Springboot automatic configuration principle, install Lombok plug-in, @Slf4j

One, Springboot automatic configuration principle

1. A lot of automatic configuration classes are defined in the META-INF\spring.fatories file; you can rely on automatic configuration components based on the starter added in the pom.xml file
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2. Through the following process, you can modify the application configuration file and change the default parameters of the automatically configured components
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eg:

Two, Lombok

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Add @Data to javabean, then you can omit the writing of getter and setter methods, and the lombok plug-in will be automatically generated.

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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">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.3</version>

    </parent>
    <groupId>cn.itcast</groupId>
    <artifactId>Spingboot_day1</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <java.version>1.9</java.version>
    </properties>

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

        <!--java配置配置数据库要的-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>

        <!--Spring Boot的属性注入需要的-->
        <dependency>
            <groupId> org.springframework.boot </groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <!--不传递依赖-->
            <optional>true</optional>
        </dependency>

        <!--lombok需要的-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
</project>

Entity class:
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package com.itheima.pojo;

import lombok.Data;
import lombok.extern.slf4j.Slf4j;

import java.util.Date;

/**
 * @author QLBF
 * @version 1.0
 * @date 2021/2/21 17:30
 */
//在编译阶段会根据注解自动生成对应的方法；data包含get/set/hashCode/equals/toString等方法
@Data

public class User {
    
    

    private Long id;
    private String user_name;
    private String password;
    private String name;
    private Integer age;
    private Integer sex;
    private Date birthday;
    private String note;
    private Date created;
    private Date updated;

}

You can add @Slf4j to the class to use log, such as:
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