http断点续传简单实现（java)

/* 95@u|#n  
**SiteFileFetch.java t>}S@T{~T  
*/ zi6J|u  
package NetFox; 6z U  
import java.io.*; wQy~5+LE  
import java.net.*; ,%IP27bPW  
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public class SiteFileFetch extends Thread { 8
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SiteInfoBean siteInfoBean = null; //文件信息Bean xtv%C  
long[] nStartPos; //开始位置 ' abEY  
long[] nEndPos; //结束位置 }?mSMqnB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .cs x"JC  
long nFileLength; //文件长度 @PNgqjd  
boolean bFirst = true; //是否第一次取文件 t`Z3*?UqI  
boolean bStop = false; //停止标志 xJ/)*?@+  
File tmpFile; //文件下载的临时信息 TM#L.xPMf  
DataOutputStream output; //输出到文件的输出流 aanS^t0  
oz=ULPZ%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O8\f]!O(  
public SiteFileFetch(SiteInfoBean bean) throws IOException B(s^(__]  
{ 8TB|Y  
siteInfoBean = bean; X+A@//,7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8h=m()Eu  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oZY|o0/9  
if(tmpFile.exists ()) A? B+  
{ +0%r@hTv&>  
bFirst = false; 56s%Qlgx  
read_nPos(); AA,/AKikd  
} nD eVYK  
else Het"x  
{ PV~D;  
nStartPos = new long[bean.getNSplitter()]; cb)7$S  
nEndPos = new long[bean.getNSplitter()]; OjlX<y.  
} E%v0@  
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} BXdk0  
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public void run() 7M~/ q.  
{ ?C fQwY#N  
//获得文件长度 AeEdqX)  
//分割文件 71[?AmxV  
//实例FileSplitterFetch 2=K|kp5  
//启动FileSplitterFetch线程 sHBTB6)lx  
//等待子线程返回 d]sqj\Q57  
try{ nm<VcCc  
if(bFirst) AzJ;EtR  
{ !6X6_ +}M  
nFileLength = getFileSize(); _p:n\9k  
if(nFileLength == -1) v?]a tb/h`  
{ F68eI%Y  
System.err.println("File Length is not known!"); hL/u5h%$  
} Rf`_q7fm  
else if(nFileLength == -2) %b*N.v1+  
{ 'q:7PkN!p  
System.err.println("File is not access!"); LRu*%3xx  
} yKj}l,i~8  
else <\$"U5"`  
{ 1K/ :  
for(int i=0;i<nStartPos.length;i++) 1HNP@9ga  
{ qZ[HILh!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fTR6]i;  
} 6:%lxG  
for(int i=0;i<nEndPos.length-1;i++) tc`3-goX  
{ 4s:M}=]N  
nEndPos = nStartPos[i+1]; yN`hW&K  
} B`R@%US  
nEndPos[nEndPos.length-1] = nFileLength; 9kWI2cLzQt  
} %+Nng<_U\T  
} |k}L=oWE  
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n;:.UGl9.  
//启动子线程 .+XK>jl+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r@r*|5
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for(int i=0;i<nStartPos.length;i++) ^(+q1O'  
{ Fl($0}ER  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,h1\PT9ULY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZJWpb  
nStartPos,nEndPos,i); 1QA/ !2E  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !\{2s!l~  
fileSplitterFetch.start(); r3' DXP  
} EmO[-W|2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X(x,6cC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @ntwdv;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rz&V.,s  
nEndPos = " + nFileLength); iB W:t  
// fileSplitterFetch[nPos.length-1].start(); XZk%5t|
t  
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//等待子线程结束 \PT!mbB?  
//int count = 0; g)Hsd0  
//是否结束while循环 YC 4c-M  
boolean breakWhile = false; FEu}zt@  
?/MkH0[G=  
d m"R0>  
while(!bStop) NvIg,@}  
{ Wf"$  
write_nPos(); S)zw[m  
Utility.sleep(500); `_)9eGQ  
breakWhile = true; U}X'
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for(int i=0;i<nStartPos.length;i++) T2]8w1l&K  
{ .?g=mh79(  
if(!fileSplitterFetch.bDownOver) ^kcuRJ0*$  
{ 8i;drvf  
breakWhile = false; w)S 4Xi=  
break; Lc
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} FLQke"6i0:  
} j}Svb1A  
if(breakWhile) m=E/um[D  
break; :kI[Pf!z  
vgtAJp+p*  
;sYDs71y  
//count++; AaB1H7r-  
//if(count>4) ulN1z  
// siteStop(); dkEbP*yXg  
} xzY/$?  
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System.err.println("文件下载结束！"); cu5}(  
} sx+k V A  
catch(Exception e){e.printStackTrace ();} '=+N )O  
} fFbJE]jW  
P]}:E+E<.I  
11QZ- ^  
//获得文件长度 S9l po_!z  
public long getFileSize() {}'Jr1  
{ \2El>>  
int nFileLength = -1; r%=a:GdAg  
try{ AFsieJ  
URL url = new URL(siteInfoBean.getSSiteURL()); rusM]Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E%E`\mFD  
httpConnection.setRequestProperty("User-Agent","NetFox"); n7ZJ< ~wl  
%2D'NZS  
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int responseCode=httpConnection.getResponseCode(); -6_<]  
if(responseCode>=400) n)a/pO_  
{ +fozE?  
processErrorCode(responseCode); Yy/,I]F  
return -2; //-2 represent access is error ;9)nG,P3  
} a0JMLLa [I  
<w~$S0_  
 7Tr '<(A  
String sHeader; pK{G2]OK{U  
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for(int i=1;;i++) 0[ "CP:u  
{ hA/Es?U]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F3!6}
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//Utility.log(in.readLine()); &-NGVPk81`  
sHeader=httpConnection.getHeaderFieldKey(i); ZI$P Qz2i  
if(sHeader!=null) ^oC>,%7  
{ qrOesSdc  
if(sHeader.equals("Content-Length")) 9b-4BON{P  
{ %<Qv?`B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &=%M("IlD  
break; wb#[&2
i  
} tD}{/`{_t  
} f9_Pn'"I  
else !T)_(}|6}  
break; :SN?t  
} OBlQ   
} j4@6`[n:  
catch(IOException e){e.printStackTrace ();} *R4=4e2#S  
catch(Exception e){e.printStackTrace ();} .u7grC C  
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Utility.log(nFileLength); 4s>L]! W$8  
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return nFileLength; p|0SA=?k"  
} yoq-H+<  
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//保存下载信息（文件指针位置） (NnE\2  
private void write_nPos() hP[/xe  
{ ;/23CFYM  
try{ }|=Fnyj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K43`$  
output.writeInt(nStartPos.length); x`w
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for(int i=0;i<nStartPos.length;i++) 7PfNPz<4+  
{ a&mL Dh/  
// output.writeLong(nPos); buKkm$@w  
output.writeLong(fileSplitterFetch.nStartPos); A;/,</  
output.writeLong(fileSplitterFetch.nEndPos); H,/=<Th;i  
} `7``1TL  
output.close(); *6_>/!ywI  
} %ID48_>*  
catch(IOException e){e.printStackTrace ();} rf^IJY[  
catch(Exception e){e.printStackTrace ();} 's"aPqF?  
} #cD$ DA  
)cOBP}j+  
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//读取保存的下载信息（文件指针位置） Ttb?x<)+8  
private void read_nPos() @1k-h;`,  
{ tnb'\}Vn  
try{ a(-t"OL\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6]!Jo)BF  
int nCount = input.readInt(); :W-xsw  
nStartPos = new long[nCount]; $RRh}w\0^  
nEndPos = new long[nCount]; - sq=|  
for(int i=0;i<nStartPos.length;i++) (S=CxK  
{ L)H/t6}i  
nStartPos = input.readLong(); [e|9%[.V  
nEndPos = input.readLong(); {Aj=Rj@  
} aJs! bx>K  
input.close(); A i#~Eu*  
} .)t*!$5=N  
catch(IOException e){e.printStackTrace ();} (LVzE_`  
catch(Exception e){e.printStackTrace ();} U; #v-'Z  
} 33"!K>wC  
|F=.NY  
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private void processErrorCode(int nErrorCode) @%MGLR{pH  
{ ~WmA55  
System.err.println("Error Code : " + nErrorCode); ,k:>Z&:  
} @9]TjZd  
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*L<<S=g$2  
//停止文件下载 FYg{IKg  
public void siteStop() 77]Fp(uI  
{ k1D|Cpnp  
bStop = true; 6SAYe%e  
for(int i=0;i<nStartPos.length;i++) zP!j {y4w  
fileSplitterFetch.splitterStop(); 7;#o?6!7  
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} r/+~4W5  
} ( ~>-6Nb 5  
//负责部分文件的抓取 /dR:\ffz2  
**FileSplitterFetch.java tg2+Z\0)4g  
*/ -?)z@L
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package NetFox; 0}>p)k3&A  
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import java.io.*; <{HV|B7  
import java.net.*; @# p{,L  
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public class FileSplitterFetch extends Thread { Og2w]B[  
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String sURL; //File URL kKVNE hTp  
long nStartPos; //File Snippet Start Position ^ -lWv  
long nEndPos; //File Snippet End Position E@@XWU21;N  
int nThreadID; //Thread's ID oHethk  
boolean bDownOver = false; //Downing is over +4]f6Zz({  
boolean bStop = false; //Stop identical ir;az{T#U  
FileAccessI fileAccessI = null; //File Access interface s<LYSrd  
&X}i%etp^2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O 0P4uq  
{ baR*4{]  
this.sURL = sURL; ?*f2P T?`  
this.nStartPos = nStart; 5W_Rg:J{P  
this.nEndPos = nEnd; j;&su=p"  
nThreadID = id; {9./-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /yO0Z1G  
} H$3:Ra+ S  
7Rr +Uzb(  

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public void run() _$gP-J  
{ S1*xM  
while(nStartPos < nEndPos && !bStop) @$|bMH*1:  
{ [jKhC<t}  
M
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try{ sH{(=N  
URL url = new URL(sURL); /onZ14  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mv`ND&  
httpConnection.setRequestProperty("User-Agent","NetFox"); /Nd`eUn  
String sProperty = "bytes="+nStartPos+"-"; JHsxaX;c  
httpConnection.setRequestProperty("RANGE",sProperty); zW; sr.  
Utility.log(sProperty); pJ@D}2u(  
'!XVz$C  
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InputStream input = httpConnection.getInputStream(); kfs[*ku  
//logResponseHead(httpConnection); Uj)`(}r  
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byte[] b = new byte[1024]; ,D{D QJ(B  
int nRead; J+Zp<Wu-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z7O$o/E-*  
{ s>e)\9c  
nStartPos += fileAccessI.write(b,0,nRead); m+dJ3  
//if(nThreadID == 1) 9.l*#A^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [Pz['q L3t  
} +)e+$ l  
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Utility.log("Thread " + nThreadID + " is over!"); #J*hZ(Pq  
bDownOver = true; p) m0\  
//nPos = fileAccessI.write (b,0,nRead); Uizg.<.  
} j:'8yFi_  
catch(Exception e){e.printStackTrace ();} 0-IL@Di`F  
} =a_ >")  
} %2`.*]L  
 D
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//打印回应的头信息 ,uCgC4EP  
public void logResponseHead(HttpURLConnection con) ;0:[X+"(  
{ #HmZe98[%  
for(int i=1;;i++) h9l 6AnbJ  
{ [|APMMYK1  
String header=con.getHeaderFieldKey(i); \) g?mj^  
if(header!=null) cFloaCz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9<1dps=c  
Utility.log(header+" : "+con.getHeaderField(header)); q3/ 0xN+?  
else Xny{8Oo<1?  
break; AP/#?   
} PI$K+}E  
} ~y8KQ-1n"  
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public void splitterStop() (cm8x  
{ EVDcj,b"^  
bStop = true; V%[34G  
} cPPTGpqw  
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} ~qezr\$2  
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/* J42/S [Rt  
**FileAccess.java Apc!!*7  
*//文件访问(定位，写) . MH;u3U  
package NetFox; )i$KrN6  
import java.io.*; `-w;/A"MJ  
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public class FileAccessI implements Serializable{ U'0e<IcY  
]q3.^F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^W,~  
RandomAccessFile oSavedFile; hf< [$B  
long nPos; @5*$yi 'Cp  
dc,qQM  
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public FileAccessI() throws IOException WXe]Q bg  
{ Mk!bmFZOZ  
this("",0); <^Jdl.G  
} M^jEp  
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28LYGrB  
public FileAccessI(String sName,long nPos) throws IOException 2[g kDZ  
{ f}w_]l#[G  
oSavedFile = new RandomAccessFile(sName,"rw"); K aNO&%qX  
this.nPos = nPos; @k-iy-|3)  
oSavedFile.seek(nPos); w7b\?]}@  
} HlraOp+  
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public synchronized int write(byte[] b,int nStart,int nLen) kt7x}F(?<  
{ kxt/I<cs  
int n = -1; c]R27r E  
try{ 
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oSavedFile.write(b,nStart,nLen); Nf)$K'/  
n = nLen; PUErvLt  
} /-
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catch(IOException e) e$o
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{ `j!XWh*$  
e.printStackTrace (); CO`?M,x>  
} [Z;ei1l  
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return n; sq;3qbz  
} 
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} K>G.HN@  
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/* fw)Q1"|  
**SiteInfoBean.java D 3Tqk^5  
*/ ) (0=w4  
package NetFox; DqHJ *x4  
aATNeAR  
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public class SiteInfoBean { YFP<^y=  
}!V-FAL  
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private String sSiteURL; //Site's URL  Lr0:yo  
private String sFilePath; //Saved File's Path k5)a|  
private String sFileName; //Saved File's Name _fS4a134R  
private int nSplitter; //Count of Splited Downloading File HJJ;gTj  
O~mQ\GlW  
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public SiteInfoBean() *U +<Hv`C  
{//nSplitter的缺省值为5 o+Fm+5t;  
//default value of nSplitter is 5 Ako]34Rl,  
this("","","",5); IYv.~IQO  
} CV)K=Br5&_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8J:=@X^}  
{ r+;k(HMY}[  
sSiteURL= sURL; h.q9p!  
sFilePath = sPath; Ko0?c.l  
sFileName = sName; %F\.1\&eE  
this.nSplitter = nSpiltter; 7[I +1  
2"_5Yyb  
*Sps^Wl  
} h s_x @6  
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9 !$&1|,*  
public String getSSiteURL() Up0kTL  
{ i6<uj  
return sSiteURL; MV]`[^xQ5  
} C-XJe~  
6q^\pJY%&7  
hbEqb{#}@  
public void setSSiteURL(String value) #4<=Ira5  
{ 6-FM<@H{  
sSiteURL = value; RK=Pm7L:`y  
} Iw?*y.z|  
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@km4qJZ  
public String getSFilePath() e$/y
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{ H!'4A&  
return sFilePath; F}=_"IkZ  
} udmLHc  
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public void setSFilePath(String value) _0UE*l$t  
{ =J|jCK[r  
sFilePath = value; BS(jC  
} \Foo:jON  
m^ Epw4eg  
4U~'Oa@p  
public String getSFileName() <KfR)7I$0a  
{ 9WI5\`*"  
return sFileName; X ]W)D S  
} hV:++g  
"!CV
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public void setSFileName(String value) ;A4j_8\[  
{ :zY;eJKm  
sFileName = value; m#[9F']Z`  
} {{?MO{Mh*  
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public int getNSplitter() $0vWC#.A]  
{ Y% JE})  
return nSplitter; *6eJmbFG  
} ~!=Am:-wr  
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public void setNSplitter(int nCount) g9CedD%40  
{ ;K~=? k  
nSplitter = nCount; }zxf~41  
} P&=YLL<W  
} &*Xrh7K2e  
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&n6L;y-  
/* E0/>E  
**Utility.java #-PMREgO  
*/ Ghc U~  
package NetFox; %?, 7!|Ls  
!#~KSO}zW2  
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public class Utility { E)`0(Z:E  
/KNR;n'  
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public Utility() j Neb*dPoK  
{
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V)`A,7X  
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} 4f~sRu
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DaJ,(DJY  
//线程睡眠 wEwRW  
public static void sleep(int nSecond) $${3I4  
{ dQ~GE}[  
try{ h Ypj  
Thread.sleep(nSecond); k=mLcP  
} L)&^Pu  
catch(Exception e) Z,/^lg c,  
{ l1|*(%p?X  
e.printStackTrace (); q'a]D
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} cMF)2^w}  
} |d-x2M[  
w\0vP  
//日志 +H?g9v40  
public static void log(String sMsg) VcXr!4M  
{ "" >Yw/'  
System.err.println(sMsg); ,A7:zxnc.V  
} Pz[UAJ  
mdyl;e{0  
n1GX`K  
public static void log(int sMsg) Dt>tTU 6  
{ 65JG#^)KaX  
System.err.println(sMsg); *0Z6H-Do,  
} 'jMs&  
} -:pVDxO  
] Ok &%-  
/4O
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/*  B9y5NX  
**TestMethod.java FyWf`XTO  
*/ ;dMr2y`6  
package NetFox; jA;b2A]G  
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-,YI>!  
public class TestMethod { DBHHJD/q  
QIU%!9Y  
rqiH!R  
public TestMethod() rp dv{CUp7  
{ ///xx/weblogic60b2_win.exe uL-kihV:-  
try{ &=*1[j\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =,q/FY:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `7y3C\zyQ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xzOvc<u  
fileFetch.start(); F):kF_ho  
} @BjB Mi,  
catch(Exception e){e.printStackTrace ();} 9eq)WI/  
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h*D -Vo  
} l3BN,HNv+  
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zi  
public static void main(String[] args) XUh&an$  
{ "~EAt$  
new TestMethod(); 9S17Lr*c  
} 0sKoNzE  
} [ ^\{>m7  
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