http断点续传简单实现（java)

/* cpu+"/\  
**SiteFileFetch.java -s:JD
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*/ <pK;D  
package NetFox; !l.Rv_o<O  
import java.io.*; D!qtb6<.  
import java.net.*; =k3QymA  
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<C${1FO7If  
public class SiteFileFetch extends Thread { e<iTU?eJM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean t MA
  
long[] nStartPos; //开始位置 ,!sAr;Rk`  
long[] nEndPos; //结束位置 RoJ&dK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Sq(=Bn6E  
long nFileLength; //文件长度 ks(PH6:]<  
boolean bFirst = true; //是否第一次取文件 kE6\G}zj  
boolean bStop = false; //停止标志 1DZ
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File tmpFile; //文件下载的临时信息 DU}q4u@)  
DataOutputStream output; //输出到文件的输出流 M&Ycw XV:Z  
%[Nef
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F!zZIaB]  
public SiteFileFetch(SiteInfoBean bean) throws IOException `DWzp5Ax  
{ <@;eN&  
siteInfoBean = bean; $5il]D`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i}+dctg/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :Tj,;0#/  
if(tmpFile.exists ()) '|WMt g  
{ f"k/j?e*  
bFirst = false; 8MW|CM4Q  
read_nPos(); 3@6f%Dyj  
} E.6^~'/  
else Yng9_w9Y  
{ .0\Wu+  
nStartPos = new long[bean.getNSplitter()]; 0{AVH/S  
nEndPos = new long[bean.getNSplitter()]; ckhW?T>l  
} G=~T)e  
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%v}:#_va]  
} p?Yovckm  
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public void run() ^f3F~XhY3  
{ hnE@+(d=qJ  
//获得文件长度 \Sm.]=br  
//分割文件 1j0yON  
//实例FileSplitterFetch n%"s_W'E  
//启动FileSplitterFetch线程 <niHJ*  
//等待子线程返回 zFQxW4G  
try{ Q&n
  
if(bFirst) .bnoK  
{ |? r,W~9`  
nFileLength = getFileSize(); 6Y}#vZ  
if(nFileLength == -1) 2
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{ ,F:l?dfB\I  
System.err.println("File Length is not known!"); oVmGZhkA@'  
} |y;+xEl6  
else if(nFileLength == -2) "d.qmM  
{ j##IJm  
System.err.println("File is not access!"); :/Sx\Nz78  
} pN%L3?2  
else q[dls_  
{ R<k4LHDy  
for(int i=0;i<nStartPos.length;i++) t3U*rr|A  
{ DZLSn Ax  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); na8A}\!<  
} oN)K2&M0  
for(int i=0;i<nEndPos.length-1;i++) ^5"s3Qn  
{ t;y>q  
nEndPos = nStartPos[i+1]; t^uX9
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} {\lu; b!  
nEndPos[nEndPos.length-1] = nFileLength; h'kgL~+$  
} f4X?\eGT  
} uCUQxFp  
HjV83S;  
]j_S2lt  
//启动子线程 SV8rZ
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9\Yj`,i
5  
for(int i=0;i<nStartPos.length;i++) }bix+/]  
{ D97oS!*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \JN<"/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yfuvU2nVH  
nStartPos,nEndPos,i); bO^%#<7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F/@#yQv?  
fileSplitterFetch.start(); #sNa}292"  
} hDVD@b
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~Bj-n6QDE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4[bw/[
  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d \0K3=h  
nEndPos = " + nFileLength); u%h]k ,(E  
// fileSplitterFetch[nPos.length-1].start(); E})PNf;  
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;~/  
//等待子线程结束 ?]$.3azO  
//int count = 0; O^sgUT1O  
//是否结束while循环 C"hc.A&4  
boolean breakWhile = false; hQHV]xW  
Vs9fAAXS4  
zjVb+Z\n  
while(!bStop) CEI#x~Oq  
{ MO/l(wO  
write_nPos(); ~_^nWT*BV  
Utility.sleep(500); B>9D@fmzs  
breakWhile = true; ?uh7m2l0D  
V&\ZqgDF  
k]I<%  
for(int i=0;i<nStartPos.length;i++) t{x&|%u  
{ l^"g
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if(!fileSplitterFetch.bDownOver) U .e Urzu  
{ )c+ZQq  
breakWhile = false; ?i9LqHL  
break; ~#) DJ  
} *:
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} MPM_/dn-  
if(breakWhile) [.3M>,)+-  
break; JX>_imo  
xr.fZMOh4  
u~a<Psp&|  
//count++; ~~wz05oRG  
//if(count>4) ~e'FPVDn  
// siteStop(); W 4 )^8/  
} y{"8VT)  
|A0kbC.  
syBYH5  
System.err.println("文件下载结束！"); .VWH  
} iOzw)<  
catch(Exception e){e.printStackTrace ();} s)_sLt8?  
} <R_3;5J%  
s)&"ga  
i[WTp??Uv  
//获得文件长度 kw?RUt0-V  
public long getFileSize() =C5[75z#+  
{ q$U;\Mg)  
int nFileLength = -1; d+"KXt5CV  
try{ 3$WK%"%T  
URL url = new URL(siteInfoBean.getSSiteURL()); p2w/jJMD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /m9t2,KB  
httpConnection.setRequestProperty("User-Agent","NetFox"); &/Tx@j^.C  
e|]g?!  
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int responseCode=httpConnection.getResponseCode(); pE15[fJ`  
if(responseCode>=400) g/JAr<  
{ ou96 P<B  
processErrorCode(responseCode); qlDL
Z.  
return -2; //-2 represent access is error M!mTNIj8~  
} PP$Ig2Q  
n |.- :Zy  
5M*q{kX)  
String sHeader; !)_5z<  
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for(int i=1;;i++) a?Q~C<k  
{ o3}12i S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~5]AXi'e~  
//Utility.log(in.readLine()); Og-Mnx3  
sHeader=httpConnection.getHeaderFieldKey(i); L'z?M]  
if(sHeader!=null) WV?iYX!  
{ AB+Zc ]  
if(sHeader.equals("Content-Length")) hoSk  
{ G{ F>=z"(l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5F&i/8Ib  
break; y$\K@B4  
} iHQFieZ.E  
} nE::9Yh8z  
else _%<7!|"  
break; _H:SoJ'  
} "B)DX*-\?  
} BWw7o{d  
catch(IOException e){e.printStackTrace ();} BAqu@F\):  
catch(Exception e){e.printStackTrace ();} MS,H12h  
Zj`eR\7~  
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0!  
Utility.log(nFileLength); .8.ivfmJh  
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return nFileLength; 0!+ab'3a  
} r+$ 0u~^  
w&f29#i;b  
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//保存下载信息（文件指针位置） x40R)Led  
private void write_nPos() '90B),c{  
{ X,T^(p  
try{ z[OW%(vrm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2evM|Dj  
output.writeInt(nStartPos.length); ^{Syg;F=  
for(int i=0;i<nStartPos.length;i++) XXe7w3x
{  
{ `.[hOQ7
 
// output.writeLong(nPos); vs6`oW"{#  
output.writeLong(fileSplitterFetch.nStartPos); a$9UUH-|  
output.writeLong(fileSplitterFetch.nEndPos);
rr9HC]63  
} ,wZ[Y 3  
output.close(); 5zEl`h  
} eaF5S'k 4$  
catch(IOException e){e.printStackTrace ();} V @
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catch(Exception e){e.printStackTrace ();} P[gk9{sv  
} QC ]z--wu  
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//读取保存的下载信息（文件指针位置） .@=d I  
private void read_nPos() 1 4(?mM3   
{ uY'Ib[H  
try{ RZ?>>Ll6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?8vjHEE  
int nCount = input.readInt(); _>3GNvS  
nStartPos = new long[nCount]; G?jY>;P)  
nEndPos = new long[nCount]; b\^Sz{  
for(int i=0;i<nStartPos.length;i++)
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{ +{Q\B}3cj1  
nStartPos = input.readLong(); i<%(Z[9Lk  
nEndPos = input.readLong(); u45e>F=  
} V|b?H6Q  
input.close(); zRf]SZ(tO  
} YK"({Z>U  
catch(IOException e){e.printStackTrace ();} .l#Pmd!  
catch(Exception e){e.printStackTrace ();} M~ *
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} vz@QGgQ9~2  
t'[vN~I'  
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private void processErrorCode(int nErrorCode) U/jJ@8
 
{ +cjNA2@  
System.err.println("Error Code : " + nErrorCode); u&pLF%'EQ  
} pRt )B`#  
gvwR16N  
@^;\(If2  
//停止文件下载 uOougSBV,  
public void siteStop() YZ*Si3L  
{ 1X#`NUJ?2  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) XtQ3$0{*%  
fileSplitterFetch.splitterStop();  uiiA)j*!  
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1 C[#]krh  
}
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} ;39{iU.m  
//负责部分文件的抓取 h]MSjC.X  
**FileSplitterFetch.java 9)f1CC]
 
*/ ?w<x_Lo  
package NetFox; S!.xmc\  
m=y6E, _  
#*Mk@XrV  
import java.io.*; y{jv-&!xB  
import java.net.*; [a+?z6qI\}  
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public class FileSplitterFetch extends Thread { av`b8cGg  
zb;2xTH+  
;q$<]X_S)}  
String sURL; //File URL 6] <?+#uQ  
long nStartPos; //File Snippet Start Position J'B;  
long nEndPos; //File Snippet End Position I s8|  
int nThreadID; //Thread's ID J^t=.-a|  
boolean bDownOver = false; //Downing is over ^g~-$t<!  
boolean bStop = false; //Stop identical M{nz~W80  
FileAccessI fileAccessI = null; //File Access interface UejG$JyHP  
B]]M?pS  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KJ(zLwQ:  
{ 6^ /C+zuX  
this.sURL = sURL; !;R{-  
this.nStartPos = nStart; ~zRW*pd  
this.nEndPos = nEnd; VfZ/SByh7p  
nThreadID = id; KTf!Pf?g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kWoy%?|RRa  
} ?m~x%[Vn  
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public void run() +}^} <|W6  
{ ]k,fEn(  
while(nStartPos < nEndPos && !bStop) k+s<;{  
{ yGN<.IP75  
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try{ xJO[pT v  
URL url = new URL(sURL); hW|t
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Hq%`DWus\  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dnd  
String sProperty = "bytes="+nStartPos+"-"; `NGCUGQ_7  
httpConnection.setRequestProperty("RANGE",sProperty); moc_}(  
Utility.log(sProperty); q=R=z$yr  
v4qvqGK  
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InputStream input = httpConnection.getInputStream(); bBDgyFSI<  
//logResponseHead(httpConnection); *1elUI2Rg  
&Nec(q<  
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byte[] b = new byte[1024]; IAtc^'l#  
int nRead; Fa>Y]Y0r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) : ;d&m  
{ 9VP|a-  
nStartPos += fileAccessI.write(b,0,nRead); N>gv!z[E  
//if(nThreadID == 1) 0?sIod  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {yfG_J  
} Z4t9q`}h  
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DE. Pw+5<.  
Utility.log("Thread " + nThreadID + " is over!"); bu$5gGWVf  
bDownOver = true; qA03EU  
//nPos = fileAccessI.write (b,0,nRead); &[kwM395  
} q
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catch(Exception e){e.printStackTrace ();} +\}]`uS:  
} fEgZ/p!g  
} .j;My%)?p  
us5`?XeX]  
O
'!k$iJNb  
//打印回应的头信息 CBO8^M<K  
public void logResponseHead(HttpURLConnection con) #"f:m`  
{ Fmsg*s7w  
for(int i=1;;i++) Y$'fds4P  
{ sG^b_3o)A  
String header=con.getHeaderFieldKey(i); :v&GAs6H
 
if(header!=null) _b#9^2o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); FiIN\  
Utility.log(header+" : "+con.getHeaderField(header)); !H.&"~w@  
else IOfo]p-  
break; ~v<r\8`OI2  
} (s"_NUj6  
} E8?Q>%_  
0gt/JI($  
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public void splitterStop() 8LiRZ"  
{ 43 |zjE  
bStop = true;  snN1  
} Ujw^j  
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} ){gOb  
(hmasy6hM  
&5zUk++  
/* i5-V$Qh  
**FileAccess.java gA.G:1v  
*//文件访问(定位，写) W_kJb  
package NetFox; YDDwvk H  
import java.io.*; ;rk}\M$+  
\8<bb<`  
D./e|i?  
public class FileAccessI implements Serializable{ 6,oi(RAf  
iVmf/N@A|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6!+"7r6  
RandomAccessFile oSavedFile; .8wR;^  
long nPos; {_Ke'" k  
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|w\D6d]o  
public FileAccessI() throws IOException hJaqW'S  
{ bt~-=\  
this("",0); 5"@<7/2qI  
} {uw'7 d/  
/i$&89yod  
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public FileAccessI(String sName,long nPos) throws IOException 6 rmK_Y  
{ &_!BMzp4  
oSavedFile = new RandomAccessFile(sName,"rw"); >~XX'}  
this.nPos = nPos; '+-R 7#  
oSavedFile.seek(nPos); :Z`4ea"w  
} U,g!KN3P  
/>+JK5  
^DIN(0u)  
public synchronized int write(byte[] b,int nStart,int nLen) }g(aZ  
{ ?#]c{Tlpz  
int n = -1; >5]Xl*{H)  
try{ M@csB.'  
oSavedFile.write(b,nStart,nLen); 4W^0K|fq  
n = nLen; +IJpqFH  
} /&ph-4\i  
catch(IOException e) ^\_`0%`>  
{ >-oa`im+  
e.printStackTrace (); [[TB.'k  
} \Z57UNI  
\'1%"JWK   
6 *Q5.g  
return n; !%5{jO1  
} 1w\Y._jK  
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} @|5B  
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/* l<v/T  
**SiteInfoBean.java gR1X@j$_  
*/ +n)(\k{
 
package NetFox; i 0L7`TB  
hW/*]7AM^  
MRmz/ZmRM  
public class SiteInfoBean { 4(Y5n?/  
]kKf4SJZFU  

}H^#}  
private String sSiteURL; //Site's URL d(
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private String sFilePath; //Saved File's Path @#o$~'my  
private String sFileName; //Saved File's Name eIg2m <9u  
private int nSplitter; //Count of Splited Downloading File @W^g(I(w  
/mr&Y}7T
 
?k"KZxpT  
public SiteInfoBean() Up/1c:<J  
{//nSplitter的缺省值为5 uw]e$,x?  
//default value of nSplitter is 5 PQf FpmG  
this("","","",5); L@G)K  
} 6"%[s@C  
e {c.4'q  
#|$7. e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oNiS"\t  
{ !3T x\a`?/  
sSiteURL= sURL; 2%WZ-l!i  
sFilePath = sPath; 9:BGA/?  
sFileName = sName; 0A}'.LI  
this.nSplitter = nSpiltter; +>I4@1qC-|  
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H|,{^b@9  
} !!` zz  
sCnZ\C@u  
EBebyQcon  
public String getSSiteURL() ([$F5 q1TR  
{ DJ<e=F!  
return sSiteURL; |,yS>kjp  
} IkkJ4G  
9jvg[H  
/M'b137  
public void setSSiteURL(String value) m"v` E7G  
{ W>@+H"pZ  
sSiteURL = value; =`/X Wem  
} eyo)Su  
iPkG=*Ip(%  
 sRoZvp5  
public String getSFilePath() B,gQeW&  
{ 1BWuFYB  
return sFilePath; s)To#  
} yp :yS  
hSg:Rqnk  
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public void setSFilePath(String value) IA+>dr  
{ se)I
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sFilePath = value; Gn_v}31d%  
} b<[eBXe  
'
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Z:n33xh=<  
public String getSFileName() AV8TP-Ls+  
{ TbXZU$[c  
return sFileName; Ni0lj:  
} cb UVeh7Q  
r@n%  
JLG5`{  
public void setSFileName(String value) S"_vD<q  
{ _VMJq9.  
sFileName = value; ev+NKUi=  
} w]%r]PwU+  
X0=R @_KY  
LLU>c]a  
public int getNSplitter() s%/0WW0y^  
{ 8[y7(Xw  
return nSplitter; t8^*s<O  
} m<076O4|`  
lX7#3ti:  
#u2PAZ@qd  
public void setNSplitter(int nCount) x'  
{ m1`ln5(R  
nSplitter = nCount; XM_S"  
} VLOyUt~O#  
} Q2#)Jx\6!  
+nqOP3  
p4el9O&-tV  
/* 4 A  
**Utility.java I]$kVa1iN  
*/ e~}+.B0  
package NetFox; 4mPg; n  
w}2yi#E[  

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public class Utility { .II'W3Fr  
Dbtw>:=  
>4ALF[oH1J  
public Utility() _R8-Hj E  
{ \K)q$E<!  
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+q2l,{|?  
} (d~'H{q  
Cf10 ud  
//线程睡眠 9wAP%xh  
public static void sleep(int nSecond) c(eu[vj:  
{ Nd( $s[  
try{ M$?~C~b!*  
Thread.sleep(nSecond); &XZ>}^lD^  
} Fs=nAn#  
catch(Exception e) 9:esj{X  
{ }LE/{]A  
e.printStackTrace (); [qb#>P2G3  
} +-{HT+W  
} t[DXG2&  
D)mqe-%1  
//日志 3XA^{&}  
public static void log(String sMsg)  k&rl%P  
{ t<`BaU  
System.err.println(sMsg); _Fer-nQ2R  
} Cx@,J\rsQ  
sNNt0q(  
R!-RSkB  
public static void log(int sMsg) cy? EX~s4  
{ dpE+[O_  
System.err.println(sMsg); .]jKuTC\<  
} }5%!:=  
} D!y Cnq=8  
W"~G]a+  
le1'r>E$  
/* ` bg{\ .q  
**TestMethod.java :,cSEST  
*/ \BS^="AcpP  
package NetFox; x0 j$]$  
Ypp>7J/  
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public class TestMethod { sbG3,'i)  
VpD9!;S  
W>h[aVTO  
public TestMethod()
4|
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{ ///xx/weblogic60b2_win.exe *O+N4tq  
try{ *}LYMrP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <oO^w&G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); whD%Oz*f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Wb^YqqE  
fileFetch.start(); wG-X833\(  
} zm_mLk$4H  
catch(Exception e){e.printStackTrace ();} 0Y[mh@(  
;K`qSX;;c(  
;i\i+:=  
} rq+E"Uj?  
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public static void main(String[] args) <r_ldkZ  
{ yn`H}@`k  
new TestMethod(); U Tw\_s  
} ~%>ke   
} 3~"G27,  
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