⭐ 应用场景:EXPLAIN 子句其实就是用于查看当前这个 sql 查询的逻辑计划以及优化的执行计划。 ⭐ SQL 语法标准: EXPLAIN PLAN FOR <query_statement_or_insert_statement> 1. 复制 ⭐ 实际案例: public class Explain_Test { public static void main(String[] args) throws Exception { FlinkEnv flinkEnv =...
EXPLAIN 子句其实就是用于查看当前这个 SQL 查询的逻辑计划以及优化的执行计划。 SQL 语法标准: EXPLAIN PLAN FOR <query_statement_or_insert_statement> 实际案例: public class Explain_Test { public static void main(String[] args) throws Exception { FlinkEnv flinkEnv = FlinkEnvUtils.getStreamTableEnv(arg...
public class Explain_Test { public static void main(String[] args) throws Exception { FlinkEnv flinkEnv = FlinkEnvUtils.getStreamTableEnv(args); flinkEnv.env().setParallelism(); String sql = "CREATE TABLE source_table (\n" + " user_id BIGINT COMMENT '用户 id',\n" + " name STRING ...
public static void main(String[] args){ Student stu = new Student(); stu.name = "kk"; stu.height = 172; stu.rest(); Student stu2 = new Student("xx",150,"Science"); } } class Person{ String name; int height; public void rest(){ System.out.println("休息一会儿!"); } } clas...
public static void main(String[] args) { File imgFile = new File("d:" + File.separator + "001.jpg"); InputStream is = null; try { is = new FileInputStream(imgFile); } catch (FileNotFoundException e1) { e1.printStackTrace(); ...
(SpringApplication类提供了一种便利的方式以便引导Spring应用从#main启动,大多数情况下,可以通过静态方法SpringApplication#run代理启动) How TO UseSpringApplication @EnableAutoConfigurationpublicclassMyApplication{// ... Bean definitionspublicstaticvoidmain(String[] args)throwsException { ...
public static void main(String[] args) throws Exception { FlinkEnv flinkEnv = FlinkEnvUtils.getStreamTableEnv(args); flinkEnv.env().setParallelism(); String sql = "CREATE TABLE source_table (\n" + " user_id BIGINT COMMENT '用户 id',\n" ...
*/packagetestPG;importjava.sql.Connection;importjava.sql.DriverManager;importjava.sql.PreparedStatement;importjava.sql.ResultSet;importjava.sql.SQLException;publicclassTestAutoExplain{publicstaticvoidmain(String[] args){try(Connectionconn=DriverManager.getConnection("jdbc:postgresql://192.168.26.28:5432/testdb...
public static void main(String[] args) { ServiceLoader<Car> load = ServiceLoader.load(Car.class); Iterator<Car> iterator = load.iterator(); while (iterator.hasNext()) { Car car = iterator.next(); car.getPrice(); } } } The above example briefly introduces the use of theJDK SPImechanis...
classAnimal{publicvoidsound(){System.out.println("Default Sound");}}publicclassDogextendsAnimal{publicvoidsound(){System.out.println("Woof");}publicstaticvoidmain(Stringargs[]){Animal obj=newDog();obj.sound();}} Abstraction:Hiding internal details and showing functionality is known as abstraction...