一步一步教你构建springboot_springboot1.x版本-优快云博客

本文链接：https://blog.youkuaiyun.com/wanglitaow/article/details/126122390

一步一步构建springboot

1 初始化springboot


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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

2 添加swagger

参考文章： springboot 2.7.0 配置swagger 3_Lab_l的博客-优快云博客

springboot 2.7.0 配置swagger 3

2.1：pom.xml 添加依赖使用新版UI

        <dependency>
            <groupId>com.github.xiaoymin</groupId>
            <artifactId>knife4j-spring-boot-starter</artifactId>
            <!--在引用时请在maven中央仓库搜索3.X最新版本号-->
            <version>3.0.3</version>
        </dependency>

2.2：在启动类Application中加上注解

package com.example.swagger;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import springfox.documentation.oas.annotations.EnableOpenApi;

@SpringBootApplication(exclude={DataSourceAutoConfiguration.class})
//exclude={DataSourceAutoConfiguration.class}：在没有连接数据库的情况下进行测试
@EnableOpenApi
public class SwaggerApplication {
    public static void main(String[] args) {
        SpringApplication.run(SwaggerApplication.class, args);
    }
}

第2.3：配置接口文档config

package com.example.swagger.config;

import io.swagger.annotations.ApiOperation;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.oas.annotations.EnableOpenApi;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;

@Configuration
@EnableOpenApi
public class SwaggerConfig {
    @Bean
    public Docket createRestApi(){
        return new Docket(DocumentationType.OAS_30)
                .apiInfo(apiInfo())
                .select()
                .apis(RequestHandlerSelectors.withMethodAnnotation(ApiOperation.class))
                .paths(PathSelectors.any())
                .build();
    }

private ApiInfo apiInfo(){
    return new ApiInfoBuilder()
            .title("Swagger3接口文档")
            .description("前后端分离的接口文档")
            .version("1.0")
            .build();
}

}

2.4 在application.properties文件中加入语句

spring.mvc.pathmatch.matching-strategy: ANT_PATH_MATCHER

2.7.0同样不支持swagger3的折衷配置，考虑升级Springboot版本或降级版本

除了参考中的springboot 2.6会有这样的问题，2.7也存在这样的问题，

如果不加的话会报错

Cause by：Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException错误原因：Springfox使用的路径匹配是基于AntPathMatcher的，而Spring Boot 2.6.X使用的是PathPatternMatcher

2.5 打开地址

http://localhost:8081/swagger-ui/index.html

3 支持mysql

Spring Boot 入门（六）使用MySQL - 小小渔 - 博客园

3.1 添加pom依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

3.2 添加配置


# 数据库设置
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

3.3 代码

package com.example.demo.controller;

import org.springframework.beans.factory.annotation.Autowired;import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class HelloWorldController {
    @Autowired
    JdbcTemplate jdbcTemplate;

    @RequestMapping("/hello")
    public String index() {
        return "Hello World";
    }

    @RequestMapping("/setMySQLKey")
    public String setMySQLKey(String val) {
        String sql = "INSERT INTO test_table(`name`) VALUES(?)";
        jdbcTemplate.update(sql, new Object[]{val});
        return "true";
    }

    @RequestMapping("/getMySQLKey")
    public List<String> getMySQLKey() {
        String sql = "SELECT name FROM test_table";
        List<String> nameList = jdbcTemplate.queryForList(sql, String.class);
        return nameList;
    }
}

4 支持mybatis

mybatis支持自定义sql和注解上写sql

4.1 pom 配置

 <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

4.2 配置文件配置

xml 文件放到resouces文件下的mapper文件下

mybatis.mapper-locations: classpath:mapper/*.xml

在Application启动文件配置扫描持久化层的路径的注解@MapperScan

@MapperScan(value = "com.wlt.plus.mapper")

4.3 添加代码

com.wlt.plus.mapper 中配置自定义的slq 和xml中的sql

package com.wlt.plus.mapper;


import com.wlt.plus.entity.Student;
import org.apache.ibatis.annotations.*;
import org.springframework.stereotype.Repository;

import java.util.List;

@Mapper
@Repository
public interface StudentMapper {
    @Select("select * from student limit 2 ")
    List<Student> getAllStudent();

    @Insert("insert into student(id,name)values(#{id},#{name})")
    int addStudent(Student student);

    @Update("update student set name=#{name} where id=#{id}")
    int updateStudent(Student student);

    @Delete("delete from student where id=#{id}")
    int delStudent(String id);

    List<Student> getAllStudent1();

    int updateStudent1(Student student);

    int delStudent1(String id);



}

student.xml 中的内容

<?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.wlt.plus.mapper.StudentMapper">
    <select id="getAllStudent1" resultType="com.wlt.plus.entity.Student">
        select * from student limit 10
    </select>

    <update id="updateStudent1">
        update student set name=#{name} where id=#{id}
    </update>

    <delete id="delStudent1">
        delete from student where id=#{id}
    </delete>
</mapper>

实体文件代码注意这里使用了lombok的插件

package com.wlt.plus.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data //使用lombok减少get、set、有参无参构造函数、tostring等方法的冗余
@AllArgsConstructor
@NoArgsConstructor
public class Student {
    private Long id;
    /**
     * 姓名
     */
    private String name;

    /**
     * 年龄
     */
    private Integer age;
    /**
     * 邮箱
     */
    private String email;
}

controller 使用配置

 

@RestController
@RequestMapping("/test")
public class StudentController {

    @Autowired
    private StudentMapper studentMapper;

    @ApiOperation("查询")
    @GetMapping("/getStudentAll")
    public List<Student> getStudentAll(){
        return studentMapper.getAllStudent1();
    }

    @ApiOperation("增加")
    @GetMapping("/addStudent")
    public List<Student> addStudent(){
        Student stu=new Student();
        stu.setName("测试");
        studentMapper.addStudent(stu);
        return studentMapper.getAllStudent();
    }

    @ApiOperation("改变")
    @GetMapping("/updateStudent")
    public List<Student> updateStudent(){
        Student stu=new Student();
        stu.setEmail("f2adf775-3cfa-4e25-97bc-ec5676e15594");
        stu.setName("修改了用户");
        studentMapper.updateStudent(stu);
        return studentMapper.getAllStudent();
    }

    @ApiOperation("删除")
    @GetMapping("/delStudent")
    public List<Student> delStudent(){
        String stuId="f2adf775-3cfa-4e25-97bc-ec5676e15594";
        studentMapper.delStudent(stuId);
        return studentMapper.getAllStudent();
    }

}

5 支持数据源Druid

springboot 学习（五） springboot使用druid - 黄易安 - 博客园

5.1 pom 配置

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.3</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

5.2 配置文件中切换数据源，同时配置druid属性

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

### 连接池配置

spring.datasource.initialSize=1
spring.datasource.minIdle=2
spring.datasource.maxActive=2
# 配置获取连接等待超时的时间
spring.datasource.maxWait=60000
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
spring.datasource.timeBetweenEvictionRunsMillis=60000
# 配置一个连接在池中最小生存的时间，单位是毫秒
spring.datasource.minEvictableIdleTimeMillis=300000
spring.datasource.validationQuery=SELECT 1 FROM DUAL
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
# 打开PSCache，并且指定每个连接上PSCache的大小
spring.datasource.poolPreparedStatements=true
spring.datasource.maxPoolPreparedStatementPerConnectionSize=20

5.3 添加代码

由于DruidDataSource需要使用上述的配置，在添加到容器中，就不能使用springboot自动生成，这时需要我们自己添加 DruidDataSource 组件到容器中，并绑定属性；代码如下

@Configuration
public class DruidConfig {

    /*
       将自定义的 Druid数据源添加到容器中，不再让 Spring Boot 自动创建
       绑定全局配置文件中的 druid 数据源属性到 com.alibaba.druid.pool.DruidDataSource从而让它们生效
       @ConfigurationProperties(prefix = "spring.datasource")：作用就是将 全局配置文件中
       前缀为 spring.datasource的属性值注入到 com.alibaba.druid.pool.DruidDataSource 的同名参数中
     */
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druidDataSource() {
        return new DruidDataSource();
    }




    //配置 Druid 监控管理后台的Servlet；
    //内置 Servlet 容器时没有web.xml文件，所以使用 Spring Boot 的注册 Servlet 方式
    @Bean
    public ServletRegistrationBean a(){
        ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");

        Map<String, String> initParameters = new HashMap<>();
        initParameters.put("loginUsername","admin");
        initParameters.put("loginPassword","12346");
        bean.setInitParameters(initParameters);
        return  bean;
    }


## 配置过滤请求，需要统计哪些sql的信息 

    //配置 Druid 监控 之  web 监控的 filter
//WebStatFilter：用于配置Web和Druid数据源之间的管理关联监控统计
    @Bean
    public FilterRegistrationBean webStatFilter() {
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());

        //exclusions：设置哪些请求进行过滤排除掉，从而不进行统计
        Map<String, String> initParams = new HashMap<>();
        initParams.put("exclusions", "*.js,*.css,/druid/*,/jdbc/*");
        bean.setInitParameters(initParams);

        //"/*" 表示过滤所有请求
        bean.setUrlPatterns(Arrays.asList("/*"));
        return bean;
    }

5.4 登录验证

配置完毕后，我们可以选择访问：http://localhost:8081/druid/login.html

6 支持mybatisPlus

切换分支plus

6.1 pom 支持

     <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.5</version>
        </dependency>

6.2 代码

CREATE TABLE `money` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(20) NOT NULL DEFAULT '' COMMENT '用户名',
  `money` int(26) NOT NULL DEFAULT '0' COMMENT '有多少钱',
  `is_deleted` tinyint(1) NOT NULL DEFAULT '0',
  `create_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `update_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
  PRIMARY KEY (`id`),
  KEY `name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8mb4;

添加MapperScan

@MapperScan(value = "com.wlt.plus.mapper")

添加domain 对应的表结构的bean

@Data
public class Money {
    @TableId(type = IdType.AUTO)   // 自增策略
    private Integer id;
    private String name;
    private Long money;
    private Integer isDeleted;
    private Timestamp createAt;
    private Timestamp updateAt;
}

添加Mapper

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.wlt.plus.entity.Money;
public interface MoneyMapper extends BaseMapper<Money> {}

应用

 Money po = new Money();
        po.setName("mybatis plus user");
        Random random = new Random();
        po.setMoney(222L);
        po.setIsDeleted(0);
        // 添加一条数据
        po.setIsDeleted(0);
        moneyMapper.insert(po);

        // 查询
        List<Money> list = moneyMapper.selectList(new QueryWrapper<Money>().lambda().eq(Money::getName, po.getName()));
        System.out.println("after insert: " + list);

        // 修改
        po.setMoney(po.getMoney() + 300);
        moneyMapper.updateById(po);
        System.out.println("after update: " + moneyMapper.selectById(po.getId()));

        // 删除
//        moneyMapper.deleteById(po.getId());

        // 查询
        HashMap<String, Object> queryMap = new HashMap<>(2);
        queryMap.put("name", po.getName());
        System.out.println("after delete: " + moneyMapper.selectByMap(queryMap));

6.3 自动生成

代码生成器（新） | MyBatis-Plus