http断点续传简单实现（java)

/* &, a3@i  
**SiteFileFetch.java ~qP[eWe  
*/ >{zk qvsQ&  
package NetFox; x!<yT?A  
import java.io.*; |V,<+BEi  
import java.net.*; *f+: <=i  
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public class SiteFileFetch extends Thread { E,[xUz"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X[$++p .
  
long[] nStartPos; //开始位置 fxQN+6;  
long[] nEndPos; //结束位置 ssQ BSbx
  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %yS3&Ju  
long nFileLength; //文件长度 3251Vq %  
boolean bFirst = true; //是否第一次取文件 1R%1h9I4'  
boolean bStop = false; //停止标志 ro~+j}*  
File tmpFile; //文件下载的临时信息 y'C-[nk  
DataOutputStream output; //输出到文件的输出流 Tny>D0Z#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =6nD sibf  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5jcte< 5I_  
{ S=|@L<O  
siteInfoBean = bean; Q /x8 #X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~aK?cP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qt e>r  
if(tmpFile.exists ()) pW\'ZRj  
{ )X+mV  
bFirst = false; 6QQfQ,  
read_nPos(); qCQ./"8  
} 15\Ph[6g  
else ! NV#U  
{ *?p|F&J  
nStartPos = new long[bean.getNSplitter()]; j Ch=@<9  
nEndPos = new long[bean.getNSplitter()]; Q4]4@96Aj  
} kLSrj
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} eDKxn8+(H  
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public void run() F=a+z/xKT  
{ &dB-r&4;+  
//获得文件长度 %q3$|>  
//分割文件 !RvRGRSyF  
//实例FileSplitterFetch lEjwgk {  
//启动FileSplitterFetch线程 /
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//等待子线程返回 F'RUel_%  
try{ =3xE:  
if(bFirst) 7E$&2U^Js  
{ iP@6hG`:  
nFileLength = getFileSize(); iPG0o %  
if(nFileLength == -1) *~XA'Vw!  
{ Kb;dKQ  
System.err.println("File Length is not known!"); $D1w5o-  
} RBKOM$7  
else if(nFileLength == -2) :*514N  
{ ]jMKC8uz  
System.err.println("File is not access!"); dtStTT  
} S^I,Iz+`S'  
else 7j<e)"  
{ Dr3n+Q  
for(int i=0;i<nStartPos.length;i++) m|tC24  
{ DbI!l`Vn4  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} 6]cryf&b  
for(int i=0;i<nEndPos.length-1;i++) U%<rn(xWXD  
{ }j5 a[L  
nEndPos = nStartPos[i+1]; alMYk  
}  l~s7Ae  
nEndPos[nEndPos.length-1] = nFileLength; Yf_6PGNzX  
} ;r\(p|e  
} Z4TL6]^R  
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b,H[I!. %  
//启动子线程 I5ss0JSl/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ={2!c0s  
for(int i=0;i<nStartPos.length;i++) nwI3|&  
{ B:TR2G9UT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e0,'+;*=g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h+~P"i}&\  
nStartPos,nEndPos,i); Nil}js27  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d
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fileSplitterFetch.start(); M5L{*>4|6  
} |H}sYp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 66&EBX}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >zvY\{WY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IV16d  
nEndPos = " + nFileLength); Oft arD  
// fileSplitterFetch[nPos.length-1].start(); Y&bMCI6U  
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.\Fss(Zn  
//等待子线程结束 U%B(5cC  
//int count = 0; b}!3;:iD  
//是否结束while循环 Z [Xa%~5>5  
boolean breakWhile = false; `NRH9l>B7  
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while(!bStop) P@}Pk  
{ Et2JxbD  
write_nPos(); shC;hR&;  
Utility.sleep(500); :t$aN|>y  
breakWhile = true; ihe(F7\U  
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for(int i=0;i<nStartPos.length;i++) 0>Z ;Ni  
{ 
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if(!fileSplitterFetch.bDownOver) \{\MxXW  
{ $& ~;@*[  
breakWhile = false; D87|q4  
break; &-yGVx  
} &a)eJF]:!  
} q0mOG^  
if(breakWhile)  NW9n  
break; ?8@>6IXn  
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//count++; yoe}
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//if(count>4) imL_lw^?  
// siteStop(); b;mSQ4+  
} \uOdALZ  
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System.err.println("文件下载结束！"); a~LC+8|JW  
} @DAF 6ygs  
catch(Exception e){e.printStackTrace ();} <G8w[hs  
} %GEJnJ  
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//获得文件长度 "VxWj}+]  
public long getFileSize() ,{eUP0]  
{ h&@R| N  
int nFileLength = -1; |aToUi.Q%  
try{ x<i}_@Sn_+  
URL url = new URL(siteInfoBean.getSSiteURL()); {U!St@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z{NC
9  
httpConnection.setRequestProperty("User-Agent","NetFox"); VObrlOkp  
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int responseCode=httpConnection.getResponseCode(); `<"m%>  
if(responseCode>=400) 9Mm!%Hu  
{ yR~-k?7b  
processErrorCode(responseCode); i7[uL
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return -2; //-2 represent access is error `BFIC7a  
} ~:Uwg+]j  
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String sHeader; l7[7_iB&E  
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for(int i=1;;i++) qf)$$qi  
{ C&\5'[*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >XW
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//Utility.log(in.readLine()); $K~LM8_CKy  
sHeader=httpConnection.getHeaderFieldKey(i); oT
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if(sHeader!=null) E N^Uki`  
{ RuW!*LI  
if(sHeader.equals("Content-Length")) |dE -^"_  
{ >cmE t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9?T{}| ?  
break; ^D67y%  
} BfTcI)  
} /nx'Z0&+X  
else :7N3N  
break; 8 (jUe  
} w
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} =dP{Gh  
catch(IOException e){e.printStackTrace ();} c>bq%}  
catch(Exception e){e.printStackTrace ();} 4IdT'  
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Utility.log(nFileLength); <msxHw  
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return nFileLength; 0pe3L  
} +0z 7KO%^^  
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//保存下载信息（文件指针位置） OU DcY@x~  
private void write_nPos() ^ ?hA@{T/1  
{ %%%fL;-y  
try{ uv{P,]lK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pj#'}ru!  
output.writeInt(nStartPos.length); {y kYW%3s  
for(int i=0;i<nStartPos.length;i++) XV>JD/K2  
{ YOyX[&oi  
// output.writeLong(nPos); rPzQ8<  
output.writeLong(fileSplitterFetch.nStartPos); |w}w.%  
output.writeLong(fileSplitterFetch.nEndPos); +m\|e{G  
} }peBR80
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output.close(); [BbutGvj  
} 1MkI0OZE  
catch(IOException e){e.printStackTrace ();} XhU@W}}  
catch(Exception e){e.printStackTrace ();} T".]m7!  
} Mc sTe|X  
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9|'
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//读取保存的下载信息（文件指针位置） }71LLzG`/  
private void read_nPos() /Poet%XvRx  
{ (3vHY`9  
try{ &7?R+ZGo  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DsDzkwJE  
int nCount = input.readInt(); y
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nStartPos = new long[nCount]; )(Iy<Y?#  
nEndPos = new long[nCount]; Tm]nEl)_  
for(int i=0;i<nStartPos.length;i++) ,0$)yZ3*3,  
{ R/b4NGW@  
nStartPos = input.readLong(); J a,d3K  
nEndPos = input.readLong(); r~[vaQQ6L  
} m,LG=s  
input.close(); lEL78l.  
} 01a-{&   
catch(IOException e){e.printStackTrace ();} u8
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catch(Exception e){e.printStackTrace ();} !,$i6gm  
} 1nj(hg  
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private void processErrorCode(int nErrorCode) Ru!He,k7  
{ @pV5}N[]  
System.err.println("Error Code : " + nErrorCode); z(RL<N%  
} ~K_Uq*dCE  
<{(/E0~V/<  
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//停止文件下载 X##1! ad
 
public void siteStop() !SOrCMHx  
{ eZhPu'id\s  
bStop = true; k ^'f[|}  
for(int i=0;i<nStartPos.length;i++) ?q2j3e[>  
fileSplitterFetch.splitterStop(); oj.A,Fh  
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} pfuW  
} Lr;(xw\[
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//负责部分文件的抓取 z~6y+  
**FileSplitterFetch.java Lju7,/UD  
*/ UQCo}vM  
package NetFox; k?nQ?B W  
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import java.io.*; u?ek|%Ok  
import java.net.*; I&c ~8Dw  
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public class FileSplitterFetch extends Thread { ~Z/ ^c,[:  
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String sURL; //File URL !H][LXB~H  
long nStartPos; //File Snippet Start Position ^^`Jcd/  
long nEndPos; //File Snippet End Position wJb#
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int nThreadID; //Thread's ID 2Tav;LKX  
boolean bDownOver = false; //Downing is over pVp:@0h  
boolean bStop = false; //Stop identical `i~ Y Fr  
FileAccessI fileAccessI = null; //File Access interface x LBQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +#@"*yj3  
{ .k{ j]{k  
this.sURL = sURL; u#7+U\  
this.nStartPos = nStart; Q~D`cc|]  
this.nEndPos = nEnd; IHfzZHy  
nThreadID = id; S&C1TC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xZ5M/YSyG  
} Z[!d*O%R_  
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public void run() o;"OSp  
{ >Y 1{rSk  
while(nStartPos < nEndPos && !bStop) K[\'"HyQ,X  
{ -u!qrJ*Z  
stl 1QO(h  
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try{ TZir>5  
URL url = new URL(sURL); %wV>0gQTf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }H4=HDO  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5y2? f  
String sProperty = "bytes="+nStartPos+"-"; aFiCZHohw  
httpConnection.setRequestProperty("RANGE",sProperty); r9 y.i(j
 
Utility.log(sProperty); _zxLwU1(x  
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InputStream input = httpConnection.getInputStream(); jg 2qGC  
//logResponseHead(httpConnection); ^ OJyN,A  
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byte[] b = new byte[1024]; ~H)4)r^  
int nRead; $v.C0 x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9_ICNG%  
{ M/PFPJ >`  
nStartPos += fileAccessI.write(b,0,nRead); $DFv30 f  
//if(nThreadID == 1) QlFZO4 P3|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?8dVH2W.  
} y<R=  
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Utility.log("Thread " + nThreadID + " is over!"); $m1<i?'m  
bDownOver = true; YIt9M,5/Q  
//nPos = fileAccessI.write (b,0,nRead); M x5`yT7  
} %HQ.|  
catch(Exception e){e.printStackTrace ();} FFhtj(hVgc  
} 1 "TVRb  
} =6FUNvP#8  
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//打印回应的头信息 +1C3`0(  
public void logResponseHead(HttpURLConnection con) wyx(FinIH  
{ $VG*q  
for(int i=1;;i++) <[aDo%,A  
{ qpoV]#iW  
String header=con.getHeaderFieldKey(i); %x;x_  
if(header!=null) =M6[URZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r#PMy$7L  
Utility.log(header+" : "+con.getHeaderField(header)); _eSdnHWx  
else LVIAF0kX  
break; "}WJd$
 
} o 6{\Zzp  
} Bsf7mcXz7z  
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public void splitterStop() }*]B-\>  
{ v1U?&C  
bStop = true; )/ Ud^wi  
} rr`;W}3  
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} 0oA{Jix  
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/* [./6At&
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**FileAccess.java }/dRU${!  
*//文件访问(定位，写) ubsSa}$q  
package NetFox; #BVtL :x@  
import java.io.*; $aCd/&  
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public class FileAccessI implements Serializable{ U=Y)V%  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 sRVIH A,  
RandomAccessFile oSavedFile; C-eA8pYY/  
long nPos; # M,
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public FileAccessI() throws IOException Jo(`zuLJ  
{ 0X8t>#uF  
this("",0); Eh</? Qv\  
} s>_V   
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public FileAccessI(String sName,long nPos) throws IOException c'6g*%2k  
{ 'XQ`g CF=  
oSavedFile = new RandomAccessFile(sName,"rw"); 0Q,g7K<d  
this.nPos = nPos; }uHrto3M  
oSavedFile.seek(nPos); iF5'ygR-Z  
} c:S] R"  
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public synchronized int write(byte[] b,int nStart,int nLen) "@@I!RwA  
{ [97:4.  
int n = -1; +[@z(N-h  
try{ j| Wv7  
oSavedFile.write(b,nStart,nLen); \?>Hu v  
n = nLen; @5
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} 'X).y1'  
catch(IOException e) 0<"k8 k@J  
{ <tpmUA[]  
e.printStackTrace (); Q'l^9Bz  
} zepop19  
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return n; M}:=zcZ l  
} +;BAV  
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;  
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} #1c]PX  
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/* T J^u"j-'  
**SiteInfoBean.java dF0,Y?  
*/ a)Q!'$"'  
package NetFox; V6$xcAE"</  
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public class SiteInfoBean { R_]{2~J+  
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private String sSiteURL; //Site's URL VUTacA Y>L  
private String sFilePath; //Saved File's Path 65z"  
private String sFileName; //Saved File's Name ^ &E}r{?  
private int nSplitter; //Count of Splited Downloading File kp?w2+rz  
1XG!$4DW  
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public SiteInfoBean() YzosZ! L!<  
{//nSplitter的缺省值为5 dpQG[vXe  
//default value of nSplitter is 5 { pu85'DV  
this("","","",5); ERwHLA  
} V^y^ ;0I}[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T +5X0 Nv  
{ `k(yZtb  
sSiteURL= sURL; s &Dg8$  
sFilePath = sPath; W{z.?$SH  
sFileName = sName; G6V
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this.nSplitter = nSpiltter; &<zd.~N"  
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} ]v[|B  
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public String getSSiteURL() 2._X|~0a  
{ JvYPC  
return sSiteURL; !8 &=y  
} T5urZq*R  
+% /s*EC'w  
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public void setSSiteURL(String value) Iff9'TE  
{ '65LKD  
sSiteURL = value; ~HQ9i%exg  
} Li*eGlId  
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public String getSFilePath()  u66XN^  
{ Z*G(5SqUh"  
return sFilePath; W\1i,ew>  
} f%5zBYCgC  
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public void setSFilePath(String value) Lb LiB*D#s  
{ MO;X>D=  
sFilePath = value; e1//4H::t  
} A+@&"  
rt JtK6t  
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public String getSFileName() 3_JCU05H}  
{ TW !&p"Us+  
return sFileName; (&$VxuJ+6y  
} !lo/xQ<  
}b1cLchl  
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public void setSFileName(String value) @FdSFQ/9  
{ #plY\0E@  
sFileName = value; ~>9_(L  
} q2HYiH^L  
4k./(f2+  
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public int getNSplitter() R^{)D3  
{ =4d (b ;  
return nSplitter; HF|oBX$_  
} w+1Gs ;  
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public void setNSplitter(int nCount) Z{'i F   
{ tTd\|  
nSplitter = nCount; |bgo;J/  
} bLt.O(T}  
} boG_f@dv(  
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/* @{Gncy|  
**Utility.java E7-@&=]v  
*/ Ov<NsNX]  
package NetFox; OR[{PU=X  
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public class Utility { `~eUee3b.~  
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public Utility() ftH:r_"O#  
{ KZPEG!-5  
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} dH
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//线程睡眠 uslQ*7S[^  
public static void sleep(int nSecond) $.]l!cmi%Q  
{ 86nN"!{l:  
try{ arf8xqR-U]  
Thread.sleep(nSecond); +^;JS3p@\  
} <$JaWL  
catch(Exception e) _V`DWR *  
{ JU&+c6>  
e.printStackTrace (); vm>b m  
} (h:Rh  
} 37}D9:#5C  
w3$   
//日志 b+Br=Fv"T  
public static void log(String sMsg) `p+Zz"/  
{ ToYAW,U[d  
System.err.println(sMsg); 47J5oPT2'  
} $\9~)Rq6  
8V~vXnkM  
%D *OO{  
public static void log(int sMsg) ?IpLf\n-  
{ (W}bG>!#Q8  
System.err.println(sMsg); >rvQw63\  
} CirZ+o  
} 6Cp]NbNrq  
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~K@'+5Pc  
/* 2WG>, 4W2  
**TestMethod.java .YuJJJv  
*/ "Wx]RN:  
package NetFox; <_
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d^`?ed\1  
%j7XEh<'  
public class TestMethod { @V!r"Bkg.  
bV"G~3COy  
p)+k=b  
public TestMethod() n0is\ZK 0  
{ ///xx/weblogic60b2_win.exe m)oJFF  
try{ [n}T|<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4WK3.6GN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6^DR0sO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m4*@o?Ow  
fileFetch.start(); G z)NwD  
} Po%(~ )S>  
catch(Exception e){e.printStackTrace ();} \QB;Ja
_  
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} I|Gp$uq _  
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public static void main(String[] args) #Skv(IL  
{ M'/aZ# b  
new TestMethod(); {26ONa#i
 
} bcupo:N  
} n93=8;&  
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