http断点续传简单实现（java)

/* ww2mL <B  
**SiteFileFetch.java VAPeMO ck  
*/ u`MMK4 %  
package NetFox; hD6
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import java.io.*; dNACE*g;q  
import java.net.*; lF}[ YL  
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public class SiteFileFetch extends Thread { (r|m&/  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k{' ZaP)  
long[] nStartPos; //开始位置 f$I=oN  
long[] nEndPos; //结束位置 { I#>6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 
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long nFileLength; //文件长度 0 QTI;3  
boolean bFirst = true; //是否第一次取文件 Y
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boolean bStop = false; //停止标志 kx,.)qKk  
File tmpFile; //文件下载的临时信息 xo>0j#  
DataOutputStream output; //输出到文件的输出流 Ho &Q}<(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） K%q5:9m  
public SiteFileFetch(SiteInfoBean bean) throws IOException rc_m{.b  
{ M @5&.  
siteInfoBean = bean; QLqtE;;)JK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J0xHpe  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &@iOB #H  
if(tmpFile.exists ()) nFnM9 pdMK  
{ ;;0'BdsL`  
bFirst = false; H|%J"  
read_nPos(); {npm9w<;  
} :=Olp;+_  
else *,\v|]fc  
{ IO)B3,g  
nStartPos = new long[bean.getNSplitter()]; 9q'9i9/3d  
nEndPos = new long[bean.getNSplitter()]; "U\RN  
} UtQj<18<  
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} x|O7}oj  
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public void run() yE}\4_0I/  
{ &8$v~  
//获得文件长度 *5)UIRd  
//分割文件 >Hf{Mx{<  
//实例FileSplitterFetch \jfK']P/H  
//启动FileSplitterFetch线程 (/:m*x*6  
//等待子线程返回 {JE [  
try{ IkCuw./  
if(bFirst) *yBVZD|?H  
{ %8*:VR  
nFileLength = getFileSize(); P
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if(nFileLength == -1) BA@E  
{ 56;u7  
System.err.println("File Length is not known!"); Oe5rRQ$O  
} u*C*O4f>OC  
else if(nFileLength == -2) ~$J;yo
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{ yqN`R\d  
System.err.println("File is not access!"); 2Q6;SF"Z  
} 
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else LG[N\%<!H  
{ .S//T/3O]Q  
for(int i=0;i<nStartPos.length;i++) s"jvO>[  
{ M}8P _<,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #9,8{ O"  
} g+#<;Gbpe  
for(int i=0;i<nEndPos.length-1;i++) h>pu^ `hk  
{ :-?ZU4)  
nEndPos = nStartPos[i+1]; Tg{5%~L]  
} #/oH #/?  
nEndPos[nEndPos.length-1] = nFileLength; +ktv:d  
} #W~jQ5NS\  
} sOhn@*X  
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//启动子线程 <K CI@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T5:Q_o]  
for(int i=0;i<nStartPos.length;i++) |Y3w6!$  
{ |=0vgwd"S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9pLe8D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x Lan1V  
nStartPos,nEndPos,i); ]0UYxv%]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); ;\K]~  
} TiD#t+g  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~4fE`-O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [Hh*lKg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iT'doF  
nEndPos = " + nFileLength); $_S-R 3L\  
// fileSplitterFetch[nPos.length-1].start(); #)'Iqaq7  
)LGVR3#  
. 1kB8&}  
//等待子线程结束 xJ>5 ol  
//int count = 0; D!.c??   
//是否结束while循环 Y(UK:LZ'  
boolean breakWhile = false; ,`f]mv l  
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, >7PG2 a  
while(!bStop) L3b0e_8>R  
{ (OiV IH  
write_nPos(); CnZ!b_J  
Utility.sleep(500); cN@_5  
breakWhile = true; 2;gvo*k  
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for(int i=0;i<nStartPos.length;i++) d88A.Z3w  
{ 9~hW
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if(!fileSplitterFetch.bDownOver) p{,#H/+J  
{ ny KfM5s_  
breakWhile = false; Z@s[8wrmPl  
break; vn}m-U XA*  
} Va )W[I  
} %`i*SF(gV  
if(breakWhile) 8\s#law  
break; SJ]6_4=y*  
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//count++;  E0!d c  
//if(count>4) |y^=(|eM  
// siteStop(); C>|.0:[%  
} h(=<-p@  
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 qNJc*@s  
System.err.println("文件下载结束！"); SCfp5W7~  
} 'vNju1sfk  
catch(Exception e){e.printStackTrace ();} B@*b 9  
} kWW2N0~$  
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//获得文件长度 !q+ #JW  
public long getFileSize() D('.17  
{ 7"!`<5o^  
int nFileLength = -1; 7<su8*?  
try{ #G#gc`S-,  
URL url = new URL(siteInfoBean.getSSiteURL()); =\lw.59  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); # Wi?I=,  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~61b^L}$  
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#@oB2%&X?  
int responseCode=httpConnection.getResponseCode(); VpJKH\)Rt(  
if(responseCode>=400) b
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{ p6%Vf  
processErrorCode(responseCode); O14QlIk  
return -2; //-2 represent access is error Z"VP<-  
} U~D~C~\2;  
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String sHeader; # >k|^*\  
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>  
for(int i=1;;i++) |Y K,&  
{ &{e ]S!D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ulxlh8=  
//Utility.log(in.readLine()); U;W9`JT<.f  
sHeader=httpConnection.getHeaderFieldKey(i); nF'YG+;|@  
if(sHeader!=null) P!]uJ8bi  
{ _tHhS@  
if(sHeader.equals("Content-Length")) Mz&/.A  
{ l:'#pZ4T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0!,uo\`  
break; =.z;:0]'n  
} Wxj_DTi[1"  
} Qa,
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else G%sq;XT61  
break; :^ywc O   
} o MJ`_  
} eyKxnB
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catch(IOException e){e.printStackTrace ();} X.>=&~[  
catch(Exception e){e.printStackTrace ();} X7!q/1$J  
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Utility.log(nFileLength); Zp)=l Td  
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return nFileLength; O&<p 8
 
} ]L~NYe9  
{_N9<i{T  
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//保存下载信息（文件指针位置） s)- ;74(  
private void write_nPos() wj6u,+  
{ Hk*1Wrs*  
try{ bY#BK_8 :  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Dy.i^`7\  
output.writeInt(nStartPos.length); N" L&Z4Z  
for(int i=0;i<nStartPos.length;i++) l$&~(YE f  
{ Os<E7l zqO  
// output.writeLong(nPos); F6}RPk\=i  
output.writeLong(fileSplitterFetch.nStartPos); t~(jA9n  
output.writeLong(fileSplitterFetch.nEndPos); p=:Vpg<!  
} ZGZNZ}~#  
output.close(); n1PptR  
} }sH[_%)  
catch(IOException e){e.printStackTrace ();} N[@H107`  
catch(Exception e){e.printStackTrace ();} DURWE,W>  
} 8GP17j  
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//读取保存的下载信息（文件指针位置） bVzi^R"  
private void read_nPos() }O*`I(  
{ @?<[//1  
try{ ;~<To9O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); KFbB}oId  
int nCount = input.readInt(); 3'.@aMA@  
nStartPos = new long[nCount]; bVUIeX'  
nEndPos = new long[nCount]; n/skDx TE  
for(int i=0;i<nStartPos.length;i++) #B5,k|"/,M  
{ o{y}c->  
nStartPos = input.readLong(); ?)1Y|W'Rv  
nEndPos = input.readLong(); xoo,}EY  
} K\2{SjL:B  
input.close(); UiG/Rn  
} ZMQ=D!kT  
catch(IOException e){e.printStackTrace ();} r>fGj\#R =  
catch(Exception e){e.printStackTrace ();} {]+t<  
} SyVGm@  
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private void processErrorCode(int nErrorCode) >>J3"XHX  
{ 5(H%Ia  
System.err.println("Error Code : " + nErrorCode); upuN$4m&{  
} zzZEX  
C=+9XfP0  
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//停止文件下载 hiS|&5#  
public void siteStop() E@ :9|5  
{ ~snj92K  
bStop = true; L"&T3i  
for(int i=0;i<nStartPos.length;i++) Z8v8@Y  
fileSplitterFetch.splitterStop(); _P.I+!w:x  
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} :$"{-n  
} Y_CVDKdcY  
//负责部分文件的抓取 V^,gpTyv*  
**FileSplitterFetch.java X8*g#lO?  
*/ N_T5sZ\  
package NetFox; ~`AB-0t.u  
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import java.io.*; $Er=i }`  
import java.net.*; 'V7LL1K^>  
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public class FileSplitterFetch extends Thread { &DMC\R*j  
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String sURL; //File URL +fk*c[FG  
long nStartPos; //File Snippet Start Position 7z$Z=cs  
long nEndPos; //File Snippet End Position 2{h2]F  
int nThreadID; //Thread's ID 8b?nr;@  
boolean bDownOver = false; //Downing is over x/O;8^b  
boolean bStop = false; //Stop identical SxYz)aF~  
FileAccessI fileAccessI = null; //File Access interface i]c{(gd`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4

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{ bX$z)]KKu  
this.sURL = sURL; WRD z*Zf  
this.nStartPos = nStart; {c*$i^T  
this.nEndPos = nEnd; @l CG)Ix<  
nThreadID = id; 2uEI@B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T!H(Y4A  
} } [#8>T  
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public void run() DKS1Sm6d0  
{ 3 ZOD2:(  
while(nStartPos < nEndPos && !bStop) A1p~K*[[  
{ %f'pAc|#  
f![] :L  
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try{ sLA.bp.O  
URL url = new URL(sURL); 4<($ZN8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +S{m!j%B  
httpConnection.setRequestProperty("User-Agent","NetFox"); zls^JTE  
String sProperty = "bytes="+nStartPos+"-"; zdwQpB,+^  
httpConnection.setRequestProperty("RANGE",sProperty); @m5J%8>k  
Utility.log(sProperty); WVeNO,?ytS  
!kSemDC  
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InputStream input = httpConnection.getInputStream(); FXr^ 4B}  
//logResponseHead(httpConnection); [k$GUU,jY  
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byte[] b = new byte[1024]; sc]#T)xG  
int nRead; qefp3&ls  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Gt*<Awn8  
{ :z8/iD y  
nStartPos += fileAccessI.write(b,0,nRead); zh2<!MH  
//if(nThreadID == 1) f$>_>E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \uTlwS  
} {LiJ=Ebt  
1vo3aF  
=u2~=t=LV  
Utility.log("Thread " + nThreadID + " is over!"); |>(Vo@  
bDownOver = true; 9\Gk)0  
//nPos = fileAccessI.write (b,0,nRead); eI ( S)q  
} 2-'_Nwkl*  
catch(Exception e){e.printStackTrace ();} >IS4  
} _-vlN  
} ;:=j{,&dl[  
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//打印回应的头信息 2e\"?yOD  
public void logResponseHead(HttpURLConnection con) WuE]pm]c  
{ &n| <NF  
for(int i=1;;i++) |y7TYjg6  
{ M<Bo<,!ua  
String header=con.getHeaderFieldKey(i); n*9QSyJN]  
if(header!=null) m u9,vH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fL|9/sojz  
Utility.log(header+" : "+con.getHeaderField(header)); yr+QV:oVA  
else zmQQ/7K  
break; {qHQ_ _Bl  
} YQD`4ND  
} X}'rPz\Lu  
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public void splitterStop() U)'YR$2<
 
{ R>"pJbS;L  
bStop = true; L<dh\5#p9Y  
} pbG-uH^  
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} J <z ^C  
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/* Uhvy2}w  
**FileAccess.java :Jyr^0`J  
*//文件访问(定位，写) Pm P&Qje7  
package NetFox; 9=}#.W3.  
import java.io.*; )Jvo%Y  
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public class FileAccessI implements Serializable{ w)<.v+u.
Y  
=,*/Ph&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 15_"U+O(/  
RandomAccessFile oSavedFile; @B0fRG y  
long nPos; @8\0@[]  
v3[ZPc;;  
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public FileAccessI() throws IOException LntRLB'  
{ +mG"m hF  
this("",0); T=w0T-[f  
} j7);N  
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public FileAccessI(String sName,long nPos) throws IOException ug}u>vQ>  
{ IHW s<U  
oSavedFile = new RandomAccessFile(sName,"rw"); [6K[P3UZx  
this.nPos = nPos; 4NRj>
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oSavedFile.seek(nPos); E @r &K  
} Lwtp,.)pR  
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R{H8@JLD  
public synchronized int write(byte[] b,int nStart,int nLen) "uZ^zV`"  
{
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int n = -1; xTG5VBv  
try{ S9*68l  
oSavedFile.write(b,nStart,nLen); KD\%B5Jy  
n = nLen; D|Tz{DRG  
} Bs3&yEq(  
catch(IOException e) on hLhrZ  
{ bfb9A+]3'  
e.printStackTrace (); zBca$Vp  
} \*5z0A9)5)  
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return n; .,VLQbtg  
} `E;xI v|  
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} I<W<;A  
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/* owa&HW/_  
**SiteInfoBean.java sOz {spA  
*/ H9;IA>  
package NetFox;  ^[I>#U  
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public class SiteInfoBean { t\:=|t,  
<2O#!bX1  
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private String sSiteURL; //Site's URL *k&V;?x|wt  
private String sFilePath; //Saved File's Path 6[FXgCb  
private String sFileName; //Saved File's Name <D& Ep  
private int nSplitter; //Count of Splited Downloading File V~8]ag4  
lRS'M,/  
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public SiteInfoBean() iig4JP'h  
{//nSplitter的缺省值为5 x*j eCD,  
//default value of nSplitter is 5 c8zok `\P_  
this("","","",5); ifWQwS/,a  
} "J&WH~8+N  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hBz>E 4mEv  
{ .i;?8?  
sSiteURL= sURL; ^!O!HMX0  
sFilePath = sPath; a&kt!%p:  
sFileName = sName; B$OV^iwxK  
this.nSplitter = nSpiltter; 6 %`h2Z  
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} CG3
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=Y
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public String getSSiteURL() S6JWsi4C:,  
{ # dUi['  
return sSiteURL; Q"!GdKM  
} lkp$rJ#6  
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public void setSSiteURL(String value) 9%Vy,  
{ klc$n07  
sSiteURL = value; L[5U(`q[  
} 'aeuL1mz  
b!/-9{  
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public String getSFilePath() Y~r)WV!G  
{ wrJ"(:VZ  
return sFilePath; ?{L'd  
} 2h@&yW2j  
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public void setSFilePath(String value) Rb^G~82d?  
{ B<.ZW}#v  
sFilePath = value; EZp >Cf7  
} ;Ob^@OM  
]W`M <hEI  
8F$]@0v`%  
public String getSFileName() }QCn>LXE  
{ dtG>iJ  
return sFileName; gL@]p  
} O"X7 DgbC  
GUJ?6;  
+'w6=qI  
public void setSFileName(String value) !4z vkJO  
{ 4kK_S.&  
sFileName = value; V~-tp^  
} %5n'+-XVj  
%Yg|QBm|  
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public int getNSplitter() " w /Odd  
{ E2=vLI]  
return nSplitter; tp"eXA0n  
} ! P$[$W  
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public void setNSplitter(int nCount) ?5%o-hB|  
{ m,5?|J=  
nSplitter = nCount; lG[j,MDs  
} qJ~fEX  
} 7?vj+1;  
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!@arPN$  
/* tu;Pm4q7  
**Utility.java pUu<0a^  
*/ jnM}N:v  
package NetFox; LXth-j=]  
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j(>xP*il  
public class Utility { xbCQ^W2YU|  
^8dCFw.rU  
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public Utility() V8pZr+AJ  
{ Mlbc
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Z(LTHAbBk|  
<<Z, 1{3F  
} iMV=R2t 2  
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m  
//线程睡眠 (bB"6 #TI  
public static void sleep(int nSecond) AW!A+?F6  
{ iG=Di)O  
try{ }{&;\^i  
Thread.sleep(nSecond); {lppv(U  
} U+["b-c  
catch(Exception e) m !i`|]m  
{ 6 =G=4{q  
e.printStackTrace (); j0{Qy;wP )  
} >V\^oh)t]t  
} |GP&!]  
5-&"nn2*}1  
//日志 b0x%#trA{  
public static void log(String sMsg) R. vV
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{ /wP2Wnq$  
System.err.println(sMsg); =u
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} Nz;\PS  
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public static void log(int sMsg) `'pAiu  
{ a#9pN?~  
System.err.println(sMsg); &zP>pQr`#  
} (I+e@UUiL  
} }EJ/H3<  
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hR.vJ2oa  
/* 5/CF_v  
**TestMethod.java &$l#0?Kc^  
*/ M23r/eg]  
package NetFox; sN#ju5  
ip1gCH/?_+  
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public class TestMethod { 2Je]dj4  
_qo\E=E  
i1bmUKZ8'L  
public TestMethod() #ZP;] W  
{ ///xx/weblogic60b2_win.exe |WOc0M[U  
try{ Oi-%6&}J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [Q/kNK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XBO( *6"E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t-<BRnxhE  
fileFetch.start(); {l
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} [%~yY&  
catch(Exception e){e.printStackTrace ();} 2. {/ls  
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} 6}|h  
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public static void main(String[] args) 8N3y(y0  
{ rI6+St  
new TestMethod(); p(Osz7K  
} qL[SwEc  
} Mq'm TM  
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