groovy basic knowledge

简单地说，Groovy 是下一代的java语言，跟java一样,它也运行在 JVM 中。
作为跑在JVM中的另一种语言，groovy语法与 Java 语言的语法很相似。同时，Groovy 抛弃了java烦琐的文法。 同样的语句，使用groovy能在最大限度上减少你的击键次数――这确实是“懒惰程序员们”的福音。

 

(1)

how to run the groovy using eclipse IDE:
1.
download the groovy plug-in for eclipse and put then under the related directory.
2.
create a java project and right-click the project,select 'groovy' then choose 'add groovy nature'. this operation let this java project support the groovy;
3.
aiming to separate the java class and the groovy class,we can create com.java,com.groovy for related classes.
create groovy class:
new-->others-->groovy-->groovy class.
follow the above steps,we can create a groovy class.
4.
run the groovy:
just like to run java class.

 

(2)

examples:

 

package com.test.groovy

import groovy.sql.Sql;

public class HelloWorld{

    public static void main(def args){
        println "Hello Word !"
        def var="Hello world"+"groovy";
        println var;
        println var.class;
        var=100;
        println var.class;
        String nullValue
//?操作符时刻都非常有用，可以极大地减少条件语句。若不为null，则会执行后面的
        nullValue?.toLowerCase()
        println "-----------------------------"
       
        def hw=new HelloWorld();
        hw.show1("hello")
        hw.show1("world",2)
        hw.show2("test",2)
//        hw.connectDB(6)
       
        println "-----------闭包，常用于循环------------------"
        def list=['a','b','c']
        list.each{println it}

        def map=['name':'john','age':14,'sex':'boy']
        map=map+['weight':25]       //添加john的体重
        map.put('length',1.27)      //添加john的身高
        map.father='Keller'         //添加john的父亲
       
        println map['name']
        println map['length']
        map.each{key,value-> println "$key:$value"}

        println "-----------------------------"
       
    }
   
    def show1(val,count=3)
    {
        for(i in 0..<count) //compare with the later method(show2)
        {
            println i
            println "this is a ${i} test: ${val} !";
        }
    }
   
    def show2(val,count)
    {
        for(i in 0..count)
        {
            println "this is a"+i+" test: "+val;
        }
    }
   
    def connectDB(id)
    {
        def url = "jdbc:oracle:thin:@10.50.74.117:1521:mssapp"
        def driver = "oracle.jdbc.driver.OracleDriver"  
        def user = "dev"  
        def password = "dev"
       
        def sql = Sql.newInstance(url,user,password,driver)
        sql.execute("insert into test_account values('5','account5')")            
        sql.execute("insert into test_account values('7','account7')")   
        sql.execute("insert into test_account values(${id},'account6')")   
        sql.execute("update test_account set ACCOUNTNAME=? WHERE AC_ID=?",["herry Test",id]) 
        sql.execute("delete from test_account where AC_ID>4")
        def row = sql.firstRow("SELECT COUNT(*) AS TOTALRECORD FROM TEST_ACCOUNT")
        println row.TOTALRECORD
       
        //使用groovy的隐含变量 it（它恰好就是迭代器的实例）
        sql.eachRow("SELECT * FROM TEST_ACCOUNT")
        {
            println it.AC_ID
            println it.ACCOUNTNAME
        }
       

    }
}

need lib:  classes12.jar

-------------------------------------------------------------------------------------------

package com.test.groovy

public class PersonInfo{
    //对于javabean各属性，默认为private(不同于groovy平时的默认设置：平时默认为public)且自动生成setter,getter.
    //对于单独的方法，如toShow()，默认仍为public
    Integer persionId
    String name
    Double weight
    public String pas;
    def addr;
   
    String toShow()
    {
        return " persionId -- ${persionId} \n name -- ${name}"
    }
}

-------------------------------------------------------------------------------------------

package com.java;
import com.test.groovy.HelloWorld;
import com.test.groovy.PersonInfo;

public class TestGroovy {

    public static void main(String[] args) {
        HelloWorld hw=new HelloWorld();
        hw.show1("testing in java");
       
        PersonInfo pi=new PersonInfo();
        pi.setPersionId(123);
        pi.setName("tom");
        pi.setWeight(120.0);
        System.out.println(pi.getName());
        System.out.println(pi.getWeight());
        System.out.println(pi.toShow());
    }
   
    public int plus(int i,int y)
    {
        return i+y;
    }

}

 

references:

基础:

http://blog.csdn.net/kmyhy/archive/2009/05/19/4200563.aspx

与 java整合：

http://sheng8407-sina-com.javaeye.com/blog/368079

实战 Groovy: 用 Groovy 进行 JDBC 编程
http://www.ibm.com/developerworks/cn/java/j-pg01115.html

用 Groovy 减少代码冗余
http://www.ibm.com/developerworks/cn/java/j-pg09196.html

与 ssh等的结合.