http断点续传简单实现（java)

/* x-T7 tr&(  
**SiteFileFetch.java 8Xa{.y"  
*/ H2{&da@D5  
package NetFox; zB8J|uG  
import java.io.*; .Fx-$Yqy  
import java.net.*; ~.Er  
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public class SiteFileFetch extends Thread { OzV|z/R2'  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #]2,1dJ  
long[] nStartPos; //开始位置 RY}:&vWDk  
long[] nEndPos; //结束位置 obK6GG?ZE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4oPr|OKj{*  
long nFileLength; //文件长度 b6^#{))"  
boolean bFirst = true; //是否第一次取文件 V9;O1  
boolean bStop = false; //停止标志 COL_c<\  
File tmpFile; //文件下载的临时信息 Bgs,6:  
DataOutputStream output; //输出到文件的输出流 a/Cc.s   
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,#.9^J  
public SiteFileFetch(SiteInfoBean bean) throws IOException b?:SCUI  
{  z:d+RMA  
siteInfoBean = bean; &ER,;^H`6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o(YF`;OhvS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Lf+3nN  
if(tmpFile.exists ()) 'ALe>\WO  
{ r5Xi2!  
bFirst = false; 4Y{&y6  
read_nPos(); ^}4ysw  
} -^,wQW:o)  
else 2+C8w%F8  
{ y^:6D(SR  
nStartPos = new long[bean.getNSplitter()]; W;T(q~XK  
nEndPos = new long[bean.getNSplitter()]; ?mh0^G  
} M5{vYk>,1Q  
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} aFDCVm%U|  
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public void run() hQLh}}B  
{ g?9%_&/})A  
//获得文件长度 ~p$ncIr2Q  
//分割文件 rm!.J0 X  
//实例FileSplitterFetch 9|2LuHQu+  
//启动FileSplitterFetch线程 ~c'R7E&Bfa  
//等待子线程返回 A[N>T\  
try{ F <.} q|b  
if(bFirst) m@y_Wt  
{ 4(p,@e
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nFileLength = getFileSize(); sX#
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if(nFileLength == -1) % ^&D,  
{ *Vp$#Rb  
System.err.println("File Length is not known!"); D}K/5iU]a  
} 1#jvr_ ga  
else if(nFileLength == -2) _R;+}1G/  
{ ^jg{MTa  
System.err.println("File is not access!"); dMoN1
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} vA#?\j2  
else Kvh6D"  
{ YL@d+ -\  
for(int i=0;i<nStartPos.length;i++) 1~9AQ[]w8  
{ ;aUI3n%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); mG+hLRTXP  
} !@@rO--&  
for(int i=0;i<nEndPos.length-1;i++) `*Jw[Bnh8  
{ Xj;5i Vq  
nEndPos = nStartPos[i+1]; Ge4tc  
} +( V+XT  
nEndPos[nEndPos.length-1] = nFileLength; R,ddH[3  
}
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} g<PdiVp+  

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//启动子线程 :]-? l4(%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AV?<D.<  
for(int i=0;i<nStartPos.length;i++) }S>:!9f  
{ z,/y2H2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M^~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gb@ |\n  
nStartPos,nEndPos,i); My\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); >jBnNA@  
} o!M*cyq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AZ
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T#w *5Qf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s*W)BK|+?  
nEndPos = " + nFileLength); ]<\; -i)  
// fileSplitterFetch[nPos.length-1].start(); Ow7I`#P  
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//等待子线程结束
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//int count = 0; G/C5o=cY  
//是否结束while循环 $;t#pN/`  
boolean breakWhile = false; Ss{  
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while(!bStop) YP vg(T  
{ Y&_1U/}h  
write_nPos(); 9=Rj9%  
Utility.sleep(500); L8j#lu  
breakWhile = true; N^8 lfc$a  
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for(int i=0;i<nStartPos.length;i++) },5
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{ ^,KN@  
if(!fileSplitterFetch.bDownOver) Q.[^5 8  
{ O@bDMg  
breakWhile = false; CmPix]YMQ  
break; ICgyCsZ,  
} ps6c>AN`A&  
} "Z6:d"S`  
if(breakWhile) t#h<'?\E  
break; VClw!bm  
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//count++; |_;Vb  
//if(count>4) D;Jb'Be  
// siteStop(); Zm@ O[:~  
} _A.?:'-  
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System.err.println("文件下载结束！"); E0*'AZi&  
} 4r [Tpb  
catch(Exception e){e.printStackTrace ();} md/Z[du:'  
} uz+b  
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//获得文件长度 RKP->@Gs  
public long getFileSize() 8_tMiIE-pS  
{ +xlxhF  
int nFileLength = -1; ~4iIG}Y<  
try{ Th%1eLQ  
URL url = new URL(siteInfoBean.getSSiteURL()); Tl3{)(ezx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0R2
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httpConnection.setRequestProperty("User-Agent","NetFox"); /-39od0  
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int responseCode=httpConnection.getResponseCode(); ^eEj 5Rh  
if(responseCode>=400) B"I>mw  
{ =`X@+~%-  
processErrorCode(responseCode); G K @]61b  
return -2; //-2 represent access is error f.=4p^  
} ZCMB]bL-e  
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String sHeader; $0Y&r]'  
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for(int i=1;;i++) 3HA$k[%7P  
{ [#td  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 05MtQB   
//Utility.log(in.readLine()); _rqOzE)  
sHeader=httpConnection.getHeaderFieldKey(i); va8V{q@t'  
if(sHeader!=null) zY|]bP[NEH  
{ -j[n^y'v  
if(sHeader.equals("Content-Length")) 5@Q4[+5&_  
{ *[7,@S/<F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kI3-G~2  
break; +2w54X%?M  
} `R^g[0 w'  
}
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else Y(SgfWeK@1  
break; tGd<{nF%2  
} 685o1c|  
} 38Z"9  
catch(IOException e){e.printStackTrace ();} XI\aZ\v  
catch(Exception e){e.printStackTrace ();} Rhx7eU#&  
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Utility.log(nFileLength); bYdC.AE  
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return nFileLength; WytCc>oL  
} n a2"Sy=Yi  
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//保存下载信息（文件指针位置） [ylGNuy  
private void write_nPos() :*&wnQMKR  
{ im+2)9f  
try{ J6[x(T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u?g!E."v  
output.writeInt(nStartPos.length); H8K<.RY  
for(int i=0;i<nStartPos.length;i++) @\!wW-:A  
{ ".xai.trr  
// output.writeLong(nPos); :Rt5=0x   
output.writeLong(fileSplitterFetch.nStartPos); Ai->,<Ig]  
output.writeLong(fileSplitterFetch.nEndPos); uU.9*B=H9  
} B;;D(NH  
output.close(); |-_5ouN.  
} 45j+n.9=  
catch(IOException e){e.printStackTrace ();} :/vB,JC  
catch(Exception e){e.printStackTrace ();} U&3*c+B4  
} !icpfxOpjQ  
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//读取保存的下载信息（文件指针位置） {u.V8%8  
private void read_nPos() 0uU%jN$  
{ kM3BP& 3m1  
try{ MmWJYF=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g-p OO/|  
int nCount = input.readInt(); SC2C%.%l`  
nStartPos = new long[nCount]; qqzQKN  
nEndPos = new long[nCount]; t48(GKF  
for(int i=0;i<nStartPos.length;i++) {C]M]b*F6(  
{ 4rM77Uw>  
nStartPos = input.readLong(); 1wc -v@E  
nEndPos = input.readLong(); -'PpY302  
} ;@d%<yMf@  
input.close(); XFu@XUk!K  
} 4E |6l  
catch(IOException e){e.printStackTrace ();} ;7`<.y  
catch(Exception e){e.printStackTrace ();} g=Qga09  
} z{#F9'\&  
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private void processErrorCode(int nErrorCode) )i_FU~ LRq  
{ INbjk;k  
System.err.println("Error Code : " + nErrorCode); \aZ(@eF@@Q  
} Ab2g),;c  
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//停止文件下载 5&X  
public void siteStop() V
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{ [QZ~~(R  
bStop = true; zt,-O7I'1  
for(int i=0;i<nStartPos.length;i++) n~&R_"mv(  
fileSplitterFetch.splitterStop(); 9uS7G*  

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} Tc88U8Gc  
} _).'SU)>  
//负责部分文件的抓取 99ha
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**FileSplitterFetch.java 'hekCZZ_I  
*/ ?Nh%!2n  
package NetFox; s3+O
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import java.io.*; 9wq%Fnt  
import java.net.*; ZM#WdP  
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public class FileSplitterFetch extends Thread { 1=;QWb6  
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String sURL; //File URL :>X7(&j8  
long nStartPos; //File Snippet Start Position !%u#J:z2  
long nEndPos; //File Snippet End Position 'd t}i<  
int nThreadID; //Thread's ID
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boolean bDownOver = false; //Downing is over M)J*Df0@  
boolean bStop = false; //Stop identical ^TEODKS  
FileAccessI fileAccessI = null; //File Access interface \W}EyA  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,#E5/'c`  
{ %UQ{'JW?K  
this.sURL = sURL; jO,<7FPs5  
this.nStartPos = nStart; aydal9M  
this.nEndPos = nEnd; r6$=|Yto  
nThreadID = id; 0wkLM-lN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eYcx+BJ  
} I)Lb"  
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public void run() ya_'
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{ U2AGH2emw  
while(nStartPos < nEndPos && !bStop) `{wku@  
{ kW!:bh  
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*(`.h\+  
try{ %f-<ol  
URL url = new URL(sURL); $dnHUBB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &!a2%%1#N  
httpConnection.setRequestProperty("User-Agent","NetFox"); lBn*G&(P  
String sProperty = "bytes="+nStartPos+"-"; iTt=aQjd  
httpConnection.setRequestProperty("RANGE",sProperty); 5HbTgNI  
Utility.log(sProperty); Eo Urc9G2  
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InputStream input = httpConnection.getInputStream(); cik@QN<[0
 
//logResponseHead(httpConnection); V[I<9xaE  
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byte[] b = new byte[1024]; ,xz^k/.  
int nRead; 68c;V
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yy
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{ .cF$f4>2  
nStartPos += fileAccessI.write(b,0,nRead); 2`I;f/Sd  
//if(nThreadID == 1) "?{yVu~9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d8kwW!m+  
} S1zw'!O5  
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Utility.log("Thread " + nThreadID + " is over!"); be/1-=m  
bDownOver = true; I.u,f:Fl'  
//nPos = fileAccessI.write (b,0,nRead); 3rY /6{  
} Mak9qaWqF>  
catch(Exception e){e.printStackTrace ();} >>bYg  
} _cw^5  
} kVrT?  
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//打印回应的头信息 tlER
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public void logResponseHead(HttpURLConnection con) y|Y3,s  
{ 1Kh?JH  
for(int i=1;;i++) 7h]R{_  
{ XC1lo4|  
String header=con.getHeaderFieldKey(i); erP>P  
if(header!=null) I|IlFu?O=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <e&QTyb  
Utility.log(header+" : "+con.getHeaderField(header)); aTh%oBrtP  
else s~$4bN>LD  
break; (YJAT  
} #=H}6!18  
} JX)z<Dz$  
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public void splitterStop() $l;t
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{ DiQkT R  
bStop = true;  GQ0(&I  
} W79A4l<  
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} ba9<(0`  
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/* 9BD|uU;0  
**FileAccess.java }PIB b  
*//文件访问(定位，写) (I[h.\%  
package NetFox; V&oT':%q  
import java.io.*; TcLaWf!c5  
H8BO*8}  
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public class FileAccessI implements Serializable{ `O=;
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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 z{3%Hq  
RandomAccessFile oSavedFile; /Tf*d>Yh;  
long nPos; ptcLJ]+)  
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public FileAccessI() throws IOException ,L{o,qzC  
{ b#;N!VX
 
this("",0); @!a]qAt  
} T7,Gf({  
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public FileAccessI(String sName,long nPos) throws IOException Px7g\[]  
{ inv{dg/2  
oSavedFile = new RandomAccessFile(sName,"rw"); _d0-%B 9m  
this.nPos = nPos; dezL{:Ya  
oSavedFile.seek(nPos); Vc52s+7=8  
} b)hOz
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public synchronized int write(byte[] b,int nStart,int nLen) ]6%%X+$7  
{ Q
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int n = -1; `?o1cf A  
try{ l&sO?P[ /  
oSavedFile.write(b,nStart,nLen); Xf_tj:eO~  
n = nLen; 5-5(`OZ{'  
} 1xdESorX(  
catch(IOException e) _IKP{WNB  
{ G2+)R^FSC  
e.printStackTrace (); D@(M+u9/%  
} ul=a\;3x#|  
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return n; ;*4tVp,  
} t6%xit+  
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} J]Gc  
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/* ^z%o];  
**SiteInfoBean.java }M9DqZ;I  
*/ Nzi/3r7m  
package NetFox; R3{*v =ov  
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public class SiteInfoBean { tY$ty0y-e  
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private String sSiteURL; //Site's URL 3^A/`8R7K  
private String sFilePath; //Saved File's Path ,F?~'-K  
private String sFileName; //Saved File's Name i9@;,4f  
private int nSplitter; //Count of Splited Downloading File b?2X>QJ  
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public SiteInfoBean() `^&1
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{//nSplitter的缺省值为5 B
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//default value of nSplitter is 5 ! F;<xgw  
this("","","",5); =wlm  
} o9T@uWh+  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8MeO U  
{ 17n+4J]  
sSiteURL= sURL; PK2R
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sFilePath = sPath; pRiH,:\  
sFileName = sName; 4l%?mvA^m  
this.nSplitter = nSpiltter; v`_i1h9p{  
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} =!g/2;-or  
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public String getSSiteURL() 0?6If+AC  
{ :?$Sb8OuIL  
return sSiteURL; ){:q;E]^fB  
} 47C(\\
 
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public void setSSiteURL(String value) %<=w[*i  
{ .o\;,l2  
sSiteURL = value; \`P2Yq  
} clq~ ;hx  
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public String getSFilePath() }rKJeOo^x?  
{ \8>  
return sFilePath; 0\EpH[m}-  
} k%Ma4_Z  
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public void setSFilePath(String value) *w'q   
{ Q3NPwM  
sFilePath = value; wr3_Bf3]  
} &O+sK4P  
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public String getSFileName() {z5V{M(|w3  
{ vgh^fa!/  
return sFileName; j.=UI-&m  
} |<j,Tr1[  
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public void setSFileName(String value) [l8V<*x%S9  
{ %k3NT~  
sFileName = value; ,>bGbx  
} [)Z'N/;0  
'!j #X_;  
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public int getNSplitter() `2B*CMW{  
{ i\kTm?BQZ  
return nSplitter; F,p`-m[q  
} DEUd[  
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public void setNSplitter(int nCount) toS(UM n  
{ ;Pol#0_(  
nSplitter = nCount; p3M#XC_H]  
} rxs~y{Xi  
} Z&+NmOY4  
/v}P)&  
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/* e-[>( n/[  
**Utility.java HG{&U:>)  
*/ ~w Zl2I  
package NetFox; ]dPVtk  
~`*1*;Q<H|  
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public class Utility { I! h(`  
'}U_D:o.b  
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public Utility() u-AWJc+F.  
{ V,>+G6e  
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} CCbkxHMf|!  
W4)kkJ  
//线程睡眠 0Y2\n-`z  
public static void sleep(int nSecond) g\ErJ+i
 
{ XIr{U5$<6  
try{ 2Pbe~[  
Thread.sleep(nSecond); Q)x?B]b-  
} w{k1Y+1  
catch(Exception e) RL?u n}Qa  
{ u] F70C^~  
e.printStackTrace (); Ni+3b  
} I#"t'=9H  
} L8K0^~Mk  
4`'8fe/"  
//日志 [8,PO  
public static void log(String sMsg) O0@w(L-  
{ 6OfdD
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System.err.println(sMsg); Yt
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} c u\ls^  
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public static void log(int sMsg) Ihdu1]~R{  
{ G
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System.err.println(sMsg); E|pk
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} VLf g
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} `@h:_d  
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/* .qSBh hH\  
**TestMethod.java 'I&|1I^  
*/ ,`;jvY~Ec  
package NetFox; ./#e1m?.  
'dkXYtKCB  
#2h+dk$1  
public class TestMethod { Ds{{J5Um%  
i\(\MzW*'  
M(qxq(#{U  
public TestMethod() PKi_Zh.D  
{ ///xx/weblogic60b2_win.exe GtF2@\  
try{ Z`rK\Bc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h2"9"*S1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -g:lOht  
SiteFileFetch fileFetch = new SiteFileFetch(bean); DKh}Y !Q=:  
fileFetch.start(); L'>s(CR  
} 1<`
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catch(Exception e){e.printStackTrace ();} w|=gSC-o  
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} (YIhTSL"]  
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public static void main(String[] args) `8,w[o oC2  
{ PfyRZ[3)c  
new TestMethod(); \ZS\i4  
} w TlGJ$D0  
} sYI~dU2H  
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