http断点续传简单实现（java)

/* --5F*a{R|  
**SiteFileFetch.java -YA,Stc-  
*/ n:5M E*  
package NetFox; [X(4
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import java.io.*; AC,RS7  
import java.net.*; lzEynMO+  
4>KF`?%4  
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public class SiteFileFetch extends Thread { 7~7L5PRW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^tB1Nu%  
long[] nStartPos; //开始位置 Vj*-E  
long[] nEndPos; //结束位置
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 }3(!kW  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 N^L@MR-  
boolean bStop = false; //停止标志 /R#zu_i  
File tmpFile; //文件下载的临时信息 DR#" 3  
DataOutputStream output; //输出到文件的输出流 ]E`<8hRB  
@*6fEG{,q  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &\h7E   
public SiteFileFetch(SiteInfoBean bean) throws IOException B8@mL-Z-;  
{ cAWn*%  
siteInfoBean = bean; &K^0PzWWof  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dOhSqx56  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v] m/$X2  
if(tmpFile.exists ()) QYH-"-)  
{ SI7rTJ]/  
bFirst = false; >ahDc!Jyu  
read_nPos(); AxEyXT(h5  
} :j\7</uu  
else -Jd|H*wWo  
{ ,-UF5U  
nStartPos = new long[bean.getNSplitter()]; H/,KY/>i  
nEndPos = new long[bean.getNSplitter()]; `|t,Uc|7!  
} RT[p!xL  
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} "hIYf7r##  
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public void run() sx,$W3zI'G  
{ X4;U4pU#  
//获得文件长度 (NJ{>@&  
//分割文件 'xW=qboOp  
//实例FileSplitterFetch .3 EZk86  
//启动FileSplitterFetch线程 JPI%{@Qc^  
//等待子线程返回 8hGyh#  
try{ +gl\l?>sr  
if(bFirst) Aztrq  
{ J8'"vc}=  
nFileLength = getFileSize(); UP](1lAf  
if(nFileLength == -1) [LVXXjkFI  
{ 2?,Jn&i5  
System.err.println("File Length is not known!"); (UkP AE  
} Fa("Gok[  
else if(nFileLength == -2) ;&d#)&O"e  
{ h.<f%&)F  
System.err.println("File is not access!"); is;g`m  
} [$dVs16K  
else f;E#CjlTL  
{ . ,|C>^  
for(int i=0;i<nStartPos.length;i++) b4L7M1l  
{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); d9{lj(2P  
} *@rA7zPFf  
for(int i=0;i<nEndPos.length-1;i++) r8:r}Qj2w[  
{ A
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nEndPos = nStartPos[i+1]; GcO2oq  
} N{Sp-J>  
nEndPos[nEndPos.length-1] = nFileLength; XIcUoKg^  
} /&gg].&2?  
}  y|LHnNQ  
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//启动子线程 &}DfIP<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <H-Nft>O  
for(int i=0;i<nStartPos.length;i++) Sca"LaW1  
{ p?gm=b#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oidZWy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dGZie.Zx  
nStartPos,nEndPos,i); KjGu !B
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t$BjJ -G  
fileSplitterFetch.start(); ,dRaV</2  
} G)vNMl  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FC0fe_U(F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ::Zo` vP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;yNc7Vl  
nEndPos = " + nFileLength); ~"+"
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// fileSplitterFetch[nPos.length-1].start();  /
 
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//等待子线程结束 ~b_DFj  
//int count = 0; )n&h
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//是否结束while循环 %+*=Vr  
boolean breakWhile = false; *'((_NZ>  
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while(!bStop) DI\=udN  
{ u99a"+  
write_nPos(); w)dnmrKDZg  
Utility.sleep(500); FL{Uz+Q  
breakWhile = true; bq/Aopfr  
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for(int i=0;i<nStartPos.length;i++) r!R-3LO0s  
{ PK]3uh  
if(!fileSplitterFetch.bDownOver) $tZ {>!N  
{ aHN"I  
breakWhile = false; w/|&N>ZOx  
break; lDL&":t  
} Gxw1P@<F:  
} B=0^Rysg  
if(breakWhile) nCYkUDnZ  
break; W3le)&  
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[ U:C62oK,  
//count++; J*;RL`  
//if(count>4) a7g;8t-&  
// siteStop(); G*9(O:  
} TUfj\d,  
c!IZLaVAr9  
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System.err.println("文件下载结束！"); &N^j }^ Z  
} h%/BZC^L]|  
catch(Exception e){e.printStackTrace ();} i.mv`u Dm  
} }Ulxt:}   
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//获得文件长度 I!hh_  
public long getFileSize() }a;xs};X;  
{ ?~o`
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int nFileLength = -1; Mq\=pxC@  
try{ zxn|]PbS  
URL url = new URL(siteInfoBean.getSSiteURL()); 1GY
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $yx\2  
httpConnection.setRequestProperty("User-Agent","NetFox"); kyHli~Nr"  
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int responseCode=httpConnection.getResponseCode(); ^`cv6;)  
if(responseCode>=400) RBQ8+^  
{ 6*Z7JiQ0  
processErrorCode(responseCode); WZ-~F/:c%  
return -2; //-2 represent access is error 0=>$J WF  
} Xl4}S"a  
}y6|H,t9  
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String sHeader; a&'9[9E1  
}#^Cj;  
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for(int i=1;;i++) }PI:O%N;  
{ &qbEF3p^@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ov+{<0Q  
//Utility.log(in.readLine()); j:%,lcF  
sHeader=httpConnection.getHeaderFieldKey(i); &@lfr623  
if(sHeader!=null) `jeATxWv  
{ -m^-p  
if(sHeader.equals("Content-Length")) E ASnh   
{ mOJdx-q?r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &. =8Q?  
break; J.UNw8z  
} OJm ]gb7  
} *tv&=  
else >J;TtNE:  
break; 2G8w&dtu  
} @ZISv'F  
} /bykIUTKI  
catch(IOException e){e.printStackTrace ();} oL]uY5eZoe  
catch(Exception e){e.printStackTrace ();} 5'set?  
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Utility.log(nFileLength); i"V.$|,  
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return nFileLength; uqcG3Pi  
} I7_lKr3  
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//保存下载信息（文件指针位置） 
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private void write_nPos() !\#Wq{p>W*  
{ W/UA%We3+L  
try{ N5K(yY_T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *Hx*s_F  
output.writeInt(nStartPos.length); Gbhw7 (&  
for(int i=0;i<nStartPos.length;i++) CW
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{ \HB fM&  
// output.writeLong(nPos); )<HvIr(xr  
output.writeLong(fileSplitterFetch.nStartPos); =bh: U90y  
output.writeLong(fileSplitterFetch.nEndPos); Vja 4WK*  
} (RI)<zaK ;  
output.close(); ,esEh5=Ir  
} #[bosb!R  
catch(IOException e){e.printStackTrace ();} ';G/,wB?`  
catch(Exception e){e.printStackTrace ();} 
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} P DY :?/  
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oU)(/  
//读取保存的下载信息（文件指针位置） 7l7VT
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private void read_nPos() \SmsS^z(]  
{ _xAru9=n^  
try{ KGOhoiR9:C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2K_ QZ  
int nCount = input.readInt(); d_(>:|oh  
nStartPos = new long[nCount]; k(G6` dY  
nEndPos = new long[nCount]; ?8$`GyjS  
for(int i=0;i<nStartPos.length;i++)  @N '_qu  
{ I._ A  
nStartPos = input.readLong(); =( ZOn=IL  
nEndPos = input.readLong(); &PXT$x[i  
} oC" [rn  
input.close(); &FmTT8"l  
} dlvU=^G#G  
catch(IOException e){e.printStackTrace ();} WCd:(8B  
catch(Exception e){e.printStackTrace ();} mKtMI!FR  
} TAh'u|{u2  
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private void processErrorCode(int nErrorCode) T7i>aM$+  
{ P4)Q5r  
System.err.println("Error Code : " + nErrorCode); 
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} :kcqf,7  
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//停止文件下载 8r>\scS  
public void siteStop() W0x9^'=s\  
{ F ]X<q uuL  
bStop = true; A ___| #R  
for(int i=0;i<nStartPos.length;i++) mKTF@DED  
fileSplitterFetch.splitterStop(); 7_36xpw  
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} f\?Rhyz  
} 5f_x.~ymA  
//负责部分文件的抓取 s8A"x`5(  
**FileSplitterFetch.java ]LsT  
*/ % dFz[b  
package NetFox; +EA ")T<l  
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import java.io.*; JkR%o #>5  
import java.net.*; cl#XiyK>  
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public class FileSplitterFetch extends Thread { vC&0UNe$  
3;b)pQ~6CJ  
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String sURL; //File URL GYy8kp84  
long nStartPos; //File Snippet Start Position q%bFR[p<*  
long nEndPos; //File Snippet End Position x_8sV?F  
int nThreadID; //Thread's ID P$Yw'3v/  
boolean bDownOver = false; //Downing is over x| D|d}  
boolean bStop = false; //Stop identical g_PP9S_?  
FileAccessI fileAccessI = null; //File Access interface Uun0FCA>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N:'GNMu  
{ i.K!;E>  
this.sURL = sURL; _nzT
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this.nStartPos = nStart; G]xYQ]  
this.nEndPos = nEnd; RwK6u-u#9  
nThreadID = id; w?3ww7yf`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q<szH1-  
} Y]~-S
 
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public void run() {{bwmNv"  
{ B(FM~TVZ  
while(nStartPos < nEndPos && !bStop) GXLh(d!C  
{ ~c+=$SL-=  
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try{ 1W.oRD&8j/  
URL url = new URL(sURL); J7dHD(R8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %H_-`A`  
httpConnection.setRequestProperty("User-Agent","NetFox"); npytb*[|c  
String sProperty = "bytes="+nStartPos+"-"; u"T9w]Z\  
httpConnection.setRequestProperty("RANGE",sProperty); @b2?BSdUp  
Utility.log(sProperty); ,QA=)~;D  
S^i8VYK,C5  
q$H@W.f  
InputStream input = httpConnection.getInputStream(); ~Sf'bj;(  
//logResponseHead(httpConnection); >X[:(m'  
8.%wnH  
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byte[] b = new byte[1024]; $t6t 6<M)  
int nRead; oFt_ yU-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0%|)=T3Slu  
{ B1I{@\z0G  
nStartPos += fileAccessI.write(b,0,nRead); wmMn1q0F  
//if(nThreadID == 1) ,'<N
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V3|" v4  
} HsRoiqo  
#;1RStb:zj  
[P6A$HC<  
Utility.log("Thread " + nThreadID + " is over!"); V%t_,AT  
bDownOver = true; ^%6f%]_  
//nPos = fileAccessI.write (b,0,nRead); s/3sOb}sA  
} ]A+t@/k  
catch(Exception e){e.printStackTrace ();} Q?>*h xzoP  
} ;Hp78!#,  
} bz,"TG[  
yk^2<?z>2  
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//打印回应的头信息 23+JuXC6>  
public void logResponseHead(HttpURLConnection con) &P*r66  
{ XCgC^c'  
for(int i=1;;i++) ;_ 1Rk&o!  
{ ;<cCT!A  
String header=con.getHeaderFieldKey(i); +,T}x+D  
if(header!=null) %rl<%%T#.M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g
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Utility.log(header+" : "+con.getHeaderField(header)); f*m^x7  
else W=#jtU`:5  
break; >r4BI}8SK<  
} !WB3%E,I  
} wk=s3^  
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public void splitterStop() a@? Bv  
{ |\C.il7  
bStop = true; 0G'v4Vj0'  
} 0N6 X;M{zh  
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} 20A:,pMb  
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/* L<Z2  
**FileAccess.java p@?(m/m$  
*//文件访问(定位，写) c(3c|n  
package NetFox; sI4 FgO  
import java.io.*; An BM*5G  
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u b@'(
*  
public class FileAccessI implements Serializable{ 6iEA._y  
k6;pi=sYNW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I wu^@  
RandomAccessFile oSavedFile; k$,y1hH;f8  
long nPos; C+C1(b;1  
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{#+'T13sx  
public FileAccessI() throws IOException CZCVC (/u  
{ 2T"[$iH!7  
this("",0); You~ 6d6Om  
} Hxj8cXUF|  
c,*a|@  
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public FileAccessI(String sName,long nPos) throws IOException S~y.>X3"P  
{ ^$8WV&5q>  
oSavedFile = new RandomAccessFile(sName,"rw"); 4DGKZh'm"  
this.nPos = nPos; h{PJ4U{W  
oSavedFile.seek(nPos); *MN("<A_  
} ,^T0!k$  
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public synchronized int write(byte[] b,int nStart,int nLen) _b[Pk;8}j;  
{ ,0n=*o@W  
int n = -1; D._7)$d  
try{ V##TG0  
oSavedFile.write(b,nStart,nLen); 8w3Wy<}y  
n = nLen; 2\[ Q{T=Qe  
} dQAo~]B  
catch(IOException e) H4e2#]*i7  
{ &$pA,Gjin\  
e.printStackTrace (); ;BEX|wxn  
} u$1^=  
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return n; #Xun>0  
} zvbz3a  
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} ~#JX 0J=  
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2{)<Df@  
/* n,|YJ,v[  
**SiteInfoBean.java FVoKNaK-  
*/ h&IF?h  
package NetFox; A@I3:V  
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public class SiteInfoBean { -"n8Wv  
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private String sSiteURL; //Site's URL ~fly6j|u  
private String sFilePath; //Saved File's Path )0 i$Bo  
private String sFileName; //Saved File's Name d>1#|  
private int nSplitter; //Count of Splited Downloading File @|Hx>|p  
~RnBs`&!  
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public SiteInfoBean() X\]Dx./  
{//nSplitter的缺省值为5 T`|>oX  
//default value of nSplitter is 5 ]"\XTL0  
this("","","",5); uGS^*W$  
} qyYf&VC}  
VV=6v;u`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C=PV-Ul+  
{ 5lakP?  
sSiteURL= sURL; R2nDK7j  
sFilePath = sPath; D$bJs O  
sFileName = sName; [r=U-  
this.nSplitter = nSpiltter; F
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>U')ICD~  
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} #.~lt8F  
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public String getSSiteURL() 82Nw6om6i  
{ ` oXL  
return sSiteURL; I KDh)Zm  
} G X>T~i\f8  
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public void setSSiteURL(String value) 55|.MXzq  
{ qy~@cPT  
sSiteURL = value; v@E/?\k"  
} z`+j]NX]  
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;Ajy54}
7  
public String getSFilePath() 3q0^7)m0  
{ <\5Y~!)  
return sFilePath; QCk(qlN'h9  
} )v?-[ oR  
(Qys`D   
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public void setSFilePath(String value) f:K`MW  
{ jF%[.n[BU  
sFilePath = value; |MXv  w6P  
} B[Fuyy?  
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public String getSFileName() ,\
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{ yS:1F PA$_  
return sFileName; -#?p16qz5  
} L]HYk}oD.  
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public void setSFileName(String value) g$ oe00b  
{ U1^R+ *yp  
sFileName = value; B>&eciY  
} #%i-{t+_>  
\dag~b<  
q#~]Hp=W5  
public int getNSplitter() %L9A6%gr  
{ #D{//P|;  
return nSplitter; R'q:Fc  
} |O]oX[~  
){oVVLs  
-cHX3UAEI  
public void setNSplitter(int nCount) pQY.MZSA  
{ 6uijxia  
nSplitter = nCount; ep<2u x  
} VoJelyzh  
} P2Ja*!K]  
1=t\|Th-  
 ,JcQp=g  
/* SAEr$F^  
**Utility.java Tx7YHE6{  
*/ :oH"  
package NetFox; :>[;XT<  
{-]/r  
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public class Utility { fodr1M4J  
[-sE:O`yt  
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public Utility() uv2!][  
{ 8F<Qc*'  
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} .Wq`qF(;  
'* +]&~b  
//线程睡眠 jBEt!Azur  
public static void sleep(int nSecond) t$=0
C  
{ 3 SQ_9{  
try{ yVxR||e  
Thread.sleep(nSecond); 5CkM0G`  
} h@z(yB j:0  
catch(Exception e) 'C~NQ{1TV  
{ &Sc}3UI/F  
e.printStackTrace ();

%xR;8IO  
} '7W?VipU  
} ,h1r6&MEY  
n\ma5"n0=\  
//日志 ~S R:,R  
public static void log(String sMsg) N L]:<FG  
{ ?#\?&uFJ}  
System.err.println(sMsg); Lvc*L6  
} 'W$jHs  
79a{Zwdd9j  
];1z%.  
public static void log(int sMsg) { >Y<!  
{ EPr{1Z  
System.err.println(sMsg); [6
!/  
} 9h$-:y3  
} 3u7E?*{sH  
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y6;'?.Y1  
/* mYb8  
**TestMethod.java /v;g v[  
*/ gzP(LfI5  
package NetFox; q[b-vTzI  
,_Fq*6  
.dp~%!"Sn,  
public class TestMethod { :%A1k2  
"^<:7_Y  
5<a)SP 0  
public TestMethod() (1(3:)@S6  
{ ///xx/weblogic60b2_win.exe Tc\^=e^N?  
try{ ^C):yxNP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w])bQ7)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z[AJat@H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *H&a_s/{Nb  
fileFetch.start(); +]CKu$,8  
} Sd^e!?bp  
catch(Exception e){e.printStackTrace ();} j>?H^fB  
"a`0s_F,^  
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} N!"GwH  
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}PyAmh$@  
public static void main(String[] args) .K}u`v T  
{ /n?5J`6  
new TestMethod(); G+b$WQn2t  
} w>H!H6Q  
} b\gl9"X  
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