http断点续传简单实现（java)

/* *?S\0a'W@  
**SiteFileFetch.java "7DPsPs  
*/  jQhf)B  
package NetFox; 03PVbDq-  
import java.io.*; =Ao;[j)*!  
import java.net.*; Gmb57z&:  
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public class SiteFileFetch extends Thread { iu .{L(m  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~Y(M>u.+!  
long[] nStartPos; //开始位置 @?U5t1O<  
long[] nEndPos; //结束位置 t9}XO M*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f W )  
long nFileLength; //文件长度 ?#'
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boolean bFirst = true; //是否第一次取文件 WBGYk);  
boolean bStop = false; //停止标志 k)J7) L  
File tmpFile; //文件下载的临时信息 k1<Py$9"  
DataOutputStream output; //输出到文件的输出流 fiZ8s
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -'2.^a-8-g  
public SiteFileFetch(SiteInfoBean bean) throws IOException *VUXw@  
{ jL# akV  
siteInfoBean = bean; *=8)]_=f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +2?[=g4;}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?/\;K1c p  
if(tmpFile.exists ()) C"}x=cK  
{ xl3U  
bFirst = false; !l~
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read_nPos(); ra3WLK  
} qrdI"  
else z(ajR*\#  
{ R8E<;^?j  
nStartPos = new long[bean.getNSplitter()]; v#6.VUAw  
nEndPos = new long[bean.getNSplitter()]; M3''xrpC  
} |lv4X}H  
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} YW5E |z  
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public void run() \@xnC$dd/  
{ W)l&4#__(  
//获得文件长度 )D^P~2  
//分割文件 zR4huo  
//实例FileSplitterFetch _eF*8 /z  
//启动FileSplitterFetch线程 ,%C$~+xjM  
//等待子线程返回 (mEZ4yM
 
try{ IkvH8E  
if(bFirst) %[0"[<1a  
{ #yqcUbJY0R  
nFileLength = getFileSize(); y
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if(nFileLength == -1) %guot~S|  
{ YP7<j*s8  
System.err.println("File Length is not known!"); z7CYYU?  
} #wo_  
else if(nFileLength == -2) 4eKJ\Q=nX5  
{ ;#+#W+0  
System.err.println("File is not access!"); [kXe)dMX8  
} =FE,G*  
else $$4% .J26Z  
{ kO4C^pl"v  
for(int i=0;i<nStartPos.length;i++) 4 qnQF]4  
{ CR/
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); $qvNv[  
} Eg9502Bl~8  
for(int i=0;i<nEndPos.length-1;i++) 4 (yHD  
{ {hl_/ aG  
nEndPos = nStartPos[i+1]; qGw6Wp~  
} suVS!} C  
nEndPos[nEndPos.length-1] = nFileLength; ~UnfS};
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} Wj3H  y4  
} :+6m<?R)T  
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<D=%55  
//启动子线程 ua{eri[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ka
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for(int i=0;i<nStartPos.length;i++) `SVR_  
{ V6!oe^a7'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #qPk,a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C?|
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nStartPos,nEndPos,i); >!$4nxq2>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UeRenp  
fileSplitterFetch.start(); s"'1|^od  
} 7yc:=^ )  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?]})Xf.A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [AU1JO`\"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *f[`Yv  
nEndPos = " + nFileLength); K@fxCj*}  
// fileSplitterFetch[nPos.length-1].start(); i{,>2KVC|  
xW09k6   
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//等待子线程结束 mMMu'N  
//int count = 0; 46
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//是否结束while循环 n_!&Wr^CX  
boolean breakWhile = false; UKzmR
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&@RU}DnvM&  
# WxH  
while(!bStop) DJ\lvT#j  
{ C>;}CH|X  
write_nPos(); $yt|nO  
Utility.sleep(500); Ft]sTA+
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breakWhile = true; %jkd}D  
| zAey\  
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for(int i=0;i<nStartPos.length;i++) gt ?&!S^  
{ T.xW|Iwx  
if(!fileSplitterFetch.bDownOver) w#o<qrpHf  
{ 0 cQf_o  
breakWhile = false; :9)>!+|'  
break; l+#`  
} $Fo ,$  
} iX,Qh2(ig  
if(breakWhile) vEb~QX0~  
break; *Vc}W  
j/W#=\xz  
f(3#5288  
//count++; 2Zl65  
//if(count>4) !~RD>N&n  
// siteStop(); bi_R.sfK&  
} J/mLB7^
R  
IXH;QwR:  
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System.err.println("文件下载结束！"); j;'NJ~NZ$  
} ~
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catch(Exception e){e.printStackTrace ();} 6L4B$'&KQZ  
} R&-bA3w$  
s0\X%U("  
R)H@'X  
//获得文件长度 ~"LOw_BRh  
public long getFileSize() dx~F [  
{ 4(Mt6{q  
int nFileLength = -1; #de]b  
try{ zRKg>GG`  
URL url = new URL(siteInfoBean.getSSiteURL()); OtC/)sX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uW[<?sFG  
httpConnection.setRequestProperty("User-Agent","NetFox");
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int responseCode=httpConnection.getResponseCode(); !|}>Y  
if(responseCode>=400) yyXJ_B  
{ HezCRtxRcc  
processErrorCode(responseCode); |~>8]3. Y  
return -2; //-2 represent access is error c,+oH<bZZs  
} `T mIrc  
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t!K|3>w  
String sHeader; <=0_[M  
?1[go+56X  
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for(int i=1;;i++) DO0["O74  
{ |S.-
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y H?>2u  
//Utility.log(in.readLine()); T\]z0M  
sHeader=httpConnection.getHeaderFieldKey(i);  Im#3sn  
if(sHeader!=null) fc M~4yP?  
{ 3GaM>w}>W  
if(sHeader.equals("Content-Length")) ?.4u'Dkn=  
{ O/GD[9$i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #$A6s~`B  
break; al^ yCoB  
} 
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} f'}23\>  
else jdhhvo
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break; ~#gVs*K  
} )2R:P`U
 
} Kyv$yf9  
catch(IOException e){e.printStackTrace ();} $H5Xa[  
catch(Exception e){e.printStackTrace ();} HC$_p,9OV  
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Utility.log(nFileLength); `OBDx ^6F  
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return nFileLength; '&U
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} VD1*br^,  
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rR."_Z2  
//保存下载信息（文件指针位置） D F0~A  
private void write_nPos() VNPuOU=  
{ d/|@"z^?  
try{ ] Li(E:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hmks\eb~  
output.writeInt(nStartPos.length); \l#=p+x5  
for(int i=0;i<nStartPos.length;i++) }B"kJNxV  
{ Z EG  
// output.writeLong(nPos); u<):gI  
output.writeLong(fileSplitterFetch.nStartPos); k8w8I$QEM  
output.writeLong(fileSplitterFetch.nEndPos); Iy"   
} y\ouIsI77  
output.close(); TG'A'wXxy  
} ;Ni+TS  
catch(IOException e){e.printStackTrace ();} b`1P%OjC  
catch(Exception e){e.printStackTrace ();} 03#r F@e  
} cA_v*`YL  
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//读取保存的下载信息（文件指针位置） @1rF9< 4g  
private void read_nPos()
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{ Ll&Y_Ry  
try{ }"_S;[{d  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %vMi kibI  
int nCount = input.readInt(); GT*\gZ  
nStartPos = new long[nCount]; B<+}_3.  
nEndPos = new long[nCount]; IUI>/87u  
for(int i=0;i<nStartPos.length;i++) _e/vw:  
{ m,Os$>{Ok  
nStartPos = input.readLong(); Z!tt(y\  
nEndPos = input.readLong(); W4T>@b.  
} (3 B; V  
input.close(); Rh~<#"G]  
} N=-hXgX^  
catch(IOException e){e.printStackTrace ();} 0hCJovSG%  
catch(Exception e){e.printStackTrace ();} `y m^0x8  
} o D^],  
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private void processErrorCode(int nErrorCode) nz+DPk["  
{ :Bda]]Y=  
System.err.println("Error Code : " + nErrorCode); ]#_,?d  
} O /aC%%  
*O+YhoR?  
,HR~oT^  
//停止文件下载 ]"aC wr  
public void siteStop() nB"q   
{ ~M+|g4W%  
bStop = true; _ 4pBJOJQ6  
for(int i=0;i<nStartPos.length;i++) CShVJ:u+K\  
fileSplitterFetch.splitterStop(); R)ejIKtY  
par $0z/  
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} .-fJ\`^mi  
} hyFq>XFo  
//负责部分文件的抓取 TRG
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**FileSplitterFetch.java GIt;Y  
*/ m?bb/o'
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package NetFox; %0. o(U  
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import java.io.*; /6b(w=pk  
import java.net.*; JYs*1
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public class FileSplitterFetch extends Thread { }8 fG+H.  
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String sURL; //File URL rB)m{)  
long nStartPos; //File Snippet Start Position 'GS1"rkW<5  
long nEndPos; //File Snippet End Position A\k@9w\Ll;  
int nThreadID; //Thread's ID DBbmM*r  
boolean bDownOver = false; //Downing is over -Z)$].~|t  
boolean bStop = false; //Stop identical ct fKxGH  
FileAccessI fileAccessI = null; //File Access interface DSD#',  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /w`{]Ntgu  
{ C KBLM2D  
this.sURL = sURL; kjJ\7x6M  
this.nStartPos = nStart; rN8 ZQiJC  
this.nEndPos = nEnd; '9]%#^[Q  
nThreadID = id; i8+kc_8#d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 u3w `(3{<  
} :/K 'P`JaL  
*!Vic#D%  
,H[-.}OO  
public void run() 78Nli/U  
{ VNx}ADXu]  
while(nStartPos < nEndPos && !bStop) e*:[#LJ]C  
{ a:7"F{D91  
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try{ &(IL`%  
URL url = new URL(sURL); :Dw;RcZQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JPS L-j  
httpConnection.setRequestProperty("User-Agent","NetFox"); S\MD]>4  
String sProperty = "bytes="+nStartPos+"-"; 45>w=O  
httpConnection.setRequestProperty("RANGE",sProperty); (;+JM*c2N  
Utility.log(sProperty); [p_R?2uT  
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InputStream input = httpConnection.getInputStream(); I^ppEgYSY  
//logResponseHead(httpConnection); Fu(e4E  
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byte[] b = new byte[1024]; 2P"@=bYT"  
int nRead; x.<^L] "  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0[x?Q[~S_0  
{ 8HxB\ !0F?  
nStartPos += fileAccessI.write(b,0,nRead); &H-39;?u  
//if(nThreadID == 1) w(<; $9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M\DUx5dJ,  
} j+88J  
)Tpc8Hr  
/Vg R[  
Utility.log("Thread " + nThreadID + " is over!"); 3-FS} {,  
bDownOver = true;  Xb&
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//nPos = fileAccessI.write (b,0,nRead); qd%5[A  
} Hvnak{5  
catch(Exception e){e.printStackTrace ();} fI t:eKHr  
} x\3tSP7Vp  
} U]@t\T3W  
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//打印回应的头信息 U3&*,xeU@H  
public void logResponseHead(HttpURLConnection con) I^qk`5w  
{ /1gKc}rB2  
for(int i=1;;i++) 7=6p  
{ VQ$=F8ivG  
String header=con.getHeaderFieldKey(i); mdoy1a  
if(header!=null) A!ba_14  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?k<wI)JR  
Utility.log(header+" : "+con.getHeaderField(header)); {(7Dz*0
  
else psta&u\ q  
break; \@:pWe  
} Q{Jz;
6"
 
} v'TkKwl  
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public void splitterStop() {o*ziZh
 
{ R5H UgI  
bStop = true; wGBQ.Ve[  
} '.#KkvE##  
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} /#G^?2oM  
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/* >hRYsWbmg  
**FileAccess.java U-Fr[1I6p  
*//文件访问(定位，写) TXH: +mc  
package NetFox; ~g;(`g  
import java.io.*; \Nb6E&+  
Rqa#;wb!(  
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public class FileAccessI implements Serializable{ #ie{!Mh  
nx $?wxIm  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H \.EKZ  
RandomAccessFile oSavedFile; ?:lOn(0&  
long nPos;
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public FileAccessI() throws IOException BaR9X ?~O$  
{ >Cb% `pe  
this("",0); DL2e
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} :c!7r
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4:nmo@K&~  
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public FileAccessI(String sName,long nPos) throws IOException ''?.6r  
{ shYcfLJ  
oSavedFile = new RandomAccessFile(sName,"rw"); Gvtd )9^<  
this.nPos = nPos; mu=u!by.E  
oSavedFile.seek(nPos); E-E+/.A  
} !r.X.C  
]m=* =LLC  
|jEKUTv,G  
public synchronized int write(byte[] b,int nStart,int nLen) IW$&V``v  
{ ky#<\
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int n = -1; +ulX(u(,  
try{ wAF>C[<\  
oSavedFile.write(b,nStart,nLen); !D7\$ g6g  
n = nLen; 9P{5bG0o8  
} H1s{JJAM>i  
catch(IOException e) 3P^eD:) w  
{ j;VYF  
e.printStackTrace (); r1}7Q7-z  
} 3|/ ;`KfQ  
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return n; ?rk3oa-  
} 0=t_a]+  
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} vkc(-n  
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&7E0H{  
/* K*7*`6iU  
**SiteInfoBean.java |os2@G$  
*/ nFw&vR/q  
package NetFox; @2YO_rL[  
B?#@<2*=L
 
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public class SiteInfoBean { Wq&TbWR  
N^%[ B9D  
\n`UkxZn+  
private String sSiteURL; //Site's URL dAym)  
private String sFilePath; //Saved File's Path %do|>7MO@  
private String sFileName; //Saved File's Name -S)
HB$8  
private int nSplitter; //Count of Splited Downloading File */O6cF7  
}gag?yQ.^  
+&(sZFW5o  
public SiteInfoBean() XfViLBY( >  
{//nSplitter的缺省值为5 G1$DVGo  
//default value of nSplitter is 5 &|/C*2A  
this("","","",5); 9#O"^.Z !  
} :_)Xe*O  
m[ifcDZ(e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YH
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{ G]QD6b9~  
sSiteURL= sURL; B:^5W{  
sFilePath = sPath; vJl4.nk  
sFileName = sName; W5J"#^kdF8  
this.nSplitter = nSpiltter; #V4_.t#  
Vi5RkUY]  
A
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} N{|N_}X`Y  
/x0zZ+}V  
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public String getSSiteURL() JfKl=vg  
{ i`Lt=)@&  
return sSiteURL; WXO@oZ!  
} _F,@mQ$!  
9FcCq*D  
`S$BBF;  
public void setSSiteURL(String value) R4@C>\c%m  
{ DX4 95<6*  
sSiteURL = value; pZjyzH{~  
} (8=Zr0
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D?X97jNm  
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public String getSFilePath() vERsrg;(  
{ `P :-a7_  
return sFilePath; l}:9)nXA
{  
} G>*s+  
//V?rs  
Hr96sN.R   
public void setSFilePath(String value) /+02BP  
{ e:NzpzI"v  
sFilePath = value; NrS1y"#d9  
} /PHktSG  
?\ho9nyK  
V, )kw{](  
public String getSFileName() I-fs*yzj;8  
{ [S3X  
return sFileName; ~w4aA<2Uq  
} (_U&EX%  
*$(9,y\  
G}}oeS  
public void setSFileName(String value) IE'OK  
{ o7]h;Zg5r  
sFileName = value; F4">go  
} |D`Zi>lv  
9Tjvc!4_b  
`|v0@-'$  
public int getNSplitter() NoDq4>   
{ -pa.-@  
return nSplitter; @36^4E>h  
} NWX~@Rg  
d3^LalAp  
>$HMZbsE  
public void setNSplitter(int nCount) gt{ei)2b  
{ k{"~G#GwP  
nSplitter = nCount; ]'2p"A0U  
}
/$I&D}uR`  
} s+Ln>c'|o  
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>.J68x  
/* CF =#?+x  
**Utility.java .^P^lQT]>  
*/ shnfH  
package NetFox; (VwS9:`
  
l|j&w[c[Q0  
~''qd\.f$  
public class Utility { X3X~`~bAD  
YgdoQBQ  
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public Utility() &AOw(?2  
{ AvP*p{w
e  
sR?_{rQ  
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} >2>xr"  
BniFEW:<  
//线程睡眠 ,7/un8:%c  
public static void sleep(int nSecond) +S0A`rL  
{ B:+}^=  
try{ >D<nfG<s Z  
Thread.sleep(nSecond); q)<5&|V  
} ( 9dV%#G\  
catch(Exception e) Z0`?  
{ kDO6:sjR7  
e.printStackTrace (); ~]c^v'k  
} :M|bw{P*  
} LUS7-~:F  
fBw+Y4nCO7  
//日志 a,&Kvh  
public static void log(String sMsg) E3NYUHfZ  
{ a;/4 ht  
System.err.println(sMsg); z-$?.?d  
} Q 7B)t;^  
`2r21rVntf  
a-i#?hld  
public static void log(int sMsg) .7E-  
{ Mt@K01MI%  
System.err.println(sMsg); D|9B1>A,m  
} CAcnH  
} pok,`yW\  
Hvor{o5|tB  
rhNdXYY>  
/* ;J?^M!l2=  
**TestMethod.java >KGQ#hnH  
*/ |W:kzTT-T  
package NetFox; hw~cS7  
nwcT8b87J  
0b*a2_|8k  
public class TestMethod { u$<FKp;I  
9R.tkc|K  
/ HaS.  
public TestMethod() {"{J*QH  
{ ///xx/weblogic60b2_win.exe C .YtjLQP$  
try{ IFpmf0;^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +H="5uO<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YWq[)F@0G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2px5>4<  
fileFetch.start(); BLMcvK\9  
} TU[f"!z^  
catch(Exception e){e.printStackTrace ();} $I1p"6  
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} 39~fP)  
{-17;M$  
g08=D$P  
public static void main(String[] args) `5GJ,*{z  
{ Y71b Lg  
new TestMethod();
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} ~@got  
} kO2im+y  
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