http断点续传简单实现（java)

/* .xT?%xSi/  
**SiteFileFetch.java J,=K1>8s  
*/ hX.cdt_?  
package NetFox; /5NWV#-  
import java.io.*; _3`GZeGV  
import java.net.*; Jt_=aMY:7  
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public class SiteFileFetch extends Thread { Kxsd@^E  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oGcgd$%ZB  
long[] nStartPos; //开始位置 _Xf1FzF+a  
long[] nEndPos; //结束位置 o?baiOkH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !db=Iz5)  
long nFileLength; //文件长度 @]Jq28  
boolean bFirst = true; //是否第一次取文件 q8{Bx03m6  
boolean bStop = false; //停止标志 )s!A\a`vEd  
File tmpFile; //文件下载的临时信息 [k7(t|Q{  
DataOutputStream output; //输出到文件的输出流 J67 thTGFq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3H#,qug$  
public SiteFileFetch(SiteInfoBean bean) throws IOException La ?A@SD  
{ YWIA(p8Qkk  
siteInfoBean = bean; iJ{axa &  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !VD$uT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (HAdr5  
if(tmpFile.exists ()) 6tH}&#K  
{ ~VsN\!G  
bFirst = false; 6s@!Yn|?
 
read_nPos(); v}DNeIh~  
} 7ys' [G|}r  
else @K"$M>n$Z  
{ YEv\!%B  
nStartPos = new long[bean.getNSplitter()]; If&))$7u  
nEndPos = new long[bean.getNSplitter()]; fzJiW@-T  
} 59.$;Ip;g  
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} v[$e{Dz(  
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public void run() J_)F/S!T  
{ =c6d$  
//获得文件长度 ^tTM 7  
//分割文件 }9ulHiR  
//实例FileSplitterFetch rCo}^M4Pb  
//启动FileSplitterFetch线程 b'O/u."O  
//等待子线程返回 k)+{Y v*  
try{ _N5pxe`  
if(bFirst) 27Gff(  
{ =ls+vH40&  
nFileLength = getFileSize(); JrBPx/?(,;  
if(nFileLength == -1) gbdzS6XW~  
{ |E6Thvl$  
System.err.println("File Length is not known!"); KcT(/!  
} -o/Vp>_UOE  
else if(nFileLength == -2) R*6TS"aL  
{ / :$WOQ  
System.err.println("File is not access!"); E?]$Y[KJKs  
} gYt=_+-  
else 5B~]%_gZr  
{ ^qL<=UC.  
for(int i=0;i<nStartPos.length;i++) @kSfF[4H  
{ Q%6zr9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r;@
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} =bp'5h8_  
for(int i=0;i<nEndPos.length-1;i++) /%g@ ;  
{ ~vYF
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nEndPos = nStartPos[i+1]; EuHQp7  
} o"qxR'V  
nEndPos[nEndPos.length-1] = nFileLength; O=K0KOj  
} 6EY\  
} 5xc e1[  
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//启动子线程 WReHep  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %Ja0:
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for(int i=0;i<nStartPos.length;i++) 0s8fF"$  
{ :H>I`)bw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I*3>
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p63fpnH  
nStartPos,nEndPos,i); q>+!Ete1p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NP3 e^  
fileSplitterFetch.start();
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} /{j._4c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kP5I+B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7Ws88Qs)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $mT)<N ;w  
nEndPos = " + nFileLength); /pRv i>_(:  
// fileSplitterFetch[nPos.length-1].start(); 
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//等待子线程结束 _rSwQ<38>  
//int count = 0; D_(NLC  
//是否结束while循环 d v4~CW%Td  
boolean breakWhile = false; 8i^ ./P  
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while(!bStop) H{*rV>%  
{ LT)I ?ud  
write_nPos(); VOYQ<tg  
Utility.sleep(500); ydVDjE Y  
breakWhile = true; Jr'a_(~  
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for(int i=0;i<nStartPos.length;i++) ]?V:+>t=  
{ M4|ION  
if(!fileSplitterFetch.bDownOver) k^d^Todq.  
{ NVQ.;"2w  
breakWhile = false; pSAtn  
break; ,+d8   
}  O,7S1  
} F7<u1Rx]  
if(breakWhile) 3;jxIo$,  
break; Z molL0y  
97HI9R  
 X   
//count++; Y4N7# 5  
//if(count>4) Js:U1q  
// siteStop(); ;I@\}!%H  
} AcJrJS)~  
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System.err.println("文件下载结束！"); u)zv`m  
} tYgHJ~1L*  
catch(Exception e){e.printStackTrace ();} DBGU:V,85  
} o; 6^:  
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)Ft+eMYti[  
//获得文件长度 b{&'r~

 
public long getFileSize() n5oX51J  
{ \FX"A#  
int nFileLength = -1; \ C$t  
try{ Ttl m&d+C  
URL url = new URL(siteInfoBean.getSSiteURL()); s;l"'6:_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *qYw  
httpConnection.setRequestProperty("User-Agent","NetFox"); <H#0pFB  
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int responseCode=httpConnection.getResponseCode(); YvuE:ia  
if(responseCode>=400) ukVBC"Ny  
{ ue?3;BF 5  
processErrorCode(responseCode); a>-qHX-l  
return -2; //-2 represent access is error Z0v?3v}9^  
} ]1zud  
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String sHeader; ~K5A$s2  
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for(int i=1;;i++) #=0 BjW*  
{ Y~!A"$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ? [5>
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//Utility.log(in.readLine()); $!$If( 7  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) 2yFT` 5+H4  
{ \1#]qs -  
if(sHeader.equals("Content-Length")) W2v'2qAs  
{ Gj%q:[r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f.%3G+  
break; 8mLW^R:`  
} =_j<x$,b-  
} @vib54G  
else ?7lW@U0  
break; liy/
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} .v}|Tp&k  
} {jwLVKT$  
catch(IOException e){e.printStackTrace ();} Zv@ Fr9m  
catch(Exception e){e.printStackTrace ();} N5`z S79W  
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Utility.log(nFileLength); 4M]l~9;A  
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return nFileLength; ~H   
} }kItVx  
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//保存下载信息（文件指针位置） Fv)E:PnKC  
private void write_nPos() MwQ4&z#wh  
{ O^6anUV0  
try{ _!vy|,w@e  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =-r); d  
output.writeInt(nStartPos.length); y3j"vKG  
for(int i=0;i<nStartPos.length;i++) |*b-m k  
{ Q@PDhISa  
// output.writeLong(nPos); XpkOCo02  
output.writeLong(fileSplitterFetch.nStartPos); |'P$zMAF  
output.writeLong(fileSplitterFetch.nEndPos); zG/? wP"  
} k?L2LIB<  
output.close(); mvTp,^1  
} Jd v;+HN[  
catch(IOException e){e.printStackTrace ();} '3sySsD&O  
catch(Exception e){e.printStackTrace ();} h<>yzr3fN  
} 9;\mq'v%  
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//读取保存的下载信息（文件指针位置） xsPt  
private void read_nPos() )[M:#;,L  
{ olL? 6)gC  
try{ 1ZRkVHiz0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q(q&(/  
int nCount = input.readInt(); cPAR.h,b?  
nStartPos = new long[nCount]; TXyiCS3  
nEndPos = new long[nCount]; Px*<-t|R-  
for(int i=0;i<nStartPos.length;i++) djw\%00&#  
{ |Ox='.oIb  
nStartPos = input.readLong(); xYW&Mfka  
nEndPos = input.readLong(); Y.tT#
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} zA.0Sm  
input.close(); Q[q`)~|  
} -/Wf iE  
catch(IOException e){e.printStackTrace ();} nSBhz  
catch(Exception e){e.printStackTrace ();} `]@=Hx(  
} 6@8z3JW.A  
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private void processErrorCode(int nErrorCode) WK7?~R%rq  
{ 7OG:G z+)x  
System.err.println("Error Code : " + nErrorCode); g3{UP]Z71  
} gVR]z9  
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//停止文件下载 IPYwUix  
public void siteStop() y@LiUe5  
{ <LXx_{=:  
bStop = true; xh9$ZavB*  
for(int i=0;i<nStartPos.length;i++) >zL5*:G  
fileSplitterFetch.splitterStop(); p nI=
 
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} %+Z*-iX  
} iI7ocyUv  
//负责部分文件的抓取 woPj>M  
**FileSplitterFetch.java ybJwFZ80  
*/ NT5
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package NetFox; t:vBVDkD  
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import java.io.*; !d!u{1Y&  
import java.net.*; pPo xx"y  
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public class FileSplitterFetch extends Thread { |rZM
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String sURL; //File URL Yb/*2iWX  
long nStartPos; //File Snippet Start Position 9`
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long nEndPos; //File Snippet End Position s<k2vbhI  
int nThreadID; //Thread's ID ]Zc|<f;  
boolean bDownOver = false; //Downing is over -rm[.  
boolean bStop = false; //Stop identical bGgpPV  
FileAccessI fileAccessI = null; //File Access interface HDZl
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &g^*ep~|#  
{ t
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this.sURL = sURL; >X05f#c"v/  
this.nStartPos = nStart; Fr  
this.nEndPos = nEnd; P+|L6w*|[  
nThreadID = id; B,w ZI4oi*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ox-eB  
} 'EXx'z;/#  
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public void run() <"P-7/j3j  
{ =D Q:0w  
while(nStartPos < nEndPos && !bStop) p&]V!O  
{ {A
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qa )BbK^i  
try{ xLOQu.  
URL url = new URL(sURL); 4m1r@ $  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KAFR.h:p9  
httpConnection.setRequestProperty("User-Agent","NetFox"); NE8W--Cg|  
String sProperty = "bytes="+nStartPos+"-"; tB,(12@W  
httpConnection.setRequestProperty("RANGE",sProperty); sTlel&  
Utility.log(sProperty); q=BljSX  
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InputStream input = httpConnection.getInputStream(); }F_c0zM  
//logResponseHead(httpConnection); fZ7AGP   
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byte[] b = new byte[1024]; FC,=g`Q!  
int nRead; RLnL9)`W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !+^'Ej)z  
{ uu,F5<y[  
nStartPos += fileAccessI.write(b,0,nRead); ZqVbNIY  
//if(nThreadID == 1) 'OziP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =huV(THU  
} .)!QsBU  
;'uQBx}  
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Utility.log("Thread " + nThreadID + " is over!"); Hn(1_I%zF  
bDownOver = true; }A24;'}  
//nPos = fileAccessI.write (b,0,nRead); V\<2oG  
} R54
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catch(Exception e){e.printStackTrace ();} X(nyTR8  
} K=v:qY4Z  
} ?[NC}LC  
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//打印回应的头信息 PLc5m5  
public void logResponseHead(HttpURLConnection con) &o;0%QgF  
{
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for(int i=1;;i++) 71c[`h*0{  
{ \{lv~I  
String header=con.getHeaderFieldKey(i); Zg(Y$ h\  
if(header!=null) vCaN[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UGhEaKH~R  
Utility.log(header+" : "+con.getHeaderField(header)); [c 8=b,EI  
else H,X|-B  
break; 0Lxz?R x]<  
} 8v& \F  
} qM(}|fMbN  
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public void splitterStop() f`uRC-B/  
{ 2(xC|  
bStop = true; E s5:S#  
} 8I#ir4z#<  
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} @ivd|*?k0  
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/* D%YgS$p[M$  
**FileAccess.java MCT1ZZpPr  
*//文件访问(定位，写) Fr8GGN~/  
package NetFox; }#O!GG{  
import java.io.*; oY18a*_>M1  
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public class FileAccessI implements Serializable{ J/?Nf2L4  
// o.+?S  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LSJ?;Zg(=z  
RandomAccessFile oSavedFile; d]l8ei@>h  
long nPos; ZYwcB]xEz  
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public FileAccessI() throws IOException )?*YrWO{  
{ I9*cEZ!l=e  
this("",0); n~*".ZC'Y  
} -1g:3'% P  
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public FileAccessI(String sName,long nPos) throws IOException g\JJkXjD#  
{ V0\[|E;F  
oSavedFile = new RandomAccessFile(sName,"rw"); HgF;[rq3Q  
this.nPos = nPos; >M,oyM"s  
oSavedFile.seek(nPos); $RaN@& Wm  
} )|F|\6:ne  
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public synchronized int write(byte[] b,int nStart,int nLen) kz"uTJK  
{ 9Yx(u2PQ  
int n = -1; 'x!\pE-  
try{ afEa@et'  
oSavedFile.write(b,nStart,nLen); V)`2Kw  
n = nLen; IY`p7 )#i  
} =?fz-HB  
catch(IOException e) $<^t][{  
{ Dm>"c;2  
e.printStackTrace (); IU
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} fd\RS1[  
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,^#Jw`w^  
return n; yGZsNd {a&  
} S(Yd.Sp  
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} S\k<  
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/* Ej(Jj\  
**SiteInfoBean.java 'Zfg
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*/ Ey46JO"  
package NetFox; c3A\~tHW  
|\5^ub,m  
0lfK} a  
public class SiteInfoBean { eU?hin@X  
!'7fOP-J]  
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private String sSiteURL; //Site's URL ~C.*Vc?|  
private String sFilePath; //Saved File's Path 0+1wi4wy/  
private String sFileName; //Saved File's Name 1uw#;3<L  
private int nSplitter; //Count of Splited Downloading File 0B NLTRv  
xt{'Be&Ya+  
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public SiteInfoBean() &NE e-cb
[  
{//nSplitter的缺省值为5 X%1TsCKMj  
//default value of nSplitter is 5 rH+OXGoB  
this("","","",5); 3FEJ 9ZyG  
} b'H'QY   
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hvd}l8  
{ Y::0v@&(  
sSiteURL= sURL; lfGyK4:  
sFilePath = sPath; C$
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sFileName = sName; T(4d5 fY  
this.nSplitter = nSpiltter; ]T4/dk&|o^  
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} n/H OP  
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public String getSSiteURL() v<qh;2  
{ '=\}dav!  
return sSiteURL; I$n=>s  
} d"$8-_K  
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public void setSSiteURL(String value) y}Ky<%A!P  
{ n\#YGL<n  
sSiteURL = value; 29R-Up!SVN  
} WL$^B@gXQ  
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public String getSFilePath() qfkHGW?1/j  
{ |.IH4 K  
return sFilePath; ,b+NhxdZ  
} R`?l.0  
4JSPD#%f  
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public void setSFilePath(String value) =lXj%V^8N  
{ ]|;+2@kDR  
sFilePath = value; (}"D x3K
 
} ,w }Po  
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j  
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public String getSFileName() 8#I>`z^F  
{ .=_p6_G  
return sFileName; eE;tiX/  
} -wlj;U  
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public void setSFileName(String value) A5?"  
{ <Ox[![SR
 
sFileName = value; <3YZ0f f>  
} ]`E+HLEQ'  
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public int getNSplitter() |Td+,>,  
{ ejRK-!  
return nSplitter; ajbe7#}  
} ijI/z5  
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y>{:[L9*  
public void setNSplitter(int nCount) :fRXLe1=  
{ qZoDeN-CC  
nSplitter = nCount; UNI< r  
} I Mgd2qIC  
} `h}eP[jA  
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d{ (,Gy>I  
/* Fc[KIG3@  
**Utility.java IS C.~q2  
*/ l}{{7~C`  
package NetFox; NGra/s,9|  
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public class Utility { lwnO  
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public Utility() ;'!x  
{ !\]^c  
(Guzj*12  
]{-.?W*$  
} jA? #!lx_  
NgNGq\!  
//线程睡眠 Hg+<GML  
public static void sleep(int nSecond) P{L=u74b{x  
{ }v(wjD  
try{ 6*8Wtq  
Thread.sleep(nSecond); V>$( N/1  
} "SF0b jG9C  
catch(Exception e) Y~~Dg?e  
{ wNONh`b  
e.printStackTrace (); ,'NasL8?We  
} .^YxhUH,G  
} 5
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337.' |ZE  
//日志 ROO*/OOd  
public static void log(String sMsg) ?7{U=1gb$  
{ |%_C$s%  
System.err.println(sMsg); *%-<Ldv  
} .soCU8i3  
}A9#3Y|F  
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public static void log(int sMsg) Z[vx0[av&  
{ FOaA}D `]  
System.err.println(sMsg); gv!8' DKn  
} Z0|5VLk,<{  
} s8j |>R|k  
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/* r}U6LE?>  
**TestMethod.java x"r0<RK  
*/ u ExLj6  
package NetFox; T+8Yd(:hX  
?y>N&\pt2  
g/?Vl2W  
public class TestMethod { G

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#h!+
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c '|*{%<e2  
public TestMethod() |jsI-?%8J  
{ ///xx/weblogic60b2_win.exe verI~M$v{  
try{ kuY^o,u-1e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B`pBIUu  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;W|kc</R*  
fileFetch.start(); UhB+c  
} ?7\V)$00(&  
catch(Exception e){e.printStackTrace ();} UG1<Xfu|  
,f03TBD}  
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} 8jK=A2pTa  
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public static void main(String[] args) e8,_"_1:F  
{ UBo0c?,4  
new TestMethod(); S)CsH1Q  
} '2,~'Zk  
} HG]ARgOB  
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