http断点续传简单实现（java)

/* Z. G<
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**SiteFileFetch.java l's*HEx
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*/ sW]fPa(cn,  
package NetFox; aJ^RY5  
import java.io.*; ]KE"|}B  
import java.net.*; B(h%>mT[  
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public class SiteFileFetch extends Thread { %uy5la  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X{G&r$  
long[] nStartPos; //开始位置 #1oyRD-  
long[] nEndPos; //结束位置 5'zD}[2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jM!Q 04(  
long nFileLength; //文件长度 3r-oZ8/n  
boolean bFirst = true; //是否第一次取文件 $;%k:&\f  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 8%Hc%T[RnT  
DataOutputStream output; //输出到文件的输出流 lLi)?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %{HeXe  
public SiteFileFetch(SiteInfoBean bean) throws IOException DA wUG  
{ $Cx?%X^b  
siteInfoBean = bean; GjH$!P=.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ny2. C?2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pW4$$2S?9  
if(tmpFile.exists ()) {ZIEIXWb2  
{ >#~>!cv6D  
bFirst = false; YwnYTt  
read_nPos(); oZwu`~h Y  
} g?i0WS  
else "9bd;Tt:  
{ vkE a[7  
nStartPos = new long[bean.getNSplitter()]; ]<Kkq!  
nEndPos = new long[bean.getNSplitter()]; "';K$&,[  
} *~SanL
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} ]L{diD2G  
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public void run() ]
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{ zSo(+D &[  
//获得文件长度 U~1)a(Yu;  
//分割文件 ) o`ep{<t  
//实例FileSplitterFetch g`\5!R1  
//启动FileSplitterFetch线程 P}8cSX9  
//等待子线程返回 R;3nL[{U  
try{ ^bG91"0A  
if(bFirst) !@3"vd{^  
{ _`.Wib+  
nFileLength = getFileSize(); Ev>P|kV&A  
if(nFileLength == -1) 2D)B%nM[  
{ 'B yB1NL  
System.err.println("File Length is not known!"); It:,8  
} 6%L#FSI  
else if(nFileLength == -2) !j%MN{#a  
{ ^bk:
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System.err.println("File is not access!"); Fv$oXg/  
} :erfs}I  
else V 0z`p"  
{ 7 F> a&r  
for(int i=0;i<nStartPos.length;i++) K;j0
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{ 45A|KaVpg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gJBw6'Z  
} <\`qRz0/  
for(int i=0;i<nEndPos.length-1;i++) "el}9OitC  
{ ~1:_wni  
nEndPos = nStartPos[i+1]; ^2C \--=;  
} yIYQ.-DkS+  
nEndPos[nEndPos.length-1] = nFileLength; _?v&\j  
} !q!5D`  
} h,|. qfUk  
>["X(%&w  
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//启动子线程 <%?!3 n*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; c"lblt5  
for(int i=0;i<nStartPos.length;i++) QERj`/
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{ w:aV2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z;~7L*|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S\L^ZH?[2  
nStartPos,nEndPos,i); H/}W_ h^^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bJoP@s  
fileSplitterFetch.start(); +$$5Cv5#<&  
} &lnM 1W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J_7#UjGA,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /tj_WO_  
nEndPos = " + nFileLength); bXi(]5  
// fileSplitterFetch[nPos.length-1].start(); suHi
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//等待子线程结束 =z zmz7op  
//int count = 0; `Z^\<{z  
//是否结束while循环 [JYy  
boolean breakWhile = false; P
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while(!bStop) &}r-C97  
{ qs{wrem  
write_nPos(); >|aVGY  
Utility.sleep(500); KAg-M#  
breakWhile = true; Fv<3VKueK[  
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for(int i=0;i<nStartPos.length;i++) =[,EFkU?B  
{ MdhD "Q  
if(!fileSplitterFetch.bDownOver) Q zp!)i  
{ MY'T%_id  
breakWhile = false; B?l0u  
break; 9Ed=`c  
} k)R~o b  
} SP"t2LTP  
if(breakWhile) c 5 `74g  
break; U".5x~UC  
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9[R+m3V/`  
//count++; +GncQs y  
//if(count>4) F^.~37=@  
// siteStop(); Q^*4
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} Irui{%T  
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System.err.println("文件下载结束！"); L7[f-cK2:  
} OXnTD!m>{  
catch(Exception e){e.printStackTrace ();} m-
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} }W0_eQ  
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//获得文件长度 ?&!e f{  
public long getFileSize() ,Xxp]*K2  
{ .}Eckqkp  
int nFileLength = -1; 6O_l;A[=1  
try{ NOmFQ)/ &  
URL url = new URL(siteInfoBean.getSSiteURL()); nNf*Q r%Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *7w!~mn[m  
httpConnection.setRequestProperty("User-Agent","NetFox"); aNBwb9X  
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int responseCode=httpConnection.getResponseCode(); md `=2l  
if(responseCode>=400) zkquXzlgB  
{ >qBJK)LHOv  
processErrorCode(responseCode); ~n$\[rQ  
return -2; //-2 represent access is error Ehxu`>@N  
} :D4'x{#H  
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String sHeader; TKQ^D  
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for(int i=1;;i++) {eVv%sbq  
{ `O5427Im  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #r/5!*3  
//Utility.log(in.readLine()); h_]*|[g  
sHeader=httpConnection.getHeaderFieldKey(i); I^HwXp([  
if(sHeader!=null) $z`l{F4eMf  
{ "L!U7|9J  
if(sHeader.equals("Content-Length")) N>CNgUyP  
{ :| !5d{8S8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Sp2DpGs~  
break; 9Y@ eXP  
} B#?rW*yEe  
} 'S|7<<>4k  
else +,cd$,18  
break; ra2{8 x  
} wbvOf X  
} ksTK'7*  
catch(IOException e){e.printStackTrace ();} 4)8e0L*[B?  
catch(Exception e){e.printStackTrace ();} HYL['B?Wid  
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Utility.log(nFileLength); 4Y1dkg1y  
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return nFileLength; !^o{}*]Pi  
} Te`@{>  
e^,IZ{  
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//保存下载信息（文件指针位置） 2j#Dwa(lZQ  
private void write_nPos() U#&+n-npO  
{ Kr[oP3  
try{ s4QCun~m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )%PMDG|  
output.writeInt(nStartPos.length); {pA&Q{ ^  
for(int i=0;i<nStartPos.length;i++) mi.,Z`]o  
{ 3@:O1i  
// output.writeLong(nPos); MkhD*\D /  
output.writeLong(fileSplitterFetch.nStartPos); )+DDIq  
output.writeLong(fileSplitterFetch.nEndPos); w!z*?k=Da  
} X%iJPJLza  
output.close(); K7@|2;e  
} JPHM+3v  
catch(IOException e){e.printStackTrace ();} evpy%/D  
catch(Exception e){e.printStackTrace ();} <LzxnTx=  
} V%z?wDC  
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//读取保存的下载信息（文件指针位置） <EQaYZY=  
private void read_nPos() z;y{QO  
{ (z8;J>7  
try{ R7K`9 c1f6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fq_>}k@fI  
int nCount = input.readInt(); ,LlYRj 5  
nStartPos = new long[nCount]; #oR`_Dm)P  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) g"k4Z  
{ 2r;h">  
nStartPos = input.readLong(); ca3SE^  
nEndPos = input.readLong(); q"6$#o{~U  
} IUDH"~f  
input.close(); 5423Ky<
 
}  wlsx|  
catch(IOException e){e.printStackTrace ();} ;^u,[d  
catch(Exception e){e.printStackTrace ();} _C(fz CK  
} :U *8S\$  
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private void processErrorCode(int nErrorCode) N/'  
{ .ZV='i()X  
System.err.println("Error Code : " + nErrorCode); Srz8sm;  
} sp MYn&p  
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//停止文件下载 NbTaI{r  
public void siteStop() wy .96  
{ ^<;CIXo  
bStop = true; Tl'wA^~H  
for(int i=0;i<nStartPos.length;i++) r>7+&s*yk  
fileSplitterFetch.splitterStop();
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} ,Q3OQ[Nmh  
} MBU|<tc  
//负责部分文件的抓取 ;']u}Nh  
**FileSplitterFetch.java @x!,iT  
*/ KO~KaN  
package NetFox; nlI3|5  
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import java.io.*; l qwy5#  
import java.net.*; [z ]P5  
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public class FileSplitterFetch extends Thread { g1}:;VG=  
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String sURL; //File URL %8h=_(X\7  
long nStartPos; //File Snippet Start Position M:/(~X{?  
long nEndPos; //File Snippet End Position /e[m;+9^&  
int nThreadID; //Thread's ID zi3v,Kq  
boolean bDownOver = false; //Downing is over iETUBZ  
boolean bStop = false; //Stop identical ~[dL:=?c  
FileAccessI fileAccessI = null; //File Access interface }A,!|m4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c"-X:m"  
{ XzSl"UPYH  
this.sURL = sURL; @eeI4Jz  
this.nStartPos = nStart; U,Uy0s2r  
this.nEndPos = nEnd; od5nRb  
nThreadID = id; m;\nMdn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \#LDX,=  
} rab$[?]  
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public void run() TfT^.p*  
{ ?jUgDwc(w  
while(nStartPos < nEndPos && !bStop) /3Gq&[R{  
{ ZOcpF1y  
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try{ 9#:fQ!3`  
URL url = new URL(sURL); +_$s9`@]6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xw_klHL-o  
httpConnection.setRequestProperty("User-Agent","NetFox"); pe0ax-Zv  
String sProperty = "bytes="+nStartPos+"-"; ]Idwy|eG  
httpConnection.setRequestProperty("RANGE",sProperty); T4Vp0i  
Utility.log(sProperty); ]'[:QGr  
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InputStream input = httpConnection.getInputStream(); JVkuSIR>  
//logResponseHead(httpConnection); m$^5{qpg  
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byte[] b = new byte[1024]; ^)Awjj9  
int nRead; Yl>Y.SO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;tVd+[8  
{ r7g@(K  
nStartPos += fileAccessI.write(b,0,nRead); "yh2+97l  
//if(nThreadID == 1) hnB`+!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xvl
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} #n{4f1TZ  
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Utility.log("Thread " + nThreadID + " is over!"); )Z1&`rv  
bDownOver = true; 9aLd!PuTN  
//nPos = fileAccessI.write (b,0,nRead); gC(S(osF  
} 4'dN7E1*f  
catch(Exception e){e.printStackTrace ();}  %G\nl  
} <mlN\BcX;  
} &g&,~Y/z;  
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//打印回应的头信息 
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public void logResponseHead(HttpURLConnection con) jT$J~MpHh  
{ 6xtgnl#T  
for(int i=1;;i++) uA[ :  
{ TP {\V>*Yz  
String header=con.getHeaderFieldKey(i); ^.iRU'{  
if(header!=null) RV_I&HD!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2(0%{*m  
Utility.log(header+" : "+con.getHeaderField(header)); _b&26!gl  
else 1uN;JN `_  
break; (}6\_k[}m  
} X,aRL6>r  
} 6`Y:f[VB  
``k[
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public void splitterStop() 4)D~S4{E5  
{  K];]  
bStop = true; F"k`PF*b  
}  B>:U  
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} lSaX!${R'T  
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/* \P+^BG!  
**FileAccess.java ]  &"`  
*//文件访问(定位，写) $%\6"P/64  
package NetFox; qMVuFwPhi  
import java.io.*; yOQae m^O  
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public class FileAccessI implements Serializable{ \1joW#  
9%|skTgIqH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 dWkQ NFKF  
RandomAccessFile oSavedFile; 'A.5T%n-  
long nPos; (>A#|N1U  
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public FileAccessI() throws IOException ;z9,c  
{ #GlFm?/6K/  
this("",0); +em!TO  
} B-]bhA4|:  
!9NF@e'&!  
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public FileAccessI(String sName,long nPos) throws IOException '+{yg+#/wV  
{ yp$jLBA  
oSavedFile = new RandomAccessFile(sName,"rw"); -hW>1s<  
this.nPos = nPos; Xwo+iZ(a  
oSavedFile.seek(nPos); *9r(lmrfj  
} kP[fhOpn  
}"WovU{*s  
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public synchronized int write(byte[] b,int nStart,int nLen)  0LL65[  
{ HP_h!pvx  
int n = -1; %La7);SeY  
try{ 7glf?oE  
oSavedFile.write(b,nStart,nLen); Ewr2popK  
n = nLen; T^#d;A  
} *5oQZ".vA*  
catch(IOException e) $dKfUlO  
{ ww7nQ}H5(  
e.printStackTrace (); rQ_cH  
} z(Uz<*h8  
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return n; a@jM%VZ  
} OET/4(C  
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} *&IvEu  
/D^ g
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/* ]!^wB 3j  
**SiteInfoBean.java HLqN=vE6  
*/ +,YK}?e  
package NetFox; NY<qoV  
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public class SiteInfoBean { h>*3i#  
3GKKC9C6  
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private String sSiteURL; //Site's URL K]B`&ih  
private String sFilePath; //Saved File's Path |pBFmm*  
private String sFileName; //Saved File's Name :TP4f ?FA  
private int nSplitter; //Count of Splited Downloading File +{=U!}3|  
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public SiteInfoBean() PPV T2;9  
{//nSplitter的缺省值为5 *2-b&PQR{  
//default value of nSplitter is 5 {
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this("","","",5); 6(7{|iY  
} Q%q;=a  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) LNR1YC1c  
{ k)D5>T  
sSiteURL= sURL; }z/%b<o_  
sFilePath = sPath; hNYO+LrI)  
sFileName = sName; zQ,M795@EA  
this.nSplitter = nSpiltter; I>l^lv&[+  
Wf8@B#^{  

q%q+2P>  
} g}Lm;gs!>  
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public String getSSiteURL() Bf  y  
{ =&k[qqxg  
return sSiteURL; 9pj6`5Zn@6  
} /mp!%j~  
h {Jio>  
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public void setSSiteURL(String value) zmD7]?|  
{ t+F_/_"B  
sSiteURL = value; N.Q}.(N0  
} seAPVzWUU  
NQuqM`LSQ  
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public String getSFilePath() ?RsPAL  
{ x\ #K2  
return sFilePath; p>J@"?%^  
} 9S9j  
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public void setSFilePath(String value) gzvgXZ1q"  
{ 1'p=
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sFilePath = value; *'H\`@L  
} m*B4a9f  
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#b)
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public String getSFileName() |N6.:K[`  
{ K% snE7X?)  
return sFileName; \Ezcr=0z{j  
} 3rHn?  

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hg<[@Q%$o  
public void setSFileName(String value) tmBt[  
{ iyR"O1]  
sFileName = value; 9dAtQwGR"6  
} `S-%}eUv  
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public int getNSplitter() $.w$x1  
{ OJA_OqVp$K  
return nSplitter; ojm IEzsz  
} aY.cx1"  
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public void setNSplitter(int nCount) .)WEg|D0Ku  
{ (xTGt",_Jo  
nSplitter = nCount; X
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} %#&
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} [lSQMoi3  
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/* j+ L:Ao  
**Utility.java `x>6Wk1  
*/ ?VRsgV'$  
package NetFox; ]2|fc5G'  
4e|N^h*!  
{SXSQ'=  
public class Utility { Val"vUZ  
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public Utility() +kE~OdZG  
{ aqQ+A:g  
8*#$3e  
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} Eld[z{n"  
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//线程睡眠 \Z42EnJ  
public static void sleep(int nSecond) `s UY$Q  
{ HIE8@Rv/3  
try{ }><[6Uz%  
Thread.sleep(nSecond); 9MI9$s2y  
} PXtF#,roP  
catch(Exception e) 3XDU(#  
{ }hg2}g99  
e.printStackTrace (); W4k$m2  
} @K*W3&TO  
} B@dCCKc%/  
^"=G=* /  
//日志 9v-Y*\!w.  
public static void log(String sMsg) /~;!Ew|q  
{ k
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System.err.println(sMsg); J}8p}8eF,  
} W|zPV`  
o_k)x3I?  
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public static void log(int sMsg) |nLq4.  
{ Rmn{Vui9\  
System.err.println(sMsg); r7?nHF  
} o37oRv]  
} |7A}LA  
{=Jo!t;f  
coPdyw'9&  
/* f##/-NG  
**TestMethod.java H%rNQxA2 +  
*/ :X-S&SX0  
package NetFox; XSK<hr0m  
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public class TestMethod { 1t^9.!$@y  
4J
(-~  
]e"!ZR?XJ  
public TestMethod() ,!%E\`  
{ ///xx/weblogic60b2_win.exe cqs.[0 z#B  
try{ s7:H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); puWMgvv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TKGaGMx6@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'yA/sZ  
fileFetch.start(); ybFxz  
} ~$[fG}C.K  
catch(Exception e){e.printStackTrace ();} q^zG+FN  
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} j} ^3v #  
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public static void main(String[] args) @>~\So|  
{ HB}rpiB  
new TestMethod(); RU6c8>"  
} sb8bCEm-\  
} 7_)38  
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