尝试使用 Java 连接到 mySQL 服务器（工作台）时出错

Question

I am trying to connect to mySQL using workbench and connectorJ ver 8.0.12 but I just can't connect and its always throws exceptions I searched for an answer for hours here and in google too but it seems that I do everything correctly.

Can anyone help me?

1. When I manually create the schema in the server and then put the command "create schema" this is all the errors that I get
2. But when I trying to create schema from starch this is the errors that I get
3. My code is here

my code :

public class MySQLClient {
private Connection connect = null;
private Statement stmt = null;
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost:3306/";
static final String USER = "root";
static final String PASS = "Pass123456";
static final String DataBaseName = "adults";


public void createSchema() {
    try {

        Class.forName(JDBC_DRIVER).newInstance();
        connect = DriverManager.getConnection(DB_URL, USER, PASS);
        System.out.println("Creating database...");
        stmt = connect.createStatement();
        String sql = "CREATE DATABASE " + DataBaseName;

        stmt.executeUpdate(sql);
        System.out.println("Database created successfully...");

        connect = DriverManager.getConnection(DB_URL + DataBaseName + "?useSSL=false", USER, PASS);
        stmt = connect.createStatement();
        createTables();
    } catch (SQLException se) {
        se.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        try {
            if (stmt != null)
                stmt.close();
        } catch (SQLException se2) {
        }// nothing we can do
        try {
            if (connect != null)
                connect.close();
        } catch (SQLException se) {
            se.printStackTrace();
        }
    }
}

errors when i created manually the schema :

connected to database...
Creating database...
Database created successfully...
Connection to Database Failed
java.sql.SQLNonTransientConnectionException: Cannot load connection class because of underlying exception: com.mysql.cj.exceptions.WrongArgumentException: Malformed database URL, failed to parse the connection string near '=false'.
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:110)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:79)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:131)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:227)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at MySQLClient.createSchema(MySQLClient.java:37)
    at MySQLCommandLineClient.main(MySQLCommandLineClient.java:20)
Caused by: com.mysql.cj.exceptions.UnableToConnectException: Cannot load connection class because of underlying exception: com.mysql.cj.exceptions.WrongArgumentException: Malformed database URL, failed to parse the connection string near '=false'.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
    ... 5 more
Caused by: com.mysql.cj.exceptions.WrongArgumentException: Malformed database URL, failed to parse the connection string near '=false'.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.conf.ConnectionUrlParser.processKeyValuePattern(ConnectionUrlParser.java:547)
    at com.mysql.cj.conf.ConnectionUrlParser.parseQuerySection(ConnectionUrlParser.java:519)
    at com.mysql.cj.conf.ConnectionUrlParser.getProperties(ConnectionUrlParser.java:644)
    at com.mysql.cj.conf.ConnectionUrl.collectProperties(ConnectionUrl.java:304)
    at com.mysql.cj.conf.ConnectionUrl.<init>(ConnectionUrl.java:289)
    at com.mysql.cj.conf.url.SingleConnectionUrl.<init>(SingleConnectionUrl.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.cj.util.Util.handleNewInstance(Util.java:210)
    at com.mysql.cj.util.Util.getInstance(Util.java:185)
    at com.mysql.cj.util.Util.getInstance(Util.java:192)
    at com.mysql.cj.conf.ConnectionUrl.getConnectionUrlInstance(ConnectionUrl.java:201)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:204)
    ... 4 more

erros that i get when trying create schema from starch :

create schema
Sun Jul 29 11:01:18 IDT 2018 WARN: Establishing SSL connection without      server's identity verification is not recommended. According to MySQL 5.5.45+,  5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if  explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Connection to Database Failed
java.sql.SQLSyntaxErrorException: Unknown database 'adults'
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:832)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:207)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at MySQLClient.createSchema(MySQLClient.java:23)
    at MySQLCommandLineClient.main(MySQLCommandLineClient.java:20)
Please enter one of the possible commands

Answer 1

Sorry but what did you mean in

connect = DriverManager.getConnection(DB_URL + "nedy" + "?useSSL=false", USER, PASS);

while your created database is "adults"? And I think you should close the first connection before open the second.

-- EDIT -- This worked fine for me

public class DatabaseConnector {

    private static final String JDBC_URL = "jdbc:mysql://localhost:3306/";

    private static final String USERNAME = "root";
    private static final String PASSWORD = "password";

    private static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";

    public static void main(String[] args) throws SQLException {
        createDatabase();
    }

    public static void createDatabase() throws SQLException {
        Connection conn = connect("");
        Statement st = conn.createStatement();
        st.executeUpdate("CREATE DATABASE test");
        //Close conn, st 
        conn = connect("test");
        st = conn.createStatement();
        st.executeUpdate("CREATE TABLE abc (id int)");
    }

    public static final Connection connect(String database) {
        Connection connection = null;
        try {
            Class.forName(JDBC_DRIVER);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

        try {
            connection = DriverManager.getConnection(JDBC_URL + database, USERNAME, PASSWORD);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return connection;
    }

}