http断点续传简单实现（java)

/* FnN@W^/z  
**SiteFileFetch.java bJJB*$jW=  
*/ m L#-U)?F  
package NetFox; !@9Vq6  
import java.io.*; d&:ABI  
import java.net.*; N5$L),?\y  
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public class SiteFileFetch extends Thread { [:x^ffs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^zv0hGk2  
long[] nStartPos; //开始位置 ?lJm}0>  
long[] nEndPos; //结束位置 KLW#+vZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7q>WO  
long nFileLength; //文件长度 S3V3<4CB  
boolean bFirst = true; //是否第一次取文件 w /$4 Rv+S  
boolean bStop = false; //停止标志 Y_3{\g|x  
File tmpFile; //文件下载的临时信息 uFDJRQJ<  
DataOutputStream output; //输出到文件的输出流 (|_1ku3!  
#?)g?u%g=  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &>UI{  
public SiteFileFetch(SiteInfoBean bean) throws IOException LXr yv;H  
{ b !FX]d1~k  
siteInfoBean = bean; _RT3Fk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *ip2|2G$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8=rD'*  
if(tmpFile.exists ()) 5Z]zul@+*  
{ :-B,Q3d  
bFirst = false; 0oI3Fb;E  
read_nPos(); 0Fr
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} A)/ 8FYc  
else ]iewukB4  
{ isaDIl;L/  
nStartPos = new long[bean.getNSplitter()]; a%"mgCB  
nEndPos = new long[bean.getNSplitter()]; ?mxBMtc  
} [A?Dx-R;(  
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} hqW4.|&\c  
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public void run() b4GD}kR  
{ ?;pw*s1Atz  
//获得文件长度 `y5?lS*  
//分割文件 Ca]+*Eb9z{  
//实例FileSplitterFetch 1 "'t5?XW  
//启动FileSplitterFetch线程 t|Cp<k]B  
//等待子线程返回 4,CQJ  
try{ RG [*:ReB9  
if(bFirst) \ct)/  
{ . :Q[Z  
nFileLength = getFileSize(); J0BA@jH5  
if(nFileLength == -1) %$/t`'&o-  
{ QiB^U^f  
System.err.println("File Length is not known!"); &kKopJH  
} 6/^$SWd2  
else if(nFileLength == -2) ',L>UIXw  
{ (Zi(6 T\z  
System.err.println("File is not access!"); SoZ$1$o2  
} tz&'!n}  
else hsIC5@s3  
{ X~ n=U4s}O  
for(int i=0;i<nStartPos.length;i++) C8qA+dri  
{ iiS^xqSNCt  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {ndL]c'v  
} Z-3i -(  
for(int i=0;i<nEndPos.length-1;i++) ]-d:wEj  
{ UR|UGldt_T  
nEndPos = nStartPos[i+1]; %~uMa  
} U4]>8L  
nEndPos[nEndPos.length-1] = nFileLength; _=9o:F  
} EoM}Co  
} vL"U=Q+/eY  
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2P9gS[Ub  
//启动子线程 7=yC*]BH-=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HMyw:?  
for(int i=0;i<nStartPos.length;i++) H^cB?i  
{ BX :77?9,+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aBk~/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o@TxDG  
nStartPos,nEndPos,i); 7'pCFeA>=T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &{${Fq
 
fileSplitterFetch.start(); <fq?{z  
} MW|Qop[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E)liuu!qI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OYKeu(=L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tFLdBv!=:^  
nEndPos = " + nFileLength); %/KN-*  
// fileSplitterFetch[nPos.length-1].start(); <Z%iP{  
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/ sI0{  
//等待子线程结束 S-{3'D[Nj  
//int count = 0; F3*
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//是否结束while循环 \ FW{&X9a  
boolean breakWhile = false; 0{bGVLp  
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while(!bStop) xBH`=e<  
{ R*~<?}Rr  
write_nPos(); b~?FV>gl  
Utility.sleep(500); u
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breakWhile = true; :A%|'HxH3  
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for(int i=0;i<nStartPos.length;i++) iHy=92/Ww  
{ kfaRN^  
if(!fileSplitterFetch.bDownOver) KLpu7D5(|  
{ w'[lIEP 2$  
breakWhile = false; (=:9pbP  
break; ax{+7 k  
} Kn~f$1  
} 2\h]*x%:  
if(breakWhile) QI*Y7R~<  
break; v;.7-9c*  
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p%) 1(R8qM  
//count++;
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//if(count>4) GKf,1kns  
// siteStop(); k(|D0%#b7  
} 69{^Vfd;Y  
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System.err.println("文件下载结束！"); 7{HJjH!zx  
} y
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catch(Exception e){e.printStackTrace ();} vto^[a6?  
} g{K*EL<  
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//获得文件长度 J#DYZ>}Y  
public long getFileSize() Zcq'u jU  
{ 7PG&G5  
int nFileLength = -1; 
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try{ b4`t, D  
URL url = new URL(siteInfoBean.getSSiteURL()); lUWX[,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); le%&r  
httpConnection.setRequestProperty("User-Agent","NetFox"); r7w1~z  
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int responseCode=httpConnection.getResponseCode(); \T)
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if(responseCode>=400) "~~Js~  
{ JWhi*je  
processErrorCode(responseCode); TR:V7d  
return -2; //-2 represent access is error 9W3zcL8  
} wc7gOrPpm  
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String sHeader; ~#/NpKHT@A  
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for(int i=1;;i++) =0,:w(Sb!  
{ v'`VyXetl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hM~9p{O  
//Utility.log(in.readLine()); 2pR+2p`  
sHeader=httpConnection.getHeaderFieldKey(i); `I|$U)'  
if(sHeader!=null) (V2~txMh  
{ b77
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if(sHeader.equals("Content-Length")) &NbhQY`k  
{ |F)BKo D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  ismx evD  
break; ,CiN@T \&  
} 0XV8B  
} )}QtK+Rq  
else olc7&R  
break; 0mcZe5RS  
} 'Fi\Qk'D@  
} jWHv9XtW  
catch(IOException e){e.printStackTrace ();} C3EQzr`  
catch(Exception e){e.printStackTrace ();} #-S%aeB  

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Utility.log(nFileLength); ykFm$ 0m+I  
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return nFileLength; K q;X(&Z  
} v@_}R_pX  
%j3XoRex><  
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//保存下载信息（文件指针位置） z ((Y\vP  
private void write_nPos() $['_m~ 2  
{ s~N WJ*i  
try{ e}%~S9\UL5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )l 0\TF  
output.writeInt(nStartPos.length); Nl~'W  
for(int i=0;i<nStartPos.length;i++) 1/b5i8I2v  
{ )b^yAzL?
 
// output.writeLong(nPos); 1F`1(MYt9  
output.writeLong(fileSplitterFetch.nStartPos); a3t[Tk;  
output.writeLong(fileSplitterFetch.nEndPos); P)7:G?OTx  
} u.!}s2wT#  
output.close(); )anprhc  
}  bT(}=j  
catch(IOException e){e.printStackTrace ();} 8YroEX[5l  
catch(Exception e){e.printStackTrace ();} #-T xhwYs  
} WdQR^'b$  
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}N@8zB~X  
//读取保存的下载信息（文件指针位置） AlZ]UGf^  
private void read_nPos() fpd4 v|(  
{ a=m4)tjk  
try{ ?T.'  q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3zC<k2B  
int nCount = input.readInt(); p'SclH[
 
nStartPos = new long[nCount]; b;kgP`%%  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) +5AWX,9,-  
{ l@
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nStartPos = input.readLong(); {'O,G$Ldkr  
nEndPos = input.readLong(); jL^3/0"o  
} e,J q<=j  
input.close(); #)A.yK`u  
} Cp!bsasj  
catch(IOException e){e.printStackTrace ();} e`]x?t<U4/  
catch(Exception e){e.printStackTrace ();} k*xMe-  
} K
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private void processErrorCode(int nErrorCode) d@d\9*mn  
{ _]oNbcbt(  
System.err.println("Error Code : " + nErrorCode); 42E%&DF  
} EV=/'f[++  
&k\`!T
1  
X ? eCK,  
//停止文件下载 |aD8  
public void siteStop() tk]>\}%  
{ 1}=@';cK*  
bStop = true; <c;U 0! m  
for(int i=0;i<nStartPos.length;i++) 4$~A%JN3  
fileSplitterFetch.splitterStop(); m$XMq  
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} )4O>V?B  
} $U*b;'o  
//负责部分文件的抓取 (U`<r-n\n  
**FileSplitterFetch.java jWpm"C  
*/ _bsAF^ ;  
package NetFox; UnVYGch  
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import java.io.*; eDkJ+5b  
import java.net.*; :{8,O-  
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public class FileSplitterFetch extends Thread { =lb5 #  
}Od=WQv+  
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String sURL; //File URL AHB_[i'>7  
long nStartPos; //File Snippet Start Position z^,P2kqK_  
long nEndPos; //File Snippet End Position K;L6<a A#  
int nThreadID; //Thread's ID !c2<-3e  
boolean bDownOver = false; //Downing is over O su 75@3  
boolean bStop = false; //Stop identical $^K12Wcp-  
FileAccessI fileAccessI = null; //File Access interface lVptA3
F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $cSmubZK  
{ }uFV\1  
this.sURL = sURL; \281X  
this.nStartPos = nStart; SJ7-lben3  
this.nEndPos = nEnd; +,q#'wSQG  
nThreadID = id; RKb{QAK!v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ->9waXRDz)  
} R+&{lc  
NG+%H1!$_  
}q?*13iy(  
public void run() >1*Dg?/=S  
{ ^ }kqAmr  
while(nStartPos < nEndPos && !bStop) M&SY2\\TB  
{ 2Q;g|*]  
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try{ ZCAg)/  
URL url = new URL(sURL); APUpqY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &iTTal.6  
httpConnection.setRequestProperty("User-Agent","NetFox"); MhDPf]` Gg  
String sProperty = "bytes="+nStartPos+"-"; n!?^:5=s  
httpConnection.setRequestProperty("RANGE",sProperty); ?910ki_  
Utility.log(sProperty); zqCr'$  
k
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InputStream input = httpConnection.getInputStream(); Q=u [j|0mc  
//logResponseHead(httpConnection);  [1Q:  
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byte[] b = new byte[1024]; ]|8*l]oc  
int nRead; Sp-M:,H3H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Yu+;vjbK-  
{ [M#I Nm}  
nStartPos += fileAccessI.write(b,0,nRead); *|B5,Ey  
//if(nThreadID == 1) gR76g4|=;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dUc?>#TU  
} 3kJ7aBiR<  
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Utility.log("Thread " + nThreadID + " is over!"); YgLHp/  
bDownOver = true; =`+c}i?  
//nPos = fileAccessI.write (b,0,nRead); p?,T%G+gqO  
} N"Cd{3  
catch(Exception e){e.printStackTrace ();} $wm8N.I3I  
} K<vb4!9Z9  
} G\C>fwrP_  
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//打印回应的头信息 {C'9?4&  
public void logResponseHead(HttpURLConnection con) 7<zI'^l  
{ Ksb55cp`  
for(int i=1;;i++) ;\54(x}|K  
{ z)f
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String header=con.getHeaderFieldKey(i); yP"D~u  
if(header!=null) ./_4D}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;~"#aL50fe  
Utility.log(header+" : "+con.getHeaderField(header)); OV`#/QL  
else UNCI"Mjb  
break; XQStlUw8+  
} t@cImmh\T  
} \~#$o34V  
t-Zk)*d/0  
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public void splitterStop() *n*po.Xr  
{ {SwvUWOf"  
bStop = true; !glGW[r/7  
} "vF7b|I  
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} i{MzQE+_^  
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/* D {N,7kT  
**FileAccess.java qM9> x:V  
*//文件访问(定位，写) ]}9D*V  
package NetFox; aMO+y91Y(  
import java.io.*; - -ZSl  
%&&;06GU}  
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public class FileAccessI implements Serializable{ ,K8(D<{  
=P`l+k3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V~4yS4  
RandomAccessFile oSavedFile; *GC9o/  
long nPos; .ZVo0  
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public FileAccessI() throws IOException m ol|E={si  
{ 9D H
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this("",0); R zn%!d^$>  
} !^IAn  
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(I ~r~5^  
public FileAccessI(String sName,long nPos) throws IOException :M\3.7q  
{ I7HP~v~  
oSavedFile = new RandomAccessFile(sName,"rw"); jB0ED0)wX  
this.nPos = nPos; t4FaU7  
oSavedFile.seek(nPos); 5tcJTz  
} &)F#cVB  
jbs)]fqC;  
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public synchronized int write(byte[] b,int nStart,int nLen) -n]E
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{ ;0Mg\~T~'  
int n = -1; > m##JzWLr  
try{ NSDls@m  
oSavedFile.write(b,nStart,nLen); l3;MjNB^V  
n = nLen; ky{-NrK  
} 8BggK6X  
catch(IOException e) dH+o
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{ >@i{8AD  
e.printStackTrace (); 4qmaL+Q  
} )/4U]c{-  
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return n; '/Ag3R  
} ~/1
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} 4<l&cP  
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/* /+{1;}AT  
**SiteInfoBean.java O K2|/y  
*/ +
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package NetFox; > @n?W"  
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%#-'|~  
public class SiteInfoBean { 6),VN>j  

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private String sSiteURL; //Site's URL `'}c- Q  
private String sFilePath; //Saved File's Path +,A7XBn  
private String sFileName; //Saved File's Name ~4C:2  
private int nSplitter; //Count of Splited Downloading File bT#re  
vGI?X#w3  
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public SiteInfoBean() @g==U{k;
t  
{//nSplitter的缺省值为5 <s(<ax30  
//default value of nSplitter is 5 ,]8$QFf  
this("","","",5); Q(7M_2e7  
} [;8vO=Z  
zx=AT
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]q|^?C  
{ V.12  
sSiteURL= sURL; ~@N0$S  
sFilePath = sPath; RlnJl
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sFileName = sName; /{+77{#Qn  
this.nSplitter = nSpiltter; nN[gAM (  
.m \y6  
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} q+}
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public String getSSiteURL() k=r)kkO)  
{ Fmu
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return sSiteURL; g xf|L>=  
} *w_f-YoXp  
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public void setSSiteURL(String value) ? bnhx  
{ 4.}J'3 .  
sSiteURL = value; z8\;XR  
} Ss c3uo0  
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public String getSFilePath() \`$RY')9|!  
{ sCwX|  
return sFilePath; EABy<i  
} 'q9='TOk  
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public void setSFilePath(String value) 9;k!dM  
{ ^lCQHz  
sFilePath = value; GO=3<Q{;  
} )OgQ&,#  
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public String getSFileName() dLIZ)16&  
{ c<n <!!
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return sFileName; x0dO^D  
} #}U*gVYe  
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public void setSFileName(String value) UM QsYD)  
{ 56Gc[<nR  
sFileName = value; ("$ ,FRTQ:  
} __N#Y/e ]  
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public int getNSplitter() 1=.+!Tg  
{ b3RCsIz  
return nSplitter; Z UCz-53  
} &T)h9fyc  
0zvA>4cq)  
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public void setNSplitter(int nCount) 84uHK)h<%  
{ pHkhs{/X  
nSplitter = nCount; 3(/J(8  
} gkN )`/`*  
} !YCus;B~  
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/* V=LJ_T"z0  
**Utility.java si|DxDx  
*/ wqyrs|P  
package NetFox; pg;y\}  
2|C(|fD4  
"/MA.zEl0,  
public class Utility { v1Wz#oP  
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public Utility() 4`Z8EV  
{
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} ejuw+@ _  
k_}aiHdG  
//线程睡眠 Im*~6[  
public static void sleep(int nSecond) Zg#VZg1 2  
{ h72#AN  
try{ 78[5@U  
Thread.sleep(nSecond); hL8GW> `a  
} D)*OQLHW  
catch(Exception e) ]J%p&y+6  
{ @&G< Np
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e.printStackTrace (); ZC\&n4~7  
} [c=T)]E1  
} n6f  
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//日志 S`qa_yI)Ed  
public static void log(String sMsg) n,E=eNc  
{ |
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System.err.println(sMsg); vS$_H<;P  
} `0qBuE_^h  
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.h;PMY+  
public static void log(int sMsg) *+wGXm  
{ Pfv| K;3i  
System.err.println(sMsg); ^bjaa  
} '`K-rvF,C  
} apxY2oE&  
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?B!=DC@?H  
/* Zoi\r  
**TestMethod.java l1h;ng6  
*/ g[d.lJ=Q-N  
package NetFox; I|#1u7X%]  
\~#$$Q-qtU  
;HOOo>%_K  
public class TestMethod { %di]1vQ  
U(jZf{`Mz  
! 9U  
public TestMethod() 4CT _MAj  
{ ///xx/weblogic60b2_win.exe > (.V(]{3y  
try{ _FJ,, /~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \z4I'"MC.9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @@O=a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #
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fileFetch.start(); dD Zds k+!  
} HaUfTQ8  
catch(Exception e){e.printStackTrace ();} ZM~kc|&  
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} BV8-\R@  
?1G7=R  
79?%g=#=  
public static void main(String[] args) EMV<PshW=  
{ Y8Bc &q}  
new TestMethod(); hLZ<h7:  
} ?y@RE  
} NPL(5@  
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