创建Springboot项目

阿里云Spring Server URL : http://start.aliyun.com

Spring Initializr - SpringBoot Server URL : http://start.spring.io

​

SpringBoot Maven依赖

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.sybkl</groupId>
    <artifactId>TestBackEnd</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>TestBackEnd</name>
    <description>TestBackEnd</description>
    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.12.RELEASE</spring-boot.version>
    </properties>
    <dependencies>
        <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>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>2.0.25</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.3</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.16</version>
        </dependency>

        <!-- mybatis-plus 代码生成器-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.5.3.1</version>
        </dependency>
        <!-- 在mybatis-plus的代码生成器中需要导入freemarker的依赖-->
        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>${spring-boot.version}</version>
                <configuration>
                    <mainClass>com.sybkl.testbackend.TestBackEndApplication</mainClass>
                    <skip>true</skip>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

说明：使用mybatis-plus可以节约我们大量的代码，尽量不要同时导入mybatis和mybatis-plus。会引起包冲突

以下是application.properties文件配置数据库连接，个人建议使用application.yaml，yaml配置文件的使用方法相对更加主流。

# 数据源配置
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?useSSL=false&userUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

application.yaml文件配置数据库连接

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/my_db01?useSSL=false&characterEncoding=UTF-8&useUnicode=true
    username: root
    password: passwd
    driver-class-name: com.mysql.cj.jdbc.Driver

server:
  port: 10029   #  数据端口

mybatis-plus:
  mapper-locations:
    classpath: mapper/*.xml
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl   # SQL语句格式化输出
#    map-underscore-to-camel-case: false    #关闭下划线映射驼峰转换

增删改查案例

编写PoJo类（Entity）

package com.sybkl.bigdatastudentmybatisplus.entity;

import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;

@Data
@TableName("student_list")
public class Table {

    @TableId
    private String id;

    @TableField("class_name")
    private String className;
    private String name;
}

编写Mapper类（Mapper）继承BaseMapper< Entity >

package com.sybkl.bigdatastudentmybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.sybkl.bigdatastudentmybatisplus.entity.Table;

public interface TableMapper extends BaseMapper<Table> {
    
}

需要在启动类或者配置类中扫描(MapperScan) mapper包

动态拼接SQL语句

由mapper标签开始，由/mapper结束，可以把它想成一个空间，是映射文件
属性namespace：空间名，主要在代理中使用。这个namespace是唯一的。
这里把mapper标签和接口联系在一起了，namespace=写接口路径，映射文件要和接口在同一目录下

<?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.sybkl.testbackend.mapper.UserMapper">
    <update id="update">
        update user
        <set>
            <if test="username != null">
                username=#{username},
            </if>
            <if test="password != null">
                password=#{password}
            </if>
        </set>

        <where>
            username=#{username}
        </where>
    </update>
</mapper>

编写服务层（Service）继承 IService< Entity>

package com.sybkl.bigdatastudentmybatisplus.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.sybkl.bigdatastudentmybatisplus.entity.Table;


public interface TableService extends IService<Table> {

}

Service ServiceImpl（继承ServiceImpl< Mapper,Entity> 实现Service）

package com.sybkl.bigdatastudentmybatisplus.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.sybkl.bigdatastudentmybatisplus.entity.Table;
import com.sybkl.bigdatastudentmybatisplus.mapper.TableMapper;
import com.sybkl.bigdatastudentmybatisplus.service.TableService;
import org.springframework.stereotype.Service;


@Service
public class TableServiceImpl extends ServiceImpl<TableMapper, Table> implements TableService {
    
}

编写控制层

package com.sybkl.bigdatastudentmybatisplus.controller;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.sybkl.bigdatastudentmybatisplus.entity.Table;
import com.sybkl.bigdatastudentmybatisplus.service.TableService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.util.List;

@RestController
@RequestMapping("/table")
public class TableController {

    @Autowired
    private TableService tableService;

    @GetMapping("/all")
    public List<Table> findAllStudent() {
        return tableService.list();
    }

    @GetMapping("/page/{pageNum}/{pageSize}")
    public IPage<Table> findPage(@PathVariable Integer pageNum, @PathVariable Integer pageSize) {
        IPage<Table> page = new Page<>(pageNum, pageSize);
        QueryWrapper<Table> queryWrapper = new QueryWrapper<>();
        return tableService.page(page, queryWrapper);
    }

    @GetMapping("/page")
    public IPage<Table> findPage(@RequestParam Integer pageNum, @RequestParam Integer pageSize, @RequestParam String input) {
        IPage<Table> page = new Page<>(pageNum, pageSize);
        QueryWrapper<Table> queryWrapper = new QueryWrapper<>();
        //通过学生姓名或者班级进行模糊查询
        queryWrapper.like("name", input).or().like("class_name", input).or().like("id", input);
        queryWrapper.orderByAsc("id");
        return tableService.page(page, queryWrapper);
    }

    //新增
    @PostMapping
    public boolean saveStudent(@RequestBody Table table) {
        return tableService.save(table);
    }

    //修改
    @PutMapping
    public boolean updateStudent(@RequestBody Table table) {
        return tableService.updateById(table);
    }

    //删除
    @DeleteMapping("/{id}")
    public boolean deleteStudent(@PathVariable String id) {
        return tableService.removeById(id);
    }

    //批量删除
    @PostMapping("/delete/batch")
    public boolean deleteBatchStudentInfo(@RequestBody List<String> ids) {
        return tableService.removeByIds(ids);
    }

}

分页插件

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
@MapperScan("com.sybkl.bigdatastudentmybatisplus.mapper")
public class MybatisPlusConfig {

    /**
     * 新的分页插件,一缓和二缓遵循mybatis的规则,需要设置 MybatisConfiguration#useDeprecatedExecutor = false 避免缓存出现问题(该属性会在旧插件移除后一同移除)
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

后端跨域

该方法引用于 程序员青戈

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;
 
@Configuration
public class CorsConfig {
    // 当前跨域请求最大有效时长。这里默认1天
    private static final long MAX_AGE = 24 * 60 * 60;
 
    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("http://localhost:8080"); // 1 设置访问源地址
        corsConfiguration.addAllowedHeader("*"); // 2 设置访问源请求头
        corsConfiguration.addAllowedMethod("*"); // 3 设置访问源请求方法
        corsConfiguration.setMaxAge(MAX_AGE);
        source.registerCorsConfiguration("/**", corsConfiguration); // 4 对接口配置跨域设置
        return new CorsFilter(source);
    }
}

Swagger2接口文档

        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.9.0</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.9.0</version>
        </dependency>

以下配置项代码swagger3.0版本不可用

//接口文档访问地址
http://localhost:10029/swagger-ui.html

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.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@Configuration
@EnableSwagger2
public class SwaggerConfig {
    /**
     * 创建API应用
     * apiInfo() 增加API相关信息
     * 通过select()函数返回一个ApiSelectorBuilder实例,用来控制哪些接口暴露给Swagger来展现，
     * 本例采用指定扫描的包路径来定义指定要建立API的目录。
     * @return
     */
    @Bean
    public Docket restApi() {
        return new Docket(DocumentationType.SWAGGER_2)
                .groupName("标准接口")
                .apiInfo(apiInfo("Spring Boot中使用Swagger2构建RESTful APIs", "1.0"))
                .useDefaultResponseMessages(true)
                .forCodeGeneration(false)
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.sybkl.testbackend.controller"))
                .paths(PathSelectors.any())
                .build();
    }

    /**
     * 创建该API的基本信息（这些基本信息会展现在文档页面中）
     * 访问地址：http://localhost:10029/swagger-ui.html
     * @return
     */
    private ApiInfo apiInfo(String title, String version) {
        return new ApiInfoBuilder()
                .title(title)
                .description("世间万千景致有大美，等我千万年，不可辜负。")
//                .termsOfServiceUrl("https://blog.csdn.net/xqnode")
//                .contact(new Contact("xqnode", "https://blog.csdn.net/xqnode", "xiaqingweb@163.com"))
                .version(version)
                .build();
    }
}

更新：Swagger3及knife4j

        <dependency>
            <groupId>com.github.xiaoymin</groupId>
            <artifactId>knife4j-spring-boot-starter</artifactId>
            <version>3.0.3</version>
        </dependency>

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.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;

/**
 * swagger3整合 knife4j 优化体验
 * 访问方式：
 * http://{ip}:{port}/doc.html，访问方式和之前的保持一致，如果项目中配置拦截器等，需要放开doc.html静态资源
 * http://localhost:10029/doc.html
 */

@Configuration
public class SwaggerConfig {
    @Bean
    public Docket desertsApi() {
        return new Docket(DocumentationType.OAS_30)
                .apiInfo(apiInfo())
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.example.myspring01.controller"))        //配置扫描路径
                .paths(PathSelectors.any())
                .build()
                .groupName("desertsGroup")
                .enable(true); // 配置是否开启swagger
    }

    // api基本信息
    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                .title("Swagger3接口文档")
                .description("继续看风景去，世间万千景致有大美，等我千万年，不可辜负。")
                .contact(new Contact("山渐青", "http://mail.qq.com", "sybkl@qq.com"))        //作者信息
                .version("1.0")
                .build();
    }
}
# mybatis # 后端
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