java Spring Boot，JPA 错误：“通过 JDBC 语句执行 DDL 时出错”
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Spring Boot, JPA error: "Error executing DDL via JDBC Statement"
提问by Xzenon
I am trying to add an entry in my MySQL database, using a pretty basic (so far) Spring Boot app. I've used some bits and pieces I've found online and this is the code that I'm trying to follow:
我正在尝试使用一个非常基本的（到目前为止）Spring Boot 应用程序在我的 MySQL 数据库中添加一个条目。我使用了一些我在网上找到的零碎部分，这是我试图遵循的代码：
netgloo/spring-boot-samples/spring-boot-mysql-springdatajpa-hibernate
netgloo/spring-boot-samples/spring-boot-mysql-springdatajpa-hibernate
Currently I get the following issues when I run my app.
目前，我在运行我的应用程序时遇到以下问题。
When I first run the app the following Exception is thrown:
当我第一次运行应用程序时，抛出以下异常：
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement
And when I make a POST request to the controller, which should create a new entry in the database I get the following Exception:
当我向控制器发出 POST 请求时，它应该在数据库中创建一个新条目，我得到以下异常：
org.springframework.orm.jpa.JpaSystemException: could not execute statement; nested exception is org.hibernate.exception.GenericJDBCException: could not execute statement
which in turn is caused by the following:
这又是由以下原因引起的：
Caused by: java.sql.SQLException: No database selected
application.properties:
应用程序属性：
# Web pages extension
spring.mvc.view.suffix =.html
# ==============================
# --- DATA SOURCE
# ==============================
# Database url
spring.datasource.url = jdbc:mysql://localhost:3306?useSSL=false
# Database credentials
spring.datasource.username = root
spring.datasource.password = root
# Keep database connection alive
spring.datasource.tomcat.test-while-idle = true
spring.datasource.tomcat.validation-query = SELECT 1
# ==============================
# --- JPA / Hibernate
# ==============================
# Hibernate ddl auto (create, create-drop, update): with "update" the database
# schema will be automatically updated accordingly to java entities found in
# the project
spring.jpa.hibernate.ddl-auto = update
# Naming strategy
spring.jpa.hibernate.naming.strategy = org.hibernate.cfg.ImprovedNamingStrategy
# Allows Hibernate to generate SQL optimized for a particular DBMS
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
pom.xml:
pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>my.group</groupId>
<artifactId>myapp</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>myapp</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.8.RELEASE</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.12.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.2.12.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20171018</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<addResources>true</addResources>
</configuration>
</plugin>
</plugins>
</build>
I have this simple interface:
我有这个简单的界面：
@Transactional
public interface UserDAO extends CrudRepository<User, Long>
{
public User findByEmail(String email);
}
And here's my controller:
这是我的控制器：
@Controller
public class UserController
{
@Autowired
private UserDAO userDAO;
@RequestMapping(value = "/register", method = RequestMethod.GET)
public String getRegisterView()
{
return "register/registerView";
}
@RequestMapping(value = "/register", method = RequestMethod.POST)
public @ResponseBody
ControllerResponse registerRequest(@RequestBody String request)
{
User user = null;
JSONObject json = new JSONObject(request);
try
{
user = new User();
user.setEmail(json.getString("email"));
user.setName(json.getString("name"));
user.setSurname(json.getString("surname"));
user.setPassword(json.getString("password"));
userDAO.save(user);
}
catch (Exception e)
{
e.printStackTrace();
}
ControllerResponse response = new ControllerResponse();
response.setMessage("Controller returned this");
response.setSuccess(true);
return response;
}
}
My User class is defined as follows:
我的 User 类定义如下：
public class User
{
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@NotNull
private String email;
@NotNull
private String password;
@NotNull
private String name;
@NotNull
private String surname;
@Column(name = "authorization_token")
private String authorizationToken;
// bunch of getters/setters
}
回答by vsoni
Your datasource url in application.properties is missing database name. Should be like this.
application.properties 中的数据源 url 缺少数据库名称。应该是这样的。
spring.datasource.url = jdbc:mysql://localhost:3306/dbname?useSSL=false
