Jython介紹

快速入門

下面咱們使用jython來調用自定義jar包中的類。

編輯java文件：Beach.java

public class Beach {

    private String name;
    private String city;


    public Beach(String name, String city){
        this.name = name;
        this.city = city;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

}

編譯成jar包：

# javac Beach.java 
# echo Main-Class: Beach >manifest.txt
# jar cvfm Craps.jar manifest.txt *.class
已添加清單
正在添加: Beach.class(輸入 = 795) (輸出 = 430)(壓縮了 45%)
正在添加: Point.class(輸入 = 708) (輸出 = 445)(壓縮了 37%)

添加Craps.jar到CLASSPATH，修改/etc/profile，修改CLASSPATH

export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:/usr/local/jython/Craps.jar

使用. /etc/profile導入變量。而後使用jython調用java代碼。

# ./jython 
Jython 2.7.0 (default:9987c746f838, Apr 29 2015, 02:25:11) 
[Java HotSpot(TM) 64-Bit Server VM (Oracle Corporation)] on java1.7.0_79
Type "help", "copyright", "credits" or "license" for more information.
>>> import Beach
>>> beach = Beach("Cocoa Beach","Cocoa Beach")
>>> beach.getName()
u'Cocoa Beach'
>>> print beach.getName()
Cocoa Beach
>>>

基礎

Linux安裝：
 

# java -jar jython-installer-2.7.0.jar 
# ./jython 
Jython 2.7.0 (default:9987c746f838, Apr 29 2015, 02:25:11) 
[Java HotSpot(TM) 64-Bit Server VM (Oracle Corporation)] on java1.7.0_79
Type "help", "copyright", "credits" or "license" for more information.
>>>

windows安裝：雙擊jython-installer-2.7.0.jar, 執行jython.exe

變量定義：

java
int x = 0;
jython：
x = 0
x = 'Hello Jython'

是動態類型的。

保留字：
 

and     assert     break     class     continue
def     del     elif     else     except
exec     finally     for     from     global
or     pass     print     raise     return
try     while     with     yield

編碼結構使用縮進。

函數名也能夠做爲函數的參數。

語句關鍵字：

if-elif-else     for
while     continue
break     try-except-finally
assert     def
print     del
raise     import

文件名和類名同樣能夠直接導入。

 

此部分參考資料：

http://www.jython.org/jythonbook/en/1.0/JythonAndJavaIntegration.html

http://www.skylit.com/javamethods/faqs/createjar.html

參考資料：

http://www.jython.org/jythonbook/en/1.0/

 

模塊和包

查看命名空間
>>> dir()
['__builtins__', '__doc__', '__name__', '__package__']

Jython的導入不像java那樣必須在頭部。導入java以右邊名優先，python以左邊名優先。模塊查找路徑：

>>> import sys
>>> sys.path
['', '/usr/local/jython2.7.0/Lib', '__classpath__', '__pyclasspath__/', '/usr/local/jython2.7.0/Lib/site-packages']

>>> import sys
>>> sys.path
['', '/usr/local/jython2.7.0/Lib', '__classpath__', '__pyclasspath__/', '/usr/local/jython2.7.0/Lib/site-packages']

>>> import sys
>>> sys.path.append("/home/andrew/code/java/mysql-connector-java-5.1.39/mysql-connector-java-5.1.39-bin.jar")
>>> import com.mysql
*sys-package-mgr*: can't write cache file for '/home/andrew/code/java/mysql-connector-java-5.1.39/mysql-connector-java-5.1.39-bin.jar'
*sys-package-mgr*: can't write index file
>>> dir(com.mysql)
['__name__', 'fabric', 'jdbc']


>>> import java.util.zip
>>> dir(java.util.zip)
['Adler32', 'CRC32', 'CheckedInputStream', 'CheckedOutputStream', 'Checksum', 'DataFormatException', 'Deflater', 'DeflaterInputStream', 'DeflaterOutputStream', 'GZIPInputStream', 'GZIPOutputStream', 'Inflater', 'InflaterInputStream', 'InflaterOutputStream', 'ZipEntry', 'ZipError', 'ZipException', 'ZipFile', 'ZipInputStream', 'ZipOutputStream', '__name__']
>>> dir(java.util.zip.ZipInputStream)
['__class__', '__copy__', '__deepcopy__', '__delattr__', '__doc__', '__ensure_finalizer__', '__eq__', '__format__', '__getattribute__', '__hash__', '__init__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', '__subclasshook__', '__unicode__', 'available', 'class', 'close', 'closeEntry', 'equals', 'getClass', 'getNextEntry', 'hashCode', 'mark', 'markSupported', 'nextEntry', 'notify', 'notifyAll', 'read', 'reset', 'skip', 'toString', 'wait']

 

Jython 查找Jar和類的方法：
python.packages.paths
python.packages.directories

java.class.path
java.ext.dirs

python.cachedir.skip

pycimport把python字節碼轉換成java字節碼。Jython導入java包可能有多個包合併。

>>> import sys
>>> sys.path_hooks
[<type 'org.python.core.JavaImporter'>, <type 'zipimport.zipimporter'>,
<type 'ClasspathPyImporter'>]

import pycimport

數據類型

Jython特定的collection，多用於給java傳遞數據。

# Import and use a Java ArrayList

>>> import java.util.ArrayList as ArrayList

>>> arr = ArrayList()

#  Add method will add an element to the list and return a boolean to signify
successsful addition

>>> arr.add(1)

True

>>> arr.add(2)

True

>>> print arr

[1, 2]

比較老的Jarray，不推薦使用，不過能夠建立空數組：

類型：

Character    Java Equivalent
z    boolean
b    byte
c    char
d    Double
f    Float
h    Short
i    Int
l    Long

>>> my_seq = (1,2,3,4,5)

>>> from jarray import array

>>> array(my_seq,'i')

array('i', [1, 2, 3, 4, 5])

>>> myStr = "Hello Jython"

>>> array(myStr,'c')

array('c', 'Hello Jython')

>>> arr = zeros(10,'z')

>>> arr

array('z', [False, False, False, False, False, False, False, False, False, False])

>>> arr2 = zeros(6, 'i')

>>> arr2

array('i', [0, 0, 0, 0, 0, 0])

 

求素數

 

>>> nums = range(2, 50) 
>>> for i in range(2, 8): 
...     nums = filter(lambda x: x == i or x % i, nums)
... 
>>> print nums

 

讀取輸入：

# Obtain a value from the command line and store it into a variable
>>> import sys
>>> fav_team = sys.stdin.readline()
Cubs
>>> sys.stdout.write("My favorite team is: %s" % fav_team)
My favorite team is: Cubs

 

函數

協程：

def search_file(filename):
    print 'Searching file %s' % (filename)
    my_file = open(filename, 'r')
    file_content = my_file.read()
    my_file.close()
    while True:
        search_text = (yield)
        search_result = file_content.count(search_text)
        print 'Number of matches: %d' % (search_result)

Jython腳本編程基礎

os.chdir不會改變jvm的啓動目錄。

>>> import os
>>> os.getcwd()
'/Users/frank/Desktop/frank/hg/jythonbook~jython-book/src/chapter8'
>>> from java.io import File
>>> f = File(".")
>>> for x in f.list():
... print x
...
args.py
search.py
>>> os.chdir("/Users/frank")
>>> os.getcwd()
'/Users/frank'
>>> os.listdir(".")
['Desktop', 'Documents', 'Downloads', 'Dropbox', 'Library', 'Movies', 'Music', 'Pictures', 'Public', 'Sites']
>>> g = File(".")
>>> for x in g.list():
...     print x
...
args.py
search.py

 

編譯代碼

#!/usr/local/jython2.7.0/bin/jython

from javax.tools import (ForwardingJavaFileManager, ToolProvider, DiagnosticCollector,)
names = ["/home/andrew/code/python/jythonbook/src/chapter8/HelloWorld.java"]
compiler = ToolProvider.getSystemJavaCompiler()
diagnostics = DiagnosticCollector()
manager = compiler.getStandardFileManager(diagnostics, None, None)
units = manager.getJavaFileObjectsFromStrings(names)
comp_task = compiler.getTask(None, manager, diagnostics, None, None, units)
success = comp_task.call()
manager.close()

 

import os
import sys
import glob

from javax.tools import (forwardingjavafilemanager, toolprovider,
         diagnosticcollector,)

tasks = {}

def task(func):
    tasks[func.func_name] = func

@task
def clean():
    files = glob.glob("\*.class")
    for file in files:
        os.unlink(file)

@task
def compile():
    files = glob.glob("\*.java")
    _log("compiling %s" % files)
    if not _compile(files):
        quit()
    _log("compiled")

def _log(message):
    if options.verbose:
        print message

def _compile(names):
    compiler = toolprovider.getsystemjavacompiler()
    diagnostics = diagnosticcollector()
    manager = compiler.getstandardfilemanager(diagnostics, none, none)
    units = manager.getjavafileobjectsfromstrings(names)
    comp_task = compiler.gettask(none, manager, diagnostics, none, none, units)
    success = comp_task.call()
    manager.close()
    return success

if __name__ == '__main__':
    from optparse import optionparser
    parser = optionparser()
    parser.add_option("-q", "--quiet",
        action="store_false", dest="verbose", default=true,
        help="don't print out task messages.")
    parser.add_option("-p", "--projecthelp",
        action="store_true", dest="projecthelp",
        help="print out list of tasks.")
    (options, args) = parser.parse_args()

    if options.projecthelp:
        for task in tasks:
            print task
        sys.exit(0)

    if len(args) < 1:
        print "usage: jython builder.py [options] task"
        sys.exit(1)

    try:
        current = tasks[args[0]]
    except KeyError:
        print "task %s not defined." % args[0]
        sys.exit(1)
    current()

 

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World");
    }
}

 

[frank@pacman chapter8]$ jython builder.py --help
Usage: builder.py [options]

Options:
    -h, --help show this help message and exit
    -q, --quiet Don't print out task messages.
    -p, --projecthelp Print out list of tasks.
[frank@pacman chapter8]$ jython builder.py --projecthelp
compile
clean
[frank@pacman chapter8]$ jython builder.py compile
compiling ['HelloWorld.java']
compiled
[frank@pacman chapter8]$ ls
HelloWorld.java HelloWorld.class builder.py
[frank@pacman chapter8]$ jython builder.py clean
[frank@pacman chapter8]$ ls
HelloWorld.java builder.py
[frank@pacman chapter8]$ jython builder.py --quiet compile
[frank@pacman chapter8]$ ls
HelloWorld.class HelloWorld.java builder.py
[frank@pacman chapter8]$