http断点续传简单实现（java)

/* *:%I|5  
**SiteFileFetch.java qgs:9V xF  
*/ |hS^eK_  
package NetFox; _1jbNQa  
import java.io.*; \'r;1W  
import java.net.*; %+((F+[  
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public class SiteFileFetch extends Thread { F0wW3+G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I^)_rOgM  
long[] nStartPos; //开始位置 Rzyaicj^
c  
long[] nEndPos; //结束位置 bZ#KfR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 th{ie2$  
long nFileLength; //文件长度 E9w"?_A)  
boolean bFirst = true; //是否第一次取文件 IrIW>r} -  
boolean bStop = false; //停止标志 (Z0.H3  
File tmpFile; //文件下载的临时信息 Vp1Q^`a{G  
DataOutputStream output; //输出到文件的输出流 9.:&u/e  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） v8 II=9  
public SiteFileFetch(SiteInfoBean bean) throws IOException </B:Zjn  
{ Uw?25+[b  
siteInfoBean = bean; yO/'}FD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); iOk`_LG#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pJ x H
  
if(tmpFile.exists ()) q&&uX-ez5W  
{ b)>l7nOc  
bFirst = false; <O41M\,  
read_nPos(); QO>)ug+  
} -M+o;  
else /IG3>|R  
{ n
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nStartPos = new long[bean.getNSplitter()]; f7a"}.D$  
nEndPos = new long[bean.getNSplitter()]; [U$`nnp  
} 3t5WwrNh  
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} 9%dO"t$-q  
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public void run() 5! ]T%.rM  
{ S] 4RGWn  
//获得文件长度 r!^VCA  
//分割文件 ?'>[
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//实例FileSplitterFetch <J]N E|:  
//启动FileSplitterFetch线程 AHT(Z~C  
//等待子线程返回 #bb$Icmtk  
try{ - v=ndJ.  
if(bFirst) 1`1Jn*|TI  
{ lrgvY>E0  
nFileLength = getFileSize(); /GA-1cS_(  
if(nFileLength == -1) 5r0Sl89J  
{ Q@s G6iz  
System.err.println("File Length is not known!"); {\VmNnw  
} /AIFgsaY  
else if(nFileLength == -2) ?U,XyxN  
{ yn2k!2]&T<  
System.err.println("File is not access!"); m~@Lt~LZs  
} tbB.n  
else YCBUc<)  
{ >qdRqy)DC  
for(int i=0;i<nStartPos.length;i++) +p-S36K~,7  
{ RRtOBrIedI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); km}E&ao  
} CbMClnF  
for(int i=0;i<nEndPos.length-1;i++) $cGV)[KWp@  
{ 'l1cuAP!+  
nEndPos = nStartPos[i+1]; InG<B,/
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} ^Uldyv/  
nEndPos[nEndPos.length-1] = nFileLength; 6a6N$v"  
} ?YM0VB,y  
} g:>dF#  
n* z;%'0  

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//启动子线程 OQ<NB7'n0A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <$%Y#I'zX  
for(int i=0;i<nStartPos.length;i++) I -XkxDw  
{ ([h
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O.?q8T)n82  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mW."lzIl  
nStartPos,nEndPos,i); !_:|mu'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z\<gm$1CB  
fileSplitterFetch.start(); k= 9a/M u  
} B 3eNvUFZg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M-5zsN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z15b'^)?9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Rx4O?7;  
nEndPos = " + nFileLength); L;'v,s  
// fileSplitterFetch[nPos.length-1].start(); KkZo|\V  
D]Gt=2\NG9  
MLn?t^v-  
//等待子线程结束 t2z@"e   
//int count = 0; ":^cb =  
//是否结束while循环 ^^(4xHN  
boolean breakWhile = false; Xx=.;FYk  
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while(!bStop) V7>{,  
{ <V*M%YWs  
write_nPos(); ;<v9i#K5  
Utility.sleep(500); {qBbzBG  
breakWhile = true; o(5 (]bJ  
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for(int i=0;i<nStartPos.length;i++) !'%`g,,
r  
{ UyOoyyd.  
if(!fileSplitterFetch.bDownOver) $@L}/MO  
{ FuO'%3;c  
breakWhile = false; gx6$:j;  
break; }!Xj{Eoc  
} xW'(]Z7_  
} +tFl  
if(breakWhile) n]%yf9,w  
break; E9S&UU,K  
[3hOc/]s  
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//count++; f<( ysl1[  
//if(count>4) .Ue1}'v*,  
// siteStop(); J+8T Ie  
} GwZ(3  
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System.err.println("文件下载结束！"); )V*V

  
} jiAN8t*P  
catch(Exception e){e.printStackTrace ();} Yc1ve  
} Uzd\#edxJ  
MQGR-WV=5  
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//获得文件长度 97(*-e=e  
public long getFileSize() VBI~U?0  
{ b$'
}IWNV  
int nFileLength = -1; a(`@u&]WZ  
try{ J;7O`5J  
URL url = new URL(siteInfoBean.getSSiteURL()); mGqT_   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q/yL={H?  
httpConnection.setRequestProperty("User-Agent","NetFox"); [0mg\n?  
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int responseCode=httpConnection.getResponseCode(); fP:g}Z  
if(responseCode>=400) Sj<WiQ%<  
{ gEU|Bx/!=  
processErrorCode(responseCode); sYb(g'W*'  
return -2; //-2 represent access is error ;-X5#  
} (lVHKg&U[  
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String sHeader; }e*OprF  
X,h"%S<c#H  
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for(int i=1;;i++)  ,L}  
{ pe$l'ur
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (-U6woB6o  
//Utility.log(in.readLine()); P>3 ;M'KsO  
sHeader=httpConnection.getHeaderFieldKey(i); /<$\)|r  
if(sHeader!=null) &udlt//^%  
{ * "Z5bKL  
if(sHeader.equals("Content-Length")) aM|^t:  
{ s!j[Ovtx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _]whHS+  
break; B#K{Y$!v  
} qKg*/)sD(  
} 7U\GX  
else G>);8T%l  
break; &z(E-w/S  
} L^0s  
} [~<X|_LG  
catch(IOException e){e.printStackTrace ();} U6@Hgi>  
catch(Exception e){e.printStackTrace ();} B#T4m]E/  
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Utility.log(nFileLength); ==\Qj{ 7`  
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return nFileLength; vC9Qe ]f  
} $ RDwy)9  
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//保存下载信息（文件指针位置） T!*lTzNHm  
private void write_nPos() 6RLYpQ$+  
{ Nf<mgOAT1  
try{ ?(4E le  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /RzL,~]  
output.writeInt(nStartPos.length); xQ=sZv^M  
for(int i=0;i<nStartPos.length;i++) |99/?T-QW  
{ B~RVFc +  
// output.writeLong(nPos); jLRh/pbz4  
output.writeLong(fileSplitterFetch.nStartPos); [Grd?mc#  
output.writeLong(fileSplitterFetch.nEndPos); 8(Ab NQ  
} +I {ZW}rA  
output.close(); *|T]('xwC  
} Xv%1W? >@/  
catch(IOException e){e.printStackTrace ();} M;\iL?,  
catch(Exception e){e.printStackTrace ();} qQu}4Ye>  
} W h^9 Aq  
}9GD'N?4  
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//读取保存的下载信息（文件指针位置） Oist>A$Z  
private void read_nPos() S}Q/CT?au  
{ VM1`:1Z:$  
try{ j<-#a^jb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mu[:b  
int nCount = input.readInt(); Qt@_C*,P  
nStartPos = new long[nCount]; +y$%S4>0tp  
nEndPos = new long[nCount]; ;p!|E3o.  
for(int i=0;i<nStartPos.length;i++) +EZ Lic  
{ SCCBTpmf2B  
nStartPos = input.readLong(); *t JgQ[  
nEndPos = input.readLong(); gua +-##)  
} bV5
{  
input.close(); 2L<iIBSJwm  
} Be=J*D!E=>  
catch(IOException e){e.printStackTrace ();} H<|ilL'fX  
catch(Exception e){e.printStackTrace ();} O#,Uz2  
} GxL;@%B  
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private void processErrorCode(int nErrorCode) pu:Ie#xTDf  
{ r
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System.err.println("Error Code : " + nErrorCode); -_bnGY%,  
} *f[nge&.  
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sw={bUr6G`  
//停止文件下载 LijisE  
public void siteStop() QgZwU$`p0  
{ o"te7nBI  
bStop = true; "%o,P/<X  
for(int i=0;i<nStartPos.length;i++) :ub 4p4h*  
fileSplitterFetch.splitterStop(); OD*\<Sc  
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} Q M#1
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} L9|55z  
//负责部分文件的抓取 ^usZ&9"@P  
**FileSplitterFetch.java J4yL"iMt  
*/ Ry@QJn I<  
package NetFox; 6`>WO_<z  
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import java.io.*; $)1i)/]9U  
import java.net.*; :2'y=t#  
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public class FileSplitterFetch extends Thread { Nl[]8G};  
=6XJr7Ay8u  
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String sURL; //File URL T
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long nStartPos; //File Snippet Start Position 5s=ZA*(sY  
long nEndPos; //File Snippet End Position CFm( yFk  
int nThreadID; //Thread's ID NUlp4i~Q  
boolean bDownOver = false; //Downing is over D5o[z:V7"  
boolean bStop = false; //Stop identical ewo]-BQS  
FileAccessI fileAccessI = null; //File Access interface i++a^f  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2 L>;M  
{ n(i Uc1Y  
this.sURL = sURL; F/ZB%;O9  
this.nStartPos = nStart; _JVFn=  
this.nEndPos = nEnd; zn,y'},  
nThreadID = id; "!ZQ`yl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lO (MF  
} U9<AL.  
b`%3>  
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public void run() eP d  
{ ;Av=/hU  
while(nStartPos < nEndPos && !bStop) W'|NYw_B  
{ :]Nn(},  
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try{ <Km ^>9  
URL url = new URL(sURL); ~4 ~c+^PF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ic 5TtN~/>  
httpConnection.setRequestProperty("User-Agent","NetFox"); !2.(iuE  
String sProperty = "bytes="+nStartPos+"-"; \kDQ[4mGq  
httpConnection.setRequestProperty("RANGE",sProperty); N\,[(LbA
&  
Utility.log(sProperty); P3Wnso  
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InputStream input = httpConnection.getInputStream(); 50s1o{xwc  
//logResponseHead(httpConnection); v qt#JdPp9  
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byte[] b = new byte[1024]; M id v  
int nRead; yQT cO^E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J0ysZ]  
{ lOp7rW]$  
nStartPos += fileAccessI.write(b,0,nRead); 3V(]*\L  
//if(nThreadID == 1) ~.Wlv;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jmp0 %:+L  
} j*.K|77WHj  
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; _ziRy  
Utility.log("Thread " + nThreadID + " is over!"); Tvd}5~ 5?  
bDownOver = true; [P'"|TM[~  
//nPos = fileAccessI.write (b,0,nRead); </hv{<  
} IP LKOT~  
catch(Exception e){e.printStackTrace ();} syJLcK+e  
} ?*)Q[P5  
} $ Jz(Lb{  
]C;X/8'Jf5  
x%v[(*F#y  
//打印回应的头信息 e3#0r  
public void logResponseHead(HttpURLConnection con) %ER"Udh  
{ ,QeJ;U  
for(int i=1;;i++) ->^Ex`  
{ kxanzsSr9  
String header=con.getHeaderFieldKey(i); lZ'WFFWLE  
if(header!=null) DruiiA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kF;N}O2?{  
Utility.log(header+" : "+con.getHeaderField(header)); JdM0f!3  
else oimM)Yo  
break; F@tfbDO?  
} _xefFy  
} 'mELW)S  
Hk1[0)  
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public void splitterStop() >\7Mf@c  
{ Ybkydc  
bStop = true; *8bj3A]vf  
} VMee"'08  
2q NA\-0i>  
[.(,vn?6  
} 33=lR-N#  
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/* k-Z:z?M  
**FileAccess.java f7SMO-3a  
*//文件访问(定位，写) e7S
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package NetFox; "5!T-Z+F  
import java.io.*; \{a!Z&df  
/szwVA  
/h7u
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public class FileAccessI implements Serializable{ [;Y,nSw  
`0
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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 g5C$#<28  
RandomAccessFile oSavedFile; 5|jsv)M+  
long nPos; -U{CWn3G  
= yFOH~_  
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public FileAccessI() throws IOException &7XsyDo6  
{ '5m4kDs  
this("",0); FNw0x6,~R  
} hh-a+] c0  
#z1/VZ  
5SMV3~*P  
public FileAccessI(String sName,long nPos) throws IOException YNB7`:  
{ j"s7P%  
oSavedFile = new RandomAccessFile(sName,"rw"); j8G$,~v  
this.nPos = nPos; l$&dTI<#  
oSavedFile.seek(nPos); Y3\EX  
} s&4&\Aq}x#  
#`ZBA>FLaQ  
AxfQ{>)0  
public synchronized int write(byte[] b,int nStart,int nLen) i5,yrPF  
{ HU/2P`DGP  
int n = -1; '~9w<dSB!r  
try{ `Frr?.3&-  
oSavedFile.write(b,nStart,nLen); +lXIv  
n = nLen; TVM19
)9  
} <N:)Xf9`  
catch(IOException e) S,s#D9NU  
{ M2$
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e.printStackTrace (); y9N6!M|'y  
} [}=a6Q>)  
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return n; 95E#  
} Ne)3@?  
2 :4o`o  
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} I.'/!11>  
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/* g%V#Z`*|  
**SiteInfoBean.java 
0R,.  
*/ ["#H/L]3  
package NetFox; X`(fJ
',  
va:<W H  
 )$GCur~  
public class SiteInfoBean { Cw"[$E'J  
I)kc[/^j$  
w!pj);jy{  
private String sSiteURL; //Site's URL 
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private String sFilePath; //Saved File's Path 8Vjv #pm  
private String sFileName; //Saved File's Name {r~=mQ  
private int nSplitter; //Count of Splited Downloading File ?t<g|H/|6  
Na4O( d`  
lCgzQZ  
public SiteInfoBean() yk'L_M(=  
{//nSplitter的缺省值为5 N4z[=b>  
//default value of nSplitter is 5 Peo-t*-06  
this("","","",5); L]%!YP\<T  
} JeN]sK)8x  
% H<@Y$r  
I4|"Ztw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /1p5KVTKv  
{ 6<9}>Wkf  
sSiteURL= sURL; !Eg2#a?  
sFilePath = sPath; &8pGq./lr=  
sFileName = sName; !C|Z+w9Y  
this.nSplitter = nSpiltter; 3 l}9'j  
~;z] _`_Va  
_^eiN'B  
} -\USDi(  
w?zy/+N~  
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public String getSSiteURL() $)nP
j_h  
{ +V(^"Z~  
return sSiteURL; vS"h`pL  
} TFm[sO0RZ  
M7T
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}]#z0'Aqsu  
public void setSSiteURL(String value) en/h`h]h  
{ g\?v 5  
sSiteURL = value; Lyf5Yf([-  
} t%G.i@{pkp  
Uf|uFGb  
)o~/yB
7  
public String getSFilePath() a6gPJF[Jo  
{ m+(g.mvK>  
return sFilePath; vQp'bRR  
} Zoc4@% n  
4x&Dz0[[S  
5Po:$(  
public void setSFilePath(String value) +$#<gp"  
{ nW^h +  
sFilePath = value; tcnO`0moK  
} gaxM#  
A'rd1"K  
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public String getSFileName() O9zMD8  
{ Dn@ZS_f  
return sFileName; !H@HgJ -  
} =+UtAf<n  
`"}).{N]C  
/t`,7y3T  
public void setSFileName(String value) +ue1+#  
{ ',xUU{5?  
sFileName = value; .>#O'Z&q9  
} UGd\`*Cj  
4`)r1D!U  
c-5AI{%bl6  
public int getNSplitter() \b%c_e  
{ :aBxyS*}G  
return nSplitter; ,}]v7DD  
} M]p-<R\  
k7Qs#L  
(_!I2"Q*  
public void setNSplitter(int nCount) vb?.`B_>&  
{ 9od*N$  
nSplitter = nCount; ~c<8;,cjYR  
} S5u$I  
} kS&>g  
XVqkw@Ia4!  
@8>bp#x/1  
/* 7M4J{}9  
**Utility.java 9PA<g3z  
*/ akNqSZwj  
package NetFox; r180vbN$  
hSw=Oq82  
Pzq^x]  
public class Utility { 9Q}g Vqn  
I<CrEL<5}~  
qPD(D{,f$  
public Utility() qbD 7\%  
{ yyljyE  
A.("jb@I  
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} .#bf9JOE  
KpYezdPF)  
//线程睡眠 @XolFOL"f"  
public static void sleep(int nSecond) `_1~[t  
{ CEI"p2  
try{ $A9Pi"/*z  
Thread.sleep(nSecond); O=V_7I5  
} RqGX(Iuv  
catch(Exception e) aVHIU3  
{ ^~-YS-.J#,  
e.printStackTrace (); _~;%zFX  
} KcpYHWCa.  
} \u{4=-C.  
u>.a;BO  
//日志 G 3,v'D5  
public static void log(String sMsg) @L~erg>8=  
{ ("t'XKP&N  
System.err.println(sMsg); (m,H
 5  
} [ 5}Q  
m{=Q88k!@.  
oRSA&hSs  
public static void log(int sMsg) YLQ0UeDN'  
{ ws5Ue4g|  
System.err.println(sMsg); z9[TjTH^}T  
} 6QY;t:/<  
} K&%CeUa  
D0xQXC3$`  
<^Vj1
s  
/* :=;{w~D  
**TestMethod.java '7el`Ff  
*/ jw=PeT|  
package NetFox; GnW MI1$  
;j/$%lC  
$Y6\m`  
public class TestMethod { \H:T)EV
y  
J??AU0vh  
$ch`.$wx  
public TestMethod() 9/{zS3h3  
{ ///xx/weblogic60b2_win.exe vuPNru" 2  
try{ EZ .3Z`
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )S%t)}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iBAP,cR?`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z``wqK  
fileFetch.start(); /m"/#; ^l  
} <A)M^,#o  
catch(Exception e){e.printStackTrace ();} *PnO$q@`  
hA5')te<  
ft(o-f7,  
} +m%%Bz>  
Icrnu}pl_  
Ha-]U:Vcx  
public static void main(String[] args) U[f00m5{HV  
{ ?$109wZ:9  
new TestMethod(); N5=BjXSAg  
} 1Y'4 g3T  
} nPXP9wmh4x  
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