http断点续传简单实现（java)

/* "i W"NFO  
**SiteFileFetch.java 4x[S\,20  
*/ ~gRf:VXX=_  
package NetFox; 2P{Gxz<#  
import java.io.*; T:W4$P  
import java.net.*; Jma1N;d  
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public class SiteFileFetch extends Thread { k~ /Nv=D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gEE\y{y  
long[] nStartPos; //开始位置 x{WD;$J  
long[] nEndPos; //结束位置 TBU&6M>{3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rguCp}r  
long nFileLength; //文件长度 c=.(!qdH  
boolean bFirst = true; //是否第一次取文件 TT3|/zwn  
boolean bStop = false; //停止标志 %FIE\9  
File tmpFile; //文件下载的临时信息 fIv*T[  
DataOutputStream output; //输出到文件的输出流 1c{DY  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PBkt~=j  
public SiteFileFetch(SiteInfoBean bean) throws IOException &H:(z4/  
{ t |A-9^t'!  
siteInfoBean = bean; Wbq
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d)f :)Ew  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,',o'2=!  
if(tmpFile.exists ()) S\!ana])
 
{ ;cN{a&  
bFirst = false; [Nbm
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read_nPos(); (mtk 4  
} C/6V9;U  
else PdtvU-(  
{ X1vd'
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nStartPos = new long[bean.getNSplitter()]; j9+w#G]hV  
nEndPos = new long[bean.getNSplitter()]; #';:2Nyq  
} K~ehP[^  
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} ]^K4i)\  
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public void run() yFlm[K5YD  
{ ..'_o~Ka  
//获得文件长度 L"Olwwmk  
//分割文件 qE3UO<FA  
//实例FileSplitterFetch +-CtjhoS  
//启动FileSplitterFetch线程 |T)6yDL  
//等待子线程返回 =k`Cr0aPF  
try{ Jd^,]  
if(bFirst) k%QpegN  
{ KE3;V2Ym f  
nFileLength = getFileSize(); >{J(>B
\  
if(nFileLength == -1) q\p:X"j|  
{ 5 -RsnF  
System.err.println("File Length is not known!"); |f_[\&<*  
} b-Q>({=i  
else if(nFileLength == -2) =uYYsC\T  
{ Hm'=aff6A  
System.err.println("File is not access!"); 6 EC*  
} 3/W'V,5G6  
else q0r>2c-d  
{ :~N-.#  
for(int i=0;i<nStartPos.length;i++) wLJ:\_Jaf  
{ xx9 g
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); <oA7'|Bu<  
} 7f!YoW;1  
for(int i=0;i<nEndPos.length-1;i++) y0.8A-2:  
{ 0+;bh {Eu  
nEndPos = nStartPos[i+1]; F Yz
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} D}8[bWF  
nEndPos[nEndPos.length-1] = nFileLength; Tl
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} .Blf5b  
} po Vx8oO8  
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qUGC"<W  
//启动子线程 RM]M@%,K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 22M1j5  
for(int i=0;i<nStartPos.length;i++) A5R<p+t6  
{ K
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OJ5#4qJ[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :hFIl0$,"3  
nStartPos,nEndPos,i); }Nm#q@o$P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Xi,CV[L\  
fileSplitterFetch.start(); %'7lbpy,f  
} @ljA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |G,tlchprs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dj7hx"BI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p,>5\Zre
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nEndPos = " + nFileLength); J1I ;Jgql(  
// fileSplitterFetch[nPos.length-1].start(); k_5L4
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:f}9
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//等待子线程结束 Y^7
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//int count = 0; !1DKLQ  
//是否结束while循环 nv%rJy*w[  
boolean breakWhile = false; EwC{R`  
,3p~w5C/+[  
(#Gw1  
while(!bStop) IsM}'.  
{ F{Jw^\  
write_nPos(); TKY*`?ct  
Utility.sleep(500); uU <=d  
breakWhile = true; D=m9fFz  
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for(int i=0;i<nStartPos.length;i++) F6OpN"UM'  
{ ")dH,:#S  
if(!fileSplitterFetch.bDownOver) 8I8 F/47x  
{ v7jq@#-   
breakWhile = false; 4UlyxA~  
break; 6[LM_eP  
} XY)&}u.  
} bRJMYs  
if(breakWhile) ?_$=l1vf  
break; gp^5#  
k*E\B@W>  
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//count++; Y/>&0wj)d  
//if(count>4) jN>{'TqW4  
// siteStop(); [t7]{d*  
} +!z{5:  
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System.err.println("文件下载结束！"); v!Pb`LCqK  
} <2|O:G  
catch(Exception e){e.printStackTrace ();} =aA+~/~8%  
} %Nhx;{  
8V)^R(\;  
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//获得文件长度 65p?Igb  
public long getFileSize() V7[zAq  
{ , GY h9  
int nFileLength = -1; ? glSC$b  
try{ e~@[18  
URL url = new URL(siteInfoBean.getSSiteURL()); 6morum  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f3{MvAy[  
httpConnection.setRequestProperty("User-Agent","NetFox"); n\5RAIg  
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int responseCode=httpConnection.getResponseCode(); #hf ak  
if(responseCode>=400) iz?tu: \v&  
{ O.Iu6D  
processErrorCode(responseCode); Z@&Dki  
return -2; //-2 represent access is error Xn,v]$M!  
} 9h%?QC  
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String sHeader; s]mY*@a%  
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for(int i=1;;i++) IlE_@gS8  
{ YoLx>8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (85Fv&a  
//Utility.log(in.readLine()); <Ib[82PU  
sHeader=httpConnection.getHeaderFieldKey(i); [],1lRYI9_  
if(sHeader!=null) !]fQ+*X0g  
{ w'fT=v
)  
if(sHeader.equals("Content-Length")) B`o]*"xkB  
{ EV^~eTz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OhmQ,  
break; GbA.UM~  
} QgD g}\P  
} W4U@%b do  
else ^Q ps>A(  
break; ,4,V4 N  
} ]f: v,a  
} 6"t;gSt4  
catch(IOException e){e.printStackTrace ();} 5qkH|*Z3  
catch(Exception e){e.printStackTrace ();} 7aYn0_NKp  
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Utility.log(nFileLength); aKlUX  
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return nFileLength; UMp/
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} ?EpSC&S\  
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//保存下载信息（文件指针位置） zrv#Xa!O\  
private void write_nPos() $DC*i-}qFg  
{ kR@Yl Yo  
try{ #9fWA
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output = new DataOutputStream(new FileOutputStream(tmpFile)); uV hCxUMQ  
output.writeInt(nStartPos.length); `)h6j)xiQ  
for(int i=0;i<nStartPos.length;i++) TLf9>= OVh  
{ {d%&zvJnD  
// output.writeLong(nPos); %Lrd6i_j  
output.writeLong(fileSplitterFetch.nStartPos); ~i_Tw#}  
output.writeLong(fileSplitterFetch.nEndPos); gx:;&4AD  
} 8dOo Q  
output.close(); c$,_>tcP  
} <U9/InN0[  
catch(IOException e){e.printStackTrace ();} A[dvEb;r  
catch(Exception e){e.printStackTrace ();} b7\ cxgRq  
} u@P[Vb   
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//读取保存的下载信息（文件指针位置） LaIJ1jf  
private void read_nPos() lE ;jCN  
{ y3;q_4.  
try{ ]G}B 0u3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .LRxP#B  
int nCount = input.readInt(); !lmWb-v%36  
nStartPos = new long[nCount]; @l(vYJ:f  
nEndPos = new long[nCount]; F'?I-jtI  
for(int i=0;i<nStartPos.length;i++) HFQR ;9]  
{ zggB$5  
nStartPos = input.readLong(); KZ:8[d  
nEndPos = input.readLong(); rba;&D;  
}
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input.close(); 5[9bWB{  
} 5NXt$k5  
catch(IOException e){e.printStackTrace ();} OAZ#|U   
catch(Exception e){e.printStackTrace ();} ]Lqt(c  
} &?p
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private void processErrorCode(int nErrorCode) 0gF!!m  
{ :Ze+%d=  
System.err.println("Error Code : " + nErrorCode); &Rz, J]  
} I#FF*@oeM  
}98>5%Uv  
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//停止文件下载 w,jcm;  
public void siteStop() 1(GHCxA8G  
{ F X1ZG!  
bStop = true; snp v z1iS  
for(int i=0;i<nStartPos.length;i++) `Xcirfp  
fileSplitterFetch.splitterStop(); 4*UP.r@  
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} =j /hl  
} tllBCuAe  
//负责部分文件的抓取 e}cnX`B  
**FileSplitterFetch.java )Z@-DA*Q-  
*/ f
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package NetFox; jV7&Y.$zF]  
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import java.io.*; C@HD(..
#  
import java.net.*; Hr
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public class FileSplitterFetch extends Thread { Ew^ @Aq  
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String sURL; //File URL ,R-Y~+!  
long nStartPos; //File Snippet Start Position ^^$vR[7  
long nEndPos; //File Snippet End Position DQ=N1pft2v  
int nThreadID; //Thread's ID mR":z|6  
boolean bDownOver = false; //Downing is over D?+ RJs
  
boolean bStop = false; //Stop identical <qiICb)~  
FileAccessI fileAccessI = null; //File Access interface /?zW<QUI  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Plz-7fy33  
{ + >sci  
this.sURL = sURL; TIRHT`"i  
this.nStartPos = nStart; zw:/!MS  
this.nEndPos = nEnd; r2G*!qK*1  
nThreadID = id; |Odu4 Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 = ?N^>zie  
} &?$\Y,{  
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public void run() yer> x  
{ |qL;Nu,d  
while(nStartPos < nEndPos && !bStop) O=O(3Pf>  
{ o?R,0 -  
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try{ 712=rUI%!  
URL url = new URL(sURL); Z oTNm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >7FSH"8[,  
httpConnection.setRequestProperty("User-Agent","NetFox"); tq E>Zx=X  
String sProperty = "bytes="+nStartPos+"-"; &8Wlps`
 
httpConnection.setRequestProperty("RANGE",sProperty); px&=((Z7>  
Utility.log(sProperty); mahi7eU P  
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InputStream input = httpConnection.getInputStream(); byj[u!{  
//logResponseHead(httpConnection); zlX!xqHj  

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byte[] b = new byte[1024]; |\p5mh  
int nRead; pFH?/D/q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =w,(M  
{ ?HxS)Pqq  
nStartPos += fileAccessI.write(b,0,nRead); xucIjPi]
 
//if(nThreadID == 1) LI$L9eNv;Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2vXGO|W  
} s{%fi*  
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Utility.log("Thread " + nThreadID + " is over!"); IgiqFV{  
bDownOver = true; :,=Fx</H  
//nPos = fileAccessI.write (b,0,nRead); \1khyF'  
} |x[$3R1@  
catch(Exception e){e.printStackTrace ();} v7$9QVze  
}
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} @>9A$w$H|a  
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//打印回应的头信息 Lj-{t% }  
public void logResponseHead(HttpURLConnection con) u> In(7\  
{ dTgM"k  
for(int i=1;;i++) K+t];(  
{ bAdAp W  
String header=con.getHeaderFieldKey(i); {C, #rj  
if(header!=null) ees^O{ 8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A9.;>8!u  
Utility.log(header+" : "+con.getHeaderField(header)); K;kLQ2)  
else 
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break; qFGB'mIrFz  
} #s/{u RYQ  
} aliQ6_  
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public void splitterStop() 6;[1Jz]?i  
{ 5]Z]j[8Y  
bStop = true; DD)mN) &T  
} )<tzm'Rc  
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} xQ_:]\EZ  
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/* 9O2a | d  
**FileAccess.java )OS>9 kFH  
*//文件访问(定位，写) FK?mS>G6  
package NetFox; re2Fv:4{  
import java.io.*; Zt7hzW  
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public class FileAccessI implements Serializable{ K7y!s :rg!  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `8qT['`#R  
RandomAccessFile oSavedFile; oT$(<$&<  
long nPos; Bl:{p>-q  
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public FileAccessI() throws IOException DHSU?o#jY  
{ :K!GR  
this("",0); Uv#>d}P  
} :H~UyrN  
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public FileAccessI(String sName,long nPos) throws IOException UA1]o5K  
{ {-:4O\/  
oSavedFile = new RandomAccessFile(sName,"rw"); "{,\]l&o  
this.nPos = nPos; 9;r48)5  
oSavedFile.seek(nPos); )UxQf37  
} f]{1ZU%4  
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public synchronized int write(byte[] b,int nStart,int nLen) d"QM;9  
{ H'j_<R N  
int n = -1; g]oc(RM  
try{ ^\Ue7,H-  
oSavedFile.write(b,nStart,nLen); U4 go8  
n = nLen; |>jqH @\P  
} ;C7BoHB9  
catch(IOException e) FB?q/_  
{ [e
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e.printStackTrace (); 1(
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} &Sa_%:*D(  
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return n; c,{&  
} fwar8 i1  
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} *_<SWTE
 
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/* `W.vW8!#  
**SiteInfoBean.java 0k.#  
*/ >qh>Qm8w  
package NetFox; Y3sNr)qss  
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public class SiteInfoBean { d=c1WK  
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private String sSiteURL; //Site's URL o0-fUCmC  
private String sFilePath; //Saved File's Path KNUMz4  
private String sFileName; //Saved File's Name /o}0oo5B  
private int nSplitter; //Count of Splited Downloading File +Y>cBSO  
 5K_N  
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public SiteInfoBean() f;_K}23  
{//nSplitter的缺省值为5 oto wvm  
//default value of nSplitter is 5 EFT02#F_f  
this("","","",5); jmZ|b6  
} #4|i@0n}D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =^%Pwkz  
{ ^r?sgJ  
sSiteURL= sURL; ;?Y`e  
sFilePath = sPath; "*H'bzK  
sFileName = sName; ]J"+VZ_"I  
this.nSplitter = nSpiltter; 9DP75 ti  
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} U K]{]-  
uN?O*h/(  
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public String getSSiteURL() VdN+~+A:  
{ {bq-: CZe  
return sSiteURL; oJz:uv8Pe.  
} QWQ6j#`  
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5M.n'*   
public void setSSiteURL(String value) f'?6D+Yw~  
{ 7`'fUhB!  
sSiteURL = value; %>*0.)wG  
} 1{fwr1b  
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public String getSFilePath() 4Xb}I;rM  
{ gm%bxr@X~  
return sFilePath; Q17o5##x7  
} 1 0Tg> H  
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=g>7|?6>=  
public void setSFilePath(String value) Qd)cFL"v  
{ HZQ3Ht3Vh  
sFilePath = value; ~9ls~$+*  
} OTjryJ^  
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public String getSFileName() `F`'b)  
{ oB}G^t  
return sFileName; -D^y)  
} sN`o_q{Q  
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public void setSFileName(String value) 'jlXLb  
{ aKFA&Xnsl  
sFileName = value; |>fS"u  
} 2P>za\  
5Yibv6:3a  
F p=Q$J|  
public int getNSplitter() C-b%PgA  
{ Y>!W&Gtu  
return nSplitter; v+_Y72h*a  
} 58ZiCvqv  
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public void setNSplitter(int nCount) xgw)`>p,W  
{ 5z mHb  
nSplitter = nCount; ?g#t3j>zoF  
} ~5dq5_  
} Gy7x?  
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/* 92ww[+RQ@  
**Utility.java Saq>o.  
*/ nVA'O  
package NetFox; \
#c+vfq  
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public class Utility { |}.B!vg(4  
}u
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public Utility() h_"/@6  
{ R6o<p<fTh  
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} kAQZj3P]  
&Zy=vk*  
//线程睡眠 $ttr_4=  
public static void sleep(int nSecond) :=7;P)  
{ /1 %0A  
try{ CKw)J}z  
Thread.sleep(nSecond); QjbPBk Q  
} vszAr
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catch(Exception e) Y]0y -H  
{ yk6UuI^/  
e.printStackTrace (); g' U^fN  
} 7%}}m&A7h  
} 717m.t,x  
T mE4p  
//日志 3YF]o9  
public static void log(String sMsg) zQfxw?~A  
{ m;1exa  
System.err.println(sMsg); H pfI  
} rmoEc]kt]  
/kVc7LC  
v
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public static void log(int sMsg) 5E(P,!-.  
{ oob0^}^  
System.err.println(sMsg); ,"R_ve  
} FJiP>S[]  
} \{mJO>x  
r
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/* \~1+T  
**TestMethod.java He23<hd!  
*/ P6'I:/V  
package NetFox; bcs(#  
^/,yZ:  
7[ji,.7  
public class TestMethod { AtYYu  
=Bx~'RYl1d  
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public TestMethod() DZZt%n8J  
{ ///xx/weblogic60b2_win.exe ( mMz]b5  
try{ }H.vH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,FO|'l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |sAg@kM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); __npX_4%S  
fileFetch.start(); !IU*Ayg  
} ?J-KB3Uv3  
catch(Exception e){e.printStackTrace ();} -l
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} 'M/&bu r  
9$i`B>C
~  
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public static void main(String[] args) 0<k!F3=  
{ ^f]pK&MAmN  
new TestMethod(); .ji%%f  
} #Xly5J  
} +(0eOO'\M  
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