我无法解决数据库连接问题。我试图从 本地主机到127.0.0.1也没有成功。 我已经解决了以前的错误，即使到那时，我也没有成功连接它。
import java.sql.Connection;
import java.sql.DriverManager;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication{
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
try
{
String url = "jdbc:mysql://localhost:3306/Doctor";
Connection conn = DriverManager.getConnection(url,"adminManu","adminManu");
}
catch (Exception e)
{
System.err.println("D'oh! Got an exception!");
System.err.println(e.getMessage());
}
}
Minhasdependências： 我对pom.xml的依赖关系如下：
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.22.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.2.3.Final</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
<version>2.0.9.RELEASE</version>
</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>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.49</version>
<scope>runtime</scope>
</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>
</dependencies>
一个月经不来的收货人： 我收到的消息：
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:403) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:335) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2187) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2220) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2015) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:768) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:403) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:385) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:323) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:117) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:123) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:365) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:194) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:460) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:534) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) ~[HikariCP-2.7.9.jar:na]
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-2.7.9.jar:na]
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.4.22.Final.jar:5.4.22.Final]
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:180) ~[hibernate-core-5.4.22.Final.jar:5.4.22.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl.getIsolatedConnection(DdlTransactionIsolatorNonJtaImpl.java:43) ~[hibernate-core-5.4.22.Final.jar:5.4.22.Final]
... 40 common frames omitted
Caused by: java.net.ConnectException: Connection refused: connect
at java.base/java.net.PlainSocketImpl.waitForConnect(Native Method) ~[na:na]
at java.base/java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:107) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403) ~[na:na]
at java.base/java.net.Socket.connect(Socket.java:608) ~[na:na]
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211) ~[mysql-connector-java-5.1.49.jar:5.1.49]
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:299) ~[mysql-connector-java-5.1.49.jar:5.1.49]
... 63 common frames omitted