http断点续传简单实现（java)

/* *}89.kCBF  
**SiteFileFetch.java LKvX~68  
*/ r:V bjmL  
package NetFox; L!xFhVA<  
import java.io.*;  Q(f0S  
import java.net.*; Dh`&B   
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public class SiteFileFetch extends Thread { E9\"@wu[d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean vy~6]hH  
long[] nStartPos; //开始位置 %q|*}l  
long[] nEndPos; //结束位置 "J,|),Yd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度 =Lkn   
boolean bFirst = true; //是否第一次取文件 fC'u-m?!Q'  
boolean bStop = false; //停止标志 sX6\AYF1M  
File tmpFile; //文件下载的临时信息 y<6Sl6l*  
DataOutputStream output; //输出到文件的输出流 ^4`x:6m  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） g s
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public SiteFileFetch(SiteInfoBean bean) throws IOException 9mHCms  
{ /UunWZ u%  
siteInfoBean = bean; &C MBTY#u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E?+~S M1~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PWS8Dpb  
if(tmpFile.exists ()) H'3 pHb  
{ S=P}Jpq?Y;  
bFirst = false;  _:\rB  
read_nPos(); Q(<A Yu  
} 'G65zz  
else sBZn0h@  
{ kI`HD
 
nStartPos = new long[bean.getNSplitter()]; !y_L~81?  
nEndPos = new long[bean.getNSplitter()]; )>h3IR  
} )*}\fmOv{  
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} di_UJ~  
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public void run() ^?fsJ  
{ oU
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//获得文件长度 VJ-t#q"  
//分割文件 Po=:-Of:  
//实例FileSplitterFetch ,9G'1%z,  
//启动FileSplitterFetch线程 z#RwgSPw6  
//等待子线程返回 MX~h>v3_R4  
try{ {G=>WAXo  
if(bFirst) 'KmM%tN  
{ 7|=SZ+g  
nFileLength = getFileSize(); !Dc?9W!b  
if(nFileLength == -1) vULDKJNHX  
{ xKL(:ePS  
System.err.println("File Length is not known!"); ]u|FcwWc3  
} I*U7YqDC9  
else if(nFileLength == -2) !N+{X\+  
{ vrmMEWPV  
System.err.println("File is not access!"); JUw|nUnl?  
} 0*]0#2Z  
else
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{ K @&c  
for(int i=0;i<nStartPos.length;i++) VB/75xK_  
{ ~uY5~Qs9G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U!+O+(  
} hFoeVM[h  
for(int i=0;i<nEndPos.length-1;i++) }6LcimQyK  
{ -U>)B  
nEndPos = nStartPos[i+1]; ,hNs{-*  
} RoHX0   
nEndPos[nEndPos.length-1] = nFileLength; c)Q-yPMl)  
} kxe{HxM$Z  
} =^M Q 4  
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=Cf@!wZ^  
//启动子线程 d^?e*USh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |oeg'T  
for(int i=0;i<nStartPos.length;i++) UBv#z&@[  
{ m6 M/G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g#{7qmM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $n8&5<  
nStartPos,nEndPos,i); KDg%sgRu}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /FXb,)1t  
fileSplitterFetch.start(); T^8`ji  
} 68~]_r.a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1| WDbk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D {E,XOi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0RdW.rZJ  
nEndPos = " + nFileLength); hT=E~|O  
// fileSplitterFetch[nPos.length-1].start(); O:V.;q2]U  
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//等待子线程结束 {3os9r,  
//int count = 0; l66 QgPA  
//是否结束while循环 4t*VI<=<[  
boolean breakWhile = false; w'i+WEU>l  
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while(!bStop) MYJDfI  
{ KxmB$x5-=8  
write_nPos(); \o,et9zDJ3  
Utility.sleep(500); R90chl  
breakWhile = true; p*$=EomY  
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for(int i=0;i<nStartPos.length;i++) :`yW^b  
{ !=vsY]  
if(!fileSplitterFetch.bDownOver) !+hw8@A  
{ /$qB&OWJn  
breakWhile = false; 0^P9)<k'  
break; A@.ruG$  
} ?)qm=mebY  
} 0a?[@ -Sz  
if(breakWhile) IH=%%AS  
break; Ka{QjW!%d<  
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//count++; *W}nw$tnBX  
//if(count>4) JDpW7OrDc  
// siteStop(); F%ukT6xp  
} slA~k;K:_  
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System.err.println("文件下载结束！"); ;cv\v(0  
} )1 0aDTlr  
catch(Exception e){e.printStackTrace ();} QSYKYgxC  
} `+(JwQC4  
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//获得文件长度 %E":Wv  
public long getFileSize() ac43d`wpK  
{ yW(A0  
int nFileLength = -1; XC[AJ!q`  
try{ BYI13jMH+Y  
URL url = new URL(siteInfoBean.getSSiteURL()); _A$V~Hp9q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {y!77>Q/  
httpConnection.setRequestProperty("User-Agent","NetFox"); rj eKG-Z@  
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int responseCode=httpConnection.getResponseCode(); ltl(SIi  
if(responseCode>=400) +P*,i$MV  
{ y9GaxW*&  
processErrorCode(responseCode); L#T`h}1Z  
return -2; //-2 represent access is error scEE$:  
} 6~Z
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String sHeader; {M0pq3SL*t  
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for(int i=1;;i++) =H^^AG\}  
{ J{#C<C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W
-"FRTI4  
//Utility.log(in.readLine()); P4"EvdV7  
sHeader=httpConnection.getHeaderFieldKey(i); }'TZ)=t{J  
if(sHeader!=null) TSd;L u%hr  
{ !B*d,_9c  
if(sHeader.equals("Content-Length")) s9YP =)I  
{ !8%{(;(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IPh_QE2g  
break; (XA]k%45  
} h,Tsb:Q"M  
} ZsDn
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else wW;!L=j  
break; )Chx,pcx<  
} 7G8M+i3q/  
} 8!dA1]2;  
catch(IOException e){e.printStackTrace ();} !P* z=  
catch(Exception e){e.printStackTrace ();} O7Awti-X  
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Utility.log(nFileLength); \CE8S+Z%  

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return nFileLength; A?OaP  
} GfT`>M?QGK  
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//保存下载信息（文件指针位置） R*psL&N  
private void write_nPos()
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{ "^@0zy@x  
try{ bQ2 '*T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uYwJ[1C  
output.writeInt(nStartPos.length); A&QO]8  
for(int i=0;i<nStartPos.length;i++) 1=%\4\  
{ mH} 1Zy  
// output.writeLong(nPos); VFwp .1oa!  
output.writeLong(fileSplitterFetch.nStartPos); 6tmn1:  
output.writeLong(fileSplitterFetch.nEndPos); z+B"
RV  
} 3YPoObY  
output.close(); CVBy&o"6A  
} +-OqO3R  
catch(IOException e){e.printStackTrace ();} [2cG 7A  
catch(Exception e){e.printStackTrace ();} sHulaX{  
} b]U%|bp  
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//读取保存的下载信息（文件指针位置） "#mr?h_  
private void read_nPos() j_*#"}Lcp  
{ e|ngnkf(G  
try{ s|Acv4| V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); m48m5>  
int nCount = input.readInt(); 5*pCb,z>q  
nStartPos = new long[nCount]; J$D#)w!$j  
nEndPos = new long[nCount]; ;M"JN:J8  
for(int i=0;i<nStartPos.length;i++) J Covk1  
{
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nStartPos = input.readLong(); QGnBNsAh  
nEndPos = input.readLong(); q.>{d%?  
} jDO[u!J6.%  
input.close();
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} \?e{/hXnl  
catch(IOException e){e.printStackTrace ();} @(:M?AO9S.  
catch(Exception e){e.printStackTrace ();} $k|k5cP8x  
} }l>0
m  
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private void processErrorCode(int nErrorCode) H`;q@  
{ 2!b+}+:  
System.err.println("Error Code : " + nErrorCode); -HU5E>xG  
} Pp[?E.]P  
,9W|$2=F  
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//停止文件下载 n`krK"Ii  
public void siteStop() d&QB?yLd  
{ D"m]`H  
bStop = true; @m[r0i0J"  
for(int i=0;i<nStartPos.length;i++) 195m0'zda  
fileSplitterFetch.splitterStop(); N%\!eHxy  
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} ;|f|d?Q\  
} \ueo^p]_?  
//负责部分文件的抓取 pAo5c4y!4  
**FileSplitterFetch.java E1'HdOh&z  
*/ gSP]& _9j  
package NetFox; 6WQT,@?  
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import java.io.*; {re<S<j&  
import java.net.*; O$ 7R<V  
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public class FileSplitterFetch extends Thread { ;{79d8/=  
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String sURL; //File URL "+iPeRF!hU  
long nStartPos; //File Snippet Start Position >'^
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long nEndPos; //File Snippet End Position Uv~r]P)  
int nThreadID; //Thread's ID Y9)
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boolean bDownOver = false; //Downing is over fG107{!g=  
boolean bStop = false; //Stop identical db%o3>>e  
FileAccessI fileAccessI = null; //File Access interface ]4m;NId  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P\B ]><!ep  
{ #MbkU])  
this.sURL = sURL;
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this.nStartPos = nStart; )DS|mM)  
this.nEndPos = nEnd; YQWGv,47\  
nThreadID = id; )A}u)PH4O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dC$z q~q  
} "#d>3M_  
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public void run() WleE$ ,  
{ Wm{Lg0Nr  
while(nStartPos < nEndPos && !bStop) :nZVP_d+  
{ )_eEM1  
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try{ !=7(3<?  
URL url = new URL(sURL); ]_6w(>A@3#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V7Z+@e-5  
httpConnection.setRequestProperty("User-Agent","NetFox"); Em?Z  
String sProperty = "bytes="+nStartPos+"-"; ' XJ>;",[  
httpConnection.setRequestProperty("RANGE",sProperty); SW!lSIk  
Utility.log(sProperty); hSQuML   
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InputStream input = httpConnection.getInputStream(); 9?5'>WO  
//logResponseHead(httpConnection); b*w@kLLN  
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byte[] b = new byte[1024]; 1]Q;fe  
int nRead; N8!V%i?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K( : NshM  
{ X}@^$'W  
nStartPos += fileAccessI.write(b,0,nRead); f3Zm
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//if(nThreadID == 1) o gec6u}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5eP8nn.D  
} I8R#EM%C#  
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Utility.log("Thread " + nThreadID + " is over!"); CatbEXO  
bDownOver = true; ZG29q>  
//nPos = fileAccessI.write (b,0,nRead); wldv^n hM  
} >yr:L{{D}G  
catch(Exception e){e.printStackTrace ();} PE $sF]/  
} 5G$N  
} |]--sUx:  
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//打印回应的头信息 hk6(y?#  
public void logResponseHead(HttpURLConnection con) !&'GWQY{(  
{ w; [ndZCY7  
for(int i=1;;i++) zSy^vM;6zf  
{ BvQMq5&  
String header=con.getHeaderFieldKey(i); 1b^e4  
if(header!=null) rC`pTN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); CD}::7$  
Utility.log(header+" : "+con.getHeaderField(header));
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else GM_~2Er]  
break; &8p]yo2zO  
} E@}N}SR  
} hkS0ae  
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public void splitterStop() c`S`.WID  
{ X
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bStop = true; WP*xu-(:  
} /\L-y,>X  
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} ;Gc,-BDFw  
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|/^ KFY"  
/* S2y_5XJ<D  
**FileAccess.java tx` Z?K[  
*//文件访问(定位，写) w)C/EHF  
package NetFox; @c;XwU]2t  
import java.io.*; 0m2%ucKw  
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public class FileAccessI implements Serializable{
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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 !4.VK-a9V%  
RandomAccessFile oSavedFile; k^VL{z:EWB  
long nPos; Q$Q>pV;uH  
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public FileAccessI() throws IOException 2:5Go  
{
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this("",0); nXU`^<nA  
} u[:-^H  
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public FileAccessI(String sName,long nPos) throws IOException U/}("i![Dy  
{ V ,+&.A23  
oSavedFile = new RandomAccessFile(sName,"rw"); ttP|}|O  
this.nPos = nPos; ! 3 ;;6  
oSavedFile.seek(nPos); hs;YMUA"  
} :)9CG!2y<M  
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public synchronized int write(byte[] b,int nStart,int nLen) <z.Y#{p?k  
{ As{Q9o5j/  
int n = -1; e w%rc.;  
try{ p>ba6BDJT  
oSavedFile.write(b,nStart,nLen); 4h*c{do  
n = nLen; %LM2CgH V  
} |*fi!nvk@  
catch(IOException e) dI(1L~  
{ 2v$\mL  
e.printStackTrace (); r+Pfq[z&  
} q1^bH6*fl  
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return n; ] /"!J6(e  
} *P01 yW0  
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}
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/* uQ
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**SiteInfoBean.java BT^Im=A  
*/ 49o/S2b4z  
package NetFox; ul-O3]\'@  
/$\N_`bM  
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public class SiteInfoBean { 6:Hd`  
%zKTrsMZ  
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private String sSiteURL; //Site's URL u<U8LR=)V5  
private String sFilePath; //Saved File's Path Mdw"^x$7  
private String sFileName; //Saved File's Name ~hxW3e  
private int nSplitter; //Count of Splited Downloading File {i<L<Y(3  
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public SiteInfoBean() lyS`X  
{//nSplitter的缺省值为5 Fy*t[>  
//default value of nSplitter is 5 `t7z LC^c  
this("","","",5); s?J
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} L9]y~[R:  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 5oe{i/#di  
{ F2>W{-H+  
sSiteURL= sURL; **CGkL  
sFilePath = sPath; 03n+kh  
sFileName = sName; {^.q
6,l  
this.nSplitter = nSpiltter; r,<p#4(>_  
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} _<6E>"*m  
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public String getSSiteURL() "sSY[6Kp!  
{ .wO-2h{Q  
return sSiteURL; !GJT-[  
} Q5&|1m Pb  
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public void setSSiteURL(String value) Y1;jRIOA  
{ {(IHHA>  
sSiteURL = value; 3V]08  
} )b~+\xL5J  
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public String getSFilePath() #~o<9O  
{ Hf+oG  
return sFilePath; N(kSE^skOa  
} ?X+PNw|pf  
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public void setSFilePath(String value) Mn 8| Knh  
{ 9JqT"zj  
sFilePath = value; ]*X z~Ox2  
} Gs>4/  
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public String getSFileName() :(K JLa]  
{ 5`6U:MDq  
return sFileName; gL&)l!2Y  
}  e**5_L  
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public void setSFileName(String value) p@?ud%  
{ *Oq&g\K)  
sFileName = value; F;MACu;x  
} kZ0z]Y  
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public int getNSplitter() ( m7qc  
{ ;D<
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return nSplitter; VFK]{!C_  
} Q yhu=_&  
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d/b\:[B@  
public void setNSplitter(int nCount) `NQ;|!  
{ 09=w  
nSplitter = nCount; _U o3_us  
} w^ X@PpP  
} /vPr^Wv  
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/* YlXqj\a  
**Utility.java `[h&Q0Du6  
*/ {Q)sR*d  
package NetFox; W!|l_/L'   
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public class Utility { K."W/A!  
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K  
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public Utility() Y=/;7T  
{ -,ojZFyRi  
Lie= DD  
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} Knp}88DR^j  
dFZh1*1  
//线程睡眠 EL6<%~,V"I  
public static void sleep(int nSecond) 3x=NSe|f  
{ L% T%6p_  
try{ qykI[4  
Thread.sleep(nSecond); !>WW(n07Ma  
} aNgJm~K0P  
catch(Exception e) 'X
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{ !,~C  
e.printStackTrace (); N.vkM`Z  
} !N/?b^y  
} aW#^@||B  
UoJMOw[  
//日志 4rypT-%^;  
public static void log(String sMsg) d 1 O+qS  
{ b(A;mt#N  
System.err.println(sMsg); UdFYG^i  
} ,]4.|A_[Rq  
5IP@_GV|  
rUmnv%qTS  
public static void log(int sMsg) XeozRfk%J|  
{ ah!fQLMH  
System.err.println(sMsg); LufZ,  
} XRn+6fn|  
} {/XU[rn  
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/* &.:yP3  
**TestMethod.java ;{rl Y>  
*/ &_Z8:5e  
package NetFox; =@k3*#\  
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public class TestMethod { )Ju$PrO  
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public TestMethod() ntF#x.1Pm  
{ ///xx/weblogic60b2_win.exe 0.!Q4bhD  
try{ 5O"wPsl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uzLIllVX*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); mGUl/.;yp-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #J4,mFMr  
fileFetch.start(); Xqas[:)7+  
} LiD-su D  
catch(Exception e){e.printStackTrace ();} (ZEDDV2  
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} B'D4]EB  
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public static void main(String[] args) kN$L8U8f  
{ ,lw<dB@7"5  
new TestMethod(); XJf1LGT5  
} :=%`\\  
} XcQ'(  
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