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JavaHelloWorld : Now as the main development project
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learning Java from scratch -
Java basics collections
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env
- Java JDK 1.8
- maven
- IntelliJ
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Relative Project
- Java Basic
- Constructor Overload - overload Constructor for cases
- This metod -
thismethod examples in java - Staic Var -
Staic varexamples in java - Staic method -
Staic Methodexamples in java - Extends method -
extends classexamples in java - ReWrite method -
ReWrite methodexamples in java - Super 1, Super 2 -
Super methodexamples in java - abstract -
abstract methodexamples in java - interface, interface 2 -
interface methodexamples in java - Runtime - Runtime is JVM running status, can check JVM/process status via it
- CheckSystem - check JVM/system properties
- StringBufferDemo - StringBuffer op demo
- Java IO 1, Java IO 2, Java IO 3- Java IO demo (stream)
- Java Copy File 1, Java Copy File with bufffer 1, Java Copy File with bufffer 2 -Java Copy File examples (stream)
- Java IO 4, Java IO 5, Java IO 6, Java IO 7 - Java IO demo (FileReader, FileWriter)
- DeleteDirectoryFiles - Example delete file/directory in java
- ListDirectoryFiles, ListDirectoryFiles2, ListDirectoryFiles3 - Example list file/directory in java
- ParallelStream - Parallel Stream example in java
- InterfaceImplementsExtends - interface, implements, extends example in java
Build
- dev
Development
mvn archetype:generate -DgroupId=com.yen.JavaBasics -DartifactId=utility-java -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4 -DinteractiveMode=falseReference
- http://www.runoob.com/sqlite/sqlite-java.html
- https://github.com/OSE-Lab/learning-spark/tree/master/examples-java
- https://stackoverflow.com/questions/22252534/how-to-run-a-spark-java-program-from-command-line
- https://stackoverflow.com/questions/23308493/how-to-download-mysql-jdbc-jar-file-on-centos
- https://github.com/databricks/learning-spark/tree/master/src/main/java/com/oreilly/learningsparkexamples/java
- https://github.com/endymecy/spark-ml-source-analysis
- https://github.com/jleetutorial/sparkTutorial
- apache-spark-course-with-java
Quick start (lagacy)
# --- run the simplist app ---
# compile
$ javac HelloWorld.java
# run java application
$ java HelloWorld# --- work with DB ---
# please download SQLiteJDBC and save as current route :
# https://bitbucket.org/xerial/sqlite-jdbc/downloads/
$ javac SQLiteJDBC.java
$ javac SQLiteJDBC_creat_table.java
$ javac SQLiteJDBC_insert_to_table.java
$ java -classpath ".:sqlite-jdbc-3.21.0.jar" SQLiteJDBC
$ java -classpath ".:sqlite-jdbc-3.21.0.jar" SQLiteJDBC_creat_table
$ java -classpath ".:sqlite-jdbc-3.21.0.jar" SQLiteJDBC_insert_to_table
$ sqlite3 test.db 'select * from company;'
# output
# 1|Paul|32|California|20000.0
# 2|Allen|25|Texas|15000.0
# 3|Teddy|23|Norway|20000.0
# 4|Mark|25|Rich-Mond |65000.0
# --- work with package ---
# please check the file structure is as below
#├── package_animals
# ├── Animal.java
# └── MammalInt.java
# compile
$ javac package_animals/MammalInt.java
$ javac package_animals/Animal.java
# run java application under package : package_animals
$ java package_animals/MammalInt
# output
# Mammal eats
# Mammal travels# --- work with spark ---
#### set up mysql ####
$ mysql.server start (mysql server should start locally at mysql://127.0.0.1 default )
# access local mysql
$ mysql -u root
# select DB
mysql> use mysql;
# create table
mysql> create table testData(name varchar(32) not null , value varchar(32) not null);
# show table data
mysql> select * from testData;
Empty set (0.00 sec)
#### set up spark ####
# please make sure you've downloaded spark core library via https://spark.apache.org/downloads.html and save that at : /Users/$USER/spark/
# please download Mysql JDBC jar and put it to the "classpath" location via https://stackoverflow.com/questions/23308493/how-to-download-mysql-jdbc-jar-file-on-centos
# compile
$ javac -classpath ".:/Users/$USER/spark/jars/*" Spark_Mysql_demo.java
# run java application
$ java -classpath ".:/Users/$USER/spark/jars/*" Spark_Mysql_demo
# back to mysql and query the output
mysql> select * from testData;
+------+-------+
| name | value |
+------+-------+
| a | abcd |
| b | abcd |
+------+-------+
2 rows in set (0.00 sec)
mysql>
# --- work with spark ML ---
# compile
$ javac -classpath ".:/Users/$USER/spark/jars/*" Spark_LinearRegression_ElasticNet_Demo.java
# run java application
$ java -classpath ".:/Users/$USER/spark/jars/*" Spark_LinearRegression_ElasticNet_Demo
# output
2018-05-26 07:38:16 INFO DAGScheduler:54 - Job 6 finished: show at Spark_LinearRegression_ElasticNet_Demo.java:69, took 0.067516 s
+--------------------+
| residuals|
+--------------------+
| -9.889232683103197|
| 0.5533794340053554|
| -5.204019455758823|
| -20.566686715507508|
| -9.4497405180564|
| -6.909112502719486|
| -10.00431602969873|
| 2.062397807050484|
| 3.1117508432954772|
| -15.893608229419382|
| -5.036284254673026|
| 6.483215876994333|
| 12.429497299109002|
| -20.32003219007654|
| -2.0049838218725005|
| -17.867901734183793|
| 7.646455887420495|
| -2.2653482182417406|
|-0.10308920436195645|
| -1.380034070385301|
+--------------------+
only showing top 20 rows
RMSE: 10.189077167598475
r2: 0.022861466913958184
# ref
# https://www.mkyong.com/maven/how-to-create-a-java-project-with-maven/
# step 1) set up JAVA project via mvn
$ mvn archetype:generate -DgroupId=com.yen.javadev -DartifactId=maven-first-java-project -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false
# step 2) Code your APP
# in this demo :
# src/main/java/com/yen/javadev/APP.java
# src/test/java/com/yen/javadev/APPTest.java
# step 2') UPDATE POM
# pom.xml
# step 3) Maven Build
$ mvn package
# step 4) package
$ mvn clean package
# step 5) run the APP
$ java -jar target/maven-first-java-project-1.0-SNAPSHOT.jar 123456
# output
# 8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92
$ java -jar target/maven-first-java-project-1.0-SNAPSHOT.jar 99999
# output
# fd5f56b40a79a385708428e7b32ab996a681080a166a2206e750eb4819186145