http断点续传简单实现（java)

/* -0$55pa/@:  
**SiteFileFetch.java 0=* 8
  
*/ E*V`":efS  
package NetFox; s.N7qO^:E  
import java.io.*; K1r#8Q!t  
import java.net.*; P"y`A}Bx  
/ ';0H_  
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public class SiteFileFetch extends Thread { pQ=>.JU  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Z~oo;xE  
long[] nStartPos; //开始位置 5iz{op<$,  
long[] nEndPos; //结束位置 5!DBmAB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 wQP^WzNE  
long nFileLength; //文件长度 e vrX
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boolean bFirst = true; //是否第一次取文件 [SHXJ4P*  
boolean bStop = false; //停止标志 %k-3?%&8  
File tmpFile; //文件下载的临时信息 n>+mL"hs  
DataOutputStream output; //输出到文件的输出流 ryW'Z{+r'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &]e'KdXF  
public SiteFileFetch(SiteInfoBean bean) throws IOException s2'yY(u/  
{ q>$ev)W  
siteInfoBean = bean; DnCP aM4%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -8
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ghx3EVqnx"  
if(tmpFile.exists ()) 
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{ q|o}+Vr  
bFirst = false; D
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read_nPos(); Vr6@>@SC  
} e+$p9k~  
else *.sVr7=j  
{ 8jd;JPz@\  
nStartPos = new long[bean.getNSplitter()]; P `}zlml  
nEndPos = new long[bean.getNSplitter()]; %QH)'GJQ  
} |Y$uqRdV  
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} UDL!43K  
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public void run() q qpgy7  
{ PD&\LbuG  
//获得文件长度 u<3HQ.:;  
//分割文件 OMWbZ>jB  
//实例FileSplitterFetch U1DXeh~V  
//启动FileSplitterFetch线程 lD^]\;?  
//等待子线程返回 =yr0bGy`-  
try{ y4*U6+#.  
if(bFirst) A'q#I>j`  
{ TD1 [  
nFileLength = getFileSize(); i5Zk_-\#H  
if(nFileLength == -1) C~nzH,5  
{ ^B(V4-|  
System.err.println("File Length is not known!"); Bt>}rYz1  
} LJk@Vy <?  
else if(nFileLength == -2) S4^vpY DeN  
{ mL{B!Q  
System.err.println("File is not access!"); <(-= 'QA  
} $FlW1E j  
else 'oF%,4 !Y  
{ As3.Q(#Z  
for(int i=0;i<nStartPos.length;i++) U}6.h&$  
{ OTGofd2zf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <KE 1f7c  
} )~+E[|  
for(int i=0;i<nEndPos.length-1;i++) +=q$x Ia
 
{ Xf02"PXC  
nEndPos = nStartPos[i+1]; : >6F+XZ  
} MHh~vy'HB5  
nEndPos[nEndPos.length-1] = nFileLength; Wc,~{  
} w.H%R-Be  
} OUeyklw  
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//启动子线程 $nb[G$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3a?o3=  
for(int i=0;i<nStartPos.length;i++) p[hZ@f(z  
{ b%<9Sn   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DB-l$rj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lDOCmdt@N  
nStartPos,nEndPos,i); 1
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2_n7=&  
fileSplitterFetch.start(); lzYEx  
} o_@4Sl8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n#q<`}u,
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K8>zF/# +  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", BybW)+~  
nEndPos = " + nFileLength); 85n1eE  
// fileSplitterFetch[nPos.length-1].start(); D}dn.$  
iVB86XZ`  
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//等待子线程结束 PV9pa/`@  
//int count = 0; `S6x<J&T\/  
//是否结束while循环 Sx?ua<`:d  
boolean breakWhile = false; JHz [7  
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S`#w+C#EW  
while(!bStop) FrTi+& <  
{ AWP"b?^G|  
write_nPos(); ]|MEx{BG-  
Utility.sleep(500); .Xce9C0SW  
breakWhile = true; ( M7pT  
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for(int i=0;i<nStartPos.length;i++) |&FkksNAl\  
{ wQe_vY  
if(!fileSplitterFetch.bDownOver) Pa~)"u8  
{ ~(Q)"s\1I  
breakWhile = false; Q^ pmQ  
break; B[V+ND'(  
} U<CTubF  
} p1&b!*o-&  
if(breakWhile) 7g%E`3)"  
break; +6';1Nb@  
&K.?p2$X  
(vb SM}P  
//count++; qOSM}ei>s  
//if(count>4) 'R c,Mq'  
// siteStop(); vU767/  
} 95YL]3V  
%]>KvoA  
pgOQIzu  
System.err.println("文件下载结束！"); KO]T<R h<  
} eu(:`uu  
catch(Exception e){e.printStackTrace ();} +tVaBhd!  
} So0f)`A  
kdl:Wt*4o  
SzjkI+-$:  
//获得文件长度 p4'G$]#  
public long getFileSize() %@.v2 cT  
{ DpUbzr41+k  
int nFileLength = -1; #7MUJY+ 9  
try{ KTP8?Q"n0  
URL url = new URL(siteInfoBean.getSSiteURL()); "J4WzA%i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ed_N[I   
httpConnection.setRequestProperty("User-Agent","NetFox"); hnDBFQ{  
[/Rf\T(,jn  
-F<Wd/Xse  
int responseCode=httpConnection.getResponseCode(); ](&{:>RNJ  
if(responseCode>=400) O+]Ifm[  
{ k&,~qoU  
processErrorCode(responseCode); Q aS\(_  
return -2; //-2 represent access is error G&4&-<  
} sOU1n  
 !"\80LP  
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String sHeader; >U%gctIg  
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for(int i=1;;i++) 1`a5C.v  
{ C!fMW+C@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BFo5\l:q8  
//Utility.log(in.readLine()); LUqB&,a}  
sHeader=httpConnection.getHeaderFieldKey(i); [[;e)SoA  
if(sHeader!=null) &o,<ijJ:^m  
{ P@9t;dZ
N  
if(sHeader.equals("Content-Length")) RLLTw ?]$  
{ cNM3I,o7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T[j#M+p  
break; ZuS0DPS`L  
} `
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} nv@8tdrc  
else ~c %hWt  
break; pKit~A,Q  
} YgUvOyaQXf  
} %?p1d!  
catch(IOException e){e.printStackTrace ();} ~v6OsH%vx  
catch(Exception e){e.printStackTrace ();} =Ur}~w&H8  
a
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Utility.log(nFileLength); Ry%Mej:  
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return nFileLength; i 7x7xtq  
} L{h%f4Du#  
vTlwRG=5  
L#+q]j+  
//保存下载信息（文件指针位置） 0tEYU:Qu  
private void write_nPos() my4giC2a  
{ _OuWB"  
try{  Kfh|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :'~Y  
output.writeInt(nStartPos.length); f;1K5Y  
for(int i=0;i<nStartPos.length;i++) @I_8T$N=  
{ =8; {\  
// output.writeLong(nPos); aC%m-m  
output.writeLong(fileSplitterFetch.nStartPos); uF1~FKB  
output.writeLong(fileSplitterFetch.nEndPos); @U3Vc|  
} e^<#53!  
output.close(); QA5QweL  
} HN&Z2v  
catch(IOException e){e.printStackTrace ();} FRg^c kb"  
catch(Exception e){e.printStackTrace ();} l}]t~!X=  
} 5[* qi?w=  
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}Rz3<eON  
//读取保存的下载信息（文件指针位置） eC[$B99\  
private void read_nPos() kH
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{ fO0XA"=  
try{ +eFFSt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y5do1Z  
int nCount = input.readInt(); n~A%q,DmF  
nStartPos = new long[nCount]; x)rM/Kq  
nEndPos = new long[nCount]; W!?7D0q  
for(int i=0;i<nStartPos.length;i++) Db;G@#x  
{ YRh BRE  
nStartPos = input.readLong(); Y6Lf@}2(i  
nEndPos = input.readLong(); (fCXxyZrr  
} mo[Zb0>  
input.close(); ?sMP~RHQ  
} 6y6<JR-V2k  
catch(IOException e){e.printStackTrace ();} ~:3QBMk::  
catch(Exception e){e.printStackTrace ();} DsT>3  
} 34d3g  
l,,>& F  
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private void processErrorCode(int nErrorCode) JWMpPzs  
{ q.2ykL  
System.err.println("Error Code : " + nErrorCode); 3>R#zJf  
} %=/)  
~Uxsn@nLr  

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//停止文件下载 L7VG`h;  
public void siteStop() \>7^f 3m  
{ O }(
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bStop = true; ^V#@QPK9  
for(int i=0;i<nStartPos.length;i++) lsy?Ac  
fileSplitterFetch.splitterStop(); GQ9\'z#+  
7D!u1?]d{  
J,AR5@)1  
} _c,'>aH=  
} +=.W<b
 
//负责部分文件的抓取 Kwg4sr5"D  
**FileSplitterFetch.java n(L\||#+  
*/ 4Qo]nre!  
package NetFox; R +WP0&d'  
,B0_MDA +  
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import java.io.*; A` AaTP  
import java.net.*; Dg} Ka7H  
69J4=5lX  
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public class FileSplitterFetch extends Thread { lhw()u  
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String sURL; //File URL -mRA#  
long nStartPos; //File Snippet Start Position ,;(PwJe  
long nEndPos; //File Snippet End Position ui@2s;1t  
int nThreadID; //Thread's ID N9vP7  
boolean bDownOver = false; //Downing is over .]sf0S!  
boolean bStop = false; //Stop identical 3Ei5pX=g  
FileAccessI fileAccessI = null; //File Access interface 86\S?=J-b  
U)o$WH.b  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException UGuxV+Nwf  
{ bIEhgiH  
this.sURL = sURL; !X<~-G2)l  
this.nStartPos = nStart; mGGsB5#w>  
this.nEndPos = nEnd; T9u<p=p  
nThreadID = id; QNxl/y\l0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $.GOZqMs  
} <]b7ZF]  
a)#1{JaoY  
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public void run() \@1=stK:F  
{ k:#P|z$UD  
while(nStartPos < nEndPos && !bStop) ,iv|Pq$!  
{ ")!,ZD  
#*g5u{k'P  
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try{ %LZ({\5K#f  
URL url = new URL(sURL); a\:VREKj,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kJ-*fe'S  
httpConnection.setRequestProperty("User-Agent","NetFox"); aBw2f[mo  
String sProperty = "bytes="+nStartPos+"-"; * C6a?]  
httpConnection.setRequestProperty("RANGE",sProperty); i![dPM  
Utility.log(sProperty); (>I`{9x>6  
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InputStream input = httpConnection.getInputStream(); y
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//logResponseHead(httpConnection); hweaGL t0  
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byte[] b = new byte[1024]; jD`d#R  
int nRead; *r$+&8V\n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _!?Hu/zo  
{ GR"Eas.$  
nStartPos += fileAccessI.write(b,0,nRead); Sf,R^9#|  
//if(nThreadID == 1) Eyh51IB.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q]w&N30  
} \0H's{uek  
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P7x =  
Utility.log("Thread " + nThreadID + " is over!"); MiRdX#+Y  
bDownOver = true; }A:<%N  
//nPos = fileAccessI.write (b,0,nRead); XFh>U7z.  
} a /:@"&Y  
catch(Exception e){e.printStackTrace ();} zBP>jM(8  
} "luR9l,RRE  
} QlHd,w  
6"D/xV3Z  
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'  
//打印回应的头信息 jOyvDY9\  
public void logResponseHead(HttpURLConnection con) j$TwL;  
{ ]d]JXt?)i  
for(int i=1;;i++) UEzb^(8>  
{ ,E$@=1)  
String header=con.getHeaderFieldKey(i); yx<WSgWZ[  
if(header!=null) Qo1eXM
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); vYU;_R  
Utility.log(header+" : "+con.getHeaderField(header));  =Mb1o[  
else (}
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break; h#hxOVl%x  
}
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} I6s3+x;O  
&V<W>Y>|l*  
7oR:1DXw|  
public void splitterStop() ) 9oH,gZ  
{ \AC|?/sH  
bStop = true; brZ sAQ+k  
} S#-tOjU*  
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} k,
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q;:6_Qr  
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/* }=2;  
**FileAccess.java )Y8",Ig  
*//文件访问(定位，写) ZJjTzEV%^B  
package NetFox; hHPs&EA.p  
import java.io.*; q,3;m[cA  
xwH?0/  
D>!6,m2  
public class FileAccessI implements Serializable{ eJo3 MK  
/LM4-S  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tWdhDt8$&  
RandomAccessFile oSavedFile; Fbp{,V@F2  
long nPos; 5c;h&  
3F#+~^2  
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public FileAccessI() throws IOException )C.yF)Ql  
{ 3~qR  
this("",0); > QFHm5Jw  
} U5]pi+r  
t nS+5F  
_7D_72  
public FileAccessI(String sName,long nPos) throws IOException 4TwQO$C  
{ cFagz* !  
oSavedFile = new RandomAccessFile(sName,"rw"); TbehR:B5g  
this.nPos = nPos; 1,V`8 [  
oSavedFile.seek(nPos); Zh/Uu6  
} e62Dx#IY  
aRc'  
)){xlFA}  
public synchronized int write(byte[] b,int nStart,int nLen) H\GkW6  
{ =ORf%f5"'  
int n = -1; "|m|E/Z-9  
try{ ZCg`z
  
oSavedFile.write(b,nStart,nLen); <q,+ON\'  
n = nLen; ?K@t0a
 
} I=O
y-  
catch(IOException e) poJg"R4  
{ 1KYN>s:  
e.printStackTrace (); ]p~IYNl2%j  
} 0~&"  
m4[g6pNx~  
?'r9"M>  
return n; 'lS`s(  
} FhIqy %X  
1|?K\B  
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} R1-k3;v^  
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/* C#w]4$/  
**SiteInfoBean.java ofW+_DKB?l  
*/ SLhEc  
package NetFox; !Do,>gO  
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c {I"R8  
public class SiteInfoBean { 8#` 6M5  
= c~I .  
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private String sSiteURL; //Site's URL uvA(Rn  
private String sFilePath; //Saved File's Path nVD Xj  
private String sFileName; //Saved File's Name Yn9j-`  
private int nSplitter; //Count of Splited Downloading File A.Bk/N1G  
IwpbfZ  
Qeb}!k2A  
public SiteInfoBean() xiyxrR;  
{//nSplitter的缺省值为5 %So]3;'  
//default value of nSplitter is 5
P=H+ #  
this("","","",5); o7+>G~i  
} Q&M'=+T  
e(1k0W4B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ih1|LR/c  
{ *T4<&  
sSiteURL= sURL; PG,U6c #  
sFilePath = sPath; D{'#er  
sFileName = sName; &HM-g7|C0E  
this.nSplitter = nSpiltter; B(l-}|m_  
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} V)D-pV V  
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public String getSSiteURL() #X
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{ ~DLIzg7p!  
return sSiteURL; 'Zk<l#"}  
} eSl-9 ^  
#Nte^
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?kt=z4h9(  
public void setSSiteURL(String value) jnoL2JR[=-  
{ 30FykNh  
sSiteURL = value; ~_!ts{[E  
} Xz;b,C&*t  
{4ptu~8  
C4$/?,K(  
public String getSFilePath() ]2+g&ox4'  
{ hbuZaxo<  
return sFilePath; wVi%
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} :G'x
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public void setSFilePath(String value) vW' 5` %  
{ b2h":G|s  
sFilePath = value; WfGH|u  
} lv:U%+A  
M@?"t_e1  
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public String getSFileName() )-&nxOP  
{ >,h1N$A+  
return sFileName; s?O&ZB2GM[  
} b?kPN:U#N/  
L(WOet('  
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public void setSFileName(String value) Sb^ b)q"  
{ A
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sFileName = value; |#T
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} $cK^23H/Fj  
eX<K5K.B  
wsg//Ec]  
public int getNSplitter() FU@uH U5fd  
{ Wp*sPZ  
return nSplitter; 6tOi^+qN  
} '\*A"8;h  
k)E;(
 
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public void setNSplitter(int nCount) fkW(Dt,  
{ 3kLOoL?  
nSplitter = nCount; - s|t^  
} ~eo^`4O{{  
} @ t@|q  
>rwYDT#m]  
v#=ayWgk  
/* n0.8)=;2  
**Utility.java rrQ0qg  
*/ X^in};&d  
package NetFox; e?)yb^7K  
 nhfwOS  
F7uhuqA]N  
public class Utility { +)-d_K.(k  
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public Utility() yv${M u  
{ }W "(cYN_  
$DV-Ieb  
fH!=Zb_{8  
} a R#Cot  
'?R=
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//线程睡眠 v,\93mNp[  
public static void sleep(int nSecond) SY6r 8RK  
{ J%4HNW*p  
try{ 70<K.T<b  
Thread.sleep(nSecond); b@-)Fy4d2  
} P`!Ak@N  
catch(Exception e) 9`&77+|;e  
{ bD@@tGr;W  
e.printStackTrace (); Orc>.~+f%A  
}  {@\/a  
} A}eOR=E  
ocP*\NR  
//日志 ~\bHfiIDy  
public static void log(String sMsg) Fhi5LhWe+.  
{ w?;b7i  
System.err.println(sMsg); ")\ *2d  
} +GPd  
#f9qlM32  
t|".=3%G  
public static void log(int sMsg) !>|`ly$6  
{ cX"G7Bh  
System.err.println(sMsg); 3qcpf:  
} 5xv,!
/@  
} Fs9W>*(  
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Ey= 4 b  
/* 8a!2zwUBV  
**TestMethod.java tAt;bYjb\  
*/ Eb7}$Ji\  
package NetFox; jQIV2TY[  
n@o  
4`G=q^GL,  
public class TestMethod { %((cFQ9  
T=yCN#cqQ`  
i\Q":4  
public TestMethod() PE7t_iSV  
{ ///xx/weblogic60b2_win.exe >!G5]?taa
 
try{
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u dUXc6U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +TW
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SiteFileFetch fileFetch = new SiteFileFetch(bean); +ks$UvtY  
fileFetch.start(); 5z[6rT=a  
} 7\ZL  
catch(Exception e){e.printStackTrace ();} jM;d>Gymx  
tQCj)Ms'X  
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} v5gQ9  
ep`/:iYW  
@s?oJpo  
public static void main(String[] args) {!tOI  
{ t.u{.P\Md\  
new TestMethod(); x6~Fb~aP  
}
kz|[
*%10  
} )rS^F<C  
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