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前言：经常在网络上看见一些关于json自动转换成javaBean的jar包，项目组里的人也在用，稍稍研究了下，都是用的反射来做的。我细细想了下里面的逻辑，我觉得直接生成JavaBean代码岂不是更加直接，反射在移动端，怎么说都是消耗资源的。
首先要梳理下，到底Bean类是一个什么样的文件，很简单的是有很多属性的class文件，属性有很多类别，但是从json的角度来看，类别又是有限的：基本类型和List。我们可以用python来模拟下：
# encoding: utf-8
‘‘‘
Created on 2014.12.24
@author: 13051041
‘‘‘
class JavaClass(object):
‘‘‘
class templete
‘‘‘
def __init__(self, name):
‘‘‘
Constructor
‘‘‘
self.mName = name;
self.mIntegerList = []
self.mStrList = []
self.mBolList = []
self.mListList = []
self.mClassList = []
self.mInClassTypeList = []
self.mIsParcelable = True
self.mPackageName = "package com.codegenerator;"
def addIntAttribute(self, str1):
‘‘‘
add String attribute
‘‘‘
self.mIntegerList.append(str1)
def addUnicodeAttribute(self, str1):
‘‘‘
add String attribute
‘‘‘
self.mStrList.append(str1)
def addBooleanAttribute(self, bol):
‘‘‘
add Boolean attribute
‘‘‘
self.mBolList.append(bol)
def addListAttribute(self, list1):
‘‘‘
add List attribute
‘‘‘
self.mListList.append(list1)
def addClassAttribute(self, cls):
‘‘‘
add Class attribute
‘‘‘
self.mClassList.append(cls)
def addInClassType(self, inClass):
‘‘‘
add Inner Class attribute
‘‘‘
self.mInClassTypeList.append(inClass)
def test(self):
print "-----this is JavaClass information start-----"
print "class‘s name is %s" % self.mName
print "class‘s integer is %s " % self.mIntegerList
print "class‘s String is %s " % self.mStrList
print "class‘s Boolean is %s " % self.mBolList
print "class‘s List is %s " % self.mListList
print "class‘s inner class is %s " % self.mClassList
print "class‘s inner class type is %s " % self.mInClassTypeList
print "-----this is JavaClass information end-----"
classNum = 0
def autoGeneratorClassName():
global classNum
classNum = classNum + 1
return "class%d" % classNum
def buildJavaClassNode(jsonObject, className):
javaclass = JavaClass(className)
keys = jsonObject.keys()
for key in keys:
t = type(jsonObject[key])
if t == int:
javaclass.addIntAttribute(key)
if t == unicode:
javaclass.addUnicodeAttribute(key)
if t == bool:
javaclass.addBooleanAttribute(key)
if t == dict:
newClassName = autoGeneratorClassName()
javaclass.addClassAttribute((newClassName, key))
javaclass.addInClassType(buildJavaClassNode(jsonObject[key], newClassName))
if t == list:
t2 = type(jsonObject[key][0])
if t2 == dict:
newClassName = autoGeneratorClassName()
javaclass.addListAttribute((newClassName, key))
javaclass.addInClassType(buildJavaClassNode(jsonObject[key][0], newClassName))
else:
javaclass.addListAttribute((t2, key))
return javaclass
我们一个叫javaclass的python类了，用python读取json，直接生成实例。现在的任务是把这个实例，写到文件里面。想想class的嵌套关系，生成最好的方法就是递归：
# encoding: utf-8
‘‘‘
Created on 2014.12.26
@author: 13051041
‘‘‘
Class_import = ‘‘‘
%s
import java.util.ArrayList;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.JSONException;
‘‘‘
Class_import_parcelable = ‘‘‘
import android.os.Parcel;
import android.os.Parcelable;
‘‘‘
Class_HEAD = ‘‘‘
public %s class %s {
‘‘‘
Class_HEAD_parcelable = ‘‘‘
public %s class %s implements Parcelable{
public %s() {
}
public %s(Parcel in) {
readFromParcel(in);
}
‘‘‘
Class_Method_END = "}\n"
Attribute_TEMP = "public %s %s;\n"
Method_Analyzer = ‘‘‘
public void analyzerJson(JSONObject jsonObject) throws JSONException {
if(jsonObject == null){
return;
}
‘‘‘
Method_TEMP = "public %s %s(%s)throws JSONException {\n"
Method_GET_INT = ‘‘‘%s = GetJsonAttributeUtil.getInt(jsonObject, "%s");‘‘‘
Method_GET_String = ‘‘‘%s = GetJsonAttributeUtil.getString(jsonObject,"%s");‘‘‘
Method_GET_Boolean = ‘‘‘%s = GetJsonAttributeUtil.getBoolean(jsonObject,"%s");‘‘‘
Method_GET_CLASS = ‘‘‘%s = new %s();
%s.analyzerJson(GetJsonAttributeUtil.getJSONObject(jsonObject,"%s"));‘‘‘
Method_GET_List = ‘‘‘
%s= new ArrayList<%s>();
JSONArray array%s = GetJsonAttributeUtil.getJSONArray(jsonObject,"%s");
int %sLen = array%s.length();
for(int i = 0;i<%sLen;i++){
%s item = new %s();
item.analyzerJson(array%s.getJSONObject(i));
%s.add(item);
}
‘‘‘
Method_Parcelable_Write = ‘‘‘public void writeToParcel(Parcel dest, int flags) {\n ‘‘‘
Mehtod_Parcelable_Value_Write = "dest.write%s(%s);\n"
Method_Parcelable_Read = ‘‘‘public void readFromParcel(Parcel in) {\n ‘‘‘
Mehtod_Parcelable_Value_Read = "%s= in.readString(); "
IS_PARCELABLE = True
FILE_NAME = "Bean"
def writeParcelabelMethod(f, jcls):
# writeToParcel method
f.write(Method_Parcelable_Write)
for attribute in jcls.mIntegerList:
f.write("dest.writeInt(%s);\n" % (attribute))
for attribute in jcls.mStrList:
f.write("dest.writeString(%s);\n" % (attribute))
for attribute in jcls.mBolList:
f.write("dest.writeByte((byte) (%s ? 1 : 0));\n" % (attribute))
for attribute in jcls.mListList:
f.write("dest.writeTypedList(%s);" % (attribute[1]))
for attribute in jcls.mClassList:
f.write("dest.writeParcelable(%s, PARCELABLE_WRITE_RETURN_VALUE);" % attribute[1])
f.write(Class_Method_END)
# readFromParcel method
f.write(Method_Parcelable_Read)
for attribute in jcls.mIntegerList:
f.write("%s= in.readInt();\n" % (attribute))
for attribute in jcls.mStrList:
f.write("%s= in.readString();\n" % (attribute))
for attribute in jcls.mBolList:
f.write("%s = in.readByte() != 0;\n" % (attribute))
for attribute in jcls.mListList:
f.write("%s = new ArrayList<%s>();" % (attribute[1], attribute[0]))
f.write("in.readTypedList(%s, %s.CREATOR);" % (attribute[1], attribute[0]))
for attribute in jcls.mClassList:
f.write("%s = in.readParcelable(%s.class.getClassLoader());" % (attribute[1], attribute[0]))
f.write(Class_Method_END)
# describeContents method
f.write("public int describeContents() {return 0;}")
f.write(‘‘‘
public static final Parcelable.Creator<%s> CREATOR =
new Parcelable.Creator<%s>() {
public %s createFromParcel(Parcel in) {
return new %s(in);
}
public %s[] newArray(int size) {
return new %s[size];
}
};
‘‘‘ % (jcls.mName, jcls.mName, jcls.mName, jcls.mName, jcls.mName, jcls.mName))
pass
def writeCls2File(jcls, f):
f.seek(0, 2)
# write class header
if IS_PARCELABLE: # if need implement parcelable
if jcls.mName == FILE_NAME:
f.write(Class_HEAD_parcelable % ("", jcls.mName, jcls.mName, jcls.mName))
else:
f.write(Class_HEAD_parcelable % ("static", jcls.mName, jcls.mName, jcls.mName))
else:
f.write(Class_HEAD % ("", jcls.mName))
# write class‘s attribute
for attribute in jcls.mIntegerList:
f.write(Attribute_TEMP % (‘int‘, attribute))
for attribute in jcls.mStrList:
f.write(Attribute_TEMP % (‘String‘, attribute))
for attribute in jcls.mBolList:
f.write(Attribute_TEMP % (‘Boolean‘, attribute))
for attribute in jcls.mListList:
f.write(Attribute_TEMP % (‘List<‘ + attribute[0] + ‘>‘, attribute[1]))
for attribute in jcls.mClassList:
f.write(Attribute_TEMP % (attribute[0], attribute[1]))
# write class‘s method analyzerJson
f.write(Method_Analyzer)
for attribute in jcls.mIntegerList:
f.write(Method_GET_INT % (attribute, attribute))
for attribute in jcls.mStrList:
f.write(Method_GET_String % (attribute, attribute))
for attribute in jcls.mBolList:
f.write(Method_GET_Boolean % (attribute, attribute))
for attribute in jcls.mClassList:
f.write(Method_GET_CLASS % (attribute[1], attribute[0], attribute[1], attribute[1]))
for attribute in jcls.mListList:
f.write(Method_GET_List % (attribute[1], attribute[0], attribute[1], attribute[1], attribute[1], attribute[1], attribute[1], attribute[0], attribute[0], attribute[1], attribute[1]))
f.write(Class_Method_END)
# write parcelable method
if IS_PARCELABLE:
writeParcelabelMethod(f, jcls)
# the method toString
f.write("public String toString(){")
f.write("String allInfo = ")
for attribute in jcls.mIntegerList:
f.write(‘‘‘ " %s="+%s + ‘‘‘ % (attribute, attribute))
for attribute in jcls.mStrList:
f.write(‘‘‘ " %s="+%s + ‘‘‘ % (attribute, attribute))
for attribute in jcls.mBolList:
f.write(‘‘‘ " %s="+%s + ‘‘‘ % (attribute, attribute))
for attribute in jcls.mListList:
f.write(‘‘‘ " %s="+%s.toString() + ‘‘‘ % (attribute[1], attribute[1]))
for attribute in jcls.mClassList:
f.write(‘‘‘ " %s="+%s.toString() + ‘‘‘ % (attribute[1], attribute[1]))
f.write(‘‘‘" ";‘‘‘)
f.write("return allInfo;")
f.write(Class_Method_END)
# write class‘s class
for innerClass in jcls.mInClassTypeList:
writeCls2File(innerClass, f)
pass
f.write(Class_Method_END)
pass
def generatorClsFile(jcls):
global IS_PARCELABLE
global FILE_NAME
IS_PARCELABLE = jcls.mIsParcelable
FILE_NAME = jcls.mName
f = open(FILE_NAME + ".java", ‘w‘)
f.write(Class_import % jcls.mPackageName)
if IS_PARCELABLE:
f.write(Class_import_parcelable)
writeCls2File(jcls, f)
完整项目：http://files.cnblogs.com/files/chenjie0949/CodeGenerator1.3.zip
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原文地址：http://www.cnblogs.com/chenjie0949/p/4815640.html
