http断点续传简单实现（java)

/* z<vO#  
**SiteFileFetch.java \j})Ku
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*/ C9Z\G 3
 
package NetFox; %x8`fm  
import java.io.*; <eFAI}=s  
import java.net.*; {AL9o2  
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hd ;S>K/C  
public class SiteFileFetch extends Thread { ck
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8u5 'g1M  
long[] nStartPos; //开始位置 ,\9mAt1O  
long[] nEndPos; //结束位置 e=jT]i*cU  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eQaxZMU  
long nFileLength; //文件长度 LSu^#B  
boolean bFirst = true; //是否第一次取文件 >"<k8wn  
boolean bStop = false; //停止标志 46P6Bwobh  
File tmpFile; //文件下载的临时信息 69j~?w)^  
DataOutputStream output; //输出到文件的输出流 &<|-> *v  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） oYh<k  
public SiteFileFetch(SiteInfoBean bean) throws IOException i$^B-  
{ Q$h:[_v  
siteInfoBean = bean; mV*/zWh_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8u'O`j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =6:L+V  
if(tmpFile.exists ()) T<e7(=  
{ d:<H?~  
bFirst = false; MjXE|3&  
read_nPos(); uGUv~bE  
} hKZ`DB4  
else ,WB_C\.#XN  
{
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nStartPos = new long[bean.getNSplitter()]; +5t
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nEndPos = new long[bean.getNSplitter()]; 7Cd_zZ  
} X:``{!~geo  
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} :IR9=nhS]  
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public void run() p;u 1{  
{ ./&zO{|0]  
//获得文件长度 ,s><kHJ  
//分割文件 'uKkl(==%  
//实例FileSplitterFetch %t`SSW7I  
//启动FileSplitterFetch线程
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//等待子线程返回 VwOG?5W/  
try{ puS&S *  
if(bFirst) m UWkb  
{ hP1 l v7P  
nFileLength = getFileSize(); B?#kW!wj  
if(nFileLength == -1) bKuj po6  
{ I!@s6tG  
System.err.println("File Length is not known!"); "\/^/vn?  
} _))I.c=v  
else if(nFileLength == -2) QOV}5 0  
{ )jlP cO-  
System.err.println("File is not access!"); 6mu<&m@  
} )W1(tEq59  
else BU9J_rCIv  
{ -!|WZ   
for(int i=0;i<nStartPos.length;i++) :GQIlA8cF$  
{ .5Knbc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )XP#W|;  
} -.{oqs
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for(int i=0;i<nEndPos.length-1;i++) 4N~+G `  
{ f{igW?Ho  
nEndPos = nStartPos[i+1]; p`:*mf  
} $Eio$TI  
nEndPos[nEndPos.length-1] = nFileLength; JYwyR++uo  
} >sQ2@"y)s2  
} w!WRa8C  
}U%^3r-  
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//启动子线程 ;NH~9# t:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !6zyJc@01  
for(int i=0;i<nStartPos.length;i++) T3Frc ]6,4  
{ SLtSqG7~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), izPh1YA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w{3Q( =&  
nStartPos,nEndPos,i); pd4cg?K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g@@&sB-A"  
fileSplitterFetch.start(); l]_b;iux  
} <Zp^lDxa  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mny'9hsl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?C &x/2lt  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", dU]i-NF  
nEndPos = " + nFileLength); Q PFeBl  
// fileSplitterFetch[nPos.length-1].start(); <t{?7_ 8  
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//等待子线程结束
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//int count = 0; ~n[b^b  
//是否结束while循环 =s'XR@  
boolean breakWhile = false; &:V@2_6"  
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while(!bStop) 'aD6>8/Hj  
{ nW4Vct  
write_nPos(); z,{e]MB)M  
Utility.sleep(500); N5nvL)a~  
breakWhile = true; >dpbCPJ9[  
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for(int i=0;i<nStartPos.length;i++) $ph0ag+  
{ [kbC'Eh*  
if(!fileSplitterFetch.bDownOver) -IBO5;2_  
{ x*.Ye5Jb  
breakWhile = false; Yd'H+r5b  
break; ajn-KG!A  
} c 9rVgLqn!  
} F=XF]  
if(breakWhile) "7Eo>g  
break; R? O-x9  
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3p=vz'  
//count++; rdO@X9z  
//if(count>4) '_B_&is  
// siteStop(); ]o-Fi$h!  
} 7zD- ?%  
* R%.a^R  
6Wj@r!u  
System.err.println("文件下载结束！"); JE0?@PI$  
} x6LjcRS|  
catch(Exception e){e.printStackTrace ();} KNy`Lj)VPY  
} cV-i*L4X  
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!#q{Z>H`  
//获得文件长度 hM~eJv  
public long getFileSize() ><[| G9  
{ U.: sK*  
int nFileLength = -1; Aj,]n>{  
try{ ],n%Xp  
URL url = new URL(siteInfoBean.getSSiteURL()); i 'qMi~{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8QV t, 'I  
httpConnection.setRequestProperty("User-Agent","NetFox"); < CDA"  
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|K%}}g[<e;  
int responseCode=httpConnection.getResponseCode(); (@ "=F6P  
if(responseCode>=400) v"rl5x  
{ vF"c  
processErrorCode(responseCode); 5^yG2&>#  
return -2; //-2 represent access is error K<FKu $

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} )o{VmXe@@  
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String sHeader; rJu[N(2k  
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for(int i=1;;i++) Gz?2b#7v  
{ L[rpb.'FG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @%c81rv?  
//Utility.log(in.readLine()); j"
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sHeader=httpConnection.getHeaderFieldKey(i);  l^P#kQA  
if(sHeader!=null) c15r':.5  
{ "3SWO3-x  
if(sHeader.equals("Content-Length")) AM'gnP>  
{ Rp0|zP,5  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +P|2m"UA  
break; vv &BhIf3  
} 1]j^d  
} > @+#  
else X(]Zr  
break; [B,'=,Hbs  
} %swR:
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} <s_=-" il  
catch(IOException e){e.printStackTrace ();} P.cO6+jGR  
catch(Exception e){e.printStackTrace ();} ,;%yf
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Utility.log(nFileLength); vf<UBa;Xm  
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return nFileLength; lyyX<=E{)  
} ^_68]l=  
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//保存下载信息（文件指针位置） Q[uAIyv0  
private void write_nPos() 77*qkKr  
{ sK&,):"]R  
try{ x`2| }AP(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kh3<V'k]  
output.writeInt(nStartPos.length); 4=xq:Tf  
for(int i=0;i<nStartPos.length;i++) %k2FPmA6  
{ FQROK4x%"  
// output.writeLong(nPos); e0 u,zg+m  
output.writeLong(fileSplitterFetch.nStartPos); ]9*;;4Mg  
output.writeLong(fileSplitterFetch.nEndPos); `XW*kxpm  
} KXf<$\+zO  
output.close(); ^O)ve^P  
} JB^Q\;$  
catch(IOException e){e.printStackTrace ();} $w)~xE5;  
catch(Exception e){e.printStackTrace ();} ;#
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} -f9]v9|l  
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//读取保存的下载信息（文件指针位置） OQScW2a&  
private void read_nPos() Z19m@vMsIP  
{ 2+.18"rvi  
try{ "ZT.k5Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _yvLuj  
int nCount = input.readInt(); OR4!YVVQ  
nStartPos = new long[nCount]; j
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nEndPos = new long[nCount]; J R$r!hX  
for(int i=0;i<nStartPos.length;i++) %ucjMa>t  
{ EB!daZH,  
nStartPos = input.readLong(); (?3[3w~  
nEndPos = input.readLong(); SdJ/4&{ !  
} 
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input.close(); 9JnY$e<&  
} =X-Tcj?3g  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} ZCYS\E7X  
} O>c$sL0g  
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private void processErrorCode(int nErrorCode) /YH`4e5g  
{ brSi<  
System.err.println("Error Code : " + nErrorCode); _U0$=V  
} {q3:Z{#>7  
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+th%enRB  
//停止文件下载 S&(^<gwl  
public void siteStop() xx)-d,S  
{ G[h(xp?,l  
bStop = true; :!Ig- +W  
for(int i=0;i<nStartPos.length;i++) l-Nly>~  
fileSplitterFetch.splitterStop(); iev>9j  
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} >MG(qi  
} 2(M6(xH>  
//负责部分文件的抓取 A}5fCx.{  
**FileSplitterFetch.java "e6|"w@8  
*/ iiG f'@/  
package NetFox; 8K{[2O7i)  
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q; jiw#_  
import java.io.*; ~n?>[88"  
import java.net.*; (GcT(~Gq)D  
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public class FileSplitterFetch extends Thread { 2c(aO[%h9  
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String sURL; //File URL 3yA2WW  
long nStartPos; //File Snippet Start Position ,v9f~qh  
long nEndPos; //File Snippet End Position jrMe G.e=D  
int nThreadID; //Thread's ID LF*&(NC  
boolean bDownOver = false; //Downing is over 0;.<~;@h  
boolean bStop = false; //Stop identical JkQ\)^5v  
FileAccessI fileAccessI = null; //File Access interface ;V5yXNQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v~|?3/{Q  
{ |=dC )Azs  
this.sURL = sURL; D@oCP =m<  
this.nStartPos = nStart; {ZsdLF#  
this.nEndPos = nEnd; !>z:m!MlQ  
nThreadID = id; %rkk>m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mXzrEI  
} %Ym^{N  
'%saL>0  
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public void run() z
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{ fJAnKUF)  
while(nStartPos < nEndPos && !bStop) H1EDMhn/  
{ "v-(g9(  
!j:`7PT\  
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try{ I97yt[,Yy  
URL url = new URL(sURL); s{bdl[7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (C;I*cv  
httpConnection.setRequestProperty("User-Agent","NetFox"); HQP}w%8x  
String sProperty = "bytes="+nStartPos+"-";  vZj`|  
httpConnection.setRequestProperty("RANGE",sProperty); h"+ `13  
Utility.log(sProperty); MV>$BW  
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2&!bfq![  
InputStream input = httpConnection.getInputStream(); .L6Zm U  
//logResponseHead(httpConnection); PU<PhuMd  
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byte[] b = new byte[1024]; WjSc/3Qy  
int nRead; "Z=5gj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6NWn(pZ]p  
{ n(seNp%_  
nStartPos += fileAccessI.write(b,0,nRead); c]-*P7W  
//if(nThreadID == 1) eY
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ufV!+$C)is  
} bi4f]^hQz  
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!p/%lU65  
Utility.log("Thread " + nThreadID + " is over!"); 8;14Q7,S  
bDownOver = true; k^"bLf(4  
//nPos = fileAccessI.write (b,0,nRead); \!]hU%Un  
} 3*UR3!Z9 *  
catch(Exception e){e.printStackTrace ();} vQ}6y  
} b75$?_+  
} ?p<.Fv8.  
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&fa5laJb  
//打印回应的头信息 7CXW#H  
public void logResponseHead(HttpURLConnection con) C'yppl%  
{ nrm+z"7  
for(int i=1;;i++) q#w8wH"  
{ 39wa|:I  
String header=con.getHeaderFieldKey(i); Vwk#qgnX  
if(header!=null) %UUH"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9^FziM  
Utility.log(header+" : "+con.getHeaderField(header)); 5irwz4.4  
else FGWN}&K  
break; 94skkEj  
} CIU1R;  
} \s"U{N-  
4(6b(]G'#  
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public void splitterStop() W14F  
{ ,GWNLm\5  
bStop = true; k3?rp`V1  
} mE`kjmX{E  
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} OU5*9_7.  
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/* -HSs^d
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**FileAccess.java g_5QA)4x  
*//文件访问(定位，写) gz2\H}  
package NetFox; 5DOBsf8Jo  
import java.io.*; i%e7LJ@5AW  
nOx4<Wk&  
d8-A*W[  
public class FileAccessI implements Serializable{ F  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 BH]Ynu&o  
RandomAccessFile oSavedFile; akw,P$i  
long nPos; bVP"(H]  
STZPYeXE  
s,#>m*Rh  
public FileAccessI() throws IOException ;%tF58&  
{ ljl^ GFo  
this("",0); `.s({/|[  
} z'T)=ycT  
V%$/#sza  
v8AS=sY4r  
public FileAccessI(String sName,long nPos) throws IOException T\~x.aH`^  
{ bR@p<;G|  
oSavedFile = new RandomAccessFile(sName,"rw"); =X.LA%Sf=u  
this.nPos = nPos; Z{&cuo.@<]  
oSavedFile.seek(nPos); T~QJO0  
} }neY<{z  
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C8FB:JNJV  
public synchronized int write(byte[] b,int nStart,int nLen) __mF?m  
{ (/35pg6\  
int n = -1; @gY)8xMbA  
try{ V#VN%{  
oSavedFile.write(b,nStart,nLen); UAoh`6vFF8  
n = nLen; )K &(  
} eX@L3BKp  
catch(IOException e) F:x [  
{ .r*2|  
e.printStackTrace (); z5ij(RE]  
} H":oNpfb  
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return n; .\>v0Du  
} (5]}5W*  
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} D3|I:Xm  
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/* L3CP`cx  
**SiteInfoBean.java ZP
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*/ ~"A+G4jl  
package NetFox; `OSN\"\ad  
7uzkp&+:  
kc0E%odF.v  
public class SiteInfoBean { |i++0BU  
6}r`/?"A1  
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private String sSiteURL; //Site's URL B}^w_
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private String sFilePath; //Saved File's Path 4?B\O`sy.  
private String sFileName; //Saved File's Name <)1qt
9  
private int nSplitter; //Count of Splited Downloading File dAuJXGo  
82l~G;.n3  
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public SiteInfoBean() HTG%t/S  
{//nSplitter的缺省值为5 ~3<> 3p  
//default value of nSplitter is 5 wmTb97o
 
this("","","",5); d3xmtG {i  
} F6z%VWU  
'inFKy'H  
)ut&@]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F w?[lS  
{ M3.do^ss  
sSiteURL= sURL; A0Qb5e  
sFilePath = sPath; $< JaLS  
sFileName = sName; }}59V&'t  
this.nSplitter = nSpiltter; 4r45i:  
A}l3cP; `#  
=i[\-  
} q.;u?,|E/  
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public String getSSiteURL()
@{25xTt  
{ JD|=>)  
return sSiteURL; uA<
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} RCpR3iC2  
4%4 }5UYN  
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public void setSSiteURL(String value) `EaLGzw  
{ }~L.qG  
sSiteURL = value; {tWf  
}  qi^7  
')cMiX\v  
9iQq.$A.  
public String getSFilePath() F%RRd/'  
{ |!4K!_y  
return sFilePath; o4Om}]Ti  
} c24dSNJg,  
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,5h)x"s  
public void setSFilePath(String value) I`!<9OTBj  
{ DW[N|-
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sFilePath = value; Vh4X%b$TV  
} BI%$c~wS  
<J`0  
.:F%_dS D  
public String getSFileName() 8]9%*2"!  
{ ;>Ib^ov  
return sFileName; @J/K-.r  
} koug[5T5  
"]} bFO7C  
dl.p\t(1  
public void setSFileName(String value) 3ca (i/c  
{ %WjXg:R  
sFileName = value; fbe[@#:  
} MDnua  
 R[D{|K@"  
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public int getNSplitter() GBPo8L"9  
{ FOE4>zE  
return nSplitter; ;@oN s-  
} YIG~MP  
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public void setNSplitter(int nCount) {'NvG  
{ cQ R]le%(  
nSplitter = nCount; ]>5/PD,wWy  
} s;ls qQk  
} vg32y /l]S  
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Po^?QVJ7  
/* zBzZxK>$  
**Utility.java u. F9g #  
*/ VY7[)  
package NetFox; _l89  
\!.B+7t=I  
UM"- nZ>[  
public class Utility { L0TFo_  
+nFu|qM}  
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public Utility() lR6@ xJd:@  
{ n{argI8wF  
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} AP?R"%  
&w_j/nW^'  
//线程睡眠 YJT&{jYi  
public static void sleep(int nSecond) vApIHI?-  
{ Yg||{  
try{ Ga^"1TZ x  
Thread.sleep(nSecond); :(P9mt  
} 8e1UmM
[  
catch(Exception e) 0ypNUG}   
{ "*e$aTZB\  
e.printStackTrace (); qN9(S:_Px  
} -=)H{  
} }C"%p8=HM  
NJWA3zz   
//日志 I-]?"Q7Jz  
public static void log(String sMsg) .ypL=~Rp  
{ ^@s1Z7  
System.err.println(sMsg); Ot_]3:`J~  
} 6]WAUK%h  
|\pj;XU  
h+g_rvIG*  
public static void log(int sMsg) t%/&c::(6  
{ JcsHt;  
System.err.println(sMsg); Z&+ g;
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} ctZ uA+  
}
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/* PR#exm&  
**TestMethod.java nv|NQ Tk  
*/ 7rc0yB  
package NetFox; &[?\k>  
'CM|@Zz%  
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public class TestMethod { [ )Iv^ U9  
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?jv
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public TestMethod() 8mvy\l EEH  
{ ///xx/weblogic60b2_win.exe K7_UP&`=J  
try{ BU/"rv"(Fg  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ohGJ1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); & p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /|6N*>l)y  
fileFetch.start(); ;#W2|'HD  
} p_gm3Q  
catch(Exception e){e.printStackTrace ();} AUG#_HE]k  
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t6"%3#s  
} r= `Jn6@  
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we//|fA<  
public static void main(String[] args) [6Izlh+D  
{ q_[o"wq/  
new TestMethod(); ]nn
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} %D{6[8  
} i &nSh ]KK  
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