✅作者简介：热爱国学的Java后端开发者，修心和技术同步精进。
本文目录
- 💖 什么是业务
- 💖 service开发流程（注册账号业务）
- ✨ 业务需求和逻辑
- ✨ 业务实现步骤
- 💫 创建表employee
- 💫 向employee表中插入数据
- 💫 封装实体类Employee
- 💫 编写EmployeeDaoImpl类（Dao层代码）
- 💫 编写EmployeeServiceImpl类（业务层代码）
- 💫 测试注册业务
- 💖 Service开发流程（转账业务）
- ✨ 业务需求和逻辑
- ✨ 业务实现步骤
- 💫 创建表account
- 💫 向account表中插入数据
- 💫 封装实体类Account
- 💫 编写AccountDaoImpl类（Dao层代码）
- 💫 编写AccountServiceImpl类（业务层代码）
- 💫 测试转账业务
- 💖 投票传送门
💖 什么是业务
（1）业务即用户完成的一个功能，可以有一个或者多个Dao的调用组成。（软件所提供的一个功能都叫业务）。
（2）你去银行取钱是一个业务，存钱是另一个业务，生活中你做的任何一件事都可以看成是一个业务。有的业务只需要一步就能完成，有的业务需要多个步骤才能完成。
💖 service开发流程（注册账号业务）
✨ 业务需求和逻辑
（1）业务需求：
- 注册一个employee账户，存入employee表中
（2）业务逻辑：
- 首先在数据库中查询你要注册的账号是否存在（根据身份证号码查询，身份证号码具有唯一性）
- 如果查询不到你想要注册的账号，则将你注册的账号存入employee表中
- 如果查询到了你要注册的账号名称，则提示账号已存在，不能注册
✨ 业务实现步骤
💫 创建表employee
CREATE TABLE IF NOT EXISTS `employee`(
`id` INT PRIMARY KEY AUTO_INCREMENT,
`name` VARCHAR(20) NOT NULL,
`age` INT NOT NULL,
`gender` VARCHAR(3),
`bornDate` DATE NOT NULL,
`identityCard` VARCHAR(18) UNIQUE NOT NULL,
`phone` VARCHAR(11) NOT NULL,
`email` VARCHAR(20) NOT NULL,
`address` VARCHAR(30) NOT NULL
);
💫 向employee表中插入数据
INSERT INTO `employee` VALUES(1001,'zhangsan',24,'男','1998-12-16','340825199812161316','13845687890','1319866912@qq.com','安徽合肥蜀山区');
INSERT INTO `employee` VALUES(1002,'lisi',25,'男','1997-12-26','340825199712261396','13845682233','1396548732@qq.com','安徽合肥瑶海区');
💫 封装实体类Employee
package com.cxyzxc.examples05;
import java.util.Date;
public class Employee {
/** 员工编号 */
private int id;
/** 姓名 */
private String name;
/** 年龄 */
private int age;
/** 性别 */
private String gender;
/** 出生日期 */
private Date bornDate;
/** 身份证号码 */
private String identityCard;
/** 手机号码 */
private String phone;
/** 邮箱 */
private String email;
/** 住址 */
private String address;
// 无参构造方法
public Employee() {
super();
}
// 有参构造方法
public Employee(String name, int age, String gender, Date bornDate,
String identityCard, String phone, String email, String address) {
super();
this.name = name;
this.age = age;
this.gender = gender;
this.bornDate = bornDate;
this.identityCard = identityCard;
this.phone = phone;
this.email = email;
this.address = address;
}
public Employee(int id, String name, int age, String gender, Date bornDate,
String identityCard, String phone, String email, String address) {
super();
this.id = id;
this.name = name;
this.age = age;
this.gender = gender;
this.bornDate = bornDate;
this.identityCard = identityCard;
this.phone = phone;
this.email = email;
this.address = address;
}
// getXxx()/setXxx()方法
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public Date getBornDate() {
return bornDate;
}
public void setBornDate(Date bornDate) {
this.bornDate = bornDate;
}
public String getIdentityCard() {
return identityCard;
}
public void setIdentityCard(String identityCard) {
this.identityCard = identityCard;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
// 重写Object类中的toString()方法
@Override
public String toString() {
return "id=" + id + ", name=" + name + ", age=" + age + ", gender="
+ gender + ", bornDate=" + bornDate + ", identityCard="
+ identityCard + ", phone=" + phone + ", email=" + email
+ ", address=" + address;
}
}
💫 编写EmployeeDaoImpl类（Dao层代码）
* （1）该类中提供对teacher表进行增、删、改、查单个、查所有5个方法。
*
* （2）该类中的代码只做数据库访问操作，不做任何业务逻辑操作。
*
* （3）该类只对数据库一张表进行操作，从而实现复用
package com.cxyzxc.examples05;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import com.cxyzxc.examples04.DBUtils;
import com.cxyzxc.examples04.DateUtils;
public class EmployeeDaoImpl {
// 新增：向employee表中插入一条数据（一条数据对应一个Employee对象）,插入成功，返回一个受影响行数值（int类型）
public int insert(Employee employee) {
Connection connection = null;
PreparedStatement preparedStatement = null;
String sql = "insert into `employee`(name,age,gender,bornDate,identityCard,phone,email,address) values(?,?,?,?,?,?,?,?);";
connection = DBUtils.getConnection();
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数，赋值
preparedStatement.setString(1, employee.getName());
preparedStatement.setInt(2, employee.getAge());
preparedStatement.setString(3, employee.getGender());
// 将java.util.Date类型日期时间转换为java.sql.Date类型，然后插入到数据库中
preparedStatement.setDate(4,
DateUtils.utilDateToSqlDate(employee.getBornDate()));
preparedStatement.setString(5, employee.getIdentityCard());
preparedStatement.setString(6, employee.getPhone());
preparedStatement.setString(7, employee.getEmail());
preparedStatement.setString(8, employee.getAddress());
// 执行SQL语句，返回受影响的行数值
int result = preparedStatement.executeUpdate();
// 将结果返回给调用者
return result;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return 0;
}
// 删除：根据员工id删除一条数据,删除成功，返回一个受影响行数值（int类型）
public int delete(int id) {
Connection connection = null;
PreparedStatement preparedStatement = null;
String sql = "delete from employee where id = ?;";
connection = DBUtils.getConnection();
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数，赋值
preparedStatement.setInt(1, id);
// 执行SQL语句，返回受影响的行数值
int result = preparedStatement.executeUpdate();
// 将结果返回给调用者
return result;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return 0;
}
// 修改：修改employee表中的数据，可能对任意的一个字段进行修改，所以方法中直接传递一个对象进行修改,修改成功，返回一个受影响行数值（int类型）
public int update(Employee employee) {
Connection connection = null;
PreparedStatement preparedStatement = null;
String sql = "update employee set name = ?,age = ?,gender = ?,bornDate = ?,identityCard = ?,phone = ?,email = ?,address = ? where id = ?;";
connection = DBUtils.getConnection();
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数，赋值
// 绑定参数，赋值
preparedStatement.setString(1, employee.getName());
preparedStatement.setInt(2, employee.getAge());
preparedStatement.setString(3, employee.getGender());
// 将java.util.Date类型日期时间转换为java.sql.Date类型，然后插入到数据库中
preparedStatement.setDate(4,
DateUtils.utilDateToSqlDate(employee.getBornDate()));
preparedStatement.setString(5, employee.getIdentityCard());
preparedStatement.setString(6, employee.getPhone());
preparedStatement.setString(7, employee.getEmail());
preparedStatement.setString(8, employee.getAddress());
preparedStatement.setInt(9, employee.getId());
// 执行SQL语句，返回受影响的行数值
int result = preparedStatement.executeUpdate();
// 将结果返回给调用者
return result;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return 0;
}
// 查询单个：根据员工id查询一条数据，查询成功返回一个结果集（ResultSet类型）,从结果集中取出元素，封装成一个Employee对象，将该对象返回
public Employee select(int id) {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
Employee employee = null;
String sql = "select * from employee where id = ?;";
connection = DBUtils.getConnection();
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数，赋值
preparedStatement.setInt(1, id);
resultSet = preparedStatement.executeQuery();
// 处理结果集，因为是查询单个数据，所以不需要循环遍历获取数据，集合中有数据就取出来
if (resultSet.next()) {
employee = new Employee();
int employeeid = resultSet.getInt("id");
String name = resultSet.getString("name");
int age = resultSet.getInt("age");
String gender = resultSet.getString("gender");
Date bornDate = resultSet.getDate("bornDate");
String identityCard = resultSet.getString("identityCard");
String phone = resultSet.getString("phone");
String email = resultSet.getString("email");
String address = resultSet.getString("address");
// 将获取的赋值给teacher对象
employee.setId(employeeid);
employee.setName(name);
employee.setAge(age);
employee.setGender(gender);
employee.setBornDate(bornDate);
employee.setIdentityCard(identityCard);
employee.setPhone(phone);
employee.setEmail(email);
employee.setAddress(address);
}
return employee;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return null;
}
// 查询单个：根据员工身份证号码查询一条数据，查询成功返回一个结果集（ResultSet类型）,从结果集中取出元素，封装成一个Employee对象，将该对象返回
public Employee select(String identityCard) {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
Employee employee = null;
String sql = "select * from employee where identityCard = ?;";
connection = DBUtils.getConnection();
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数，赋值
preparedStatement.setString(1, identityCard);
resultSet = preparedStatement.executeQuery();
// 处理结果集，因为是查询单个数据，所以不需要循环遍历获取数据，集合中有数据就取出来
if (resultSet.next()) {
employee = new Employee();
int employeeid = resultSet.getInt("id");
String name = resultSet.getString("name");
int age = resultSet.getInt("age");
String gender = resultSet.getString("gender");
Date bornDate = resultSet.getDate("bornDate");
String idCard = resultSet.getString("identityCard");
String phone = resultSet.getString("phone");
String email = resultSet.getString("email");
String address = resultSet.getString("address");
// 将获取的赋值给teacher对象
employee.setId(employeeid);
employee.setName(name);
employee.setAge(age);
employee.setGender(gender);
employee.setBornDate(bornDate);
employee.setIdentityCard(idCard);
employee.setPhone(phone);
employee.setEmail(email);
employee.setAddress(address);
}
return employee;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return null;
}
// 查询所有：将employee表中的所有数据全部查询出来，查询成功返回一个结果集（ResultSet类型）,从结果集中取出元素，封装成多个Employee对象，将多个对象存储在集合中，返回这个集合
public List<Employee> selectAll() {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
Employee employee = null;
List<Employee> employeeList = new ArrayList<Employee>();
String sql = "select * from employee;";
connection = DBUtils.getConnection();
try {
preparedStatement = connection.prepareStatement(sql);
resultSet = preparedStatement.executeQuery();
// 查询出来多个结果，存在resultSet结果集中，遍历该结果集
while (resultSet.next()) {
int employeeid = resultSet.getInt("id");
String name = resultSet.getString("name");
int age = resultSet.getInt("age");
String gender = resultSet.getString("gender");
Date bornDate = resultSet.getDate("bornDate");
String identityCard = resultSet.getString("identityCard");
String phone = resultSet.getString("phone");
String email = resultSet.getString("email");
String address = resultSet.getString("address");
employee = new Employee(employeeid, name, age, gender,
bornDate, identityCard, phone, email, address);
employeeList.add(employee);
}
return employeeList;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return null;
}
}
💫 编写EmployeeServiceImpl类（业务层代码）
* 注册账号的业务逻辑：
* 1、查询你要注册的员工是否存在（根据身份证号码进行查询）
* 2、如果要注册的员工不存在，就注册账号
* 3、如果注册的员工已经存在，就返回已经注册该员工
package com.cxyzxc.examples05;
public class EmployeeServiceImpl {
public void register(Employee employee) {
EmployeeDaoImpl employeeDaoImpl = new EmployeeDaoImpl();
// 1、查询你要注册的员工是否存在
Employee emp = employeeDaoImpl.select(employee.getIdentityCard());
// 2、如果要注册的员工不存在（emp为null），就注册账号
if (emp == null) {
employeeDaoImpl.insert(employee);
System.out.println("员工注册成功（数据插入成功）");
} else {
System.out.println("该员工已经注册（数据插入失败）");
}
}
}
💫 测试注册业务
package com.cxyzxc.examples05;
public class TestRegister {
public static void main(String[] args) {
EmployeeServiceImpl employeeServiceImpl = new EmployeeServiceImpl();
Employee employee = new Employee("赵六", 30, "男",
DateUtils.strDateToUtilDate("1992-11-29"),
"340825199211291123", "13877884455", "13877884455@qq.com",
"安徽合肥肥西");
employeeServiceImpl.register(employee);
}
}
💖 Service开发流程（转账业务）
✨ 业务需求和逻辑
（1）业务需求：
- 一个账户向另一个账户转账
（2）业务逻辑：
- 首先在数据库中查询转账账号是否存在
- 然后在数据库中查询转账账号密码是否存在
- 再验证转账账号的余额是否足够转账
- 再验证收款账号是否存在
- 执行转账操作，转账账号余额减少，收款账号余额增加（减少的金额与增加的金额相等）
✨ 业务实现步骤
💫 创建表account
CREATE TABLE IF NOT EXISTS `account`(
`cardNo` VARCHAR(20) PRIMARY KEY,
`pwd` VARCHAR(20) NOT NULL,
`name` VARCHAR(20) NOT NULL,
`balance` DOUBLE NOT NULL COMMENT '账户余额'
);
💫 向account表中插入数据
INSERT INTO account VALUES('6001','123456','zhangsan',10000);
INSERT INTO account VALUES('6002','123456','lisi',5000);💫 封装实体类Account
package com.cxyzxc.examples06;
public class Account {
/** 账号 */
private String cardNo;
/** 密码 */
private String pwd;
/** 用户名 */
private String name;
/** 账户余额 */
private double balance;
// 无参构造方法
public Account() {
super();
}
// 有参构造方法
public Account(String cardNo, String pwd, String name, double balance) {
super();
this.cardNo = cardNo;
this.pwd= pwd;
this.name = name;
this.balance = balance;
}
// getXxx()/setXxx()方法
public String getCardNo() {
return cardNo;
}
public void setCardNo(String cardNo) {
this.cardNo = cardNo;
}
public String getPassword() {
return pwd;
}
public void setPassword(String pwd) {
this.pwd= pwd;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
// 重写Object类中的toString()方法
@Override
public String toString() {
return "cardNo=" + cardNo + ", pwd=" + pwd+ ", name=" + name
+ ", balance=" + balance;
}
}
💫 编写AccountDaoImpl类（Dao层代码）
package com.cxyzxc.examples06;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class AccountDaoImpl {
// 新增：插入一个Account对象到数据库中
public int insert(Account account) {
Connection connection = null;
PreparedStatement preparedStatement = null;
connection = DBUtils.getConnection();
String sql = "insert into account values(?,?,?,?)";
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数
preparedStatement.setString(1, account.getCardNo());
preparedStatement.setString(2, account.getPassword());
preparedStatement.setString(3, account.getName());
preparedStatement.setDouble(4, account.getBalance());
// 执行SQL
int result = preparedStatement.executeUpdate();
return result;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return 0;
}
// 删除：根据卡号，删除账号
public int delete(String cardNo) {
Connection connection = null;
PreparedStatement preparedStatement = null;
connection = DBUtils.getConnection();
String sql = "delete from account where cardNo = ?;";
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数
preparedStatement.setString(1, cardNo);
// 执行SQL
int result = preparedStatement.executeUpdate();
return result;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return 0;
}
// 修改
public int update(Account account) {
Connection connection = null;
PreparedStatement preparedStatement = null;
connection = DBUtils.getConnection();
String sql = "update account set pwd= ?,name = ?,balance = ? where cardNo=?;";
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数
preparedStatement.setString(1, account.getPassword());
preparedStatement.setString(2, account.getName());
preparedStatement.setDouble(3, account.getBalance());
preparedStatement.setString(4, account.getCardNo());
// 执行SQL
int result = preparedStatement.executeUpdate();
return result;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, null);
}
return 0;
}
// 查询单个
public Account select(String cardNo) {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
Account account = null;
connection = DBUtils.getConnection();
String sql = "select * from account where cardNo = ?";
try {
preparedStatement = connection.prepareStatement(sql);
// 绑定参数
preparedStatement.setString(1, cardNo);
// 执行SQL
resultSet = preparedStatement.executeQuery();
if (resultSet.next()) {
String cardNumber = resultSet.getString("cardNo");
String pwd= resultSet.getString("pwd");
String name = resultSet.getString("name");
double balance = resultSet.getDouble("balance");
account = new Account(cardNumber, pwd, name, balance);
}
return account;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, resultSet);
}
return null;
}
// 查询所有
public List<Account> selectAll() {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
Account account = null;
List<Account> accountList = new ArrayList<Account>();
connection = DBUtils.getConnection();
String sql = "select * from account;";
try {
preparedStatement = connection.prepareStatement(sql);
// 执行SQL
resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
String cardNumber = resultSet.getString("cardNo");
String pwd= resultSet.getString("pwd");
String name = resultSet.getString("name");
double balance = resultSet.getDouble("balance");
account = new Account(cardNumber, pwd, name, balance);
accountList.add(account);
}
return accountList;
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtils.closeAll(connection, preparedStatement, resultSet);
}
return null;
}
}
💫 编写AccountServiceImpl类（业务层代码）
* 转账业务
* @param fromNo 转账人账号
* @param pwd 转账人账号密码
* @param toNo 收款人账号
* @param money 转账金额
package com.cxyzxc.examples06;
public class AccountServiceImpl {
public void transfer(String fromNo, String pwd, String toNo,
double money) {
AccountDaoImpl accountDaoImpl = new AccountDaoImpl();
try {
// 1.验证fromNo账号是否存在
Account fromAccount = accountDaoImpl.select(fromNo);
if (fromAccount == null) {
throw new RuntimeException("卡号不存在");
}
// 2.验证fromNo的密码是否正确
if (!fromAccount.getPassword().equals(pwd)) {
throw new RuntimeException("密码错误");
}
// 3.验证余额是否充足
if (fromAccount.getBalance() < money) {
throw new RuntimeException("余额不足");
}
// 4.验证toNo账号是否存在
Account toAccount = accountDaoImpl.select(toNo);
if (toAccount == null) {
throw new RuntimeException("对方卡号不存在");
}
// 5.减少fromNo账号的余额
fromAccount.setBalance(fromAccount.getBalance() - money);
accountDaoImpl.update(fromAccount);
// 6.增加toNo账号的余额
toAccount.setBalance(toAccount.getBalance() + money);
accountDaoImpl.update(toAccount);
System.out.println("转账成功");
} catch (Exception e) {
System.out.println("转账失败");
e.printStackTrace();
}
}
}
💫 测试转账业务
package com.cxyzxc.examples06;
public class TestTransfer {
public static void main(String[] args) {
AccountServiceImpl AccountServiceImpl = new AccountServiceImpl();
AccountServiceImpl.transfer("6001", "123456", "6002", 2000);
}
}
