http断点续传简单实现（java)

/* XhJP87A  
**SiteFileFetch.java 
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*/ bCJ<=X,g`K  
package NetFox; ~(w=U *
  
import java.io.*; V
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import java.net.*; 5n&)q=jk=  
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public class SiteFileFetch extends Thread { 9Bbm7Gd  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4\ uZKv@,  
long[] nStartPos; //开始位置 4OqE.LFu  
long[] nEndPos; //结束位置 aPcGI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {9m!UlTtw  
long nFileLength; //文件长度 ~@)-qV^~  
boolean bFirst = true; //是否第一次取文件 Vz=j)[  
boolean bStop = false; //停止标志 XL"v21X  
File tmpFile; //文件下载的临时信息 es*_Oo1  
DataOutputStream output; //输出到文件的输出流 s>9z+;~!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Xr  
public SiteFileFetch(SiteInfoBean bean) throws IOException
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{ :N+K^gI)  
siteInfoBean = bean; p``;!3~~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SopNtcu!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) "63zc1  
{ )cv0$  
bFirst = false; 
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read_nPos(); 0pZ.; /<{  
} s)`1Rf  
else g4.'T51  
{ 2>_brz|7:|  
nStartPos = new long[bean.getNSplitter()]; IlC:dA  
nEndPos = new long[bean.getNSplitter()]; qxg7cj2  
} \$$b",2 h  
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} V5(tf'  
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public void run() jl 30\M7  
{ sJjl)Qs)T  
//获得文件长度 ECE{xoc  
//分割文件 mPw56>  
//实例FileSplitterFetch 6qHvq A
,  
//启动FileSplitterFetch线程 "0!eb3n  
//等待子线程返回 |({UV-`  
try{ 4%#V^??E  
if(bFirst) ; ei<Q =[  
{ ]<o.aMdV  
nFileLength = getFileSize(); (x@i,Ba@  
if(nFileLength == -1) QB.*R?A  
{ ;?HZ,"^I  
System.err.println("File Length is not known!"); AT'_0>x8  
} '
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else if(nFileLength == -2) fjK]m.w  
{ 4LKs'$:A=  
System.err.println("File is not access!"); %RT6~0z  
} J!TK*\a2  
else ,nu7r1}  
{ ]%Q]C 8[C  
for(int i=0;i<nStartPos.length;i++) 71n uTE%!  
{ i"\AyKiJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P/1UCITq}  
} |<+|Du1  
for(int i=0;i<nEndPos.length-1;i++) L]L~TA<D9i  
{ @e?[oojrM  
nEndPos = nStartPos[i+1]; u`H@Q&(^wa  
} {eD>E(Y@z1  
nEndPos[nEndPos.length-1] = nFileLength; O( 5L2G  
}
<*6y`X  
} MTFVnoZMQ_  
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p*W ZY=Q  
//启动子线程 mSfk
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]9yA0,z/  
for(int i=0;i<nStartPos.length;i++) lo]B5_en  
{ ~"<VUJ=Ly:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p?`|CE@h7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +<9q]
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nStartPos,nEndPos,i); $=QGua V  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lj SR?:\  
fileSplitterFetch.start(); uI:3$  
} |@Idf`N$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #3:'lGBIK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 39a]B`y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ptcH>wM!  
nEndPos = " + nFileLength); Rp%\`'+Xz  
// fileSplitterFetch[nPos.length-1].start(); C4SD  
as\K(c9  
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//等待子线程结束 52C-D+zCJ  
//int count = 0; x#e\H F  
//是否结束while循环 rEpKX  
boolean breakWhile = false; vdFQf ^l  
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while(!bStop) B| 0s4E  
{ j C1^>D  
write_nPos(); e#e
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Utility.sleep(500); <+1w'-  
breakWhile = true; ]v,y(yl  
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for(int i=0;i<nStartPos.length;i++) \g6 #MNW  
{ o)'=D(  
if(!fileSplitterFetch.bDownOver) Vx4pP$S  
{ 0&L0j$&h  
breakWhile = false; gy.; "W  
break; E~ kmU{D  
} ^;d;b<  
} Y*f<\z(4  
if(breakWhile) LTHS&3%2  
break; S;~_9i]upe  
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//count++; XJ+sm^`vOf  
//if(count>4) 9q?gmAn.  
// siteStop(); }$ der  
} (%1*<6ka  
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System.err.println("文件下载结束！"); Y/gCtSF  
} 2S3F]fG0  
catch(Exception e){e.printStackTrace ();} B!0[LlF+  
} y\x<!_&D  
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//获得文件长度 -_+0[Nb.  
public long getFileSize() ORNE>6J H  
{ y-YYDEl  
int nFileLength = -1; sQw-#f7t  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); E_P]f%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BKk*<WMD  
httpConnection.setRequestProperty("User-Agent","NetFox"); tq[C"| dH  
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int responseCode=httpConnection.getResponseCode(); iVRz  
if(responseCode>=400) cP,jC(<N  
{ W7 $yE},
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processErrorCode(responseCode); `{%*DHa  
return -2; //-2 represent access is error iBCM?RiG  
} O7W}Z1G  
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String sHeader; YA jk'  
4'M#m|V  
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for(int i=1;;i++) HDYf^mcW  
{ kI]1J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w[XW>4xK  
//Utility.log(in.readLine()); <7XdT  
sHeader=httpConnection.getHeaderFieldKey(i); b\?`721BG  
if(sHeader!=null) .*,ZcO  
{ -{?Rq'H  
if(sHeader.equals("Content-Length")) _v\QuI6  
{ +x1sV*S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kDrGl{U}  
break; <mxUgU  
} LxbVRw  
} F]&9Lp} "  
else G} p~VLf  
break; C/XOI>  
} pT <H&  
} &8N\ 6K=  
catch(IOException e){e.printStackTrace ();} U!h!z`RU54  
catch(Exception e){e.printStackTrace ();} 5g=" #  
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Utility.log(nFileLength); 0o#lB^e;l  
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return nFileLength; ` H"5nQRV  
} NQb?&.C   
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//保存下载信息（文件指针位置） >[#4Pb7_Y  
private void write_nPos() ?FLjvmE9  
{ =y<Fz*aA  
try{ !j(R_wOq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _&T$0SZco  
output.writeInt(nStartPos.length); 2iUF%>  
for(int i=0;i<nStartPos.length;i++) @{bf]Oc  
{ !"wIb.j}0  
// output.writeLong(nPos); Ruf*aF(  
output.writeLong(fileSplitterFetch.nStartPos); _*+M'3&=  
output.writeLong(fileSplitterFetch.nEndPos); yO !*pC  
} h0GXN\xI  
output.close(); hAY_dM  
} [=iq4F'7  
catch(IOException e){e.printStackTrace ();} f"[C3o2P  
catch(Exception e){e.printStackTrace ();} vt1!|2{ h  
} d"V^^I)yx&  
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//读取保存的下载信息（文件指针位置） ]$7|1-&Y  
private void read_nPos() =[P||  
{ 6(eyUgnb  
try{ 1PWDK1GI8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z*k}I{0,-  
int nCount = input.readInt(); Alrk3I3{  
nStartPos = new long[nCount]; >OQ<wO6  
nEndPos = new long[nCount]; 7{p,<Uz<"U  
for(int i=0;i<nStartPos.length;i++) ec{pWzAe  
{ 5y.kOe4vH  
nStartPos = input.readLong(); |kjk{  
nEndPos = input.readLong(); Tfj%Sb,zM  
} 5YRa2#d  
input.close(); AH;h#dT  
} PJ);d>tz  
catch(IOException e){e.printStackTrace ();} V ]Z{0  
catch(Exception e){e.printStackTrace ();} gI[xOK#  
} q$\KE4v"  
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private void processErrorCode(int nErrorCode) Mq-;sPsFP  
{ -cMqq$  
System.err.println("Error Code : " + nErrorCode); q>,i `*  
} 0PZpE "$X  
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b8Y-!]F  
//停止文件下载 l@':mX3xd  
public void siteStop() 59GS:  
{ Z[ys>\_To  
bStop = true; =ove#3  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); E<0Y;tR  
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} <5=^s%H  
} *!vwW T  
//负责部分文件的抓取 2|m461  
**FileSplitterFetch.java iOw'NxmY  
*/ GP1b/n3F1  
package NetFox; @2V#bK  
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import java.io.*; ]5wc8Kh"  
import java.net.*; _pL:dKfy7  
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public class FileSplitterFetch extends Thread { H}`}qu #~V  
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ZPRkk?M}.  
String sURL; //File URL FK<1SOE  
long nStartPos; //File Snippet Start Position r"c<15g2'  
long nEndPos; //File Snippet End Position =5J}CPKbZI  
int nThreadID; //Thread's ID EP,lT.u3  
boolean bDownOver = false; //Downing is over Re-4y5f  
boolean bStop = false; //Stop identical
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FileAccessI fileAccessI = null; //File Access interface 8do-z"-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #L ffmS  
{ ^O}`i  
this.sURL = sURL; )CKPzNf  
this.nStartPos = nStart; ^z)p@sk#  
this.nEndPos = nEnd; t[VA|1gG  
nThreadID = id; 22$M6Qof]n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "&W80,O3  
} z&Cz!HrS  
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public void run() s,Azcqem  
{ H85JMPZ7  
while(nStartPos < nEndPos && !bStop) NH~\k
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{ k^K>*mcJ  
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try{ dg-nv]7  
URL url = new URL(sURL); b@`h]]~:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `|(S]xPHM  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^Y,nv,gYn  
String sProperty = "bytes="+nStartPos+"-"; W"$sN8K>)  
httpConnection.setRequestProperty("RANGE",sProperty); +VT/c  
Utility.log(sProperty); C%H{"  
)B)ecJJ_  
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InputStream input = httpConnection.getInputStream(); db#svj*  
//logResponseHead(httpConnection); OXp(rJ*bK  
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byte[] b = new byte[1024]; B63puX{u#  
int nRead; 07b=Zhh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &PZ&'N|P  
{ P.aN4 9`=  
nStartPos += fileAccessI.write(b,0,nRead);
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//if(nThreadID == 1) RqB8g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A{|^_1  
} 17la/7l<  
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Utility.log("Thread " + nThreadID + " is over!"); &
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bDownOver = true; #|8Ia:=s
 
//nPos = fileAccessI.write (b,0,nRead); >UNx<=ry  
} z*k(` '  
catch(Exception e){e.printStackTrace ();} h>k[  
} < #FxI  
} Nux  
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//打印回应的头信息 uo`zAKM&A  
public void logResponseHead(HttpURLConnection con) u43W.4H13  
{ nEHmiG  
for(int i=1;;i++) 4g+Dp&U  
{ L _D#  
String header=con.getHeaderFieldKey(i); i+90##4<?  
if(header!=null) 7D&O5Z=%+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *q
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Utility.log(header+" : "+con.getHeaderField(header)); xB`j* %  
else }i$ER,hXh  
break; QZ& 4W  
} q\Q'9Rl0(  
} 7K5 tBUNQ  
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public void splitterStop() { k>T*/  
{ ;&c9!LfP  
bStop = true; xciwKIpS  
} ?[?;%Y  
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} \&/V p`  
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/* YJGP8  
**FileAccess.java otA'+4\  
*//文件访问(定位，写) |_njN  
package NetFox; +\-cf,WkI  
import java.io.*; :'2h0 5R  
+I3j2u8L  
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public class FileAccessI implements Serializable{ Z H2   

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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 ~^bf1W[  
RandomAccessFile oSavedFile; nc3u
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long nPos; 8 qlQC.VA[  
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public FileAccessI() throws IOException #f@}$@  
{ pz=/A  
this("",0); K;7ea47m N  
} {X
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public FileAccessI(String sName,long nPos) throws IOException jr(|-!RVMN  
{ KwNOB _  
oSavedFile = new RandomAccessFile(sName,"rw"); 0SR[)ma  
this.nPos = nPos; & LhQr-g  
oSavedFile.seek(nPos); %mAwK<MY`  
} bgeJVI  
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public synchronized int write(byte[] b,int nStart,int nLen) CC)Mws+2  
{ 3tW}a`z9  
int n = -1; ivg W[]  
try{ 3aw-fuuIb  
oSavedFile.write(b,nStart,nLen); 9^7z"*@#  
n = nLen; 4k!>JQor  
} |?v .5|1  
catch(IOException e) &D91b
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{ y[ZVi5) ,  
e.printStackTrace (); vRb7=fXf  
} lWDSF]ZYV  
}Te+Rv7{E  
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return n; ASB3|uy_  
} lS|F&I5j  
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} P~84#5R1  
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N)/7j7c~;  
/* H#M;TjR  
**SiteInfoBean.java 0a9[}g1=#  
*/ l{QlJ>%~{;  
package NetFox; BCO (,k  
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public class SiteInfoBean { (coaGQ@d  
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private String sSiteURL; //Site's URL <qVOd.9c  
private String sFilePath; //Saved File's Path JQ
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private String sFileName; //Saved File's Name ^fV-m&F)K*  
private int nSplitter; //Count of Splited Downloading File \E6 0  
{]%7-4E  
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public SiteInfoBean() uqVarRi$  
{//nSplitter的缺省值为5 w\M"9T  
//default value of nSplitter is 5 fZ(k"*\MZ  
this("","","",5); XP[~ :+  
} r?9".H  
3e>U(ES  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r)B55;*Fh  
{ XT
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sSiteURL= sURL; 411z-aS  
sFilePath = sPath;
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sFileName = sName; MAp#1+k  
this.nSplitter = nSpiltter; %jJIR88  
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} dGUiMix{N  
WHqw=!G  
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public String getSSiteURL() *uSlp_;kB  
{ ZENblh8fs  
return sSiteURL; +Ht(_+To1  
} _;R#B`9Iu  
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public void setSSiteURL(String value) !}5+hj!6  
{ Vh^ :.y  
sSiteURL = value; qoZe<jW (  
} 2V~uPZ  
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public String getSFilePath() TEbIU8{Y  
{ 11Uu5e!.  
return sFilePath; |WNI[49  
} F$'po#  
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public void setSFilePath(String value) B`w8d[cL7  
{ a|DCpU}  
sFilePath = value; t*fH&8(  
} T+S\
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public String getSFileName() JEK_W<BD  
{ <<V"4 C2  
return sFileName; wv=U[:Y  
} i ~)V>x  
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public void setSFileName(String value) jAovzZ6BL  
{ %zR5q  Lb  
sFileName = value; RjR+'<7E^  
} E>:#{%  
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public int getNSplitter() VA`VDUG,  
{ PP/#Z~.M  
return nSplitter; $GOF'  
} @1qdnU  
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public void setNSplitter(int nCount) i>C%[dk9  
{ _n4_;0  
nSplitter = nCount; 9Z"WV5o  
} Ft}nG&D  
} ,zdK%V}  
@:@5BCs<  
CYsLyk  
/* %s;5  
**Utility.java s2F[v:|Wq  
*/ /XNC^!z6Js  
package NetFox; -S&d5(
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public class Utility { IsVR4t]  
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public Utility() 7UqDPEXU]`  
{ 4QYStDFe  
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} `uqe[u;`6  
k^#*x2b  
//线程睡眠 4^9qs%&  
public static void sleep(int nSecond) iG"1~/U
 
{ uz:r'+v  
try{ x7i,jMR  
Thread.sleep(nSecond); :.f(}sCS  
} ezhfKt]j  
catch(Exception e) G7KOJZb+D  
{ ,#9i=gp  
e.printStackTrace (); +i}uRO  
} MlLM $Y-@  
} ,Ww.W'#P  
bIzBY+P  
//日志 &'/bnN +R  
public static void log(String sMsg) Tm0\Oue0  
{ M5xMTP-  
System.err.println(sMsg); (Zej\lEN  
} F^lau f  
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:OqEkh"$#  
public static void log(int sMsg) 1_8@yO  
{ {$7vd  
System.err.println(sMsg); .
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} 1suP7o A;  
} Mp^G7JY,  
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k9&W0$I#  
/* Gs4t6+Al  
**TestMethod.java i&<@}:,  
*/ dsK*YY jH  
package NetFox; ;Y`8Ee4vH  
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public class TestMethod { tiRi_  
J/rF4=j%xy  
<"S`ZOn  
public TestMethod() j9}.U \  
{ ///xx/weblogic60b2_win.exe BFqM6_/J  
try{ 61sEeM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B"`86qc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q6o}2<T@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 
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fileFetch.start(); \ >#y*W<  
} Z4{N
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catch(Exception e){e.printStackTrace ();} T:!H^  
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} > lI2r}  
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public static void main(String[] args) ?
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{ R[#B|$  
new TestMethod(); R$">
 
} KB{/L5  
} 
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