http断点续传简单实现（java)

/* ZM"t.  
**SiteFileFetch.java %]-tA,
u  
*/ 8:f(PN  
package NetFox; w"~T5%p  
import java.io.*; HkrNt/]  
import java.net.*; !59q@Mya[  
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public class SiteFileFetch extends Thread { k@?<Aw8_X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean LVSJK.B  
long[] nStartPos; //开始位置 hQ9VcS6=gD  
long[] nEndPos; //结束位置 JH 8^ZP:d'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %NvY~,  
long nFileLength; //文件长度 k{; 2*6b0  
boolean bFirst = true; //是否第一次取文件 37VSE@Z+  
boolean bStop = false; //停止标志 i9d.Ls  
File tmpFile; //文件下载的临时信息 1'ZBtX~A  
DataOutputStream output; //输出到文件的输出流 nkxVc  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5( 3tPbm{  
public SiteFileFetch(SiteInfoBean bean) throws IOException z;T?2~g!  
{ KyjN'F$  
siteInfoBean = bean; ?Pa5skqR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HJDM\j*5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q:fkF^>  
if(tmpFile.exists ()) *t63c.S  
{ e7-U0rrE  
bFirst = false; kEi!q  
read_nPos(); Ay[6rU
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} n;[d{bU  
else _k&vW(O=:  
{ HZ/e^"cpM  
nStartPos = new long[bean.getNSplitter()]; @,
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nEndPos = new long[bean.getNSplitter()]; @I9A"4Im  
} "~XAD(T6  
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} g/eE^o~;  
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public void run() >HyZ~M  
{ (V&$KDOA  
//获得文件长度 A|7%j0T  
//分割文件  t
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//实例FileSplitterFetch S/V%<<[>p]  
//启动FileSplitterFetch线程 `@RTfBBg  
//等待子线程返回 UZz/v#y~  
try{ FG/1!8F  
if(bFirst) ]v=A}}kS  
{ 7*.nd
 
nFileLength = getFileSize(); ^?}-x  
if(nFileLength == -1) @cukoLAn  
{ -e(e;e  
System.err.println("File Length is not known!"); MaN6bM  
} 4}`z^P<C  
else if(nFileLength == -2) ew?4;  
{ ~wvu7  
System.err.println("File is not access!"); yw\Q>~$n[=  
} evjj~xkt
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else GCZx-zD~>  
{ WUrE1%u  
for(int i=0;i<nStartPos.length;i++) lha)4d  
{ gamE^Ee  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); c^3,e/H  
} SMonJ;Y  
for(int i=0;i<nEndPos.length-1;i++) z9Z4MXl  
{ -Gy=1W`09  
nEndPos = nStartPos[i+1]; w$iQ,--  
} "zj[v1K9-A  
nEndPos[nEndPos.length-1] = nFileLength; HA$Xg j  
} 5\V""fH  
} (1 (~r"4I  
1%ENgb:8  
zX lcu_rc  
//启动子线程 PzOnS   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1J([*)  
for(int i=0;i<nStartPos.length;i++) u8.F_'`z  
{ ,BUrZA2\U$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), > a;iX.K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gFqF&t  
nStartPos,nEndPos,i); IdqCk0lVD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S/"G=^~  
fileSplitterFetch.start(); Dj>eAO>  
} EQN)y27poW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .' }jd#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {0~\T[qm  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Unvl~lm6  
nEndPos = " + nFileLength); 9#TD1B/  
// fileSplitterFetch[nPos.length-1].start(); Bm
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~| b\1SR  
//等待子线程结束 D&i\dgbK  
//int count = 0; Y?TS,   
//是否结束while循环 )X?oBNsj  
boolean breakWhile = false; 7HkFDI()1  
/jNvHo^B  
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while(!bStop) 6@TU9AZS`  
{ l]4=W<N  
write_nPos(); b"uO BB  
Utility.sleep(500); qCg<
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breakWhile = true; 9w- )??  
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for(int i=0;i<nStartPos.length;i++) o3V\  
{ gUNhN1=  
if(!fileSplitterFetch.bDownOver) LD ]-IX&L  
{ b3EGtC}^  
breakWhile = false; pJx7S sW  
break; g'KxjjYT,  
} vP x/&x  
} K(i}?9WD  
if(breakWhile) Asv]2> x  
break; 0u1ZU4+EC  
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//count++; I<O$);DV'  
//if(count>4) Bhxs(NO  
// siteStop(); D3cJIVM  
} g35!a<JW  
Iz1x|EQ  
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System.err.println("文件下载结束！"); tGgxID  
} TY)QE  
catch(Exception e){e.printStackTrace ();} h{gFqkDoTI  
} 5X20/+aT  
/QY F|%7!  
1(-!TJ{  
//获得文件长度 Up{[baWF  
public long getFileSize() }:m/@LKB  
{ QQBh)5F  
int nFileLength = -1; F%h3?"s  
try{ B W<Dmn  
URL url = new URL(siteInfoBean.getSSiteURL()); \IE![=p\w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "iA0hA  
httpConnection.setRequestProperty("User-Agent","NetFox"); @khFk.LBD  
1Ng+mT  
,B[j{sE  
int responseCode=httpConnection.getResponseCode(); SLKplLO  
if(responseCode>=400) T&lgWOls  
{ bZ\R0[0  
processErrorCode(responseCode); QselW]  
return -2; //-2 represent access is error x~V[}4E%>  
} ECOJ .^  
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String sHeader; CIx(SeEF  
t>[W]%op  
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for(int i=1;;i++) hq 3n&/  
{ IMkE~0x4</  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Wef%f]u  
//Utility.log(in.readLine()); xqt?z n  
sHeader=httpConnection.getHeaderFieldKey(i); ij ?7MP  
if(sHeader!=null) (QDKw}O2b  
{ (xHmucmwp  
if(sHeader.equals("Content-Length")) h3o'T=`Sm  
{ %T({;/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T Rv  
break; :C:6bDQ  
} "'U^8NA2  
} ubwM*P  
else ;7'O=%  
break; {DRk{>K,  
} #*o0n>O  
} tF:AnNp=  
catch(IOException e){e.printStackTrace ();} .nPOjwEx&Y  
catch(Exception e){e.printStackTrace ();} <Ht"t]u*Bn  
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Utility.log(nFileLength); i#'K7XM2  
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return nFileLength; y bhFDx  
} !"N,w9MbD  
W'C>Fn}lO?  
@IL04' \  
//保存下载信息（文件指针位置） |'h(S|  
private void write_nPos() N3%#JdzZ$  
{ _%e8GWf  
try{ Db|f"3rq?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Fi i(dmn  
output.writeInt(nStartPos.length); 3"h*
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for(int i=0;i<nStartPos.length;i++) 1#vu)a1+b  
{ if*V-$[I  
// output.writeLong(nPos); o%_-u +  
output.writeLong(fileSplitterFetch.nStartPos); cXq9k!I%  
output.writeLong(fileSplitterFetch.nEndPos); ~P\4 N  
} L]=]/>jQ6  
output.close(); }>{R<[I!G  
} [+\He/M6  
catch(IOException e){e.printStackTrace ();} rS [4Pey  
catch(Exception e){e.printStackTrace ();} vFUp$[  
} \@@G\\)er  
b7sfr!t_d  
#:?:gY<  
//读取保存的下载信息（文件指针位置） TAYh#T=S  
private void read_nPos() DGHSyB^+1  
{ HhynU/36  
try{ z4YDngf=4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A|"T8KSMB  
int nCount = input.readInt(); {,Z|8@Sl%  
nStartPos = new long[nCount]; E-WpsNJ)X  
nEndPos = new long[nCount]; }ILBX4c  
for(int i=0;i<nStartPos.length;i++) f&vMv.  
{ :Ra
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nStartPos = input.readLong(); p*<Jg l  
nEndPos = input.readLong(); mZiKA-t  
} XJo.^<m  
input.close(); }1 O"?6  
} X5o*8Bg4M  
catch(IOException e){e.printStackTrace ();} ?=7k<a~  
catch(Exception e){e.printStackTrace ();} "~VKUvDu  
} ]y#'U  
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private void processErrorCode(int nErrorCode) Z`kVyuQ  
{ ./I?|ih  
System.err.println("Error Code : " + nErrorCode); \:@6(e Bh  
} |Ua);B~F  
Jj)J5S /  
|OLXb+7X  
//停止文件下载 GJ
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public void siteStop() T`^Jws{;7  
{ reR@@O  
bStop = true; qb;b.P?~D$  
for(int i=0;i<nStartPos.length;i++) \dQc!)&C9  
fileSplitterFetch.splitterStop(); >,Y+1  
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}  dw;<Q  
} ;HCK iHC  
//负责部分文件的抓取 5BA:^4zr?  
**FileSplitterFetch.java -"zW"v)\  
*/ $%$zZJ@/  
package NetFox; %KVmpWku  
O)W+rmToI  
a;bmlV04  
import java.io.*; |*48J1:1y  
import java.net.*; }bRn&)e  
>-V632(/{o  
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public class FileSplitterFetch extends Thread { HT/!+#W.  
kxJs4BY
0  
E!ZLVR.K  
String sURL; //File URL uhj]le!  
long nStartPos; //File Snippet Start Position ?#a&eW  
long nEndPos; //File Snippet End Position \s[L=^!  
int nThreadID; //Thread's ID p8XvfM  
boolean bDownOver = false; //Downing is over +-b'+mF  
boolean bStop = false; //Stop identical ..Dm@m}  
FileAccessI fileAccessI = null; //File Access interface 9_
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-J=6)  
b5MU$}:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;ZuHv {=  
{ 'DXT7|Df  
this.sURL = sURL; fn/?I\  
this.nStartPos = nStart; 1.u^shc&|  
this.nEndPos = nEnd; M]X!D7  
nThreadID = id; P0; y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :LB*l5\  
} ..h@QQ  
">!pos`<C  
qi/k`T  
public void run() ysi=}+F.  
{ s)E8}-v  
while(nStartPos < nEndPos && !bStop) U:99w  
{ =\u,4  
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try{ Y,L[0%  
URL url = new URL(sURL); IR]5,K^l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); H!0m8LCnb  
String sProperty = "bytes="+nStartPos+"-"; 1p5'.~J+Q  
httpConnection.setRequestProperty("RANGE",sProperty); Uc_}="  
Utility.log(sProperty); Y=|20Y\K  
/Z]nV2$n)V  
LN(\B:wAY  
InputStream input = httpConnection.getInputStream(); 8ZbXGQ  
//logResponseHead(httpConnection); L'a+1O1q&i  
AvZ5?rN$  
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byte[] b = new byte[1024]; u0<yGsEGD  
int nRead; %'g)MK!e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )uAY_()/  
{ R}w}G6"\  
nStartPos += fileAccessI.write(b,0,nRead); h{_\okC>  
//if(nThreadID == 1) hC8WRxEGq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #hn  
} _#v"sGmN  
{[:C_Up)f  
BI%~0Gj8  
Utility.log("Thread " + nThreadID + " is over!"); _:NQF7X#ug  
bDownOver = true; *k#"@  
//nPos = fileAccessI.write (b,0,nRead); .czUJyFms}  
} 2!}F+^8'P  
catch(Exception e){e.printStackTrace ();} w^zqYGxG
)  
} VI9rezZ*  
} ^S;{;c+'  
Qp[
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bJ 6ivz  
//打印回应的头信息 p{_*<"cfYn  
public void logResponseHead(HttpURLConnection con) V;RgO}  
{ 3f^jy(  
for(int i=1;;i++) Jb$G  
{ u"oO._a(  
String header=con.getHeaderFieldKey(i); +J{ErsG?6P  
if(header!=null) \kUQe-:he  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &0[L2x}7  
Utility.log(header+" : "+con.getHeaderField(header)); ;CS[Ja>e  
else Q3=5q w^  
break; _2`b$/)-  
} #mUQ@X@K  
} Hicd -'  
SX'NFdY  
|6?s?tC"u  
public void splitterStop() Md>C!c  
{ RAhDSDf  
bStop = true; =AzkE]  
} uSI@Cjp  
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8;"%x|iBoL  
} t>%b[(a  
` W);+s  
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/* Jia@HrLR  
**FileAccess.java r|ZB3L|7  
*//文件访问(定位，写) :epB:r  
package NetFox; saZK+kD4I  
import java.io.*; zb[kRo&a0W  
Nlm}'Xt  
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public class FileAccessI implements Serializable{ G6>sAOf  
&,PA+#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 paN=I=:*M  
RandomAccessFile oSavedFile; $
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long nPos; 5M'cOJ  
3l`"(5  
2<n18-|OQ  
public FileAccessI() throws IOException (O09HY:  
{ tGl|/  
this("",0); rmvrv.$3  
} /o6ido  
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public FileAccessI(String sName,long nPos) throws IOException
6 mLC{X[  
{ 3K~^H1l  
oSavedFile = new RandomAccessFile(sName,"rw"); yRyRH%p)  
this.nPos = nPos; [-Y~g%M  
oSavedFile.seek(nPos); e'G3\h}#  
} <x;g9Z>(  
|SMigSu r`  
p
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public synchronized int write(byte[] b,int nStart,int nLen) 'CqAjlj  
{ im:[ViR {  
int n = -1; n@bkZ/G  
try{ Qz{Vl>"  
oSavedFile.write(b,nStart,nLen); !(Y|Vm'  
n = nLen; U$a)lcJd  
} G^|b*n!!  
catch(IOException e) l1 08.ao  
{ leizjL\P  
e.printStackTrace (); 9,Dw;|A]  
} c??m9=OX1  
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.|L9}<  
return n; ^Vh^Z)gGi  
} w\Q(wH'  
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} E'8XXV^I?P  
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/* 5 8U
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**SiteInfoBean.java l!j=em@  
*/ +\PLUOk  
package NetFox; OaN"6Ge#  
5
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|P9)*~\5  
public class SiteInfoBean { KV{  
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y?}<SnjP:  
private String sSiteURL; //Site's URL mSFA i  
private String sFilePath; //Saved File's Path 9a1R"%Z  
private String sFileName; //Saved File's Name r:U<cLT[9  
private int nSplitter; //Count of Splited Downloading File V5jy,Qi)  
] TZ/=Id  
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public SiteInfoBean() .k!2{A  
{//nSplitter的缺省值为5 NZ^hp\q  
//default value of nSplitter is 5 &)!N5Veb  
this("","","",5); r0'a-Mk;  
} j{ri]?p  
/(s N@kt  
1[RI 07g7*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4*q6#=G  
{ C6tfFS3bq  
sSiteURL= sURL; =G 'c%  
sFilePath = sPath; u~N'UD1x  
sFileName = sName; 2XjH1  
this.nSplitter = nSpiltter; >dDc
m  
=| r% lx  
X4bZ4U*  
} PP6gU=9[)  
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public String getSSiteURL() b|.<rV'BTt  
{ 8feLhWg'P  
return sSiteURL; P$/Y9o  
} 
/EZ -  
~^g*cA t}  
|[/XG2S  
public void setSSiteURL(String value) ae+*gkPv8  
{ ~.S/<:`U  
sSiteURL = value; KM oDcAjH  
} l
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public String getSFilePath() J>0RN/38o  
{ $j0<ef!  
return sFilePath; '^:q|h  
} 3+vMi[YO  
'81WogH:  
;'4Kg@/  
public void setSFilePath(String value) n1y*`5!  
{ sFRQFX0XoY  
sFilePath = value; @l~MY*hp  
} S^SF!k=  
Rap_1o9#\  
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public String getSFileName() >% E=l  
{ <d3a  
return sFileName; idZ]d6  
} KyzdJ^xC"  
].x`Fq3  
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public void setSFileName(String value) S\A9r!
2  
{ EvDg{M}  
sFileName = value; ,@@FAL  
} 1lHBg  
,k6V?{ZA  
X}]g;|~SN  
public int getNSplitter() -+ Mh('K  
{ J<ZG&m362p  
return nSplitter; wB%;O`Oh  
} 2NWQiSz  
!u%XvxJwDb  
h_xzqElZu  
public void setNSplitter(int nCount) .v#Tj|w^  
{ qa/VSk!{  
nSplitter = nCount; d>`s+B9K0  
} 8FT@
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} #j6qq3OG  
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2~W8tv0^b2  
/* kBJx`tjtp  
**Utility.java ]*yUb-xY  
*/ r[kmgPld  
package NetFox; p!p:LSk"/b  
&v&e-|r8;  
:3By7BZgj  
public class Utility { 4*_.m9{  
@"B
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public Utility() kk7M$)>d  
{ xSZ+6R|  
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} %&S :W%qm?  
kZHIzU  
//线程睡眠 @hIHvLpRB  
public static void sleep(int nSecond) mpDQhD[n  
{ h<IPV'1  
try{ GF^?#Jh  
Thread.sleep(nSecond); XiN@$  
} ?<eH!MHF  
catch(Exception e) ">"B  
{ J={IGA  
e.printStackTrace (); |s*tRag  
} w]
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} "}jv5j5  
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//日志 _t;Mi/\P  
public static void log(String sMsg) x"n)y1y  
{ kJG0X%+w  
System.err.println(sMsg); G}p*oz~  
} Q[.HoqWK  
tAH0o\1;  
Jx4"~ 4  
public static void log(int sMsg) 4WZ"8  
{ g~Agy  
System.err.println(sMsg); $WHmG!)*  
} qQx5n  
}  N2Q%/}+,  
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6F4OISy%3  
/* 23~Kz
C  
**TestMethod.java oV Hh  
*/ %:hU:+G E  
package NetFox; J}37 9  
}KCb5_MDF  
sDzlNMr?P+  
public class TestMethod { /5 6sPl 7}  
]\Q9j7}37+  

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public TestMethod() 'SE?IE{  
{ ///xx/weblogic60b2_win.exe -P7JaH/Q  
try{ =[T_`*s&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RbGq$vYol/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I-?Dil3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Vv3{jn6%  
fileFetch.start(); q]>m#yk   
} nFY6K%[  
catch(Exception e){e.printStackTrace ();} wEJ) h1=)^  
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} ~99DE78  
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public static void main(String[] args) WC<K(PP  
{ S
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new TestMethod(); :`w'}h7m  
} )r^)e4UI  
} "UDV4<|^k  
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