connection = JdbcUtils.getConnection(); String sql = "SELECT * FROM test3"; preparedStatement = connection.prepareStatement(sql); resultSet = preparedStatement.executeQuery(); //如果读取到数据,就把数据写到磁盘下 if (resultSet.next()) { InputStream inputStream = resultSet.getBinaryStream("blobtest...
preparedStatement = connection.prepareStatement(sql);//获取到文件的路径Stringpath=Demo5.class.getClassLoader().getResource("BigTest").getPath();Filefile=newFile(path);FileReaderfileReader=newFileReader(file);//第三个参数,由于测试的Mysql版本过低,所以只能用int类型的。高版本的不需要进行强转preparedState...
The PostgreSQL™ server allows clients to compile sql statements that are expected to be reused to avoid the overhead of parsing and planning the statement for every execution. This functionality is available at the SQL level via PREPARE and EXECUTE beginning with server version 7.3, and at the...
Statement stmt=null; Connection conn=null;try{//1.注册驱动Class.forName("com.mysql.cj.jdbc.Driver");//2.建立连接conn = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&serverTimezone=Asia/Shanghai&characterEncoding=UTF-8&useSSL=FALSE","root","");//...
如果用 Statement 实现只能是拼接参数的形式，代码如下 publicstaticvoidmain(String[]args)throws...
jdbc操作步骤和preparedStatment相比Statment的好处,java操纵数据库封装了一组API,通过这组API可以透明的操作各种数据库,一般来讲,操纵数据库的步骤是:一、try{1、加载数据库驱动Class.forName("数据库驱动类");2,获得数据库连接Connectioncon=DriverManager.getConne
上图截自com.mysql.jdbc.ConnectionImpl#prepareStatement(java.lang.String, int, int)这里有两个很重要的参数useServerPrepStmts以及emulateUnsupportedPstmts用于控制是否使用服务端预编译语句。 由于上述程序中我们没有启用服务端预编译,因此MySQL驱动在上面的prepareStatement方法中会进入使用客户端本地预编译的分支进入...
That update affects one row in the table, so n is equal to 1. When the method executeUpdate is used to execute a DDL (data definition language) statement, such as in creating a table, it returns the int value of 0. Consequently, in the following code fragment, which executes the DDL ...
* */@Testpublicvoidread(){Connection connection=null;PreparedStatement preparedStatement=null;ResultSet resultSet=null;try{connection=JdbcUtils.getConnection();String sql="SELECT * FROM test2";preparedStatement=connection.prepareStatement(sql);resultSet=preparedStatement.executeQuery();if(resultSet.next()){...
.java:594) [mariadb-java-client-3.0.3.jar!/:?] ... 195 more Caused by: java.sql.BatchUpdateException: java.sql.SQLException: (conn=92) This command is not supported in the prepared statement protocol yet at org.mariadb.jdbc.export.ExceptionFactory.createBatchUpdate(ExceptionFactory.java:213...