百度网站建设微信封面,易派客网站是谁做的,网站 自适应js,上饶网站建设哪家好基于SpringBoot3和JDK17#xff0c;集成H2数据库和jpa
学会用H2数据库#xff0c;为了快速写出需要处理数据关系的demo。 文章目录 基于SpringBoot3和JDK17#xff0c;集成H2数据库和jpa工程配置pom.xml文件application.properties文件 练习H2数据库的操作h2数据库的建表自…基于SpringBoot3和JDK17集成H2数据库和jpa
学会用H2数据库为了快速写出需要处理数据关系的demo。 文章目录 基于SpringBoot3和JDK17集成H2数据库和jpa工程配置pom.xml文件application.properties文件 练习H2数据库的操作h2数据库的建表自增主键控制 练习动态调整日志引入依赖打开管理apiapplication.properties查看类的目前的日志级别修改类的日志级别测试类 工程配置
完整demohttps://download.csdn.net/download/weixin_43820556/89385337
pom.xml文件
?xml version1.0 encodingUTF-8?
project xmlnshttp://maven.apache.org/POM/4.0.0 xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersionparentgroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-parent/artifactIdversion3.2.6/versionrelativePath//parentgroupIdcom.donny.demo/groupIdartifactIdh2/artifactIdversion0.0.1-SNAPSHOT/versionnameh2/namedescriptionDemo project for Spring Boot/descriptionpropertiesjava.version17/java.version/propertiesdependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-actuator/artifactId/dependencydependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-data-jpa/artifactId/dependencydependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-web/artifactId/dependencydependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-devtools/artifactIdscoperuntime/scopeoptionaltrue/optional/dependencydependencygroupIdcom.h2database/groupIdartifactIdh2/artifactIdscoperuntime/scope/dependencydependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-configuration-processor/artifactIdoptionaltrue/optional/dependencydependencygroupIdorg.projectlombok/groupIdartifactIdlombok/artifactIdoptionaltrue/optional/dependencydependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-test/artifactIdscopetest/scope/dependency/dependenciesbuildpluginsplugingroupIdorg.springframework.boot/groupIdartifactIdspring-boot-maven-plugin/artifactIdconfigurationexcludesexcludegroupIdorg.projectlombok/groupIdartifactIdlombok/artifactId/exclude/excludes/configuration/plugin/plugins/build/projectapplication.properties文件
spring.application.nameh2
spring.jpa.show-sqltrue
spring.jpa.hibernate.ddl-autoupdate
spring.jpa.database-platformorg.hibernate.dialect.H2Dialect
spring.datasource.driver-class-nameorg.h2.Driver
# 内存模式
#spring.datasource.urljdbc:h2:mem:test
# 文件持久化模式
spring.datasource.urljdbc:h2:./db/testdb;AUTO_SERVERTRUE;
spring.datasource.usernamesa
spring.datasource.passwordsa
#spring.sql.init.schema-locationsclasspath:db/schema.sql
spring.h2.console.path/h2
spring.h2.console.enabledtrue
logging.configclasspath:logback-spring.xml
management.endpoints.web.exposure.includeloggers练习H2数据库的操作
h2数据库的建表
/*学生*/
DROP TABLE IF EXISTS student;
CREATE TABLE student
(id INTEGER auto_increment primary key,name varchar(50) not null
);/*老师,一个老师可以交好几个班级*/
DROP TABLE IF EXISTS teacher;
CREATE TABLE teacher
(id INTEGER auto_increment primary key,name varchar(50) not null,subject varchar(50) not null
);/*班级一个学生只能在一个班级一个班级有多名老师和学生*/
DROP TABLE IF EXISTS grade;
CREATE TABLE grade
(id INTEGER auto_increment primary key,student_id INTEGER,teacher_id INTEGER,name varchar(50)
);-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO student
VALUES (0, 张三);
INSERT INTO student
VALUES (1, 少杰);
INSERT INTO student
VALUES (10, 赵子龙);
-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO teacher
VALUES (0, 张老师, 语文);
INSERT INTO teacher
VALUES (1, 王老师, 数学);
INSERT INTO teacher
VALUES (2, 陈老师, 英语);
-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO grade
VALUES (1, 0, 0, 1班);
INSERT INTO grade
VALUES (2, 1, 2, 2班);
INSERT INTO grade
VALUES (3, 10, 1, Z班);
自增主键控制
如果单独插入了数据则不会与JPA的数据插入时主键相关联例如在建表的同时写入了id为1的数据则JPA在新增的时候也会不会新增id为2的数据还是新增id为1的数据此时即报错。本人并未解决这种问题而是将插入数据的操作全部交由JPA来做是实现主键自增的统一如果有网友可以解决此问题可以留言。
通过JPA来操作数据库
多对多关系建议拆解成多个1对多的关系进行表设计。 通过注解控制外键关系
OneToOne双向关系实体键的关系是一对一此注解用在单端上
ManyToOne双向关系实体键的关系是多对一此注解用在单端上练习动态调整日志
引入依赖 dependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-actuator/artifactId/dependency打开管理apiapplication.properties
management.endpoints.web.exposure.includeloggers查看类的目前的日志级别
GET请求http://127.0.0.1:8080/actuator/loggers/com.donny.demo.h2.controller.LogController
结果
{effectiveLevel:DEBUG}修改类的日志级别
POST请求
http://127.0.0.1:8080/actuator/loggers/com.donny.demo.h2.controller.LogController 请求体 {configuredLevel:info}
重新查询
{configuredLevel:ERROR,effectiveLevel:ERROR}结果会是在LogController中增加一个配置项。若要取消configuredLevel只要将请求体改为 {configuredLevel:null}
测试类
package com.donny.demo.h2.controller;import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** author 1792998761qq.com* version 1.0* since 2024年06月01日 上午11:56*/
RestController
RequestMapping(/log)
Slf4j
public class LogController {GetMapping(/logger)public String loggerLevel() {log.trace(logger level is trace);log.info(logger level is info);log.debug(logger level is debug);log.warn(logger level is warn);log.error(logger level is error);return success;}
}开启日志级别为debug时输出的是[2024-06-01 15:24:25,180][http-nio-8080-exec-5][ERROR][com.donny.demo.h2.controller.LogController:23] logger level is error。说明生效了。
