SpringBoot之事務管理Transactional

以前學ssh ssm都有事務管理service層通過applicationContext.xml配置，所有service方法都加上事務操作；

用來保證一致性，即service方法里的多個dao操作，要么同時成功，要么同時失敗；

springboot下的話 一個@Transactional即可搞定；

我們這里搞一個實例，轉賬實例，A用戶轉賬給B用戶xx元

設計如下：

Account類

package com.hik.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

/**
 * 賬戶實體
 * @author jed
 *
 */
@Entity
@Table(name="t_account")
public class Account {

    @Id
    @GeneratedValue
    private Integer id;
    
    @Column(length=50)
    private String userName;
    
    private float balance;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public float getBalance() {
        return balance;
    }

    public void setBalance(float balance) {
        this.balance = balance;
    }
    
    
}

id 編號 userName用戶名 balance余額

運行啟動類，數據庫里我們加兩個數據

新建AccountDao接口

package com.hik.dao;

import org.springframework.data.jpa.repository.JpaRepository;

import com.hik.entity.Account;

/**
 *  賬戶Dao接口
 * @author jed
 *
 */
public interface AccountDao extends JpaRepository<Account, Integer>{
    
}

AccountService接口

package com.hik.service;

/**
 * 帳號Service接口
 * @author jed
 *
 */
public interface AccountService {

    public void transferAccounts(int fromUser,int toUser,float account);
}

AccountServiceImpl接口實現類

package com.hik.service.impl;

import javax.annotation.Resource;

import org.springframework.stereotype.Service;

import com.hik.dao.AccountDao;
import com.hik.entity.Account;
import com.hik.service.AccountService;

/**
 * 帳號Service實現類
 * @author jed
 *
 */
@Service("accountService")
public class AccountServiceImpl implements AccountService{

    @Resource
    private AccountDao accountDao;
    
    @Override
    public void transferAccounts(int fromUser, int toUser, float account) {
        Account fromUserAccount = accountDao.getOne(fromUser);
        fromUserAccount.setBalance(fromUserAccount.getBalance()-account);
        accountDao.save(fromUserAccount); // fromUser扣錢
        
        Account toUserAccount = accountDao.getOne(toUser);
        toUserAccount.setBalance(toUserAccount.getBalance()+account);
        accountDao.save(toUserAccount);// toUser加錢
    }

}

AccountController類

package com.hik.Controller;

import javax.annotation.Resource;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.hik.service.AccountService;

/**
 * 賬戶Controoler類
 * @author jed
 *
 */
@RestController
@RequestMapping("/account")
public class AccountController {
    
    @Resource
    private AccountService accountService;

    @RequestMapping("/transfer")
    public String transferAccounts() {
        try {
            accountService.transferAccounts(1, 2, 200);
            return "ok";
        }catch(Exception e) {
            return "no";
        }
    }
}

application.yml

server: 
    port: 80
    context-path: /

spring: 
    datasource: 
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/db_bank
      username: root
      password: passwd
    jpa: 
      hibernate:
        ddl-auto: update
      show-sql: true

 

我們執行啟動類

瀏覽器輸入：http://localhost/account/transfer

運行OK

查看數據庫表

 

OK 我們先把數據恢復到700  300

現在我們把service層方法改下 

package com.hik.service.impl;

import javax.annotation.Resource;

import org.springframework.stereotype.Service;

import com.hik.dao.AccountDao;
import com.hik.entity.Account;
import com.hik.service.AccountService;

/**
 * 帳號Service實現類
 * @author jed
 *
 */
@Service("accountService")
public class AccountServiceImpl implements AccountService{

    @Resource
    private AccountDao accountDao;
    
    @Override
    public void transferAccounts(int fromUser, int toUser, float account) {
        Account fromUserAccount = accountDao.getOne(fromUser);
        fromUserAccount.setBalance(fromUserAccount.getBalance()-account);
        accountDao.save(fromUserAccount); // fromUser扣錢
        
        Account toUserAccount = accountDao.getOne(toUser);
        toUserAccount.setBalance(toUserAccount.getBalance()+account);
        int zero =1/0;
        accountDao.save(toUserAccount);// toUser加錢
    }

}

 

這時候 扣錢dao能執行成功  加錢操作執行不了了 因為前面會報錯

 

我們重啟啟動類

瀏覽器輸入：http://localhost/account/transfer

運行NO

查看數據庫

 

這時候 錢扣了 但是 沒加錢  導致了數據不一致性

 

這時候 我們需要用上事務

在service方法上加上@Transactional即可

 

package com.hik.service.impl;

import javax.annotation.Resource;
import javax.transaction.Transactional;

import org.springframework.stereotype.Service;

import com.hik.dao.AccountDao;
import com.hik.entity.Account;
import com.hik.service.AccountService;

/**
 * 帳號Service實現類
 * @author jed
 *
 */
@Service("accountService")
public class AccountServiceImpl implements AccountService{

    @Resource
    private AccountDao accountDao;
    
    @Transactional
    public void transferAccounts(int fromUser, int toUser, float account) {
        Account fromUserAccount = accountDao.getOne(fromUser);
        fromUserAccount.setBalance(fromUserAccount.getBalance()-account);
        accountDao.save(fromUserAccount); // fromUser扣錢
        
        Account toUserAccount = accountDao.getOne(toUser);
        toUserAccount.setBalance(toUserAccount.getBalance()+account);
        int zero =1/0;
        accountDao.save(toUserAccount);// toUser加錢
    }

}

 

 

我們恢復下數據700  300

然后再重啟啟動類，

瀏覽器輸入：http://localhost/account/transfer

運行NO

 

 

但是數據庫數據沒變化 說明啟動作用了。

 

 

 OK，保證事務一致性，方法上加Transactional即可。