Java 将MySQL连接到Spring应用程序

我想使用MySQL数据库，而不是像hsqldb那样使用运行时数据库。我已经克隆了它，它正在使用hsqldb作为它的数据库

我想学习如何将关系数据库与基于rest的spring应用程序结合使用。因此，我对pom.xml做了以下更改： 已更改pom.xml：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.springsource.restbucks</groupId>
    <artifactId>restbucks</artifactId>
    <packaging>war</packaging>
    <version>1.0.0.BUILD-SNAPSHOT</version>
    <name>Spring RESTBucks</name>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.1.5.RELEASE</version>
    </parent>

    <properties>
        <spring-data-releasetrain.version>Evans-RC1</spring-data-releasetrain.version>
        <tomcat.version>8.0.9</tomcat.version>
    </properties>

    <dependencies>

        <!-- Spring Data REST -->

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.hibernate</groupId>
                    <artifactId>hibernate-entitymanager</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

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

        <!-- JDK 8 DateTime support for Hibernate -->

        <dependency>
            <groupId>org.jadira.usertype</groupId>
            <artifactId>usertype.extended</artifactId>
            <version>3.2.0.GA</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
        </dependency>

        <!-- Database >

        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <scope>runtime</scope>
        </dependency -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- Misc -->

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx-events</artifactId>
            <version>1.0.0.BUILD-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.14.4</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>com.jayway.jsonpath</groupId>
            <artifactId>json-path</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>

        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-libs-snapshot</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>spring-libs-snapshot</id>
            <url>http://repo.spring.io/libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

</project>

但我面临着大约15个错误，比如：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'orderInitializer' defined in file [/home/jimish/projects/spring_projects/spring/spring-restbucks/target/classes/org/springsource/restbucks/order/OrderInitializer.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springsource.restbucks.order.OrderInitializer]: Constructor threw exception; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet

所以，若有人能建议如何将mysql连接到spring应用程序，那个就太好了。

---

谢谢。

您可以验证pom文件，并确保至少有以下JAR可用

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </dependency>
        <!-- Spring AOP -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
        </dependency>

        <!-- MySQL JDBC connector -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>


        **Make sure you are reading your db.properties file from application-context.xml**

        <bean id="propertyConfigurer"
        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
          <property name="locations">
            <list>
                <value>classpath:db.properties</value> 
            </list>
        </property> 
        </bean>

        **Make sure you use proper datasource and entity manager in application-context.xml**

        <bean id="dataSource" class="{our.DataSource}" destroy-method="close">
            <property name="driverClass" value="${driver}"/>
            <property name="jdbcUrl" value="${url}"/>
            <property name="user" value="${username}"/>
            <property name="password" value="${password}"/>
        </bean>

        <bean id="entityManagerFactory"
            class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
            <property name="persistenceUnitName" value="spring-jpa" />
            <property name="dataSource" ref="dataSource" />
            <property name="jpaVendorAdapter">
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                    <property name="generateDdl" value="true" />
                    <property name="showSql" value="false" />
                    <property name="databasePlatform" value="${dialect}" /> 
                </bean>
            </property>

        </bean>

    **Make sure you are adding minimum of below properties in db.properties**

    dialect=org.hibernate.dialect.MySQL5InnoDBDialect
    url=jdbc:mysql://localhost:3306/dbName
    driver=com.mysql.jdbc.Driver
    username=root
    password=test

org.springframework
春豆
org.springframework
SpringWebMVC
org.springframework.data
spring数据jpa
org.springframework
spring上下文
org.springframework
春季方面
org.hibernate
休眠实体管理器
mysql
mysql连接器java
**确保正在从application-context.xml读取db.properties文件**
类路径：db.properties
**确保在application-context.xml中使用正确的数据源和实体管理器**
**确保在db.properties中添加以下属性的最小值**
方言=org.hibernate.dialogue.mysql5innodbdialogue
url=jdbc:mysql://localhost:3306/dbName
driver=com.mysql.jdbc.driver
用户名=根
密码=测试

阐述@M.Deinum的评论。。。您需要在使用时指定JPA配置信息

添加标准JPA属性并指定数据库平台（）应该可以使JPA连接正常工作

spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

# Enable spring data repos 
spring.data.jpa.repositories.enabled=true

# Replace with your connection string
spring.datasource.url=jdbc:mysql://localhost:3306/restbucks

# Replace with your credentials
spring.datasource.username=sa
spring.datasource.password=

spring.datasource.driverClassName=com.mysql.jdbc.Driver

---

在类路径中的application.properties中只包含以下配置，它将非常有效：

 spring.datasource.url=jdbc:mysql://localhost/jpa_example
 spring.datasource.username=root
 spring.datasource.driver-class-name=com.mysql.jdbc.Driver
 spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

数据库服务器IP、端口号和数据库名称 spring.datasource.url=jdbc:mysql://localhost/sample

数据库服务器用户名 spring.datasource.username=root

数据库服务器密码 spring.datasource.password=root123

每次服务器启动时更新数据库

---

spring.jpa.hibernate.ddl auto=update

将MySQL连接器/J添加到类路径：

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>6.0.5</version>
</dependency>

---

我尝试了上述配置，但1小时后未连接。我通过在password=（password=）后放置空格来连接。

在application.properties文件中添加以下属性：

# Use one of create/update/create-update    
spring.jpa.hibernate.ddl-auto=update  
spring.datasource.url=jdbc:mysql://localhost:3306/db?createDatabaseIfNotExist=true   
spring.datasource.username=root  //your db user name  
spring.datasource.password=root  //your db user password 
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.jpa.database-platform=org.hibernate.dialect.MySQL8Dialect  
#If your MySql version 5 then use MySQL5Dialect


# Enable spring data repos
spring.data.jpa.repositories.enabled=true
spring.jpa.show-sql=true
spring.jpa.database=mysql

---

请添加mysql连接器java依赖项

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>

---

确保您的设置正确，您的数据库存在并且正在运行，并且您可以通过该用户连接到该数据库。另外，请确保您为Hibernate选择了正确的方言，否则您可能会使用错误的SQL。嘿，我的数据库存在，并且正在运行。。。但是我不知道如何为hibernate选择方言。你能提出一些有用的相关建议吗？我建议你阅读一下文档，而不是只是随便看看。但是，设置

spring.jpa.properties.hibernate.dialogue=org.hibernate.dialogue.mysql5innodbdialogue

就可以了。您可能还希望将完整堆栈跟踪添加到您的帖子中。他在解析结果时遇到问题，应用程序运行正常，因此依赖关系正常。此外，依赖项来自一个springbootstarter项目，该项目已经包含了适当的依赖项。

spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://localhost:3306/boot
spring.datasource.username=root
spring.datasource.password=

# Use one of create/update/create-update    
spring.jpa.hibernate.ddl-auto=update  
spring.datasource.url=jdbc:mysql://localhost:3306/db?createDatabaseIfNotExist=true   
spring.datasource.username=root  //your db user name  
spring.datasource.password=root  //your db user password 
spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.jpa.database-platform=org.hibernate.dialect.MySQL8Dialect  
#If your MySql version 5 then use MySQL5Dialect


# Enable spring data repos
spring.data.jpa.repositories.enabled=true
spring.jpa.show-sql=true
spring.jpa.database=mysql

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>

# Hibernate ddl auto (create, create-drop, validate, update)
spring.jpa.hibernate.ddl-auto = update
spring.datasource.url=jdbc:mysql://localhost:3306/yourDatabaseName?useSSL=false
spring.datasource.username=root
spring.datasource.password=YourPassword
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver