Spring Boot中整合Druid和Jpa实现简单的curd

痛定思痛。 2024-04-17 06:27 39阅读 0赞

# 简述 #

jpa对操作数据库的一些方法进行了封装，我们创建一个表的时候不需要直接在数据库上进行操作，我们只需要定义一个entity,jpa就会帮我们在数据库创建相应的table，操作的时候只需要继承JpaRepository，里面有各种操作数据的方法，如果它给予的方法不满足我们的需求时，可以自定义接口。jpa的好处就是自适应各种数据库，切换数据库的时候不需要重新定义一套相关的接口，而且简单的sql不需要我们去编写，快来尝试一下吧.

# 一、jar包的引入 #

<dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.1.19</version>
            </dependency>
    
            
            
            <dependency>
                <groupId>io.springfox</groupId>
                <artifactId>springfox-swagger2</artifactId>
                <version>2.7.0</version>
            </dependency>
            <dependency>
                <groupId>com.gizwits</groupId>
                <artifactId>springfox-swagger-ui</artifactId>
                <version>2.7.0</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-jpa</artifactId>
            </dependency>
            
            <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>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <scope>runtime</scope>
                <optional>true</optional>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-configuration-processor</artifactId>
                <optional>true</optional>
            </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>

# 二、配置文件的配置 #

spring:
      datasource:
          username: root
          password: 1
          url: jdbc:mysql://192.168.43.243:3306/test
          type: com.alibaba.druid.pool.DruidDataSource
    
          initialSize: 5
          minIdle: 5
          maxActive: 20
          maxWait: 60000
          timeBetweenEvictionRunsMillis: 60000
          minEvictableIdleTimeMillis: 300000
          validationQuery: SELECT 1 FROM DUAL
          testWhileIdle: true
          testOnBorrow: false
          testOnReturn: false
          poolPreparedStatements: true
          # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
          #filters: stat,wall,log4j
          maxPoolPreparedStatementPerConnectionSize: 20
          useGlobalDataSourceStat: true
          connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
      jpa:
        hibernate:
          # 更新或者创建数据表结构
          ddl‐auto: update
          # 控制台显示SQL
        show‐sql: true

# 三、添加配置类 #

> druid配置类

import com.alibaba.druid.pool.DruidDataSource;
    import com.alibaba.druid.support.http.StatViewServlet;
    import com.alibaba.druid.support.http.WebStatFilter;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.boot.web.servlet.FilterRegistrationBean;
    import org.springframework.boot.web.servlet.ServletRegistrationBean;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import javax.sql.DataSource;
    import java.util.Arrays;
    import java.util.HashMap;
    import java.util.Map;
    
    @Configuration
    public class DruidConfig { 
    
        @ConfigurationProperties(prefix = "spring.datasource")
        @Bean
        public DataSource druid(){ 
            return new DruidDataSource();
        }
    
        //配置Druid的监控
        //1.配置一个管理后台的servlet
        @Bean
        public ServletRegistrationBean statViewServlet(){ 
            ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
            Map<String,String> initParams = new HashMap<>();
            initParams.put("loginUsername","admin");
            initParams.put("loginPassword","123456");
            initParams.put("allow","");
            initParams.put("deny","192.168.23.243");
            bean.setInitParameters(initParams);
            return bean;
        }
    
    
        //2.配置一个监控的filter
        @Bean
        public FilterRegistrationBean druidFilter(){ 
            FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
            filterRegistrationBean.setFilter(new WebStatFilter());
            Map<String,String> initParams = new HashMap<>();
            initParams.put("exclusion","*.js,*.css,/druid/*");
    
            filterRegistrationBean.setInitParameters(initParams);
            filterRegistrationBean.setUrlPatterns(Arrays.asList("/*"));
            return filterRegistrationBean;
        }
    }

> swagger的配置类

import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.CorsRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    import springfox.documentation.builders.ApiInfoBuilder;
    import springfox.documentation.builders.PathSelectors;
    import springfox.documentation.builders.RequestHandlerSelectors;
    import springfox.documentation.service.ApiInfo;
    import springfox.documentation.spi.DocumentationType;
    import springfox.documentation.spring.web.plugins.Docket;
    import springfox.documentation.swagger2.annotations.EnableSwagger2;
    
    @Configuration
    @EnableSwagger2
    public class Swagger2Config { 
    
        //设置swagger跨域，提供给service调用
        @Bean
        public WebMvcConfigurer crosConfigurer(){ 
            WebMvcConfigurer webMvcConfigurerAdapter = new WebMvcConfigurer() { 
                @Override
                public void addCorsMappings(CorsRegistry registry) { 
                    registry.addMapping("/v2/api-docs");
                }
            };
            return webMvcConfigurerAdapter;
        }
    
        @Bean
        public Docket createRestApi(){ 
            return new Docket(DocumentationType.SWAGGER_2)
                    .apiInfo(apiInfo())
                    .select()
                    .apis(RequestHandlerSelectors.basePackage("com.example.jpa.controller")) //基础扫描包路径
                    .paths(PathSelectors.any())
                    .build();
        }
    
        private ApiInfo apiInfo(){ 
            return new ApiInfoBuilder()
                    .title("果核项目")
                    .description("果核项目")
                    .termsOfServiceUrl("https://javacfox.github.io") //地址
                    .contact("lwx640993") //负责人
                    .version("0.1")
                    .build();
        }
    
    }

# 四、编写entity #

import lombok.Data;
    
    import javax.persistence.*;
    
    @Data
    @Entity
    @Table(name = "user")
    public class User { 
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY) //主键自增
        private Integer id;
        @Column(name = "user_name",length = 50)
        private String userName;
        @Column(name = "gender",length = 2)
        private Integer gender;
        @Column(name = "age")
        private Integer age;
    }

# 五、添加Repository #

import com.example.jpa.entity.User;
    import org.springframework.data.jpa.repository.JpaRepository;
    
    public interface UserRepository extends JpaRepository<User,Integer> { 
    }

这里值得一说的是，可以继承两种接口：

> 1.CrudRepository: 只实现了简单的curd功能

> 2.JpaRepository: 在实现了curd的基础上添加了分页功能

# 六、service层的编写 #

import com.example.jpa.entity.User;
    import com.example.jpa.repository.UserRepository;
    import com.example.jpa.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.Pageable;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    import java.util.Optional;
    
    @Service
    public class UserServiceImpl implements UserService { 
    
        @Autowired
        private UserRepository userRepository;
    
        @Override
        public User getUserById(Integer id) { 
            Optional<User> byId = userRepository.findById(id);
            return byId.get();
        }
    
        @Override
        public List<User> getAll() { 
            return userRepository.findAll();
        }
    
        @Override
        public User saveUser(User user) { 
            return userRepository.save(user);
        }
    
        @Override
        public User updateUser(User user) { 
            return userRepository.save(user); //当user带id的时候就更新，没有id的时候就保存
        }
    
        @Override
        public void deleteUserById(Integer id) { 
            userRepository.deleteById(id);
        }
    
        @Override
        public Page<User> getAll(Pageable pageable){ 
            return userRepository.findAll(pageable);
        }
    }

# 七、controller层 #

import com.example.jpa.entity.User;
    import com.example.jpa.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.PageRequest;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.*;
    
    import java.util.List;
    
    @Controller
    public class UserController { 
    
        @Autowired
        private UserService userService;
    
        @GetMapping("/user")
        @ResponseBody
        public User getUserById(@RequestParam Integer id){ 
            return userService.getUserById(id);
        }
    
        @GetMapping("/users")
        @ResponseBody
        public List<User> getAll(){ 
            return userService.getAll();
        }
    
        @GetMapping("/usersByPage")
        @ResponseBody
        public Page<User> getAllByPage(@RequestParam Integer pageOffset,@RequestParam Integer pageSize){ 
            return userService.getAll(PageRequest.of(pageOffset,pageSize));
        }
    
        @PostMapping("/user")
        @ResponseBody
        public User saveUser(@RequestBody User user){ 
            return userService.saveUser(user);
        }
    
        @PutMapping("/user")
        @ResponseBody
        public User updateUser(@RequestBody User user){ 
            return userService.updateUser(user);
        }
    
        @DeleteMapping("/user")
        @ResponseBody
        public void deleteUser(Integer id){ 
            userService.deleteUserById(id);
        }
    
    
    }

# 八、接口测试 #

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