SpringBoot--05.SpringBoot2.0学习小结

怼烎@ 2022-04-12 04:12 261阅读 0赞

### 1、SpringBoot2.0学习小结 ###

用springBoot创建项目时、只关注三点：《启动器》、《全局属性》、《启动类》

（1）、启动器 ： pom.xml配置依赖  
**父工程坐标**

<parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.0.4.RELEASE</version>
        </parent>

**添加web启动器**

<dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
        </dependencies>

**管理jdk版本**

**完整pom.xml**

（2）、全局属性：application.properties /application.yml

mybatis:
      type-aliases-package: com.day01sboot.pojo
      mapper-locations: classpath:mappers/**/*.xml
      configuration:
        map-underscore-to-camel-case: true
    
    
    spring:
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/mybatis?useSSL=false
        username: root
        password: sswqzx
    
    server:
      port: 8080

（3）、启动类Application.java

@SpringBootApplication
    @MapperScan("com.springcloud.mapper")//扫mapper包、不写就要在mapper接口上写
    public class Application {
    
        public static void main(String[] args) {
            SpringApplication.run(Application.class,args);
        }
    }

### 2、SpringBoot2.0整合SpringMvc ###

（1）、要在springboot中使用springmvc，只需要引入`spring-boot-starter-web`即可

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>

（2）、自定义配置springMVC就修改application.yml

# 映射端口
    server:
        port: 80

### 3、SpringBoot2.0整合Jdbc和事务 ###

(1)、在pom.xml添加SpringBoot提供的jdbc启动器

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>

（2）、数据库驱动

<dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

（3）、事务：哪里要处理事务就在哪里添加注解、@Transactional

@Transactional
        public void deleteById(Long id){
            this.userMapper.deleteByPrimaryKey(id);
        }

（4）、连接池参数、application.yml

spring:
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/mybatis
        username: root
        password: root

### 4、SpringBoot2.0整合连接池 ###

（1）、如果在pom.xml没有引入连接池启动器、SpringBoot自动帮我们引入了一个连接池 ：HikariCP 、名日：光

所以、只要在application.yml指定连接池参数就行了

spring:
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/mybatis
        username: root
        password: root

（2）、如果要要用其他的连接池、就在pom.xml引入依赖（启动器）

<dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.6</version>
    </dependency>

### 5、SpringBoot2.0整合mybatis ###

(1)启动器:也就是pom.xml依赖

<dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.2</version>
    </dependency>

（2）、全局属性：配置resources/application.yml

mybatis:
      # mybatis 别名扫描
      type-aliases-package: com.leyou.pojo
      # mapper.xml文件位置,如果没有映射文件，请注释掉
      mapper-locations: classpath:mappers/**/*.xml

注、mapper接口要么要接口上加@Mapper注解、要么在启动类上加扫包注解：@MapperScan("com.springboot01.mapper")

**（3）、三层事例：（思路、写全springboot三要点。启动器:pom.xml、启动类：app.java、全局属性：application.yml）**

**项目结构图：**

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**A、创建maven工程、引入依赖:启动器**

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pom.xml依赖、springboot叫启动器、父工程 、jdk版本、web启动器必引

注：不用的启动器不能乱引。会出bug

<?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.day01springboot</groupId>
        <artifactId>day01boot</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.0.4.RELEASE</version>
        </parent>
    
        
        <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.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>
    
        </dependencies>
    </project>

**B、编写相关类，启动类。。。(一个springboot只有一个启动类)**

**App.java**

package com.day01sboot;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 0:11 2018/12/1
     */
    @MapperScan("com.day01sboot.mapper")//扫包、不用在一个个在mapper接口上加
    @SpringBootApplication
    public class App {
        public static void main(String[] args) {
            SpringApplication.run(App.class,args);
        }
    }

**web层：controller/QueryController.java**

package com.day01sboot.controller;
    
    import com.day01sboot.pojo.User;
    import com.day01sboot.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 9:38 2018/12/1
     */
    @RestController
    @RequestMapping("user")
    public class QueryController {
    
        @Autowired
        private UserService userService;
    
        @RequestMapping("query/{id}")
        public User queryById(@PathVariable("id")Long id){
            return  userService.queryById(id);
        }
    }

**Service层：service/UserService.java接口**

package com.day01sboot.service;
    
    import com.day01sboot.pojo.User;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 9:44 2018/12/1
     */
    public interface UserService {
        User queryById(Long id);
    }

**Service层：service/UserServiceImpl.java实现类**

package com.day01sboot.service.Impl;
    
    import com.day01sboot.mapper.UserMapper;
    import com.day01sboot.pojo.User;
    import com.day01sboot.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 9:48 2018/12/1
     */
    @Service
    public class UserServiceImpl implements UserService {
    
        @Autowired
        private UserMapper userMapper;
    
        @Override
        public User queryById(Long id) {
           return userMapper.queryById(id);
        }
    }

**持久层：mapper/UserMapper.java接口**

package com.day01sboot.mapper;
    
    import com.day01sboot.pojo.User;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 0:55 2018/12/1
     */
    public interface UserMapper {
    
        User queryById(Long id);
    }

**映射文件、存放SQL语句：resources/mappers/UserMapper.xml**

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
            PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    
    <mapper namespace="com.day01sboot.mapper.UserMapper">
    
        <resultMap type="User" id="userMap" autoMapping="true">
            <id column="id" property="id"/>
        </resultMap>
    
    
        <sql id="commonSql">
          id,user_name,password,name,age,sex,birthday,created,updated
       </sql>
    
        <select id="queryById" resultMap="userMap">
            select <include refid="commonSql"></include> from tb_user where id = #{id}
        </select>
    
        <select id="findAllUsers" resultType="User">
            select <include refid="commonSql"></include> from tb_user
        </select>
    
        <insert id="insertUser" useGeneratedKeys="true" keyColumn="id" keyProperty="id">
            INSERT INTO tb_user (
            user_name,
            password,
            name,
            age,
            sex,
            birthday,
            created,
            updated
            )
            VALUES
            (
            #{userName},
            #{password},
            #{name},
            #{age},
            #{sex},
            #{birthday},
            NOW(),
            NOW()
            )
        </insert>
    
        <update id="updateUser">
            UPDATE tb_user set
            user_name = #{userName},
            password = #{password},
            name = #{name},
            age = #{age},
            sex = #{sex},
            birthday = #{birthday},
            updated = NOW()
            WHERE
            id = #{id}
        </update>
    
        <delete id="deleteUser">
            delete from tb_user where
            id = #{id}
        </delete>
    
        
        <select id="login" resultType="User">
            select * from tb_user where user_name = #{userName} and password = #{password}
        </select>
    
    </mapper>

**实体类：pojo/User.java**

package com.day01sboot.pojo;
    
    import java.io.Serializable;
    import java.util.Date;
    
    
    public class User implements Serializable {
    
        private static final long serialVersionUID = 1L;
    
        private Long id;
    
        // 用户名
        private String userName;
    
        // 密码
        private String password;
    
        // 姓名
        private String name;
    
        // 年龄
        private Integer age;
    
        // 性别，1男性，2女性
        private Integer sex;
    
        // 出生日期
        private Date birthday;
    
        // 创建时间
        private Date created;
    
        // 更新时间
        private Date updated;
    
        public Long getId() {
            return id;
        }
    
        public void setId(Long id) {
            this.id = 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 getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        public Integer getSex() {
            return sex;
        }
    
        public void setSex(Integer sex) {
            this.sex = sex;
        }
    
        public Date getBirthday() {
            return birthday;
        }
    
        public void setBirthday(Date birthday) {
            this.birthday = birthday;
        }
    
        public Date getCreated() {
            return created;
        }
    
        public void setCreated(Date created) {
            this.created = created;
        }
    
        public Date getUpdated() {
            return updated;
        }
    
        public void setUpdated(Date updated) {
            this.updated = updated;
        }
    
        @Override
        public String toString() {
            return "User [id=" + id + ", userName=" + userName + ", password=" + password + ", name=" + name
                    + ", age=" + age + ", sex=" + sex + ", birthday=" + birthday + ", created=" + created
                    + ", updated=" + updated + "]";
        }
    
    }

数据库：

**C、springboot配置文件、application.yml**

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《也学学大佬们、把源码传到github

**源码下载**：[https://github.com/sswqzx/day01boot][https_github.com_sswqzx_day01boot]

### 6、通用mapper.... ###

极其方便的使用mybatis单表的增删改查

支持单表、但不支持通用的多表联合查询

通用mapper使用：

### 继承通用的Mapper<T>，必须指定泛型<T> ###

泛型(实体类)<T>的类型必须符合的要求
    
    1、表名默认使用类名,驼峰转下划线(只对大写字母进行处理),如UserInfo默认对应的表名为user_info。
    
    2、表名可以使用@Table(name = "tableName")进行指定,对不符合第一条默认规则的可以通过这种方式指定表名.
    
    3、表字段默认为Java对象的Field名字驼峰转下划线形式.
    
    4、可以使用@Column(name = "fieldName")指定不符合第3条规则的字段名
    
    5、使用@Transient注解可以忽略字段,添加该注解的字段不会作为表字段使用.
    
    6、建议一定是有一个@Id注解作为主键的字段,可以有多个@Id注解的字段作为联合主键.

实例：

启动类：pom.xml

<?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">
        <parent>
            <artifactId>SpringCloud01</artifactId>
            <groupId>com.springclouds</groupId>
            <version>1.0-SNAPSHOT</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>com.springclouds</groupId>
        <artifactId>user-service</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>
            <dependency>
                <groupId>tk.mybatis</groupId>
                <artifactId>mapper-spring-boot-starter</artifactId>
            </dependency>
        </dependencies>
    
    </project>

启动类：App.java

package com.springcloud;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import tk.mybatis.spring.annotation.MapperScan;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 11:52 2018/11/30
     */
    @SpringBootApplication
    @MapperScan("com.springcloud.mapper")
    public class App {
        public static void main(String[] args) {
            SpringApplication.run(App.class,args);
        }
    }

相关类：

controller/UserController.java

package com.springcloud.controller;
    
    import com.springcloud.pojo.User;
    import com.springcloud.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 11:14 2018/11/30
     */
    @RequestMapping("/user")
    @RestController
    public class UserController {
    
        @Autowired
        private UserService userService;
    
        @RequestMapping("/{id}")
        public User queryById(@PathVariable("id")Long id){
            return userService.queryById(id);
        }
    }

service/UserService.java

package com.springcloud.service;
    
    import com.springcloud.mapper.UserMapper;
    import com.springcloud.pojo.User;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 11:46 2018/11/30
     */
    @Service
    public class UserService {
    
        @Autowired
        private UserMapper userMapper;
    
        public User queryById(Long id){
            return userMapper.selectByPrimaryKey(id);
        }
    }

mapper/UserMapper

package com.springcloud.mapper;
    
    import com.springcloud.pojo.User;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 11:47 2018/11/30
     */
    public interface UserMapper extends tk.mybatis.mapper.common.Mapper<User> {
    }

pojo/User.java

package com.springcloud.pojo;
    
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.Table;
    import java.util.Date;
    
    /**
     * @ Author     ：ShaoWei Sun.
     * @ Date       ：Created in 11:41 2018/11/30
     */
    @Table(name = "tb_user")
    public class User {
        private static final Long serialVersionUID = 1L;
    
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Long id;
        // 用户名
        private String userName;
    
        // 密码
        private String password;
    
        // 姓名
        private String name;
    
        // 年龄
        private Integer age;
    
        // 性别，1男性，2女性
        private Integer sex;
    
        // 出生日期
        private Date birthday;
    
        // 创建时间
        private Date created;
    
        // 更新时间
        private Date updated;
    
        public static Long getSerialVersionUID() {
            return serialVersionUID;
        }
    
        public Long getId() {
            return id;
        }
    
        public void setId(Long id) {
            this.id = 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 getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        public Integer getSex() {
            return sex;
        }
    
        public void setSex(Integer sex) {
            this.sex = sex;
        }
    
        public Date getBirthday() {
            return birthday;
        }
    
        public void setBirthday(Date birthday) {
            this.birthday = birthday;
        }
    
        public Date getCreated() {
            return created;
        }
    
        public void setCreated(Date created) {
            this.created = created;
        }
    
        public Date getUpdated() {
            return updated;
        }
    
        public void setUpdated(Date updated) {
            this.updated = updated;
        }
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", userName='" + userName + '\'' +
                    ", password='" + password + '\'' +
                    ", name='" + name + '\'' +
                    ", age=" + age +
                    ", sex=" + sex +
                    ", birthday=" + birthday +
                    ", created=" + created +
                    ", updated=" + updated +
                    '}';
        }
    }

全局属性：resources/application.yml

server:
      port: 8081
    
    spring:
      datasource:
        url: jdbc:mysql://localhost:3306/mybatis
        username: root
        password: sswqzx
    
    mybatis:
      type-aliases-package: com.springcloud.pojo

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源码：[https://github.com/sswqzx/SpringCloud01][https_github.com_sswqzx_SpringCloud01]

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[https_github.com_sswqzx_day01boot]: https://github.com/sswqzx/day01boot
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[https_github.com_sswqzx_SpringCloud01]: https://github.com/sswqzx/SpringCloud01