stuid;
		this.stuname = stuname;
		this.gender = gender;
		this.grade = grade;
		this.phone = phone;
		this.address = address;
	}
	@Override
	public String toString() {
		return "Students [stuid=" + stuid + ", stuname=" + stuname + ", gender=" + gender + ", grade=" + grade
				+ ", phone=" + phone + ", address=" + address + "]";
	}
}

Grade

public class Grade {
	private int gradeId;
	private String gradeName;
	public int getGradeId() {
		return gradeId;
	}
	public void setGradeId(int gradeId) {
		this.gradeId = gradeId;
	}
	public String getGradeName() {
		return gradeName;
	}
	public void setGradeName(String gradeName) {
		this.gradeName = gradeName;
	}
	public Grade(int gradeId, String gradeName) {
		super();
		this.gradeId = gradeId;
		this.gradeName = gradeName;
	}
	public Grade() {
		super();
	}
	@Override
	public String toString() {
		return "Grade [gradeId=" + gradeId + ", gradeName=" + gradeName + "]";
	}	
}

异常

cn.edu.xcu.sims.exception

StudentNameExistsException

public class StudentNameExistsException extends RuntimeException{
	public StudentNameExistsException(String e) {
		super(e);
	}	
}