http断点续传简单实现（java)

/* :*cHA  
**SiteFileFetch.java 2`E!|X  
*/ .:[`j3s)Y  
package NetFox; b}}y=zO|$  
import java.io.*; v8  
import java.net.*; \OA L Or  
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public class SiteFileFetch extends Thread { dE GX3 -  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ZMJ3NN]F  
long[] nStartPos; //开始位置 ydup)[n  
long[] nEndPos; //结束位置 {lMqcK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MX?}?"y  
long nFileLength; //文件长度 5QOZ%9E&M  
boolean bFirst = true; //是否第一次取文件 ]!
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boolean bStop = false; //停止标志 Pt(tRHB  
File tmpFile; //文件下载的临时信息 3>M.]w6{  
DataOutputStream output; //输出到文件的输出流 }7Jp :.qk  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） i pwW%"6  
public SiteFileFetch(SiteInfoBean bean) throws IOException qw2)v*Fn  
{ p+)C$2YK  
siteInfoBean = bean; #@E(<Pu4`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sS|<&3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g&kH'fR8  
if(tmpFile.exists ()) SM
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{ zuMO1s  
bFirst = false; 7jT#BWt  
read_nPos(); E[ 0Sst x  
} {KsVK4\r  
else T\fudmj&  
{ Az9J\V~"  
nStartPos = new long[bean.getNSplitter()]; b*`fLrqV.  
nEndPos = new long[bean.getNSplitter()]; CC>($k"  
} 0Gx*'B=  
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} H4 =IY  
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public void run() $YPQC  
{ PF`:1;PU  
//获得文件长度 m|mG;8}pI  
//分割文件 hwp/jO:7\  
//实例FileSplitterFetch wa2~C [  
//启动FileSplitterFetch线程 Hva{A #  
//等待子线程返回 DP0Z*8Ia  
try{ 3<3t;&e  
if(bFirst) Z@u ;Z[@  
{ 'f8 p7_F  
nFileLength = getFileSize(); kR_E6Fl  
if(nFileLength == -1) m EFWo  
{ .T{U^0 )  
System.err.println("File Length is not known!"); >pnz_MQ  
} :/~_sJt C  
else if(nFileLength == -2)  X
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{ eWw y28t  
System.err.println("File is not access!"); }FZp840  
} g&P9UW>qS  
else -: C[P  
{ `!_?uT  
for(int i=0;i<nStartPos.length;i++) N4s$.`  
{ Nl=+.d6Qo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +yvBSpY  
} 0$!.c~
  
for(int i=0;i<nEndPos.length-1;i++) F; 0Dp
 
{ #|q;t   
nEndPos = nStartPos[i+1]; ,rXW`7!2  
} bu;vpNa  
nEndPos[nEndPos.length-1] = nFileLength; u$\Tg3du2  
} ~O8]3+U  
} >H8^0n)?  
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//启动子线程 ,znL,%s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z"+(LO!  
for(int i=0;i<nStartPos.length;i++) RBPYGu'6B  
{  eMztjN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /1U,+g^O>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aQC7V!v  
nStartPos,nEndPos,i); E|\3f(aF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K:C+/O  
fileSplitterFetch.start(); b\H/-7<  
} /oBK&r[(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H_v/}DEG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gZ=)qT]Pj  
nEndPos = " + nFileLength); ;wfH^2HxE)  
// fileSplitterFetch[nPos.length-1].start(); (]oFB$  
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//等待子线程结束 Og
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//int count = 0; oK%K+h  
//是否结束while循环 #xDDh`  
boolean breakWhile = false; +38Lojb}  
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while(!bStop) hl=oiUf[s  
{ x`wZtv\  
write_nPos(); Tm0?[[3hC  
Utility.sleep(500); 4{c`g$j>  
breakWhile = true; M,I68  
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for(int i=0;i<nStartPos.length;i++) |P^ikx6f5  
{  j@s=ER  
if(!fileSplitterFetch.bDownOver) &IxxDvP3k  
{ G;87in ,}  
breakWhile = false; ~y( ,EO  
break; @fUX
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} 9*"[pt+tA  
} W5M ]  
if(breakWhile) XT\Td}>  
break; `1}HWLBX.  
# r2$ZCo3o  
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//count++; 8.6no  
//if(count>4) 9N`+ O  
// siteStop(); Z1E`I89<  
} Q3'(f9 x  
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System.err.println("文件下载结束！"); WlF+unB!9  
} 56/.*qa  
catch(Exception e){e.printStackTrace ();} N^)<)?  
} btJ,dpir  
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//获得文件长度 ?
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public long getFileSize() /r#b  
{ U0lqGEZ  
int nFileLength = -1; $sB48LJuU'  
try{ My`josJ`Pb  
URL url = new URL(siteInfoBean.getSSiteURL()); $fq-wl-=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n3-GnVC][  
httpConnection.setRequestProperty("User-Agent","NetFox"); (Q*2dd>  
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int responseCode=httpConnection.getResponseCode(); `Pz!SJ|  
if(responseCode>=400) 5pN08+  
{ Off: ~  
processErrorCode(responseCode); )of5229  
return -2; //-2 represent access is error eHfG;NsV/  
} GFSlYG  
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String sHeader; 7M&.UzIY`  
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for(int i=1;;i++) w>1l@%Uo  
{ +?J_6Mo@X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,4h!"c  
//Utility.log(in.readLine()); #L).BM  
sHeader=httpConnection.getHeaderFieldKey(i); js%4;  
if(sHeader!=null) FcJ.)U  
{ ,Yiq$Z{qQ  
if(sHeader.equals("Content-Length")) U>3%!83kF  
{ 9g<_JcN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,_e/a
  
break; J7&.>y1%  
} =X%R*~!#Of  
} !/=9VD{U!  
else =l?"=HF  
break; m,kvEQ3  
} "OlI-^y  
} N`L' 4v)  
catch(IOException e){e.printStackTrace ();} VygXhh^7\  
catch(Exception e){e.printStackTrace ();} c DEe?WS  
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Utility.log(nFileLength); ID{Pzmt-  
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return nFileLength; _Oaso >  
} ZQJw2LAgO  
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//保存下载信息（文件指针位置） |n-a\  
private void write_nPos() 7!` C TE  
{ D{Jc+Q$  
try{ 
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output = new DataOutputStream(new FileOutputStream(tmpFile)); F(J!dG5#  
output.writeInt(nStartPos.length); '6Z/-V4k  
for(int i=0;i<nStartPos.length;i++) Xbsj:Ko]]U  
{ A<*tn?M
]  
// output.writeLong(nPos); *6\`A!C  
output.writeLong(fileSplitterFetch.nStartPos);
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output.writeLong(fileSplitterFetch.nEndPos); Nsy9 h}+A  
} Hi4@!]  
output.close(); 5G42vTDzS4  
} ;]O 7^s#v  
catch(IOException e){e.printStackTrace ();} QBBJ1U  
catch(Exception e){e.printStackTrace ();} [K|>s(Sf*  
} Br.$L  
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//读取保存的下载信息（文件指针位置） .ON$vn7  
private void read_nPos() *|.y
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{ Ow&'sR'CX  
try{ H?zCI
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); V=8{CmqT  
int nCount = input.readInt(); =:R[gdA#1  
nStartPos = new long[nCount]; BR0p0%  
nEndPos = new long[nCount]; zWR*g/i  
for(int i=0;i<nStartPos.length;i++) CH R?i1e  
{ ED
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nStartPos = input.readLong(); L}sm R,  
nEndPos = input.readLong(); 80l3.z,:  
}  vCH v  
input.close(); 1H2u,{O  
} qT-nD}  
catch(IOException e){e.printStackTrace ();} yrvSbqR  
catch(Exception e){e.printStackTrace ();} F" #3s=  
} ju2X*  
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private void processErrorCode(int nErrorCode) SJ|.% gn  
{ vng8{Mx90*  
System.err.println("Error Code : " + nErrorCode); >=q!!'$:  
} 6[Pr<4J  
%_X[{(  
%~v76;H<  
//停止文件下载 bMK'J  
public void siteStop() MdTd$ 4J3  
{ !?>p]0*<  
bStop = true;  "lnk  
for(int i=0;i<nStartPos.length;i++) Zn=JmZ  
fileSplitterFetch.splitterStop(); `a1R "A  
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} #}]il0d  
} 3E2.v5*  
//负责部分文件的抓取 %?{2uMfq-f  
**FileSplitterFetch.java 2*
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*/ sB1tce  
package NetFox; PFn[[~5V  
6s"bstc{  
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import java.io.*; JMe[ .Sx  
import java.net.*; `LHfAXKN  
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public class FileSplitterFetch extends Thread { !v;_@iW3e  
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String sURL; //File URL (R 2P<
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long nStartPos; //File Snippet Start Position R"kE5:  
long nEndPos; //File Snippet End Position Chi<)P$^  
int nThreadID; //Thread's ID 1Qe!  
boolean bDownOver = false; //Downing is over l?<z1Acd&  
boolean bStop = false; //Stop identical z{M,2  
FileAccessI fileAccessI = null; //File Access interface n[w,x;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException IF?B`TmZ  
{ 3*23+}^G  
this.sURL = sURL; r#w_=h)  
this.nStartPos = nStart; >mDubP  
this.nEndPos = nEnd; s/&]gj"  
nThreadID = id; &^D@(m7>{K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~E|V{z%  
} GpQF* x  
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public void run() o 0 #]EMr  
{ U$JIF/MO_  
while(nStartPos < nEndPos && !bStop) WsDe0F  
{ R3!vS+5rR  
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try{ `Q^Sm`R  
URL url = new URL(sURL); KIl.?_61O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M4PUJZ]  
httpConnection.setRequestProperty("User-Agent","NetFox"); iBW6<2@oZF  
String sProperty = "bytes="+nStartPos+"-"; RvZ-w$E&?  
httpConnection.setRequestProperty("RANGE",sProperty); e(% Solkm?  
Utility.log(sProperty); 1Moh`  
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InputStream input = httpConnection.getInputStream(); /+U)!$zm*  
//logResponseHead(httpConnection); SpiC0  
' 1]bjW*!  
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byte[] b = new byte[1024]; [MP:Eeg  
int nRead; 1e| M6*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g*imswj7
 
{ /%w[q:..h  
nStartPos += fileAccessI.write(b,0,nRead); AFJY!ou~6  
//if(nThreadID == 1) Yf`.Cq_:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D ;I;,Z  
} __%E!*m"<_  
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Utility.log("Thread " + nThreadID + " is over!"); (>`SS#(T!  
bDownOver = true; x`l; ;  
//nPos = fileAccessI.write (b,0,nRead); w:+#,,rwzV  
} Bzt`9lg  
catch(Exception e){e.printStackTrace ();} E}j8p_p  
} zFQkUgb  
} fzG1<Gem  
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/\I%)B47^9  
//打印回应的头信息 l#.,wOO{  
public void logResponseHead(HttpURLConnection con) RteTz_z{  
{ r@UY$z  
for(int i=1;;i++) M.^A`  
{ `bF;Ew;  
String header=con.getHeaderFieldKey(i); 2![W N*N>O  
if(header!=null) &bK$!8Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rM.<Gi05Qe  
Utility.log(header+" : "+con.getHeaderField(header)); cHct|Z u  
else )Dpt<}}\  
break; 3(p6ak2lv  
} Q8:ocEhR  
} o_m.MMEU  
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public void splitterStop() dph6aN(49  
{ k(+u"T  
bStop = true; )B4c;O4t  
} =nZd"t'p|  
CxQ,yd;>  
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} Bz~h-  
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/* E1g$Wh
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**FileAccess.java [&V%rhi  
*//文件访问(定位，写) S6X<3L`FfH  
package NetFox; Rx-i.EtZ  
import java.io.*; zD-8#H35X"  
+N_%|!F-c  
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public class FileAccessI implements Serializable{ 3<V!y&a  
#_\~Vrf(#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A@'W $p?5r  
RandomAccessFile oSavedFile; E=trJge  
long nPos; 6LQO>k  
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public FileAccessI() throws IOException RtL'fd  
{ _3[BS9  
this("",0); ^4NH.q{  
} qNL~m'  
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public FileAccessI(String sName,long nPos) throws IOException :h~!#;w_  
{ z(eAwmuli  
oSavedFile = new RandomAccessFile(sName,"rw"); S}O\<6&  
this.nPos = nPos; Ts6X:D4,  
oSavedFile.seek(nPos); V1;-5L75  
} 2jC\yY |PN  
WE]^w3n9  
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public synchronized int write(byte[] b,int nStart,int nLen) JqZ5DjI:  
{ _"V0vV  
int n = -1; lsi8?91  
try{ &0`7_g7G  
oSavedFile.write(b,nStart,nLen); &r%3)Z8Et  
n = nLen; `_i-BdW  
} JY16|ia  
catch(IOException e) `_`,XkpzCJ  
{ ic#drpl,  
e.printStackTrace (); @eWx4bl  
} i-b7  
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return n; Km-B=6*QY  
} Wz]S+IpY  
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} $n"Llw&)  
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V 
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/* vxx3^;4p  
**SiteInfoBean.java YSif`W!  
*/ Qrh9JFqdG6  
package NetFox; cj *4XYu  
,YTIYG](  
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public class SiteInfoBean { 3>6o=7/PU  
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b.;W|$.  
private String sSiteURL; //Site's URL 6wgOmyJx  
private String sFilePath; //Saved File's Path T\>=o]  
private String sFileName; //Saved File's Name ,}0pK\Y>$  
private int nSplitter; //Count of Splited Downloading File .bGeZwvf:G  
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public SiteInfoBean() b&1@rE-  
{//nSplitter的缺省值为5 S)%x22sqf  
//default value of nSplitter is 5 D~:fn|/Brp  
this("","","",5); s-B\8&^C  
} Xc^~|%+  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G
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{ icmDPq  
sSiteURL= sURL; |sh U  
sFilePath = sPath; 3[rB:cE/  
sFileName = sName; xo$ZPnf(zv  
this.nSplitter = nSpiltter; "K<VZ  
85mQH
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j^.P=;  
} RAC-;~$WB  
./d (@@  
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public String getSSiteURL() !MC Wt  
{ ]O."M"B  
return sSiteURL; @w0[5ZAj  
} "^H+A-R[  
\<} nn?~n  
L;"<8\vWB  
public void setSSiteURL(String value) jo^*R'}  
{ i*<,@*  
sSiteURL = value; @4i DN  
} i?>"}h  
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public String getSFilePath() !NCT) #G`  
{ M<"D!h9YP  
return sFilePath; DKZ69^  
} ARE~jzakg  
;Yj}9[p;T  
|1D`
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public void setSFilePath(String value) nCrNZ&P  
{ Mw~?@Sq  
sFilePath = value; J:5n/m^A  
} RjDFc:bB  
o;.-I[9h]  
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public String getSFileName() nTAsy0p]  
{ 2Y+*vNs3  
return sFileName; ZLkJYZk  
} j{g{`Qa  
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AS7!FD6b  
public void setSFileName(String value) eZcm3=WV|  
{ {x8`gP\H  
sFileName = value; XP7A.I#q0  
} 2B4c:jJ  
&eg,*K}'  
4Qv|Z+$i  
public int getNSplitter() `Ao:}  
{ t`AD9 H"\!  
return nSplitter; N]duv~JS  
} 1jL?z6S  
1pV"<,t  
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public void setNSplitter(int nCount) f_7p.H6\  
{ `&_qK~&/X  
nSplitter = nCount; 073(xAkL{  
} x\jHk}Buj  
} [V2l&ZUni  
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L
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/* (/Ubw4unI  
**Utility.java g@QpqrT  
*/ c|7Pnx%gT  
package NetFox; i`Tne3)  
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public class Utility { U2aE:$oeYi  

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public Utility() rdb%/@.-  
{ |3i~?] A  
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} <ESAoY"RPN  
4Mprc~ 7vr  
//线程睡眠 3!,%;Vz=  
public static void sleep(int nSecond) {\V)bizY;  
{ Di
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try{ t3M/ThIE  
Thread.sleep(nSecond); ,Xn%-OT  
} TX>;2S3q  
catch(Exception e) B0Z@ Cf  
{ #U1soZ7  
e.printStackTrace (); MwuH.# Ez  
} HV sIbQS  
} j.z#fU  
-X=f+4j  
//日志 Dx
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public static void log(String sMsg) g9gyWz  
{ b,cvQD  
System.err.println(sMsg); L$b9|j7  
} !O5UE  
.,c8cq?  
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public static void log(int sMsg) !yxb<  
{ a%AU9?/q#  
System.err.println(sMsg); C{c (K!  
} :70oO}0m.  
} u4S3NLG)  
dlWw=^  
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/* :>,d$f^tqE  
**TestMethod.java M6e"4Gh  
*/ H1l'\  
package NetFox; Ki'EO$  
@1>83-p"X  
w qsPGkJJ7  
public class TestMethod { S&VN</p  
]\jhtC=2  
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public TestMethod() 7DI8r|
~  
{ ///xx/weblogic60b2_win.exe E5o0^^  
try{ P`"dj@1'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9@h>_1RJz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0nv3JX^l]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G q8/xxt  
fileFetch.start(); nK:39D$(  
} 
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catch(Exception e){e.printStackTrace ();} %(NRH?  
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} ^iGIF~J9  
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@}FRiPo6  
public static void main(String[] args) S`J_}>  
{ BFMM6-Ve  
new TestMethod(); 
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} E J 9A 4B  
} %o?fE4o'  
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