http断点续传简单实现（java)

/* D|rcSa.M  
**SiteFileFetch.java 1ps_zn(  
*/ JU\wvP5j  
package NetFox; jXALN  
import java.io.*; dgsD~.((A  
import java.net.*; X*Dt<i};v  
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public class SiteFileFetch extends Thread { TDnbX_xC<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Yt% E,U~g  
long[] nStartPos; //开始位置 ZUxlk+o9d  
long[] nEndPos; //结束位置 !ii'hwFm$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 oHI/tS4 _  
long nFileLength; //文件长度 ]psx\ZMa  
boolean bFirst = true; //是否第一次取文件 e:H9!  
boolean bStop = false; //停止标志 SuU %x2  
File tmpFile; //文件下载的临时信息 jQ[M4)>_k`  
DataOutputStream output; //输出到文件的输出流 +HxL>\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） eg vgi?y  
public SiteFileFetch(SiteInfoBean bean) throws IOException _$Hx:^p:  
{ KB^i=+xr  
siteInfoBean = bean; |#D$9+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fW'U7&O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 999E0A$dkv  
if(tmpFile.exists ()) F6h|AF|"  
{ ;r}>1LhN  
bFirst = false; ;4rTm@6  
read_nPos(); !j|93*  
} HD95>%  
else _2C[F~ +l  
{ 2AZ)|dM'`  
nStartPos = new long[bean.getNSplitter()]; G,J~Ed  
nEndPos = new long[bean.getNSplitter()]; zrJ/Fs+s  
} u/2!v
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} |,wp@)e6h  
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public void run() A/4
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{ )|@ H#kv?  
//获得文件长度 [# '38  
//分割文件 0u'qu2mV  
//实例FileSplitterFetch +Eh^j3W  
//启动FileSplitterFetch线程 T]fu[yRVvg  
//等待子线程返回 Cp@' k;(  
try{ ?]#
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if(bFirst) Aj;F$(su  
{ G`HL^/Z*  
nFileLength = getFileSize(); bqt*d)$  
if(nFileLength == -1) tsA+B&R_]  
{ VYZkHjj)2i  
System.err.println("File Length is not known!"); #+- /0{HT  
} Aey*n=V4#F  
else if(nFileLength == -2) G}&{]w@  
{ :uD*Q/  
System.err.println("File is not access!"); #*<*|AwoW|  
} AGN5=K*D  
else d:"]*EZ [  
{ $`emP Hel  
for(int i=0;i<nStartPos.length;i++) <+QXGz1  
{ T&]J3TFJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 07_ym\N  
} 6DFF:wrm&  
for(int i=0;i<nEndPos.length-1;i++) .kO;9z\B  
{ ~Zc=FP:1  
nEndPos = nStartPos[i+1]; 9p#Laei].  
} wf<=rW'  
nEndPos[nEndPos.length-1] = nFileLength; rK%A=Q
 
} '$3]U5KOwK  
} +hIS
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//启动子线程 9;^r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) \P;%f

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{ aF9p%HPDw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?_L)|:WL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5UQz6D
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nStartPos,nEndPos,i); [`~E)B1Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >h0iq  
fileSplitterFetch.start(); R`wL%I!?f  
} 6_m5%c~;+r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \tj7Jy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "Z&-:1tP{9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #S/]=D  
nEndPos = " + nFileLength); hZE" 8%\q  
// fileSplitterFetch[nPos.length-1].start(); f;C*J1y  
p`
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//等待子线程结束 vap,)kILF  
//int count = 0; MqBA?7  
//是否结束while循环 J2$L[d^  
boolean breakWhile = false; +P?!yH,n  
>[=fbL@N<@  
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while(!bStop) ?v-( :OF  
{ RnN]m!"5  
write_nPos(); JM-spi o  
Utility.sleep(500); cY|?iEVs)  
breakWhile = true; pcd*K)  
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for(int i=0;i<nStartPos.length;i++) WB2An7i@"{  
{ IcM99'P(  
if(!fileSplitterFetch.bDownOver) L7
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{ R^
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breakWhile = false; gAA2S5th  
break; 8,Jjv
*  
} v+NdO$o  
} T[}A7a6g_  
if(breakWhile) X|}yp|  
break; /STFXR1@.u  
b]'Uv8fbF  
}Km+5'G'U  
//count++; cnQ;6LtFTz  
//if(count>4) c/Fy1Lv\  
// siteStop(); l,n0=Ew  
} jP?YV  
]d$:R`;  
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System.err.println("文件下载结束！"); 4+ BWHV  
} R36BvW0X  
catch(Exception e){e.printStackTrace ();} /DG+8u  
} ?v4-<ewD  
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 -a``  
//获得文件长度 eSNwAExm  
public long getFileSize() }Ut*Y*  
{ mR
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int nFileLength = -1; x;&01@m.  
try{ #-xsAKi  
URL url = new URL(siteInfoBean.getSSiteURL()); OOzk@j^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v=kQ/h  
httpConnection.setRequestProperty("User-Agent","NetFox"); -}u=tiNG  
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 L|hdV\  
int responseCode=httpConnection.getResponseCode(); H ?Vo#/  
if(responseCode>=400) F-L!o8o  
{ I}djDtJ  
processErrorCode(responseCode); SV2DvrIR  
return -2; //-2 represent access is error ,(H`E?m1w4  
} {tUjUwhz(  
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String sHeader; UF3g]>*  
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for(int i=1;;i++) )-D
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{ C
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); ldd|"[Ds  
sHeader=httpConnection.getHeaderFieldKey(i); ]ZV.@%+  
if(sHeader!=null) v6Vieo=  
{ J!O{.
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if(sHeader.equals("Content-Length")) ]ow$VF{y  
{ Gwyjie9t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [D!-~]5  
break; k9>2d'Q  
} O$F<x,  
} mlq+Z#9  
else h(q,-')l_  
break; 5Lmhip  
} pKeK6K\8  
}  -&N^S?  
catch(IOException e){e.printStackTrace ();} F1m 1%
  
catch(Exception e){e.printStackTrace ();} $AGW8"  
n}KF)W=  
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Utility.log(nFileLength); :<
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return nFileLength; 5c(mgEvq  
} Un[olp  
j#}wg`P"A  
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//保存下载信息（文件指针位置） e70#"~gt[  
private void write_nPos() _ELuQ>zM]+  
{ MIV<"A  
try{ L="ipM:Z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); h(M_ K  
output.writeInt(nStartPos.length); ^^q9+0@  
for(int i=0;i<nStartPos.length;i++) I-?PTr  
{ 0\qLuF[)  
// output.writeLong(nPos); R,]J~TfPK  
output.writeLong(fileSplitterFetch.nStartPos); x;Qs_"t];3  
output.writeLong(fileSplitterFetch.nEndPos); I},]Y~Y3  
} R^v-%mG9  
output.close(); uu5AW=j  
} MR=dQc  
catch(IOException e){e.printStackTrace ();} gLm ]*  
catch(Exception e){e.printStackTrace ();} 9%{V?r]k  
} %y7&~me  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() 54X=58Q  
{ '?j[hhfB-  
try{ ;kW+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F0.Rv):  
int nCount = input.readInt(); WruSL|4iH  
nStartPos = new long[nCount]; cSbyVC[r  
nEndPos = new long[nCount]; HPGIz!o  
for(int i=0;i<nStartPos.length;i++) V/p+Xv(Zt  
{ c(@(j8@S  
nStartPos = input.readLong(); _wp>AJ r  
nEndPos = input.readLong(); @ Sq =q=S  
} }PC_qQF  
input.close(); ID{62>R  
} }s9eRmJs  
catch(IOException e){e.printStackTrace ();} V-1H(wRu  
catch(Exception e){e.printStackTrace ();} 5|nT5oS  
} 4q9+a7@  
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private void processErrorCode(int nErrorCode) %S`ygc}|  
{ hg2a,EU\Z  
System.err.println("Error Code : " + nErrorCode); U z*7J  
} MNuBZnO  
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//停止文件下载 3np |\i  
public void siteStop() _Wb3,E a=  
{ 5L?_AUL  
bStop = true; `\p5!Iq Q  
for(int i=0;i<nStartPos.length;i++) G+_Q7-o&d6  
fileSplitterFetch.splitterStop(); k},@2#W]  
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} 8QJ^@|
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} "c9T4=]&t  
//负责部分文件的抓取 K2Z]MpLD  
**FileSplitterFetch.java #F|q->2`o  
*/ zl]Ic' _i  
package NetFox; (WCczXm)  
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import java.io.*; =<BPoGs5  
import java.net.*; S9 p*rk~  
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public class FileSplitterFetch extends Thread { w\K(kNd(  
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String sURL; //File URL
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long nStartPos; //File Snippet Start Position pu"m(9  
long nEndPos; //File Snippet End Position U} K]W>Z  
int nThreadID; //Thread's ID G?,b51"  
boolean bDownOver = false; //Downing is over <MQTOz oj  
boolean bStop = false; //Stop identical JEL.*[/  
FileAccessI fileAccessI = null; //File Access interface >s%&t[r6  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HV?Q{XK.b  
{ JK%Ua
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this.sURL = sURL; .:~{+ <*`  
this.nStartPos = nStart; (drDC1\  
this.nEndPos = nEnd; EGL7z`nt  
nThreadID = id; MnPk+eNJm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yq=rv$.s  
} |34M.YjA  
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public void run() %a=^T?8  
{ it.'.aK4  
while(nStartPos < nEndPos && !bStop) *[|a$W  
{ =C(((T.  
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try{ Hob n{E  
URL url = new URL(sURL); :z^,>So:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1sIPhOIys  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8XG|K`'u  
String sProperty = "bytes="+nStartPos+"-"; k .#I
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httpConnection.setRequestProperty("RANGE",sProperty); j /)A<j$  
Utility.log(sProperty); oc>N| ww:  
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InputStream input = httpConnection.getInputStream(); <*3#nA-O>i  
//logResponseHead(httpConnection); )JXlPU  
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byte[] b = new byte[1024]; VkD}gJY  
int nRead; Q`zW[Y&]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Gl6M(<f\5  
{ VBN=xg}  
nStartPos += fileAccessI.write(b,0,nRead); <hBd #J  
//if(nThreadID == 1) =M."^X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DX(!G a  
} kQ99{lH,5  
&
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Utility.log("Thread " + nThreadID + " is over!"); 8#ZF<BY  
bDownOver = true; `gX$N1(  
//nPos = fileAccessI.write (b,0,nRead); nrM_ay  
} 9>-]*7  
catch(Exception e){e.printStackTrace ();} ws([bS2h  
} ?3yrX_Qm{  
} (hi{i  
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//打印回应的头信息 IIY3/  
public void logResponseHead(HttpURLConnection con) |@Ze{\  
{ z5g4+y,  
for(int i=1;;i++) N Wf IRL  
{ j2`%sBo  
String header=con.getHeaderFieldKey(i); .L8g(F(=:  
if(header!=null) L#`Vr$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r!&}4lHYi  
Utility.log(header+" : "+con.getHeaderField(header)); s(8e)0Tl  
else '&!:5R59  
break; c2Yrg@) [  
} ~[Z,:=z  
} mO0}Go8  
.YlhK=d4  
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public void splitterStop() oqa8v6yG'  
{ 0]Qk*u<  
bStop = true; y7T<Auue`  
} V|vXxWm/  
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} )W^$7Em  
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62 9g_P)  
/* s-Qq#T  
**FileAccess.java kLe{3>}j  
*//文件访问(定位，写) 6^sH3=#  
package NetFox; i'3)5  
import java.io.*; b6d}<b9#  
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public class FileAccessI implements Serializable{ 'Gqo{wl  
4Cp)!Bq?/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M&}_3  
RandomAccessFile oSavedFile; f/670Acv  
long nPos; Vtv1{/@+c  
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public FileAccessI() throws IOException C#@-uo2  
{ srryVq
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this("",0); ]2rCn};  
} |F49<7XB[~  
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public FileAccessI(String sName,long nPos) throws IOException U"535<mR  
{ ]92=PA>75  
oSavedFile = new RandomAccessFile(sName,"rw"); >rY^Un{Z  
this.nPos = nPos; 3 p!t_y|SX  
oSavedFile.seek(nPos); jJV1 /]TJ  
} D77s3AyHK  
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public synchronized int write(byte[] b,int nStart,int nLen) e3WEsD+  
{ w"q^8"j!  
int n = -1; :_:o%  
try{ """pe+Y  
oSavedFile.write(b,nStart,nLen); KvumU>c#A  
n = nLen; 9)$g
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} 5s:g(gy3BR  
catch(IOException e) rih@(;)1  
{ /hYFOZ  
e.printStackTrace (); d0YQLh  
} XblZlWP#  
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return n; tja7y"(]  
} bO+e?&vQ%  
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} CcZM0  
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cd
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/* $9ys! <g  
**SiteInfoBean.java H^JFPvEc  
*/ KeWIC,kq  
package NetFox; ,p V3O`z  
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public class SiteInfoBean { y'_2|5!Qs  
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private String sSiteURL; //Site's URL w|:
ev_c|  
private String sFilePath; //Saved File's Path {j%7/T{  
private String sFileName; //Saved File's Name /\U:F  
private int nSplitter; //Count of Splited Downloading File Go !{T  
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public SiteInfoBean() S$qpClXS,  
{//nSplitter的缺省值为5 O)INM  
//default value of nSplitter is 5 UB]]oC<  
this("","","",5); vvP]tRZ  
} Bkdt[qDn5P  
-H$C3V3]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) > QK"r7f/  
{ 5UvqE_  
sSiteURL= sURL; Y{<SD-ibZ$  
sFilePath = sPath; 6*s:I&  
sFileName = sName; V82hk0*j  
this.nSplitter = nSpiltter; Z`>m  
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} sV`p3L8pl  
i!+0''i{#  
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public String getSSiteURL() Xj$'i/=-+c  
{ R_Uy.0=4  
return sSiteURL; fz<GPw  
} @"n]v)[4  
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public void setSSiteURL(String value) -_irkpdC[  
{ lbC9^~T+  
sSiteURL = value; /|8/C40aY  
} <X ([VZ  
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public String getSFilePath() HAAU2A9B2  
{ Wo~;h(6  
return sFilePath; g1&q6wCg|  
} > mEB,  
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public void setSFilePath(String value) S^nI=H
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{ Sw`+4 4  
sFilePath = value; ;Mz7emt  
} \`-a'u=S  
{tUxRX  
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public String getSFileName() {=9"WN
 
{ (1Klj+"p%  
return sFileName; dg4q+  
} 7,FhKTV1/  
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[BFPIVD)h]  
public void setSFileName(String value) Uwg*kJ3H  
{ &[kFl\  
sFileName = value; %wN*Hu~E
  
} 5-POYug  
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public int getNSplitter() iIc/%< ;  
{ %nyZ=&u  
return nSplitter; K$5mDScoJ  
} sv2XD}}  
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public void setNSplitter(int nCount) ?fQ8Ff  
{ ~r&+18Z;  
nSplitter = nCount; 7-d.eNQl  
} H.&"
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} 6)_h'v<|M  
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/* #^xj"}o@  
**Utility.java ~$m:j];  
*/ l{hO"fzy  
package NetFox; ISg-?h/  
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+$#ytvDy  
public class Utility { "-g5$v$de  
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public Utility() E6fs&  
{ 6\xfoy|j  
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jz,Gj}3;  
} zh9B8r)C  
SDko#  
//线程睡眠 s,H }km  
public static void sleep(int nSecond) a!\^O).pA  
{ (;(2n;i[M  
try{ WMnxN34  
Thread.sleep(nSecond); )3)x/WM  
} lFa?l\jLXZ  
catch(Exception e) _Q7]Dw/w\  
{ {2LV0:k2  
e.printStackTrace (); m3=Cg$n  
} [midNC+,  
} v;d3uunqv  
d^I:{Ii'  
//日志 c=33O,_  
public static void log(String sMsg) Z
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{ JdX!#\O  
System.err.println(sMsg); t!o=-k  
} Yduj3Ht:w  
9 !V,++j  
9(hI%idq  
public static void log(int sMsg) 4{LKT^(!f  
{ ~9c jc  
System.err.println(sMsg); :"`1}Q  
} VlS`m,:{  
} R{q<V uN  
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/* 5Vlm?mPU  
**TestMethod.java L | #"Yn  
*/ _C@<*L=Q  
package NetFox; 90gKGyxF  
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public class TestMethod { xmHW,#%ui\  
,soXX_Y>  
/@@?0xjX  
public TestMethod() \omfWW
pK  
{ ///xx/weblogic60b2_win.exe UD^
=@?^7  
try{ @*iT%p_L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [uFv_G{H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $>hH{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ORFi0gFbA  
fileFetch.start(); mX GW+  
} :.SwO<j  
catch(Exception e){e.printStackTrace ();} C^*}*hYk$  
-+kTw06_C  
@-.Tgpe@a  
} ;R^=($X  
k]S`A,~  
.5iXOS0 G  
public static void main(String[] args) $"fO/8Ex  
{ j){0>O.V  
new TestMethod(); PKYm{wO-  
} U%KsD 4B  
} fDwqu.K  
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