本文主要讲解如何在springboot下整合mybatis，并访问数据库。由于mybatis这个框架太过于流行，所以我就不讲解了。
引入依赖
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter<artifactId>
<version>1.3.0</version>
</dependency>
引入数据库连接依赖：
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.29</version>
</dependency>
引入数据源
application.properties配置文件中引入数据源：
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
这样，springboot就可以访问数据了。
创建数据库表
建表语句：
-- create table `account`
# DROP TABLE `account` IF EXISTS
CREATE TABLE `account` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(20) NOT NULL,
`money` double DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;
INSERT INTO `account` VALUES ('1', 'aaa', '1000');
INSERT INTO `account` VALUES ('2', 'bbb', '1000');
INSERT INTO `account` VALUES ('3', 'ccc', '1000');
具体实现
这篇文篇通过注解的形式实现。
创建实体：
public class Account {
private int id ;
private String name ;
private double money;
setter...
getter...
}
dao层
@Mapper
public interface AccountMapper {
@Insert("insert into account(name, money) values(#{name}, #{money})")
int add(@Param("name") String name, @Param("money") double money);
@Update("update account set name = #{name}, money = #{money} where id = #{id}")
int update(@Param("name") String name, @Param("money") double money, @Param("id") int id);
@Delete("delete from account where id = #{id}")
int delete(int id);
@Select("select id, name as name, money as money from account where id = #{id}")
Account findAccount(@Param("id") int id);
@Select("select id, name as name, money as money from account")
List<Account> findAccountList();
}
service层
@Service
public class AccountService {
@Autowired
private AccountMapper accountMapper;
public int add(String name, double money) {
return accountMapper.add(name, money);
}
public int update(String name, double money, int id) {
return accountMapper.update(name, money, id);
}
public int delete(int id) {
return accountMapper.delete(id);
}
public Account findAccount(int id) {
return accountMapper.findAccount(id);
}
public List<Account> findAccountList() {
return accountMapper.findAccountList();
}
}
controller层，构建restful API
package com.forezp.web;
import com.forezp.entity.Account;
import com.forezp.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping("/account")
public class AccountController {
@Autowired
AccountService accountService;
@RequestMapping(value = "/list", method = RequestMethod.GET)
public List<Account> getAccounts() {
return accountService.findAccountList();
}
@RequestMapping(value = "/{id}", method = RequestMethod.GET)
public Account getAccountById(@PathVariable("id") int id) {
return accountService.findAccount(id);
}
@RequestMapping(value = "/{id}", method = RequestMethod.PUT)
public String updateAccount(@PathVariable("id") int id, @RequestParam(value = "name", required = true) String name,
@RequestParam(value = "money", required = true) double money) {
int t= accountService.update(name,money,id);
if(t==1) {
return "success";
}else {
return "fail";
}
}
@RequestMapping(value = "/{id}", method = RequestMethod.DELETE)
public String delete(@PathVariable(value = "id")int id) {
int t= accountService.delete(id);
if(t==1) {
return "success";
}else {
return "fail";
}
}
@RequestMapping(value = "", method = RequestMethod.POST)
public String postAccount(@RequestParam(value = "name") String name,
@RequestParam(value = "money") double money) {
int t= accountService.add(name,money);
if(t==1) {
return "success";
}else {
return "fail";
}
}
}
通过postman测试通过。
springboot 开启事物很简单，只需要加一行注解就可以了，前提你用的是jdbctemplate, jpa, mybatis，这种常见的orm。
事物
service层
@Service
public class AccountService2 {
@Autowired
AccountMapper2 accountMapper2;
@Transactional
public void transfer() throws RuntimeException{
accountMapper2.update(90,1);//用户1减10块 用户2加10块
int i=1/0;
accountMapper2.update(110,2);
}
}
@Transactional，声明事务，并设计一个转账方法，用户1减10块，用户2加10块。在用户1减10 ，之后，抛出异常，即用户2加10块钱不能执行，当加注解@Transactional之后，两个人的钱都没有增减。 当不加@Transactional，用户1减了10，用户2没有增加，即没有操作用户2 的数据。可见@Transactional注解开启了事物。
