http断点续传简单实现（java)

/* <M+ZlF-`  
**SiteFileFetch.java xx9qi^  
*/ tLV9b %i(  
package NetFox; yt_?4Hc"  
import java.io.*; ^dqyX(
 
import java.net.*; "d.qmM  
! daXF&q  
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public class SiteFileFetch extends Thread { +-8uIqZ  
5F <zW-;  

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SiteInfoBean siteInfoBean = null; //文件信息Bean >rYP}k  
long[] nStartPos; //开始位置 ,gkxZ{Eh  
long[] nEndPos; //结束位置 h-jea1m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <R]?8L0{h  
long nFileLength; //文件长度 B8B^@   
boolean bFirst = true; //是否第一次取文件 (h`||48d  
boolean bStop = false; //停止标志 k[G?22t  
File tmpFile; //文件下载的临时信息 Cww$ A %}  
DataOutputStream output; //输出到文件的输出流 OZk(VMuI  
8$3Tu"+;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5QMu=/  
public SiteFileFetch(SiteInfoBean bean) throws IOException dwAju:-H  
{ .sjM$#V=  
siteInfoBean = bean; z@<`]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0v',+-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &XgB-}^:  
if(tmpFile.exists ()) F=d#$-yg  
{ CS6,mX  
bFirst = false; 2ht<"  
read_nPos(); dwJ'hg  
} MdEZ839J  
else qZA?M=NT?  
{ Ibpk\a
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nStartPos = new long[bean.getNSplitter()]; my*UN_]  
nEndPos = new long[bean.getNSplitter()]; Mx$VAV^\  
} qw"`NubX  
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} dos$d3B4  
j:]/AReOL  
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public void run() yfuvU2nVH  
{ y;#p=,r  
//获得文件长度 E: XzX Fxx  
//分割文件 #7gOtP#{  
//实例FileSplitterFetch 7nIg3s%  
//启动FileSplitterFetch线程 &)\0mpLK9  
//等待子线程返回 0W]Wu[k  
try{ d [K56wbpx  
if(bFirst) BflF*-s ^  
{ bQ  
nFileLength = getFileSize(); !|Vjv}UO  
if(nFileLength == -1) u%h]k ,(E  
{ _|H]X+|  
System.err.println("File Length is not known!"); "kf7??Z  
} m,*t}j0 7  
else if(nFileLength == -2) A
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{ i3#]_ p{  
System.err.println("File is not access!"); mL3'/3-7:V  
} }54\NSj0  
else
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{ !BK^5,4?--  
for(int i=0;i<nStartPos.length;i++) N}.h_~6  
{ p3sz32RX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a>""MC2  
} h2uO+qEsu  
for(int i=0;i<nEndPos.length-1;i++) x?Q;o+2v  
{ Wq"
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nEndPos = nStartPos[i+1]; ap_(/W  
} SznNvd <  
nEndPos[nEndPos.length-1] = nFileLength; ^@L  
} B;?a. 81~  
} $,'r} %  
7xWX:2l*?  
CIYD'zR[2  
//启动子线程 =B;rj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _0Wdm*  
for(int i=0;i<nStartPos.length;i++) -,zNFC:6g  
{ !~>u\h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :Wb+&|dU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EY> %#0  
nStartPos,nEndPos,i); 6=|Q>[K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @8V8gV?zm  
fileSplitterFetch.start(); '4N[bRCn  
}  (lt/ t  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !X |Tf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )RA7Y}e|m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]+fL6"OD/2  
nEndPos = " + nFileLength); ){8^l0b  
// fileSplitterFetch[nPos.length-1].start(); %H%>6z x  
^H&6'A`  
]9b*!n<z  
//等待子线程结束 H( cY=d,  
//int count = 0; 5UjXpS  
//是否结束while循环 p?6
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boolean breakWhile = false; {?eD7xL:-  
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while(!bStop) _(oJ8h(  
{ kdgQ -UN$  
write_nPos(); RHE< QG  
Utility.sleep(500); =Z%&jul  
breakWhile = true; Pu}r` E_  
#!Kg?BR2  
,X9Y/S l  
for(int i=0;i<nStartPos.length;i++) CX\# |Q8q  
{ L(AY)gB  
if(!fileSplitterFetch.bDownOver) gIRFqEz@o  
{ FnL~8otPF'  
breakWhile = false; |A0kbC.  
break; Wp T.25  
} syBYH5  
} oh,
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if(breakWhile) IsnC_"f  
break; S@T>u,t'  
+gK7`:v4O*  
wK|&[ms  
//count++; x!LUhX '  
//if(count>4) P+oCcYp  
// siteStop(); ]NsbV  
} 3}Uae#oy  
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System.err.println("文件下载结束！"); |V:k8Ab  
} gp(w6:w  
catch(Exception e){e.printStackTrace ();} }2JSa8  
} *|hICTWL  
#YjV3O5<  
JWH}0+1*  
//获得文件长度 +O9l@X$l=  
public long getFileSize() X @r5^A[9  
{ QWfwoe&;R:  
int nFileLength = -1; rpy`Wz/[  
try{ .RoO6:T6  
URL url = new URL(siteInfoBean.getSSiteURL()); 7|"11^q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G}] ZZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2t#9ih"9  
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int responseCode=httpConnection.getResponseCode(); Ntg#-_]  
if(responseCode>=400) 0^{zq|%Q!  
{
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processErrorCode(responseCode); wBCnP  
return -2; //-2 represent access is error f)N67z6  
} sHh2>f@x$  
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q;Qpd]H  
String sHeader; r\_aux^z  
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for(int i=1;;i++) e`8z1r  
{ gY;N>Yq,C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vjbot^W9  
//Utility.log(in.readLine()); 6U# C  
sHeader=httpConnection.getHeaderFieldKey(i); ;?%2dv2d  
if(sHeader!=null) Q;5aM%a`  
{ yvNYY
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if(sHeader.equals("Content-Length")) @WFjM  
{ d|DIqT~{W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ZYu^Q6b3  
break; 0~BQ8O=+mn  
} cCWOGd  
} -hhE`Y  
else [xM07%:  
break; SLZv`  
} qF( ]Ce  
} p|Z"< I7p(  
catch(IOException e){e.printStackTrace ();} /"Rh bE  
catch(Exception e){e.printStackTrace ();} KasOh"W.P  
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Utility.log(nFileLength); 7B+?1E(  
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return nFileLength; ChGwG.-%L  
} _v]I6<!5U  
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//保存下载信息（文件指针位置） 1&wZJP=  
private void write_nPos() 0nhsjN}v  
{ -YSn 3=  
try{ +$8hTi,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GpxGDN3?  
output.writeInt(nStartPos.length); L{ .r8wSrI  
for(int i=0;i<nStartPos.length;i++) 9YB~1M  
{ |%zhwDQ.  
// output.writeLong(nPos); lWnV{/q\X  
output.writeLong(fileSplitterFetch.nStartPos); TSE(K
t  
output.writeLong(fileSplitterFetch.nEndPos); xZ4\.K\f]  
} >+1^XeeS  
output.close(); c WK@O>  
} o{>hOs &  
catch(IOException e){e.printStackTrace ();} VO++(G)  
catch(Exception e){e.printStackTrace ();} vP&*(WfO)  
} t"RgEH@  
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//读取保存的下载信息（文件指针位置） {"4t`dM  
private void read_nPos() gxt2Mq;q~}  
{ AS4m227  
try{ a$;+-Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :gQc@)jZ(*  
int nCount = input.readInt(); 7e}p:Vfp  
nStartPos = new long[nCount]; T
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nEndPos = new long[nCount]; !.3 MtXr  
for(int i=0;i<nStartPos.length;i++) '90B),c{  
{ /Tv< l  
nStartPos = input.readLong(); oHeo]<
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nEndPos = input.readLong(); 'fK_J}+P  
} :~6%nFo  
input.close(); | b@?]M  
} |Zkcs]8M!  
catch(IOException e){e.printStackTrace ();} S7N54X2JwL  
catch(Exception e){e.printStackTrace ();} @,zBZNX y  
} )t)tk=R9N  
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private void processErrorCode(int nErrorCode) ,9W0fm\t  
{ t}*teo[  
System.err.println("Error Code : " + nErrorCode); 3PBg3Y$  
} !gJAK<]iW  
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//停止文件下载 = ng\  
public void siteStop() EcwHO  
{ e(!a~{(kq%  
bStop = true; `{tykYwCLc  
for(int i=0;i<nStartPos.length;i++) :i:Zc~%  
fileSplitterFetch.splitterStop(); wl(}F^:/`  
=PO/Q|-v?  
:q6hT<f;  
} &TC  
} G?jY>;P)  
//负责部分文件的抓取 XUMCz7&j  
**FileSplitterFetch.java )%#hpP M^  
*/ a#G7pZX/I}  
package NetFox; 3OM\R%M  
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import java.io.*; _$Z46wHmB  
import java.net.*; Do2y7,jv  
<_42h|-  
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public class FileSplitterFetch extends Thread { c}rRNS$F  
D:.^]o[  
-AcQ_dS  
String sURL; //File URL C"0gAN  
long nStartPos; //File Snippet Start Position bS0^AVA  
long nEndPos; //File Snippet End Position QouTMS-b  
int nThreadID; //Thread's ID /B}]{bcp$  
boolean bDownOver = false; //Downing is over Fb-NG.Z#  
boolean bStop = false; //Stop identical *sL'6"#Cre  
FileAccessI fileAccessI = null; //File Access interface +.>O%pNj  
z!RA=]3h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wBeOMA  
{ &dOV0y_  
this.sURL = sURL; FK mFjqY  
this.nStartPos = nStart; %\5y6  
this.nEndPos = nEnd; eZg31.  
nThreadID = id; cl)MI,/>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G%'h'AV"  
} ]=]'*Z%  
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public void run() r-[z!S  
{ pCpj#+|_)  
while(nStartPos < nEndPos && !bStop) aIqNNR  
{ dIM:U:c  
b<:s{f"t,  
@?e;Jp9  
try{ lzxn} TO}  
URL url = new URL(sURL); ,QKG$F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $F/&/Aa  
httpConnection.setRequestProperty("User-Agent","NetFox"); QP\vN|r  
String sProperty = "bytes="+nStartPos+"-"; X)nOY*  
httpConnection.setRequestProperty("RANGE",sProperty); I~q}M!v~  
Utility.log(sProperty); %t<Y6*g  
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InputStream input = httpConnection.getInputStream(); :ye)%UU"|:  
//logResponseHead(httpConnection); (& ~`!]  
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n.7 $*9)#  
byte[] b = new byte[1024]; `5q`ibyPI  
int nRead; {]Lc]4J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &4{%3w_/  
{ .|iUDp6vz  
nStartPos += fileAccessI.write(b,0,nRead); T-<^mX[}  
//if(nThreadID == 1) ;$|+H"g|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z;%qpsq  
} yM#W,@  
 ym${4  
w#JF7;  
Utility.log("Thread " + nThreadID + " is over!"); ]8H;LgM2  
bDownOver = true; Oe;9[=
L[  
//nPos = fileAccessI.write (b,0,nRead); {J99F  
} 8#kFS@  
catch(Exception e){e.printStackTrace ();} ,t)mCgbcO  
} zGz5|u  
} SM^6+L"BE  
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//打印回应的头信息 HP?e?3.T  
public void logResponseHead(HttpURLConnection con) A:p0p^*  
{ VQ}=7oe%q  
for(int i=1;;i++) Z2 t0l%  
{ F92n)*[  
String header=con.getHeaderFieldKey(i); ?G8 D6  
if(header!=null) kdoE)C   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wvUph[j}J  
Utility.log(header+" : "+con.getHeaderField(header)); <-lz_  
else `ZNjA},.  
break; LW2Sko?Yo  
} lGcHfW)Y  
} *nH?o* #  
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public void splitterStop() S++}kR);  
{ ZZeqOu7^  
bStop = true; g5Hs=c5=\  
} b LxV  
wS:323 !l$  
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} sL!6-[N  
rc;| ,\  
_$, .NK,6  
/* G=b`w;oL:  
**FileAccess.java AE<AEq  
*//文件访问(定位，写) hl# 9a?  
package NetFox; \kg2pF[V  
import java.io.*; J0s8vAs  
@<w$QD  
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public class FileAccessI implements Serializable{ ,:,c kul  
9O
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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  0J_Np  
RandomAccessFile oSavedFile; #s]]\  
long nPos; #}B~V3UD  
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52:oe1-8  
public FileAccessI() throws IOException jh=:QP/  
{ }K&K{ 9}  
this("",0); ;Y)?6^"  
} Z4t9q`}h  
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public FileAccessI(String sName,long nPos) throws IOException v#nFPB=z  
{ YjsaTdZ!&  
oSavedFile = new RandomAccessFile(sName,"rw"); "5>p]u>  
this.nPos = nPos; v3hNvcMpf  
oSavedFile.seek(nPos); *1>XlVx,  
} a?D\H5TF-  
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`N|WCiBV.  
public synchronized int write(byte[] b,int nStart,int nLen) );$~/H4  
{ *emUQ/uvf  
int n = -1; P~]BB.tog  
try{ !'PPj_Hp]  
oSavedFile.write(b,nStart,nLen); O81})r*Y  
n = nLen; w|RG  
} 4>, <b1Y  
catch(IOException e) S&]JY  
{ 8LkC/  
e.printStackTrace (); .11iu
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} m_St"`6 .  
<27e7H*6  
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return n; ) d\Se9!  
} E8?Q>%_  
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} 27Lya!/  
 snN1  

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/* D* Vr)J  
**SiteInfoBean.java *y`^Fc  
*/ ?+dI/jB4X  
package NetFox; xat)9Yb}0  
3xj<ATSe  
9K)OQDv%6D  
public class SiteInfoBean { .Yh-m  
{Y IVHl  
aY"qEH7]  
private String sSiteURL; //Site's URL y0rT=kU  
private String sFilePath; //Saved File's Path 9l(e:_`_  
private String sFileName; //Saved File's Name D./e|i?  
private int nSplitter; //Count of Splited Downloading File tuUk48!2I  
W_M]fjL.  
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public SiteInfoBean() Z0E+EMo  
{//nSplitter的缺省值为5 fzw6VGTf  
//default value of nSplitter is 5 )B8[w  
this("","","",5); hgsE"H<V  
} N*@bJ*0  
*d(wOl5[  
a{]1H4+bQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hBN!!a|l  
{ Iye  
sSiteURL= sURL; *]F3pP[  
sFilePath = sPath; |!&,etu  
sFileName = sName; GO`XKE  
this.nSplitter = nSpiltter; #%+IU  
g,Q!F  
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} ,`H=
%#  
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XFd[>U<X  
public String getSSiteURL() uOZ+9x(  
{ @ZT25CD  
return sSiteURL; +mAMCM2N  
} T@k&YJ  
t6js@Ih  
>5]Xl*{H)  
public void setSSiteURL(String value) vA+RZ  
{ `W|2Xi=^5  
sSiteURL = value; !Ng^k>*h  
} x)V.^-  
\Lh,dZ}d  
+5^*c
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public String getSFilePath() o#w6]Fmc  
{ Ry/NfF=  
return sFilePath; ^S, "iV  
} x\t>|DB  
'OJXllGi  
b6g,mzqu  
public void setSFilePath(String value) 0MPsF{Xw[  
{ ]=h Ts%]w  
sFilePath = value; A6#ob
  
} }V9146  
kv)LH{  
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public String getSFileName() l65'EO|  
{ ]4hXK!^Uu  
return sFileName; ,[~Ydth  
} to,=Q8)0  
gR1X@j$_  
g]jtVQH']  
public void setSFileName(String value) nw\p3  
{ PqvwM2}4  
sFileName = value; $aGK8%.O  
} 5%G+
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$\a;?>WA"  
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public int getNSplitter() 6x -PGq  
{ 5X~ko>  
return nSplitter; ~|!q>z  
} sU{+.k{  
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public void setNSplitter(int nCount) vtr:{   
{ vqL{~tR  
nSplitter = nCount; `cZG&R  
} uomFE(  
} '^P Ud`  
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0<i~XN0g  
/* Y&gfe8%5N  
**Utility.java =OjzBiHR  
*/ /=Xen mmS  
package NetFox; SuuWrt}5  
"~FXmKcX  
cYGZZC8|K  
public class Utility { flb3Iih  
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public Utility() |y=CmNG,  
{ (EohxLl!p  
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} H) (K  
pX*mX]  
//线程睡眠 S - 7JDE>  
public static void sleep(int nSecond) DJ<e=F!  
{ kXG+zsT  
try{ ^,`Lt *  
Thread.sleep(nSecond); OU{PVF={   
} 6^ KDc  
catch(Exception e) Xi0/Wb h\  
{ XK&#K? M  
e.printStackTrace (); >EMCG.**  
} %:oGyV7a  
} BkO"{  
h]'fX  
//日志 v4Nb/Y  
public static void log(String sMsg) U&B~GJT+  
{ }]?RngTt  
System.err.println(sMsg); <F!:dyl  
} 1BWuFYB  
bNL E=#ro  
r&TxRsg{  
public static void log(int sMsg) !`aodz*PO  
{ s:fnOMv "  
System.err.println(sMsg); fSun{?{  
} |-e=P9,  
} WxXVL"  
VD=$:

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*w%;$\^  
/* 4&&j7$aV  
**TestMethod.java EIF[e|kZ<  
*/ oxad}Y  
package NetFox; t zV"|s=o  
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$~`(!pa:  
public class TestMethod { Mz"kaO  
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public TestMethod() \SMH",u  
{ ///xx/weblogic60b2_win.exe t@4vEKw?.X  
try{ C{>?~@z&5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); TbXZU$[c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 50'6l X(v,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -R\}Q"  
fileFetch.start(); )s^XVs.-  
} L\"=H4r  
catch(Exception e){e.printStackTrace ();} s5z@`M5'm  
:;|x'[JoE?  
{O"dj;RU  
} C6,Bqlio  
c=Z#7?k=Uz  
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public static void main(String[] args) ! q1Ql18n  
{ {+`ep\.$&  
new TestMethod(); XRNL;X%}7  
} "Dy&`  
} X0=R @_KY  
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