http断点续传简单实现（java)

/* zl
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**SiteFileFetch.java [;J>bi;3N  
*/ 55fC~J<  
package NetFox; ^=-y%kp"  
import java.io.*; Sb82}$sO  
import java.net.*; {.INnFGP@)  
nX`u[ks  
]@u6HH~^  
public class SiteFileFetch extends Thread { RtM8yar+sn  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1waTTT?"Ho  
long[] nStartPos; //开始位置 L}pt)w*V1j  
long[] nEndPos; //结束位置 W@I|Q -  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Zo~  
long nFileLength; //文件长度 @P?~KW6<|  
boolean bFirst = true; //是否第一次取文件 io8'g3<  
boolean bStop = false; //停止标志 ]&Rx@&e*  
File tmpFile; //文件下载的临时信息 u@cYw:-C  
DataOutputStream output; //输出到文件的输出流 #*UN
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |3KLk?2  
public SiteFileFetch(SiteInfoBean bean) throws IOException  ^0\  
{ Y<%@s}zc  
siteInfoBean = bean; aq@8"b(.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '?p<lu^^B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XLrwxj0  
if(tmpFile.exists ()) }*S `qW;B  
{ yvO{:B8%  
bFirst = false; |M,iM]  
read_nPos(); #6HA\dE  
} t,+nQ9  
else wG-HF'0L  
{ 85Otss/mM  
nStartPos = new long[bean.getNSplitter()]; y1+*
6|  
nEndPos = new long[bean.getNSplitter()]; z?*w8kU&>  
} 7\s"o&G  
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} Evg_q>  
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public void run() c2'Lfgx4  
{ #W.#Hjpp  
//获得文件长度 2Tp1n8FV  
//分割文件 M:[ %[+6  
//实例FileSplitterFetch I7n"&{s"*  
//启动FileSplitterFetch线程 naR0@Q"\h  
//等待子线程返回 +{f:cea (1  
try{ @a0DT=>dT  
if(bFirst) Ni-xx9)=  
{ U`NjPZe5^  
nFileLength = getFileSize(); '9 [vDG~  
if(nFileLength == -1) %1xb,g KO  
{ zv\kPfGDK  
System.err.println("File Length is not known!"); OX?\<),  
} ij(B,Y  
else if(nFileLength == -2) TU,s*D&e  
{ m!tbkZHQn0  
System.err.println("File is not access!"); m4hg'<<V  
} 7>))D'l57  
else oldA#sA$  
{ P"IPcT%Ob%  
for(int i=0;i<nStartPos.length;i++) ?kH8Lw~{5W  
{ Z
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); xRzFlay8  
} 1q:2\d]  
for(int i=0;i<nEndPos.length-1;i++) jZ~n[ f+Q  
{ 2q=AEv/  
nEndPos = nStartPos[i+1]; PGhY>$q>b  
} bB1UZ O  
nEndPos[nEndPos.length-1] = nFileLength; Vr`R>S,-
 
} ;RC{<wBTx  
} \F/hMXDlJ  
q$Zh@  
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//启动子线程 d"*uB
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }Mp:JPH&S4  
for(int i=0;i<nStartPos.length;i++) H Y&DmE  
{ [S9K6%w_!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;5S9y7[i|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1Z+8r  
nStartPos,nEndPos,i); W14 J],{L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !Sh&3uy_qN  
fileSplitterFetch.start(); >,$_| C  
} z"-u95H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D%OQ e#!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r%yvOF\>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~=6xyc/c  
nEndPos = " + nFileLength); +eK"-u~K  
// fileSplitterFetch[nPos.length-1].start(); aW)-?(6>  
mD$A4Y-'p  
>~[c|ffyo/  
//等待子线程结束 H8Bs<2  
//int count = 0; `>f6)C-  
//是否结束while循环 (:TjoXXiY  
boolean breakWhile = false; DEG[Z7Ju  
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;=eDO(Ij  
while(!bStop) n22zq6m  
{ )_syZ1j  
write_nPos(); ; >hNt  
Utility.sleep(500); &5fJPv &  
breakWhile = true; c'>/  
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{\  
for(int i=0;i<nStartPos.length;i++) XHK<AO^  
{ }Jy8.<Gd^  
if(!fileSplitterFetch.bDownOver) 4
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{ u~7hWiY<2  
breakWhile = false; H]{v;;'~  
break; jnKWZ/R  
} y&q*maa[  
} Fq~yL!#!  
if(breakWhile) ,Ys %:>?  
break; ZRh~`yy  
eL10Q(;P`  
3G,Oba[$<  
//count++; [YF>:ydk  
//if(count>4) nBjqTud  
// siteStop(); [R(`W#W  
} Y!~49<;  
$+8cc\fq  
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System.err.println("文件下载结束！"); =9y[1t  
} ?26I,:;  
catch(Exception e){e.printStackTrace ();} p4.wh|n  
} Se:.4<  
2,$8icM  
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t}"^  
//获得文件长度 l2zFKCGF(  
public long getFileSize() @Owb?(6?  
{ cs,N <|  
int nFileLength = -1; +%zAQeb  
try{ V)Z}En["1  
URL url = new URL(siteInfoBean.getSSiteURL()); >Wm`v.-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q8X feoUV  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]fx"4qKM  
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>BIMi^  
int responseCode=httpConnection.getResponseCode(); f=(?JT  
if(responseCode>=400) ][gq#Vx@  
{ 3GaQk-  
processErrorCode(responseCode); 5,3'=mA6  
return -2; //-2 represent access is error hm84Aq= f  
} t
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1->dMm}G[  
bU>U14ix<  
String sHeader; *g:4e3Iy  
I WTwz!+  
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for(int i=1;;i++) /f:dv?!km  
{ =)M/@T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Hu\B"fdS  
//Utility.log(in.readLine()); R0P iv:  
sHeader=httpConnection.getHeaderFieldKey(i); nOt&pq7  
if(sHeader!=null) zvYq@Mhr  
{ N=4G=0 `ke  
if(sHeader.equals("Content-Length")) MW! srTQ_  
{ 7L`A{L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )
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break; iZ#!O*>  
} ]{)a,c NG  
} 4,bv)Im+ `  
else Ttu2skcv  
break; p#ol*m5wE  
} A_XY'z1  
} hv`~?n)D66  
catch(IOException e){e.printStackTrace ();} N|8P)  
catch(Exception e){e.printStackTrace ();} <":;+Ng+  
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Utility.log(nFileLength); <6EeD5{*  
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return nFileLength; R+2+-j4  
} y~Bh  
#zG&|<hc  
`n#H5Oyn  
//保存下载信息（文件指针位置） O!mvJD  
private void write_nPos() _BM" ]t*  
{ K{x\4  
try{ $Z!`Hb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y'c>:;JEe  
output.writeInt(nStartPos.length); W^0w  
for(int i=0;i<nStartPos.length;i++) O}+.U<V  
{ NO~*T?&  
// output.writeLong(nPos); ; o?-yI&T*  
output.writeLong(fileSplitterFetch.nStartPos); AJf4_+He  
output.writeLong(fileSplitterFetch.nEndPos); [="e ziM{  
} i'a?kSy  
output.close(); t
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} H2&@shOOQJ  
catch(IOException e){e.printStackTrace ();} r;B8i!gD  
catch(Exception e){e.printStackTrace ();} I(]}XZq  
} J@^8ko  
=+/
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&Lt}=3G  
//读取保存的下载信息（文件指针位置） t#Z-mv:(  
private void read_nPos() E.r>7`E  
{ /,89p&h  
try{ 1%EBd%`#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xe#FUS 3  
int nCount = input.readInt(); yyoqX"v[  
nStartPos = new long[nCount]; nc~F_i=  
nEndPos = new long[nCount]; s:OFVlC%\  
for(int i=0;i<nStartPos.length;i++) 1/RsptN"v  
{ 5A%w 8Qv  
nStartPos = input.readLong(); jK!Au  
nEndPos = input.readLong(); PpGL/,]X  
} jq-p;-i  
input.close(); iWei  
} fdxLAC  
catch(IOException e){e.printStackTrace ();} J{l1nHQZSu  
catch(Exception e){e.printStackTrace ();} )hd@S9Z
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} u\E?Y[1  
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private void processErrorCode(int nErrorCode) O!zV)^r  
{ N96jJk  
System.err.println("Error Code : " + nErrorCode); Y&[1`:-~-  
} VGfMN|h  
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nA?`BOe(  
//停止文件下载 {s)+R[?m<o  
public void siteStop() BHd&yIyI  
{ Jpj}@,  
bStop = true; _,zA ^*b  
for(int i=0;i<nStartPos.length;i++) G3{Q"^S"  
fileSplitterFetch.splitterStop(); -|kA)M[  
=CK4.   
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} X- pqw~$  
} /+8JCp   
//负责部分文件的抓取 ICuF %  
**FileSplitterFetch.java wihH?~]  
*/ So{x]x:f  
package NetFox; F ;{
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import java.io.*; &/mA7Vf>eR  
import java.net.*; yN~dU0.G6!  
4
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public class FileSplitterFetch extends Thread { 2GFLnz  
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String sURL; //File URL `%CtWJ(e  
long nStartPos; //File Snippet Start Position =fu :@+  
long nEndPos; //File Snippet End Position -%2[2p  
int nThreadID; //Thread's ID 0*%Z's\M"  
boolean bDownOver = false; //Downing is over `1'6bp`Z  
boolean bStop = false; //Stop identical n_
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FileAccessI fileAccessI = null; //File Access interface dArDP[w  
e:DkGy`-s  
{88)~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /[O(ea$U  
{ 6WV\}d:  
this.sURL = sURL;
'
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this.nStartPos = nStart; &F\?  
this.nEndPos = nEnd; VGtC)mG8)  
nThreadID = id; 1v,Us5s<"6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }Mo=PWI1?  
} r~N"ere26  

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public void run() +SsK21f"r  
{ /b]oa!  
while(nStartPos < nEndPos && !bStop) |3F02
 
{ cU ?0(z7  
GN
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try{ 3BB%Z6F  
URL url = new URL(sURL); G:<`moKgL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i-bJS6  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yiry["[]Q  
String sProperty = "bytes="+nStartPos+"-"; #?q&r_@@  
httpConnection.setRequestProperty("RANGE",sProperty); CLeG<Hi ~  
Utility.log(sProperty); /DQc&.jK  
1"/He ` 4  
]?3un!o3o  
InputStream input = httpConnection.getInputStream(); `VKf3&|<A  
//logResponseHead(httpConnection); AgV G`q  
?"zY"*>4  
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byte[] b = new byte[1024]; xZ|Y?R5m  
int nRead; 5O~HWBX.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /rq VB|M  
{ T^T[$26  
nStartPos += fileAccessI.write(b,0,nRead); q6_u@:3u  
//if(nThreadID == 1) T%6&PrQ7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SG
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} ?sh
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}Z{=|rVE  
1QmH{jM  
Utility.log("Thread " + nThreadID + " is over!"); PUo/J~v  
bDownOver = true; \2ZPj)&-E
 
//nPos = fileAccessI.write (b,0,nRead); A-,up{g  
} sXi=70o  
catch(Exception e){e.printStackTrace ();} kGdt1N[  
} {]E+~%Va  
} T/^Hz4uA7  
/%0<p,T  
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//打印回应的头信息 `}BF${vF  
public void logResponseHead(HttpURLConnection con) 7<%<Ff@^)O  
{ -8r  
for(int i=1;;i++) =+-Yxh|*  
{ krsYog(^z  
String header=con.getHeaderFieldKey(i); ]Ar\c["  
if(header!=null) /e]'u&a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {e+-vl  
Utility.log(header+" : "+con.getHeaderField(header)); uq,
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else TjHwjRa  
break; JJ{9U(`_y6  
} P(XaTU&-  
} 6oLwfTy  
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EL8NZ%:v:  
public void splitterStop() vG;zJ#c  
{ h$.:Uj8/  
bStop = true; aX~%5mF  
}
Eh =~T9  
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^|/](  
} x.3J[=z=>  
d
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94 e): jS  
/* ;x:rZV/  
**FileAccess.java ~v'3"k6  
*//文件访问(定位，写) (tCUlX2  
package NetFox; vfl5Mx4  
import java.io.*; H|ER  
H}H7lO  
-K rxMi  
public class FileAccessI implements Serializable{ [Z~ 2  
i
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LwhyE:1  
RandomAccessFile oSavedFile; )13dn]o=2  
long nPos; $Bj;D=d@V  
-s|}Rh?Y  
 qNm$Fx  
public FileAccessI() throws IOException -jn WZ5.  
{ x5QaM.+=J  
this("",0); '0\@McU]  
} 4<cz--g  
"Ae@lINn[y  
WBNw~|DO]  
public FileAccessI(String sName,long nPos) throws IOException >0dv+8Mn  
{ M/q E2L[y  
oSavedFile = new RandomAccessFile(sName,"rw");
^{xeij/  
this.nPos = nPos; .[Ap=UYI>  
oSavedFile.seek(nPos); +=]!P#  
} Hewd4k  
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X^\>:<  
public synchronized int write(byte[] b,int nStart,int nLen) t9Y=m6  
{ cwm_nQKk  
int n = -1; b:R-mg.VT{  
try{ k51Eyy50(  
oSavedFile.write(b,nStart,nLen); 9_QP!,  
n = nLen; -AhwI  
} MB%Q WU  
catch(IOException e) QT9n,lX
 
{ K]U;?h&CZc  
e.printStackTrace (); sTOa  
}
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return n; A<6%r7&B'  
} q~@]W=  
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} "Tm[t?FMbe  
,^gyH \  
nOQa_G]Gz  
/* zNY)'  
**SiteInfoBean.java _{Sm k[  
*/ M:P0m6ie  
package NetFox; R(-<BtM!-  
}BiiE%a  
$2<d<Um~z  
public class SiteInfoBean { ]c&<zeX,  
4GR!y)  
{8R"O{  
private String sSiteURL; //Site's URL McoK@q;  
private String sFilePath; //Saved File's Path ~GuMlV8  
private String sFileName; //Saved File's Name 8)kLV_+%  
private int nSplitter; //Count of Splited Downloading File 'S[++w?Qq  
4QIE8f Y  
557(EM  
public SiteInfoBean() wHIj<"2  
{//nSplitter的缺省值为5 %?aS#4jI  
//default value of nSplitter is 5 pGSai&  
this("","","",5); Yk42(!  
} ?x^z]N|P  
~V/?H!r'{}  
2kv7UU#q2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `)qVF,Z}  
{ h(qQsxIOhS  
sSiteURL= sURL; pDQ}*  
sFilePath = sPath; lc_E!"1  
sFileName = sName; EwS!]h?  
this.nSplitter = nSpiltter; lpRR&
  
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6YuY|JD  
} l<Q>N|1#k%  
|oub!fG4  
d*oUf
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public String getSSiteURL() DI`%zLDcY  
{ ,-+"^>  
return sSiteURL; j F-v%?  
} X[2[!)Rk  
cpt<WK}  
GabYfUkO  
public void setSSiteURL(String value) }<PxWZ`,\  
{ |v[Rp=?]  
sSiteURL = value; P/JK$nb  
} l88A=iLgv  
kD) $2I?  
}pa9%BQI  
public String getSFilePath() 4d_s%n?C  
{ M7>(hVEAW'  
return sFilePath; P]i =r] i  
} V:/7f*n7  
_SACqamo5s  
JlKM+UE:  
public void setSFilePath(String value) +,v-=~5  
{ F`nb21{0y&  
sFilePath = value; QQe;1O  
}  KluA  
/H:I 68~  
KOg?FmD  
public String getSFileName() [TF8'jI0  
{ ^uS/r#l  
return sFileName; >xA),^ YT  
} W$qd/'%  
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]APvp.Tw:  
public void setSFileName(String value) dr{y0`CCN  
{ -[OXSaf6  
sFileName = value; .Hc(y7HV  
} okq[ o90  
\V2,pi8'v  
g\GdkiI
j  
public int getNSplitter() I _i6-<c.Q  
{ CzV(cSS9-  
return nSplitter; {FN;'Uc  
} Jti(b*~  
:Vg}V"QR  
CK_(b"  
public void setNSplitter(int nCount) *n(> ^  
{ pium$4l2#  
nSplitter = nCount; y[O-pD`  
} +pH@oFNK  
} \Hqc9&0  
n:U>Fj>q  
0Q593F  
/* DWt*jX*  
**Utility.java 4$,,Ppn  
*/ qQxz(}REu9  
package NetFox; 0aR,H[r[?  
JK#vkCkyM  
vRA',(](  
public class Utility { zH=!*[d8  
qQ7w&9r.M  
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public Utility() K?#]("De6  
{ ,pK|SL  
NHw x:-RH  
gM>=%/.  
} 4z:#I;  
`ya;:$(6  
//线程睡眠 oK+ WF  
public static void sleep(int nSecond) P&*sB%B  
{ O`cu_  
try{ Uz%Z&K  
Thread.sleep(nSecond); OlxX.wP  
} Aox3s?  
catch(Exception e) lf>nbv
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{ }tST)=M`  
e.printStackTrace (); ly4Qg\l  
} +c206.  
} TrE3S'EU#R  
v7trr W}  
//日志 `PI(%N  
public static void log(String sMsg) v4*rPGv  
{ X`zC^z}  
System.err.println(sMsg); =l
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} Q"J-tP!  
Q^eJ4{Ya:  
ul5|.C  
public static void log(int sMsg) H D/5!d  
{ dc0@Y  
System.err.println(sMsg); j!#OG  
} ){Mu~P  
} sLcY,AH  
xc'vS>&  
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/* 0x)dnq\  
**TestMethod.java pe04#zQK  
*/ ,8K'
F  
package NetFox; Mpx/S<Z  
)3?rXsSR  
'u[%}S38  
public class TestMethod { &d$
~6'x*  
CyM}Hc
&w  
/Ic[N&  
public TestMethod() wODvc9p}]  
{ ///xx/weblogic60b2_win.exe ahIE;Y\j'  
try{ 2wh#$zGy  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4L:>4X[T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g
T1P*N;v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V7<eQ0;m  
fileFetch.start(); -Wo15O"  
} VQ |^   
catch(Exception e){e.printStackTrace ();} ZCiY,;c  
K84
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o'UHStk
 
} K;kM_%9u  
2cnj@E:5l  
f]_mzF=&  
public static void main(String[] args) T1~)^qQ  
{ E/O5e(h  
new TestMethod(); 79ZxqvB\  
} Pz~q%J  
} -0|K,k  
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