http断点续传简单实现（java)

/* &1yJrj9y  
**SiteFileFetch.java U4fv$gV  
*/ iD G&Muc  
package NetFox; 't&1y6Uu  
import java.io.*; \t&!
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import java.net.*; TB* t^E  
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public class SiteFileFetch extends Thread { UMe?nAC  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "aF2:E'  
long[] nStartPos; //开始位置 F |BY]{  
long[] nEndPos; //结束位置 bs?\ )R5/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~`FRU/@r  
long nFileLength; //文件长度 g9|OhymB  
boolean bFirst = true; //是否第一次取文件 5L[imOM0  
boolean bStop = false; //停止标志 D]fuX|f~ul  
File tmpFile; //文件下载的临时信息 v:QUwW  
DataOutputStream output; //输出到文件的输出流 )'T].kWW  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T` h%=u|D  
public SiteFileFetch(SiteInfoBean bean) throws IOException
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{ G=|?aK{p  
siteInfoBean = bean; 1F,U^O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oo\^}jb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %%}l[W  
if(tmpFile.exists ()) AXHY
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{ rHB>jN@$  
bFirst = false; Y3DqsZ@  
read_nPos(); dN3^PK  
} RU7+$Z0K  
else q"<=^vi  
{ t3Gy *B  
nStartPos = new long[bean.getNSplitter()]; Os-Z_zSl6  
nEndPos = new long[bean.getNSplitter()]; JX&]>#6|E  
} m;l[flQ~  
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}
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)/@KdEA:  
public void run() fc@<'-VA  
{ XjN=UhC  
//获得文件长度 klnNBo!  
//分割文件  94PI  
//实例FileSplitterFetch dxAGO(  
//启动FileSplitterFetch线程 ,$:u^;V(  
//等待子线程返回 k- 9i  
try{ :XFQ}Cl  
if(bFirst) LF!KP  
{ \O"H#gt  
nFileLength = getFileSize(); m`-:j"]b$  
if(nFileLength == -1) T$"~Vu  
{ fYy w2"  
System.err.println("File Length is not known!"); U<0Wa>3zj  
} ,]wQ]fpt  
else if(nFileLength == -2) STjb2t,a  
{ A?#i{R  
System.err.println("File is not access!"); _lkVT']  
} 8iaMr278W  
else c=\_[G(  
{ ME]4tu  
for(int i=0;i<nStartPos.length;i++)  VQH48{X  
{ =@M9S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `oikSx$vB.  
} ]^>Inh!  
for(int i=0;i<nEndPos.length-1;i++) ^UKY1Q.  
{ f\= @jV  
nEndPos = nStartPos[i+1]; \-]Jm[]^  
} 1
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nEndPos[nEndPos.length-1] = nFileLength; YQC.jnb2  
} e
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} 4N$Wpx  
? bWc<]  
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//启动子线程 1$E[``
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 98R/^\  
for(int i=0;i<nStartPos.length;i++) N\ Mdia  
{ mv:@D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n$SL"iezW?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Uz_ob9l<#H  
nStartPos,nEndPos,i); qbq2Bi'a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?3fnt"  
fileSplitterFetch.start(); Z1q<) O1QX  
} npkT>dB+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nw/g[/<;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); VO:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oe^JDb#  
nEndPos = " + nFileLength); GPh;r7xg6  
// fileSplitterFetch[nPos.length-1].start(); #]c
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"" ^n^$  
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//等待子线程结束 5g-1pzP9  
//int count = 0; }o!b3*#  
//是否结束while循环 Gq1C"s$4'  
boolean breakWhile = false; o<48'>[  
Hfj.8$   
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while(!bStop) a
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{ 8u)>o* :  
write_nPos(); 3+'vNc  
Utility.sleep(500); C3=0st$  
breakWhile = true; <Af&Q0J  
F7C+uGTs  
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for(int i=0;i<nStartPos.length;i++) =jm\8sl~~  
{ 9wfE^E1  
if(!fileSplitterFetch.bDownOver) |a7Kn/[`,  
{ ^"lEa-g&  
breakWhile = false; VgbT/v  
break; y]R+/  
} `Zmdlp@  
} GE] QRKf  
if(breakWhile) #G(ivRo  
break; n|H
8O3@  
c]k+ Sx&}  
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//count++; -8"
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//if(count>4) {l/`m.Z  
// siteStop(); >u0XV"g$  
} H0B=X l[  
t&JOASY
C  
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System.err.println("文件下载结束！"); PpLhj  
} ^pY8'LF6  
catch(Exception e){e.printStackTrace ();} 6,1oLvU  
} pR2U&OA  
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//获得文件长度 @R;k@b   
public long getFileSize() xp^Jp  
{ k`'*niz  
int nFileLength = -1; uTO%O}D N  
try{ z&#^9rM"  
URL url = new URL(siteInfoBean.getSSiteURL()); /Trbr]lWy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4%<wxrod  
httpConnection.setRequestProperty("User-Agent","NetFox"); XCxxm3t  
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int responseCode=httpConnection.getResponseCode(); `25<;@  
if(responseCode>=400) ZhRdml4U2  
{ q!><:"#[G  
processErrorCode(responseCode); :YX5%6  
return -2; //-2 represent access is error Ue`Y>T7+!  
} )Xt#coagS  
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5}5oj37x  
String sHeader; 5TeGdfu @  
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for(int i=1;;i++) Ed_Fx'  
{ &Wdi 5T8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5V/]7>b1  
//Utility.log(in.readLine()); o7PS1qcya<  
sHeader=httpConnection.getHeaderFieldKey(i); ;jPiD`Kyv  
if(sHeader!=null) OYmutq  
{ TB<$9FCHK  
if(sHeader.equals("Content-Length")) "?iyvzo  
{ '4M;;sKW  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -i91nMi]  
break; r1=j$G  
} 8NNs_~+x}  
} QWt3KW8)  
else  
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break; qf@P9M  
} G%!i="/9  
} w|0
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catch(IOException e){e.printStackTrace ();} U ){4W0  
catch(Exception e){e.printStackTrace ();} ![I|hB  
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Utility.log(nFileLength); HvZSkq^
  
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return nFileLength; 7j#Ix$Ur  
} bkpN`+c  
<{YzmN\Z  
23'{{@30  
//保存下载信息（文件指针位置） FKhgUnw  
private void write_nPos() @FF{lK?[  
{ ofI,[z3  
try{ sint":1FC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'w<^4/L Q  
output.writeInt(nStartPos.length); ^LXsU] R  
for(int i=0;i<nStartPos.length;i++) 3Tw9Uc\vT  
{ cT&lkS  
// output.writeLong(nPos); O69TU[Vn  
output.writeLong(fileSplitterFetch.nStartPos); ~*^o[~x]\  
output.writeLong(fileSplitterFetch.nEndPos); c@nh>G:y{&  
} %uiCC>cC  
output.close(); ,R7j9#D  
} Fo~q35uB  
catch(IOException e){e.printStackTrace ();} $S2 /*  
catch(Exception e){e.printStackTrace ();} tWaGCxaE  
} @`^Z5n.4  
*mYGs )|  
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//读取保存的下载信息（文件指针位置） F|oyrG  
private void read_nPos() [ `_sH\  
{ w?M"`O(  
try{ &5B/>ag1!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Are0Nj&?
 
int nCount = input.readInt(); \CS4aIp  
nStartPos = new long[nCount]; j+gh*\:q  
nEndPos = new long[nCount]; S+^hK1jL  
for(int i=0;i<nStartPos.length;i++) m*i,|{UZ  
{ Imclz4'8  
nStartPos = input.readLong(); +br' 2Pn  
nEndPos = input.readLong(); JP^
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} $GhL-sqm  
input.close(); 1>2 /1>  
} S&'s/jB  
catch(IOException e){e.printStackTrace ();} KilN`?EJ  
catch(Exception e){e.printStackTrace ();} %@q2  
} vkG%w;  
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private void processErrorCode(int nErrorCode) g]BA/Dw  
{ ~xws5n}F  
System.err.println("Error Code : " + nErrorCode); 3.ShAL  
} v5?ct?q  
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//停止文件下载 WqCj;Tj|  
public void siteStop() hew"p(`  
{ adgd7JjI*  
bStop = true;  s%5XB
I  
for(int i=0;i<nStartPos.length;i++) ,u-9e4  
fileSplitterFetch.splitterStop(); ]'hel#L;l  
mGmZ}H'{  
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} zx+}>(U\U  
} ^6Yt2Bhs  
//负责部分文件的抓取 VrhHcvnZ  
**FileSplitterFetch.java "kIlxf3  
*/ t47;X}y f  
package NetFox; \DD4=XGA  
:gRVa=}=  
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import java.io.*; 0Xn,q]@Z  
import java.net.*; pDhUD}1G  
;DKJ#tS}"  
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public class FileSplitterFetch extends Thread { )?LZg<<  
>dwWqcP  
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String sURL; //File URL mW,b#'hy  
long nStartPos; //File Snippet Start Position OekE]`~w  
long nEndPos; //File Snippet End Position 'b
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int nThreadID; //Thread's ID C?<-`$0  
boolean bDownOver = false; //Downing is over y T&#k1  
boolean bStop = false; //Stop identical z 61Fq  
FileAccessI fileAccessI = null; //File Access interface REsw=P!b  
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oI  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `v2Xp3o4f  
{ yi(IIW  
this.sURL = sURL; 2l:cP2fa  
this.nStartPos = nStart; 3+iryW(\  
this.nEndPos = nEnd; )N\BC  
nThreadID = id; 2)QZYgfh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5rQu^6&  
} KAu>U3\/  
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public void run() TDy$Mv=y  
{ WWOjck#  
while(nStartPos < nEndPos && !bStop) :j/sTO=  
{ (>lH=&%zj  
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try{ (rBYE[@,  
URL url = new URL(sURL); >m%7dU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \uJ+~db
=  
httpConnection.setRequestProperty("User-Agent","NetFox"); Fp]ErDan  
String sProperty = "bytes="+nStartPos+"-"; cXYE!(  
httpConnection.setRequestProperty("RANGE",sProperty); 6C ?,V3Z  
Utility.log(sProperty); <R%TCVwC@  
7(|f@Y~*  
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InputStream input = httpConnection.getInputStream(); .>1Y-NM  
//logResponseHead(httpConnection); q[+KQ,  
.5 {<bY  
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byte[] b = new byte[1024]; (/{bJt~b  
int nRead; PZ?kv4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g!cW`B'  
{ ho^jmp  
nStartPos += fileAccessI.write(b,0,nRead); d(KK7SQg  
//if(nThreadID == 1) g{K
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m)r,  
}
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@
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Utility.log("Thread " + nThreadID + " is over!"); b+$wx~PLi  
bDownOver = true; ;r.#|b  
//nPos = fileAccessI.write (b,0,nRead); 0eK>QZ_  
} oc[z dIk  
catch(Exception e){e.printStackTrace ();} !>GDp>0  
} jQBn\^w  
} HLc3KYIk  
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f=8{cK0j  
//打印回应的头信息 4VC8#x1  
public void logResponseHead(HttpURLConnection con) q_"w,28  
{ b"OHXu  
for(int i=1;;i++) l?Ls=J*  
{ E, oR.B  
String header=con.getHeaderFieldKey(i); ,VzbKx,  
if(header!=null) gebL6oc%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;sx4w!Y,  
Utility.log(header+" : "+con.getHeaderField(header)); s'Qmrs a  
else :H:+XIgoR  
break; S?c<Lf~W  
} f=7[GZoDn  
} \vS >jB  

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public void splitterStop() `-?`H>+OG  
{ ^nD
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bStop = true; ~4mRm!DP  
} Ua~8DdW  
7d+0'3%  
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} g?cxqC<  
)a%E $`  
<KE%|6oER  
/* )d|s$l$?7  
**FileAccess.java #6pJw?[  
*//文件访问(定位，写) ,)VAKrSg  
package NetFox; {j4&'=C:  
import java.io.*; lB!M;2^)X  
gQ<{NQMzvd  
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public class FileAccessI implements Serializable{ T#vY(d  
Rv.IHSQUo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vV"I}L  
RandomAccessFile oSavedFile; QcjsQTAbk  
long nPos; hb9HVj  
0vMKyT3 c  
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public FileAccessI() throws IOException {]dvzoE]  
{ K1&t>2=%  
this("",0); _3#_6>=M  
} gN*b~&G  
{xICR ~,*  
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public FileAccessI(String sName,long nPos) throws IOException J5z\e@?.0\  
{ >X=VPh8  
oSavedFile = new RandomAccessFile(sName,"rw"); /Kd'!lMuz  
this.nPos = nPos; Y)#,6\=U  
oSavedFile.seek(nPos); a :cfr*IsK  
} F'JT7#eX  
8I<j"6`+Q  
A.RG8"  
public synchronized int write(byte[] b,int nStart,int nLen) 0r?]b*IEK  
{ I$XwM  
int n = -1; Tl+PRR6D*
 
try{ `P$X`;SwE  
oSavedFile.write(b,nStart,nLen); F
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n = nLen; 0<^Qj.(9  
} q%,y66pFr  
catch(IOException e) !Y/S
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{ APCE}%1U  
e.printStackTrace (); 4ti,R'  
} U r8JG&,  
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return n; kxmsrQ
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} =?N$0F!  
6}Rb-\N  
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} _SH~.Mt_!  
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j+>N&.zs
 
/* .B'ws/%5\  
**SiteInfoBean.java HYZp=*eb  
*/ S>Gb Jt(]  
package NetFox; d@tNlFfS  
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j(M.7Z7^  
public class SiteInfoBean { Bw9
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private String sSiteURL; //Site's URL =Q6JXp  
private String sFilePath; //Saved File's Path +6n\5+5  
private String sFileName; //Saved File's Name iP1yy5T  
private int nSplitter; //Count of Splited Downloading File H29vuGQjq  
k7(lwEgNG  
uC[F'\Y  
public SiteInfoBean() 0C6T>E7  
{//nSplitter的缺省值为5 7y$U$6  
//default value of nSplitter is 5 3FMYs&0r4  
this("","","",5); ^Cj3\G4,  
} 8v=t-GJW  
JIf.d($ ~:  
qa4j>;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \VypkbE+  
{ l7Wdbx5x0  
sSiteURL= sURL; ^+kymZ  
sFilePath = sPath; -U;=]o1  
sFileName = sName; !wZIXpeL  
this.nSplitter = nSpiltter; L D%SLJ:  
8?w#=@s  
`1#Z9&bO  
} (?i4P5s[!  
K 28s<i`  
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public String getSSiteURL() x Vw1  
{ 0%yPuY>  
return sSiteURL; f?(g5o*2  
} 8:Dkf
v  
r&~]6 U  
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public void setSSiteURL(String value) b{ tp qNm~  
{ }{[JS=A^  
sSiteURL = value; O@skd2  
} %H3iX^}*  
[]?*}o5&>T  
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public String getSFilePath() cmY `$=  
{ ?Iag-g9#=m  
return sFilePath; a;&0u>  
} ~RV9'v4  
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public void setSFilePath(String value) SjcX|=S  
{ h|<;:o?yh  
sFilePath = value; tv;?W=&P  
} -.-@|*5  
5H( ]"C  
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public String getSFileName() N1U.1~U  
{ xX8c>p  
return sFileName; d-gcXaA-8  
} SUL\|z`5  
oq(W|  
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public void setSFileName(String value) 2\F'So  
{ sBNqg~HwB?  
sFileName = value; BT f  
} t{Ks}9
B  
-.
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aLwEz}-   
public int getNSplitter() EWWCh0 {  
{ JZqJ& 
 
return nSplitter; eUD 5V  
} m`4N1egCt  
GZmfE`  
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public void setNSplitter(int nCount) `'pfBVBz  
{ D"{%[;J
 
nSplitter = nCount; zJOyr"B'8  
} 9|K:\!7  
} m,F4N$  
5{-54mwo  
&0+Ba[Z ^  
/* gGs"i]c  
**Utility.java ifmX<'(9A  
*/ -)DxF<8B  
package NetFox; 4OG1_6K  
i\* b<V  
zXe]P(p<  
public class Utility { 0bu!(Tpg7  
qR4-~p8  
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public Utility() q%XjJ -s:  
{ @J6V,  
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_gpf9ad  
} v}@Uc-(  
HYNpvK  
//线程睡眠 '"6*C*XS  
public static void sleep(int nSecond) 8]4W@~c  
{ =vL >&$  
try{ yx7y3TSq  
Thread.sleep(nSecond); QO4eDSW  
} NkAu<> G _  
catch(Exception e) LfvRH?<W  
{ `U>]*D68  
e.printStackTrace (); >Hd!o"I
 
} |"}rC >+  
} A|m0.'/  
QjTs$#eMW  
//日志 {Ut,x
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public static void log(String sMsg) /K<>OyR?  
{ l_ LH!Tu  
System.err.println(sMsg); ZtpbKy!\$B  
} "}0)~,{xB  
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NH'Q
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public static void log(int sMsg) {$C"yksr  
{ Jn20^YG  
System.err.println(sMsg); 3+!G9T!  
} 0uI=8j  
} /@",5U#  
c >xHaA:V  
BD mF+  
/* P[H 4Yp  
**TestMethod.java 4u1au1c  
*/ BD M
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package NetFox; bq{eu#rQJ  
X$_z"t  
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public class TestMethod { jori,"s  

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qh6Q#s>tH  
public TestMethod() 'Ojxzz*tT  
{ ///xx/weblogic60b2_win.exe so@ijl4{Z  
try{ -hGLGF??  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )OFf nKh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fD2 N}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2
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fileFetch.start(); H$6;{IUz~  
} M4t:)!dji?  
catch(Exception e){e.printStackTrace ();} pwNF\ ={  
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} RZ?abE8  
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< WQ ~X<1D  
public static void main(String[] args) ~@"H\):/  
{ 5W09>C>OC  
new TestMethod(); @\U] hN?  
} $WsyAUl  
} 3k:`7E.  
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