[toc]
前言
最近公司app项目2.5进入了收尾阶段，基本Task也都完成了，也就剩下小部分的UI走查和重构，所以重拾下SpringBoot学习。
一开始就卡在了mybatis上面，实在是没用过...一开始还傻傻地问开发大佬：
redis和mybatis的区别啥的...哎，真惭愧。
hibernate和Mybatis的比较
这个我还了解得不多，等我网罗好资料再来完善
Mybatis 初步使用
项目结构
项目结构
导入MyBatis
在pom文件中导入
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.0</version>
</dependency>
导入MySql驱动
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
完整的pom文件如下：
<?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>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.Ly</groupId>
<artifactId>mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>mybatis</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- mysql 数据库驱动. -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.0</version>
</dependency>
<!-- 分页插件. 最低是4.1.5 -->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>4.2.1</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
配置
链接数据库配置
spring.datasource.url = jdbc:mysql://localhost:3306/blog?serverTimezone=UTC
spring.datasource.username = root
spring.datasource.password = 123456
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.max-active=20
spring.datasource.max-idle=8
spring.datasource.min-idle=8
spring.datasource.initial-size=10
logging.level.com.kfit=DEBUG
配置MyBatis
在application中配置Mapper扫描
@MapperScan("com.ly.mybatis.mapper")
@SpringBootApplication
public class MybatisApplication {
public static void main(String[] args) {
SpringApplication.run(MybatisApplication.class, args);
}
}
注意这里com.ly.mybatis.mapper对应的是我们包结构里面的mapper
搭建实体类
User类
/**
* Author: Ly
* Data：2018/12/19-22:41
* Description:
*/
public class User {
private int id;
private String name;
private Date updateTime;
private SexEnums sex;
private String email;
public User() {
}
public User(int id, String name, Date updateTime, SexEnums sex, String email) {
this.id = id;
this.name = name;
this.updateTime = updateTime;
this.sex = sex;
this.email = email;
}
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 Date getUpdateTime() {
return updateTime;
}
public void setUpdateTime(Date updateTime) {
this.updateTime = updateTime;
}
public SexEnums getSex() {
return sex;
}
public void setSex(SexEnums sex) {
this.sex = sex;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
定义Sex枚举
BaseEnum
/**
* Author: Ly
* Data：2018/12/20-21:08
* Description:
*/
public interface BaseEnum {
int getValue();
}
SexEnums
/**
* Author: Ly
* Data：2018/12/19-22:57
* Description:
*/
public enum SexEnums implements BaseEnum {
MAN(1), WOMEN(2);
SexEnums(int type) {
this.type = type;
}
int type;
@Override
public int getValue() {
return type;
}
}
枚举工具类
因为我们User里面使用了枚举，那前端该怎么传对应的值过来的？
在之前做安卓的时候有这种情况，解决方法一般是:
直接使用
因为是app内部，所以直接使用枚举类就ok了，虽然这个是废话...
枚举内部进行一个遍历
但是如果是app外部，比如说和vue交互的时候，这个方法就不可以了，所以我会在枚举里面做文章，这样vue只需要传对应的index就那可以。
public enum MODEL {
//关注，粉丝
FOLLOW("关注",0), FANS("粉丝",1);
private String name;
private int index;
MODEL(String name,int index){
this.name = name;
this.index = index;
}
public static String getName(int index){
for (MODEL m:MODEL.values()){
if (m.getIndex() == index){
return m.getName();
}
}
return null;
}
public static MODEL getType(int index){
for (MODEL m:MODEL.values()){
if (m.getIndex() == index){
return m;
}
}
return null;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getIndex() {
return index;
}
public void setIndex(int index) {
this.index = index;
}
}
使用Converter
不过上面的方法感觉都比较low，在springboot里面我们可以用比较新的方法
UniversalEnumConverterFactory
/**
* Author: Ly
* Data：2018/12/20-21:07
* Description:
*/
public class UniversalEnumConverterFactory implements ConverterFactory<String, BaseEnum> {
private static final Map<Class, Converter> converterMap = new WeakHashMap<>();
@Override
public <T extends BaseEnum> Converter<String, T> getConverter(Class<T> targetType) {
Converter result = converterMap.get(targetType);
if(result == null) {
result = new IntegerStrToEnum<T>(targetType);
converterMap.put(targetType, result);
}
return result;
}
class IntegerStrToEnum<T extends BaseEnum> implements Converter<String, T> {
private final Class<T> enumType;
private Map<String, T> enumMap = new HashMap<>();
IntegerStrToEnum(Class<T> enumType) {
this.enumType = enumType;
T[] enums = enumType.getEnumConstants();
for(T e : enums) {
enumMap.put(e.getValue() + "", e);
}
}
@Override
public T convert(String source) {
T result = enumMap.get(source);
if(result == null) {
throw new IllegalArgumentException("No element matches " + source);
}
return result;
}
}
}
MyWebAppConfigurer配置文件
/**
* Author: Ly
* Data：2018/12/20-21:06
* Description:
*/
@Configuration
class MyWebAppConfigurer extends WebMvcConfigurerAdapter {
@Override
public void addFormatters(FormatterRegistry registry) {
registry.addConverterFactory(new UniversalEnumConverterFactory());
}
}
定义需要的mapper
/**
* Author: Ly
* Data：2018/12/19-23:27
* Description:
*/
@Repository
public interface UserMapper {
@Select("select * from User where name =#{name}")
List<User> getUserListLikeName(String name);
@Select("select * from user")
List<User> findAllUser();
@Select("select * from User where id= #{id}")
User getUserById(long id);
@Insert("insert into User(name,email,sex,updateTime) values (#{name},#{email},#{sex},#{updateTime})")
@Options(useGeneratedKeys=true, keyColumn="id")
void insert(User user);
}
定义需要的Service
/**
* Author: Ly
* Data：2018/12/19-23:34
* Description:
*/
@Service
public class UserService {
private final UserMapper mUserMapper;
@Autowired
public UserService(UserMapper mUserMapper) {
this.mUserMapper = mUserMapper;
}
public void addUser(User user){
mUserMapper.insert(user);
}
public List<User> findAllUser(){
return mUserMapper.findAllUser();
}
public List<User> getUserLikeName(String name) {
return mUserMapper.getUserListLikeName(name);
}
}
定义需要的Controller
/**
* Author: Ly
* Data：2018/12/19-23:40
* Description:
*/
@RestController
class UserController {
private final UserService mUserService;
@Autowired
public UserController(UserService mUserService) {
this.mUserService = mUserService;
}
@GetMapping("/findAllUser")
public List<User> findAllUser(){
return mUserService.findAllUser();
}
@GetMapping("/getUserLikeName")
public List<User> getUserLikeName(@RequestParam(value = "name")String name){
return mUserService.getUserLikeName(name);
}
@PostMapping("/addUser")
public void addUser(User user){
user.setUpdateTime(new Date());
mUserService.addUser(user);
}
}
进行测试
查询数据
image.png
插入数据
image.png
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