http断点续传简单实现（java)

/* &he:_p$x  
**SiteFileFetch.java =J]M#6N0  
*/ X&Sah}0V&  
package NetFox; 4vNH"72P  
import java.io.*; wFjQ1
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import java.net.*; gSf>+|  
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public class SiteFileFetch extends Thread { 8~T=p:z'  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s'OK])>`  
long[] nStartPos; //开始位置 EVE"F'Ww,_  
long[] nEndPos; //结束位置 &.PAIe.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 e_g&L)  
long nFileLength; //文件长度 ux,eY  
boolean bFirst = true; //是否第一次取文件 \rE] V,,2  
boolean bStop = false; //停止标志 U#<{RqY  
File tmpFile; //文件下载的临时信息 F`,Hf Cb\  
DataOutputStream output; //输出到文件的输出流 Nq|y\3]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） M1T.  
public SiteFileFetch(SiteInfoBean bean) throws IOException m"6K_4r]  
{ 'I:_}q  
siteInfoBean = bean; Bwu?DK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); IkxoW:L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `$FB[Z} &  
if(tmpFile.exists ()) qEVpkvEq  
{ P+C5 
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bFirst = false; ?.n1t@sG&  
read_nPos(); \j &&o  
} ` k(Q:  
else nc1?c1s,f  
{ vZs~=nfi#|  
nStartPos = new long[bean.getNSplitter()]; vsQvJDna~  
nEndPos = new long[bean.getNSplitter()]; _>r(T4}]  
} jhBfy|Ftu  
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} -Owb@
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public void run() px(~ZZB
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{ N/<c;"o  
//获得文件长度 _H-Fm$Q  
//分割文件 PO^#G@  
//实例FileSplitterFetch (ak&>pk;  
//启动FileSplitterFetch线程 UUa@7|x  
//等待子线程返回 K$B~vy6E`  
try{ }lCQ+s!  
if(bFirst) bH:C/P<x  
{ hlz/TIP^N3  
nFileLength = getFileSize(); 4/v[.5  
if(nFileLength == -1) Xq"Es  
{ 9l:[jsk<d  
System.err.println("File Length is not known!"); BB ::zBg  
} 8*|*@  
else if(nFileLength == -2) Dtyw]|L\H  
{ 8i<]$
 
System.err.println("File is not access!"); c?aOX/C'  
} sGpAaGY>  
else fzAkUv
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{ G>jC+0nkry  
for(int i=0;i<nStartPos.length;i++) /ge
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{ O
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); r=p^~tuyxr  
} AJ3Byb=.  
for(int i=0;i<nEndPos.length-1;i++) Xg\unUHa  
{ <7zz"R  
nEndPos = nStartPos[i+1]; _lRIS_^;eE  
} hzpl;Mj  
nEndPos[nEndPos.length-1] = nFileLength; (]10Z8"fJ  
} w'7J`n:{]  
} YPO24_B  
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//启动子线程 ;Cjj_9e,:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dxH.  
for(int i=0;i<nStartPos.length;i++) y(E<MRd8V  
{ -Rr !J37  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {~G~=sC$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LlVbY=EX7  
nStartPos,nEndPos,i); {<#b@=G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jE8}Ho_#)  
fileSplitterFetch.start(); Vs Z7n~e  
} qv4r!x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -3 "<znv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 563ExibH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N^k& 8  
nEndPos = " + nFileLength); 7{9M ^.}  
// fileSplitterFetch[nPos.length-1].start(); ic l]H  
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//等待子线程结束 d#W^S
[[  
//int count = 0; Lf%}\0:  
//是否结束while循环 ,4B8?0sH|  
boolean breakWhile = false; }r;=<mc,O  
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while(!bStop) #.C2_MN>  
{ A]drNFE  
write_nPos(); WLta{A?  
Utility.sleep(500); VZtFgN$J  
breakWhile = true; 2]FRIy d  
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for(int i=0;i<nStartPos.length;i++) _j*I\  
{ xVN!w\0  
if(!fileSplitterFetch.bDownOver) 3Wx\Liw,  
{ C@<gCMj,"  
breakWhile = false; #7}YSfm^6  
break; xr7M#n  
} F[W0gjUc  
} z+CX$
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if(breakWhile) *O\lR-z!k  
break; wm9wnAy  
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//count++; \~t!M~H  
//if(count>4) TmM~uc7mj  
// siteStop(); nHp(,'R/  
} H$pgzNL  
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System.err.println("文件下载结束！"); 8U4In[4  
} ~[~#PO  
catch(Exception e){e.printStackTrace ();} Pv3G?u=4  
} :uC9 #H"b  
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//获得文件长度 b)E<b{'W  
public long getFileSize()
o|#F@L3i  
{ [,MK)7DU  
int nFileLength = -1; 0"ooHP$1  
try{ tF./Jx]_  
URL url = new URL(siteInfoBean.getSSiteURL()); pF8+< T3y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ELG9ts+5Uj  
httpConnection.setRequestProperty("User-Agent","NetFox"); G%= gCR  
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int responseCode=httpConnection.getResponseCode(); 5r~hs6H  
if(responseCode>=400) (A=Z,ed  
{ $H]NC-\+>  
processErrorCode(responseCode); aygK$.wos  
return -2; //-2 represent access is error cRNVqMpg  
} GdrVH,j  
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String sHeader; r6:e 423  
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for(int i=1;;i++) i->G{_gH  
{ i XGy*#>V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OPogH=vf  
//Utility.log(in.readLine()); rR#wbDr5  
sHeader=httpConnection.getHeaderFieldKey(i); _{eA8J(A<  
if(sHeader!=null) G-;EB  
{ mG0_&'"YIG  
if(sHeader.equals("Content-Length")) m&be55M;  
{ 3"k n5)x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BglbQ'6p  
break; {y%@1q%"  
} 5@I/+D  
} "}H2dn2n  
else a0Fq$  
break; -%{+\x2  
} 9U=6l]Np  
} =A$
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catch(IOException e){e.printStackTrace ();} *19a\m=>oi  
catch(Exception e){e.printStackTrace ();} q9a6s{,  
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Utility.log(nFileLength); {k[dg0UV  
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return nFileLength; ZA@zs,o%  
} lLglF4  

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//保存下载信息（文件指针位置） )p:
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private void write_nPos() &n0Ag]$P  
{ =Mxu,A  
try{ /g!Xe]Ss  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :m/qR74+"  
output.writeInt(nStartPos.length); eIN0T;1T  
for(int i=0;i<nStartPos.length;i++) P7l3ZH( g  
{ C',uY7}<  
// output.writeLong(nPos); pr,1pqiAf  
output.writeLong(fileSplitterFetch.nStartPos); AI9922}*  
output.writeLong(fileSplitterFetch.nEndPos); kXlI*h  
} \|M[W~
8  
output.close(); z3>4 xn{  
} ap
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catch(IOException e){e.printStackTrace ();} [~`p~@\+  
catch(Exception e){e.printStackTrace ();} P4|A\|t  
} 141xi;o  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() k5+ Fxf  
{ t'.:"H8BI  
try{ }"v#_vJfz7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >}JEX]V  
int nCount = input.readInt(); }LLQ+  
nStartPos = new long[nCount]; 'SrDc'?  
nEndPos = new long[nCount]; 4nh0bIN1  
for(int i=0;i<nStartPos.length;i++) HYY+Fv5  
{ dNov= w  
nStartPos = input.readLong(); [6/8O
 
nEndPos = input.readLong(); NZFUCD)  
} :()K2<E  
input.close(); \(`C*d  
} L&uPNcZ`-  
catch(IOException e){e.printStackTrace ();} IMzt1l =7  
catch(Exception e){e.printStackTrace ();} =e9<.{]S/  
} a( N;|<  
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private void processErrorCode(int nErrorCode) 78?cCj{e  
{ j8rxhToC  
System.err.println("Error Code : " + nErrorCode); Vh]=sd<F  
} X gtn}7N.  
L;+e)I]  
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//停止文件下载 +[$Td%6  
public void siteStop() jyidNPLm4  
{ t2rZ%[O  
bStop = true; r
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for(int i=0;i<nStartPos.length;i++) %*IH~/Ld;]  
fileSplitterFetch.splitterStop(); `49!di[  
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} ZU2D.Kf_:  
} wnQi5P+  
//负责部分文件的抓取 >enP~uW[#  
**FileSplitterFetch.java ,_=LV  
*/ Z^mQb2e.  
package NetFox; 4\uq$.f-  
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import java.io.*; nB5^  
import java.net.*; g9d/nRX&  
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public class FileSplitterFetch extends Thread { !FB2\hiM  
1CV?  
9[`\ZGWD  
String sURL; //File URL XIl#0-E0X  
long nStartPos; //File Snippet Start Position
{>TAnb?n  
long nEndPos; //File Snippet End Position N4{g[[ T  
int nThreadID; //Thread's ID A.r.tf}:  
boolean bDownOver = false; //Downing is over m2ph8KC  
boolean bStop = false; //Stop identical O(_f&a  
FileAccessI fileAccessI = null; //File Access interface :?i,!0#"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vy>(?[  
{ gT,iH.  
this.sURL = sURL; r]wy-GT  
this.nStartPos = nStart; -OKXfN]  
this.nEndPos = nEnd; U<'z,P
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nThreadID = id; w[)HQ1K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DQ0 UY  
} JxM32?Rm*w  
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public void run() GW%!?mJ  
{ *GdJ<B$  
while(nStartPos < nEndPos && !bStop) %0 U@k!lP  
{ WM=)K1p0u  
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try{ FEBRUk6.h  
URL url = new URL(sURL); tlI]);iE,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k9VWyq__  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]J/;Xp  
String sProperty = "bytes="+nStartPos+"-"; 6k+tO%{~  
httpConnection.setRequestProperty("RANGE",sProperty); !L/.[:X  
Utility.log(sProperty); {`Mb),G  
)]m4FC:  
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InputStream input = httpConnection.getInputStream(); ?3v-ppw%  
//logResponseHead(httpConnection); QPvWdjf#mM  
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byte[] b = new byte[1024]; f&&Ao  
int nRead; C?6q]k]r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -:b<~S[  
{ 2t=&h|6EW  
nStartPos += fileAccessI.write(b,0,nRead); ?4Rq +  
//if(nThreadID == 1) LVL#qNIu  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); : >$v@d  
} (?.h<v1}  
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" ;\EU4R  
Utility.log("Thread " + nThreadID + " is over!"); +hH7|:JQ  
bDownOver = true; &@PAv5iNf  
//nPos = fileAccessI.write (b,0,nRead); iA'p!l|P  
} 'p%w_VbI  
catch(Exception e){e.printStackTrace ();} 90wnwz  
} s;tI?kR>%  
} DnF|wS  
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0-d&R@lX.  
//打印回应的头信息 1d&Q E\2}  
public void logResponseHead(HttpURLConnection con) qs9r$o.\l  
{ ~BBh4t&  
for(int i=1;;i++) V9 EC@)  
{ NpA%7Q~B$,  
String header=con.getHeaderFieldKey(i); NpGz y`&b  
if(header!=null) |m$]I4Jr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); PK_2  
Utility.log(header+" : "+con.getHeaderField(header)); Y)M-?|4  
else Ow-;WO_HQ  
break; wMM1Q/-#  
} /5\{(=0  
} &kH7_Lz  
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public void splitterStop() S7R*R}
 
{ UK[+I]I p  
bStop = true; iciRlx.$c  
} z qd1G(tO  
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} 7? ="{;  
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/* 7~H$p X  
**FileAccess.java ;$4: &T  
*//文件访问(定位，写) QCfR2Nn}  
package NetFox; i \.&8  
import java.io.*; ^4{{ +G)j  
5ai$W`6  
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public class FileAccessI implements Serializable{ ]:4\rBR3  
@ZcI]G%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !zfV(&  
RandomAccessFile oSavedFile; j<L!(6B  
long nPos; JS&;7Z$KX  
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#}
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public FileAccessI() throws IOException RggZ'.\  
{ ~jC$C2A0  
this("",0); &Hl w2^  
} ZP.~Y;Ch;-  
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public FileAccessI(String sName,long nPos) throws IOException 9
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{ AxCFZf5  
oSavedFile = new RandomAccessFile(sName,"rw"); asbFNJG{  
this.nPos = nPos; *+J`Yk7}  
oSavedFile.seek(nPos); O+~@S~  
} \Oe8h#%  
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public synchronized int write(byte[] b,int nStart,int nLen) Ja%isIdh  
{ X@~R<  
int n = -1; $oi8<8Y  
try{ Ga;Lm?6-  
oSavedFile.write(b,nStart,nLen); $ Vsf?ID  
n = nLen; qwd T=H  
} v=YI%{tx)  
catch(IOException e) Gn%k#  
{ ,Aq |IH3j  
e.printStackTrace (); rX|{
nb  
} W!a'KI'  
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return n; 0-Wv$o[  
} v&"sTcS|  
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} :U'Oc3l#Y  
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/* m=MM  
**SiteInfoBean.java -QQU>_  
*/ f5#VU7=1F2  
package NetFox; %){)/~e&  
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public class SiteInfoBean {
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private String sSiteURL; //Site's URL lZD"7om  
private String sFilePath; //Saved File's Path C)ebZ3  
private String sFileName; //Saved File's Name 
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private int nSplitter; //Count of Splited Downloading File 9Ljd or  
{Ytqs(`   
v <E#`4{  
public SiteInfoBean() V}q=!zz  
{//nSplitter的缺省值为5 /6#i$\ j  
//default value of nSplitter is 5 p+:MZP -%(  
this("","","",5); `q?@ Ob&  
} sq}uq![?
M  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) W%K=N-kE_  
{ ?qczMck_  
sSiteURL= sURL;
j$khGR!  
sFilePath = sPath; f,8PPJ:,  
sFileName = sName; c.;<+dYsm*  
this.nSplitter = nSpiltter; ob7hNo#  
[vcSt5R=  
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} 8Y~\:3&1<  
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public String getSSiteURL() I<$m%  
{ gPy}.g{tH$  
return sSiteURL; !F#^Peb  
} e `IL7$  
&=v5M9GR]  
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public void setSSiteURL(String value) Q%_MO`<]$  
{ ROr| <  
sSiteURL = value; 6Vy4]jdT5  
} wZ~eE'zx+  
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public String getSFilePath() v'u}%FC  
{ XM?C7/^k  
return sFilePath; 3qrjb]E%}  
} a*Ng+~5)6  
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public void setSFilePath(String value) )F%zT[Auph  
{ !+ ??3-q  
sFilePath = value; :.W</o~\s  
} v^1n.l %E  
4XArpKA  
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public String getSFileName() lgh+\pj  
{ 3b1%^@,ACy  
return sFileName; RRR=R]  
} G'6f6i|<I@  

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public void setSFileName(String value) lxOUV?m^N  
{ p!2t/X
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sFileName = value; tcj3x<  
} 3Cl&1K #5  
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3("E5lI(g:  
public int getNSplitter() r[RO"Ej"  
{ U7d05y'  
return nSplitter; 2B=+p83<  
} {#}?-X  
S)G*+)  
<+e&E9;>6  
public void setNSplitter(int nCount) q|N4d9/b  
{ ,PZ[CX;H@  
nSplitter = nCount; ]gB:ht  
} q%8Ck)xz  
} }y#aO  
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/* km9@*@)  
**Utility.java ]d50J@W c  
*/ (,2U?p  
package NetFox; _}:#T8h  
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public class Utility { VyxX5Lrj  
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g9:V00^<  
public Utility() .0#{?R,  
{ Yjp*T:6  
k= oCpXq^  
s,;L6nX"  
} 5D`!Tu3  
R(<_p"9(  
//线程睡眠 6gJc?+  
public static void sleep(int nSecond) gL6.,4q+1  
{ rJ fO/WK  
try{ Ihg1%.^V\  
Thread.sleep(nSecond); y_N h5  
} PW GNUNc  
catch(Exception e)  '' Pfs<!  
{ ?/^x)Nm  
e.printStackTrace (); C+Pw  
} lsRW.h,  
} +"Mlj$O  
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//日志 H0Ck%5
  
public static void log(String sMsg) ^ lM.lS>)  
{ wb/@g=`d  
System.err.println(sMsg);
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} m15> ^i^W  
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public static void log(int sMsg) )>8k8E  
{ ,kw:g&A  
System.err.println(sMsg); m0+'BC{$u  
} Q(ec>+oi  
} 5u
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d m$iiRY  
/* [rtMx8T  
**TestMethod.java k|[86<&[  
*/ geEETb}+y  
package NetFox; $' >|r]  

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public class TestMethod { 8VR! Y0`e  
k{w  
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public TestMethod() )SsO,E+t=U  
{ ///xx/weblogic60b2_win.exe #FsoK*F  
try{ ,ku3;58O<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A!fRpN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TrmrA$5f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0%>_fMaA  
fileFetch.start(); f l*O)r  
} H"J>wIuGX  
catch(Exception e){e.printStackTrace ();} Ur2)];WZ  
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!DNk!]|  
} LXx`Vk>ky  
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&<oDl_^  
public static void main(String[] args) #i0f}&
 
{ QsH?qI&2jp  
new TestMethod(); eCX
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} :}p<Hq 8Z  
} NGOyd1$7N  
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