SpringBoot 整合Mybatis (1) 通过Mappe
2019-12-18 本文已影响0人
X_xxieRiemann
通用mapper文档
文件结构目录：
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pom.xml：
添加mybatis、mysql、mapper、web依赖，这里的mapper和mybatis均会关联jdbc的依赖，所以可以不添加jdbc的依赖。web只是为了方便测试，并非必须。
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.bingo</groupId>
<artifactId>springboot-mybatis</artifactId>
<version>1.0.0-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.6.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--mybatis -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<!-- 通用mapper -->
<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper-spring-boot-starter</artifactId>
<version>2.0.2</version>
</dependency>
<!--jdbc的启动器，默认使用HikariCP连接池-->
<!-- <dependency>-->
<!-- <groupId>org.springframework.boot</groupId>-->
<!-- <artifactId>spring-boot-starter-jdbc</artifactId>-->
<!-- </dependency>-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
</dependencies>
</project>
在resources资源文件夹中添加application.yml：
spring:
datasource:
url: jdbc:mysql://localhost:3306/springbootmybatis?characterEncoding=UTF-8&useSSL=false
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver
mybatis:
type-aliases-package: com.demo.pojo
添加实体类：
这里需要一些注解来声明主键，实体类成员变量命名与数据库中存放的一致。这边默认有驼峰命名到下划线命名的这种转换关系，可以参考文档关闭自动转换。一旦有一个不匹配，直接返回错误。
可以通过@Column(name = "数据库内的名字")来注解实体类成员变量，从而实现映射。
package com.demo.pojo;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
private Integer id;
private String username;
private String password;
private String realname;
public Integer getId() {
return id;
}
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;
}
public String getRealname() {
return realname;
}
public void setRealname(String realname) {
this.realname = realname;
}
public void setId(Integer id) {
this.id = id;
}
}
添加mapper接口：
由于继承了Mapper<T>类，所以已经有很多增删改查的方法可以调用了。
package com.demo.mapper;
import com.demo.pojo.User;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface UserMapper extends tk.mybatis.mapper.common.Mapper<User> {
}
添加引导类：
用@MapperScan扫描mapper包下的接口。
package com.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import tk.mybatis.spring.annotation.MapperScan;
@SpringBootApplication
@MapperScan("com.demo.mapper")
public class ApplicationBoot {
public static void main(String[] args) {
SpringApplication.run(ApplicationBoot.class, args);
}
}
定义service接口：
定义增删改查的抽象方法。
package com.demo.service;
import com.demo.pojo.User;
import java.util.List;
public interface UserService {
/**
* 根据id查询某一个具体的User
*
* @param id
* @return
*/
User queryById(int id);
/**
* 查询全体User信息
*
* @return
*/
List<User> queryAll();
/**
* 根据id删除掉某个User
*
* @param id
* @return
*/
int deleteById(int id);
/**
* 更新一个用户信息
*
* @param id
* @param username
* @param password
* @param realname
* @return
*/
int updateUser(int id, String username, String password, String realname);
/**
* 添加一个用户
*
* @param username
* @param password
* @return
*/
int insertUser(String username, String password);
}
定义service的实现类：
调用Mapper类里面提供的方法，来执行SQL语句。
package com.demo.service.impl;
import com.demo.mapper.UserMapper;
import com.demo.pojo.User;
import com.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
@Override
public User queryById(int id) {
return this.userMapper.selectByPrimaryKey(id);
}
@Override
public List<User> queryAll() {
return this.userMapper.selectAll();
}
@Override
@Transactional
public int deleteById(int id) {
return this.userMapper.deleteByPrimaryKey(id);
}
@Override
@Transactional
public int updateUser(int id, String username, String password, String realname) {
User user = new User();
user.setId(id);
user.setUsername(username);
user.setPassword(password);
user.setRealname(realname);
return this.userMapper.updateByPrimaryKey(user);
}
@Override
@Transactional
public int insertUser(String username, String password) {
User user = new User();
user.setUsername(username);
user.setPassword(password);
return this.userMapper.insert(user);
}
}
写controller层进行测试：
package com.demo.controller;
import com.demo.pojo.User;
import com.demo.service.impl.UserServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
// 用于测试
@RestController
@RequestMapping("user")
public class UserController {
@Autowired
private UserServiceImpl userServiceImpl;
// select
@RequestMapping(value = "/all", method = RequestMethod.GET)
public List<User> getAllUsers() {
return userServiceImpl.queryAll();
}
// select
@RequestMapping(value = "/{id}", method = RequestMethod.GET)
public User getUserById(@PathVariable("id") int id) {
return userServiceImpl.queryById(id);
}
// update
@RequestMapping(value = "/{id}", method = RequestMethod.PUT)
public String updateAccount(@PathVariable("id") int id,
@RequestParam(value = "username", required = true) String username,
@RequestParam(value = "password", required = true) String password,
@RequestParam(value = "realname", required = true) String realname) {
int t = userServiceImpl.updateUser(id, username, password, realname);
if (t == 1) {
return "success";
} else {
return "fail";
}
}
// delete
@RequestMapping(value = "/{id}", method = RequestMethod.DELETE)
public String delete(@PathVariable(value = "id") int id) {
int t = userServiceImpl.deleteById(id);
if (t == 1) {
return "success";
} else {
return "fail";
}
}
// post
@RequestMapping(value = "", method = RequestMethod.POST)
public String postAccount(@RequestParam(value = "username") String username,
@RequestParam(value = "password") String password) {
int t = userServiceImpl.insertUser(username, password);
if (t == 1) {
return "success";
} else {
return "fail";
}
}
@GetMapping("hello")
public String test() {
return "hello mybatis";
}
}
通过postman测试成功。
补充说明：
一些注解：
Mybatis中用到的注解：
在实体类中：命名最好与数据库一致，注意userName这种小驼峰命名，会被解析成user_name来执行SQL语句。
1、表名
@Table(name = "tb_user")
1、修饰id主键，没有注解的话会使得Mapper<T>里的方法无法使用。但是如果用的是其他方法来执行SQL语句，则没有关系。
@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
2、用户名
@Length(min = 4,max = 15,message = "用户名只能在4~15位之间")
3、密码
@JsonIgnore
@Length(min = 6,max = 25,message = "密码只能在6~25位之间")
4、手机号
@Pattern(regexp = "^1[35678]\\d{9}$", message = "手机号格式不正确")
package com.leyou.user.pojo;
import com.fasterxml.jackson.annotation.JsonIgnore;
import org.hibernate.validator.constraints.Length;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.validation.constraints.Pattern;
import java.util.Date;
/**
* @Author: 98050
* @Time: 2018-10-21 18:42
* @Feature: 用户实体类
*/
@Table(name = "tb_user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
/**
* 用户名
*/
@Length(min = 4,max = 15,message = "用户名只能在4~15位之间")
private String username;
/**
* 密码
*/
@JsonIgnore
@Length(min = 6,max = 25,message = "密码只能在6~25位之间")
private String password;
/**
* 电话
*/
@Pattern(regexp = "^1[35678]\\d{9}$", message = "手机号格式不正确")
private String phone;
/**
* 创建时间
*/
private Date created;
//Getter和Setter
//.......................
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", phone='" + phone + '\'' +
", created=" + created +
'}';
}
}
@Transactional
声明是 Spring 的事务管理，用的必须是jdbctemplate, jpa, mybatis，这种常见的orm。
@Transient
表示该属性并非一个到数据库表的字段的映射,ORM框架将忽略该属性.
@MapperScan("com.demo.mapper")
加入引导类，用于扫描mapper包下的Mapper类，加入到IoC容器中。
@org.apache.ibatis.annotations.Mapper
用于mapper类，声明这是一个Mapper接口
SQL方法：
增：
int insert(T t)
int insertSelective(T t):Selective表示不必完整地给实体类赋值
insertSelective和insert的区别？
删：
int delete(T t)
int deleteByExample(object o)
int deleteByPrimaryKey(Object id)
查：
T selectByPrimaryKey(object id)：根据主键查找实体T，在实体类定义的时候必须添加@Id声明主键
List<T> select(T t)
List<T> selectAll()
List<T> selectByExample(Objcet o)
List<T> selectByExampleAndRowBounds(Object o, ssss)
List<T> selectByRowBounds(T t, xxxx)
T selectOne(T t)
T selectOneByExample(Object o)
int selectCount(T t)
int selectCountByExample(Object o)
改：
int updateByExample(T t, Object o)
int updateByExampleSelective(T t, Object o)
int updateByPrimaryKey(T t)
int updateByPrimaryKeySelective(T t)
其他：
boolean existsWithPrimaryKey(object o)
