http断点续传简单实现（java)

/* S6yLq|W0  
**SiteFileFetch.java ~^~+p  
*/ ,I f9w$(z  
package NetFox; W\ARCcTQ  
import java.io.*; ))6iVgSE$  
import java.net.*; kQ6YQsJ.*  
!*k'3rKOW  
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public class SiteFileFetch extends Thread { 2F,?}jJ.K  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |JUAR{  
long[] nStartPos; //开始位置 RDqQ6(e"  
long[] nEndPos; //结束位置 :WSszak  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 tF!C']  
long nFileLength; //文件长度 }"^d<dvuz  
boolean bFirst = true; //是否第一次取文件 .X4UDZQg  
boolean bStop = false; //停止标志 y 0fI7:e3  
File tmpFile; //文件下载的临时信息 0)|;uW  
DataOutputStream output; //输出到文件的输出流 =\jPnov!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） te3\MSv;O  
public SiteFileFetch(SiteInfoBean bean) throws IOException !V0)
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{ _cc9+o  
siteInfoBean = bean; wqQrby<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >$A,B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); VsRdZ4  
if(tmpFile.exists ()) N?%FVF  
{ kgFx  
bFirst = false; _~b]/]|z#N  
read_nPos(); Oim
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} (Vy`u)gG  
else M ~6k[ew  
{ Ot!*,%sjQ  
nStartPos = new long[bean.getNSplitter()]; <;E>1*K}8  
nEndPos = new long[bean.getNSplitter()]; Z#_VxA>]v  
} $olITe"$g  
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} |0N1]Hf  
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public void run() <K~mg<ff$  
{
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//获得文件长度 PKNpR  
//分割文件 Si[xyG6=  
//实例FileSplitterFetch uI&<H T?
 
//启动FileSplitterFetch线程 IlP@a[:_  
//等待子线程返回 9Or  
try{ l:"zYcp%  
if(bFirst) (qy82F-|2  
{ x4S0C[k  
nFileLength = getFileSize(); TSYe~)I  
if(nFileLength == -1) a)M#O\i`  
{ rt!Uix&  
System.err.println("File Length is not known!"); vqBT^Q_q;  
} G2_l}q~  
else if(nFileLength == -2) kF"G {5  
{ k/#321Z  
System.err.println("File is not access!"); JclG*/Wjg4  
} %-, -:e  
else ~]lVixr9  
{ 8` f=Eh  
for(int i=0;i<nStartPos.length;i++) P'CDV3+  
{ -]vPF|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <<ifd?  
} zE4TdT1y|  
for(int i=0;i<nEndPos.length-1;i++) vZ2/>}!Z=  
{ 4>8'.8S  
nEndPos = nStartPos[i+1]; tv7A&Z)Rh  
} iN@+,]Yjl  
nEndPos[nEndPos.length-1] = nFileLength; JlN<w  
} T! fF1cpF\  
} gJI(d6  
!T8h+3I  
9^1.nE(R&  
//启动子线程 yBxWBW*e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nQ^<h
.  
for(int i=0;i<nStartPos.length;i++) [n;GP@A]R  
{ |R$/oq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p7Q %)5o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Wfyap)y  
nStartPos,nEndPos,i); M8' GbF=1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sAU!u  
fileSplitterFetch.start(); 0hx EI  
} ni
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \A9hYTC)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p4'Qki8Hd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lip1wR7  
nEndPos = " + nFileLength); $P%b?Y/  
// fileSplitterFetch[nPos.length-1].start(); f^[:w1X$sM  
OQm-BL  
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//等待子线程结束 XDrNc!XN  
//int count = 0; 4^rO K  
//是否结束while循环  } h0 )  
boolean breakWhile = false; O E56J-*}x  
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while(!bStop) H-aSLc  
{ WAt| J2  
write_nPos(); } h pTS_  
Utility.sleep(500); Y^W.gGM  
breakWhile = true; ^l"  
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for(int i=0;i<nStartPos.length;i++) `^7ARr/  
{ LlfD>cN  
if(!fileSplitterFetch.bDownOver) DsP FBq  
{ KD5}Nk)t  
breakWhile = false; }vLK-Vv  
break; Vr=c06a2  
} U[ $A=e?\Y  
} N [iv.B  
if(breakWhile) ;^j2>Azn  
break; $5)ZaYx<  
]B"YW_.x2  
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//count++; H7"m/Bia  
//if(count>4) <_"^eF+fZ  
// siteStop(); E1e#E3Yq}s  
} T m0m$l  
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System.err.println("文件下载结束！"); T]tG,W1>i  
} Gf{FFIe
(  
catch(Exception e){e.printStackTrace ();} g^EkRBU  
} U0kEhMIIf  
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//获得文件长度 szy^kj^2  
public long getFileSize() 9"YOj_z  
{ s
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int nFileLength = -1; ITu6m<V  
try{ .w`1;o  
URL url = new URL(siteInfoBean.getSSiteURL()); 'h&"xXv4|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =fZ)2q  
httpConnection.setRequestProperty("User-Agent","NetFox"); okO^/"  
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int responseCode=httpConnection.getResponseCode(); loLN ~6  
if(responseCode>=400) L[Dr[  
{ W
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processErrorCode(responseCode); aQK>q. t  
return -2; //-2 represent access is error aBO%qmtt  
} MWS=$N)v*  
)"IBw0]  
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String sHeader; *y;(c)_w/%  
2vit{  
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for(int i=1;;i++) 9aE!! (E  
{ 6_# >s1`R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d|9B3I*I  
//Utility.log(in.readLine()); Lit@ m2{\  
sHeader=httpConnection.getHeaderFieldKey(i); tDl1UX  
if(sHeader!=null) 9(>l trA  
{ S"Dw8_y7}  
if(sHeader.equals("Content-Length")) CR-6}T  
{ QJaF6>m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XD8MF)$9  
break; tp,e:4\8Q  
} +([ iCL  
} CmNd0S4v  
else x*A_1_A  
break; $~V,.RD  
} 'ju{j`b  
} Rmrv@.dr!  
catch(IOException e){e.printStackTrace ();} >!vb;a!  
catch(Exception e){e.printStackTrace ();} P-?ya!@"  
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Utility.log(nFileLength); RfMrGC^?  
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return nFileLength; "`Q.z~  
} v}v! hs Q  
/\S1p3EW*  
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//保存下载信息（文件指针位置） IQFt4{aK3  
private void write_nPos() {o?+T);Z  
{ 6}YWM]c%  
try{ D|u! KH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0{/P1  
output.writeInt(nStartPos.length); f*VBSg[`  
for(int i=0;i<nStartPos.length;i++) g9fS|T  
{ m8q3Pp  
// output.writeLong(nPos); 7[wHNJ7)r  
output.writeLong(fileSplitterFetch.nStartPos); A d0dg2Gw  
output.writeLong(fileSplitterFetch.nEndPos); Cc?BJ  
} / ;U  
output.close(); B*+3A!{s  
} D2`tWRm0  
catch(IOException e){e.printStackTrace ();} ic}M)S FD;  
catch(Exception e){e.printStackTrace ();} 2l)J,z  
} K +oFu%  
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//读取保存的下载信息（文件指针位置） Y~qv 0O6K  
private void read_nPos() KKR@u(+"a  
{ _R!KHi  
try{ x<'(b7{U0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k\T,CZ<  
int nCount = input.readInt(); }*{@-v|_R  
nStartPos = new long[nCount]; s6(iiB%d  
nEndPos = new long[nCount]; D{&0r.2F  
for(int i=0;i<nStartPos.length;i++) 8#OcrJzC  
{ -uDB#?q:W  
nStartPos = input.readLong(); D@V1}/$UoN  
nEndPos = input.readLong(); '2u(fLq3h  
} xS) njuq4  
input.close(); `.f {V  
} |fMjg'%{}  
catch(IOException e){e.printStackTrace ();} "5]Fl8c?  
catch(Exception e){e.printStackTrace ();} _`>F>aP  
} :/N/u5.]  
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private void processErrorCode(int nErrorCode) j +j2_\  
{ *t{$GBP  
System.err.println("Error Code : " + nErrorCode); !c`KzqP  
} x/NR_~Rnk  
>^#OtFHuT)  
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//停止文件下载 289@O-  
public void siteStop() jXEuK:exQ  
{ Lw 7,[?,Z  
bStop = true; &u62@ug#}  
for(int i=0;i<nStartPos.length;i++) [E_eaez
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fileSplitterFetch.splitterStop(); ~+1t3M e  
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(3YI>/#  
} ;\@co5.=  
} olNgtSX  
//负责部分文件的抓取 =Rl?. +uE  
**FileSplitterFetch.java ~429sT(  
*/ <#U9ih 2  
package NetFox; sh []OSM
 
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import java.io.*; #rL%K3'  
import java.net.*; j rX.e  
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public class FileSplitterFetch extends Thread { &uwj&-u?  
{{b&l!  
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String sURL; //File URL C9-IJj  
long nStartPos; //File Snippet Start Position \{F{yq(  
long nEndPos; //File Snippet End Position u~#QvA~]  
int nThreadID; //Thread's ID vEJ2d&  
boolean bDownOver = false; //Downing is over 9$&+0  
boolean bStop = false; //Stop identical hlPZTr=a  
FileAccessI fileAccessI = null; //File Access interface 9Foo8e  
p`// *gl  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pyEi@L1p  
{ T:ye2yg  
this.sURL = sURL; /"A)}>a  
this.nStartPos = nStart; d'~sy>  
this.nEndPos = nEnd; 8}m bfuo1  
nThreadID = id; <szD"p|K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nJJ9>#<g$  
} Nf0'>`/  
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public void run() SG1o<#>  
{ $dAQ'\f7  
while(nStartPos < nEndPos && !bStop) >[ r TUn;  
{ | ,bCYK  
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i)nb^  
try{ 3,~M`~B  
URL url = new URL(sURL); Si,[7um  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YqsN#E3pf  
httpConnection.setRequestProperty("User-Agent","NetFox"); G[4TT#  
String sProperty = "bytes="+nStartPos+"-"; xOCHP|?  
httpConnection.setRequestProperty("RANGE",sProperty); OhmKjY/}  
Utility.log(sProperty); 'p=5hsG  
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InputStream input = httpConnection.getInputStream(); 7XKPC+)1ya  
//logResponseHead(httpConnection); Vv=/{31  
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byte[] b = new byte[1024]; WvG0hts=[  
int nRead; Lpw9hj|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;[%_sVIy  
{ RZm}%6##ZC  
nStartPos += fileAccessI.write(b,0,nRead); ]>R|4K_  
//if(nThreadID == 1) yT Pi/=G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (are2!Oq  
} !w['@x.  
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Utility.log("Thread " + nThreadID + " is over!"); KlMrM% ;y  
bDownOver = true; Z$R6'EUb1  
//nPos = fileAccessI.write (b,0,nRead); /\L|F?+@  
} R<VNbm;  
catch(Exception e){e.printStackTrace ();} -.A%c(|Q  
} P(I`^x  
} 5~T`R~Uqb  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) I`"8}d@Jm  
{ J+f .r|?  
for(int i=1;;i++) n}9vAvC  
{ 6AeX$>k+  
String header=con.getHeaderFieldKey(i); -lHSojq~H  
if(header!=null) fj X~"U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZD{%0uh  
Utility.log(header+" : "+con.getHeaderField(header)); +]|aACt]  
else hzIP ?0^E  
break; -x~h.s,  
} m9bR %j  
} &jCT-dj  
* z|i{=W F  
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public void splitterStop() fUQuEh5_  
{ q[4{Xh  
bStop = true; ^UP!y!&N  
} ,L#Qy>MOb  
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} '>[l1<d!G  
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t  
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/* UpL1C~&  
**FileAccess.java Qs2E>C  
*//文件访问(定位，写) yidUtSv=,  
package NetFox; FQdz":5  
import java.io.*; O9OD[VZk  
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public class FileAccessI implements Serializable{ =}N&c4I[j  
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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 fE"Q:K6r2  
RandomAccessFile oSavedFile; N9LBji;nH  
long nPos; j-wSsjLk  
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public FileAccessI() throws IOException ?>b>LDpx?  
{ L><# I  
this("",0); WP,Ll\K)7  
} {awv=s  
.`Ey'T_  
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public FileAccessI(String sName,long nPos) throws IOException D=}UKd  
{ %H=d_Nm{  
oSavedFile = new RandomAccessFile(sName,"rw"); C?@vBM}  
this.nPos = nPos; n_;qB7,,  
oSavedFile.seek(nPos); N3?hyR<T  
} SN!TE,=I  
6?y<F4  
qzk/P1{-  
public synchronized int write(byte[] b,int nStart,int nLen) 2E~WcB  
{ W.OcmA>x  
int n = -1; 5W/!o&x~7  
try{ 5WN^8`{'3  
oSavedFile.write(b,nStart,nLen); _ndc^OG  
n = nLen; y]
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} V<~.:G$3H  
catch(IOException e) <<#-IsT  
{ _'9
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e.printStackTrace (); [fF0Qa-  
} r':wq
 
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return n; 6"@+Jz  
} 0* Ox>O>  
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/  
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} C9^[A4O@X!  
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/* ovv<7`  
**SiteInfoBean.java .FUws  
*/ VO#x+u]/  
package NetFox; GT$.#};u  
+"8 [E~Bih  
)!+M\fT  
public class SiteInfoBean { 8U,VpuQ:  
[ kI|Thx  
sT.;*3{  
private String sSiteURL; //Site's URL H4%2"w6|!  
private String sFilePath; //Saved File's Path 0V*B3V<  
private String sFileName; //Saved File's Name sywSvnPuYZ  
private int nSplitter; //Count of Splited Downloading File Hc?8Q\O:  
RbPD3&.  
/Y=Cg%+  
public SiteInfoBean() f4A;v|5_  
{//nSplitter的缺省值为5 =l6aSr   
//default value of nSplitter is 5 cj ?aCVa  
this("","","",5); eVL#3|=  
} ${(v Er#}k  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ckR>ps[u  
{ \G}02h  
sSiteURL= sURL; 0#\K9|.  
sFilePath = sPath; ra87~kj<  
sFileName = sName; 8 xfn$  
this.nSplitter = nSpiltter; Y0nnn  
pq8XCOllXx  
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} k'O^HMAn!  
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public String getSSiteURL() f uzz3#  
{ )`,||sQ  
return sSiteURL; OIi8x? .~]  
} bv %Bo4s  
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[bE-Uu7q5P  
public void setSSiteURL(String value) Y j[M>v  
{ _~q!
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sSiteURL = value; .3xpDVW^e  
} ug?gVK  
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public String getSFilePath() p~(+4uA  
{ m Acny$u  
return sFilePath; UZcsMMKH  
} w'Y(doY,  
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public void setSFilePath(String value) -cDS+*[  
{ z{wW6sgPr  
sFilePath = value; P X9GiJN"  
} d|I_SI1  
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TA2HAMx)  
public String getSFileName() VO"/cG;]*  
{ 6JrwPZB  
return sFileName; Zv[D{  
} Y.}"<{RQ  
/l.:GH36f  
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public void setSFileName(String value) hc"l^a!7ic  
{ AN193o   
sFileName = value; kSW=DE|#}  
} L{pz)')I  
x*`S>_j27=  

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public int getNSplitter() |uUGvIsXn  
{ #%Hk-a=>)#  
return nSplitter; =g.R?H8cj5  
} I{bDa'rX  
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public void setNSplitter(int nCount) fyt ODsb>  
{
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nSplitter = nCount; ni2GZ<1j  
} q fc:%ks2  
} ye<b`bL2.  
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/* Fb2,2Px  
**Utility.java }na0  
*/ D_SXxP[! g  
package NetFox; >-&B#Z^,  
8k( zU>^  
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public class Utility { k kZ2Jxvx  
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public Utility() <mrvuWg0  
{ LoUHStt  
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J#>)+  
} a/\SPXQ/9  
x5w5xw  
//线程睡眠 &nV/XLpG  
public static void sleep(int nSecond) lQS(\}N  
{ ^cUmLzM  
try{ "h@=O c  
Thread.sleep(nSecond); #r|qitL3  
} R\a6#u3  
catch(Exception e) FmtgH1u:=  
{ I`~Giz7@  
e.printStackTrace (); ^ABtg#  
} t
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} n1!}d%:  
VGYx(  
//日志 k~0#Iy_{M  
public static void log(String sMsg) r*
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{ cv{icz,%w  
System.err.println(sMsg); 3u 'VPF2  
} 7"_m?c8  
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public static void log(int sMsg) aZ,j1j0p  
{ -lY,lC>{  
System.err.println(sMsg); exZgk2[0  
} 2jVvK"C  
} '^n,)oA/G  
.Ei#mG-=}&  

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/* !.G knDT  
**TestMethod.java cMfJq}C<  
*/ 3jqV/w[-  
package NetFox; #0"Pd8@  
e**<et.  
*g*~+B :  
public class TestMethod { \y(ZeNs  
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aMJW__,  
public TestMethod() ~W2Od2p!  
{ ///xx/weblogic60b2_win.exe sv.?C pE  
try{ 7;I;(iY  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]Sey|/@D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4C#r=Uw`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); eP|_  
fileFetch.start(); yMz dM&a!*  
} LE|DMz|J  
catch(Exception e){e.printStackTrace ();} Q\nIU7:bZ  
@CtnV|  
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} u}">b+{!  
H %Dcp#k  
[$DI!%e|  
public static void main(String[] args) zNO,vR[\  
{ x MFo  
new TestMethod(); U>i}C_7g  
} /u&7!>,  
} 0;L.h|R T(  
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