http断点续传简单实现（java)

/* (a9d
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**SiteFileFetch.java +{
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*/ 5n
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package NetFox; h gJ[LU|>  
import java.io.*; |>@W ]CX[  
import java.net.*; @{Gncy|  
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public class SiteFileFetch extends Thread { A!^q J#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w3jO6*_ M  
long[] nStartPos; //开始位置 vq34/c^  
long[] nEndPos; //结束位置 r(gXoq_w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !?Wp+e6  
long nFileLength; //文件长度 }@.|?2b +  
boolean bFirst = true; //是否第一次取文件 FLEo*9u>b  
boolean bStop = false; //停止标志 ]qhPd_$?D'  
File tmpFile; //文件下载的临时信息 ~/j\Z  
DataOutputStream output; //输出到文件的输出流 >:lnt /N3  
+}jJ&Z9)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1?Z4K/  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;;&}5jc
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{ -W>'^1cR  
siteInfoBean = bean; n_'{^6*O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); S6fbf>[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Uix6GT;  
if(tmpFile.exists ()) Z0l+1iMx  
{ J4Dry<  
bFirst = false; Mw9 \EhA  
read_nPos(); V')0 Mr  
} $ImrOf^qt  
else 4`,j=3  
{ Dc)dE2  
nStartPos = new long[bean.getNSplitter()]; s.8{5jVG  
nEndPos = new long[bean.getNSplitter()]; Z1"
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} X.:]=,aGW  
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} k1Q?'<`  
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public void run() + nF'a(  
{ G8Du~h!!U  
//获得文件长度 2WG>, 4W2  
//分割文件 .YuJJJv  
//实例FileSplitterFetch ?,/U^rf^4  
//启动FileSplitterFetch线程 NIw\}[-Z0E  
//等待子线程返回 5xL~`-IA&v  
try{ 0Lb4'25.  
if(bFirst) TsTPj8GAl[  
{ ({o'd=nO  
nFileLength = getFileSize(); K$d$m <  
if(nFileLength == -1) hJPlq0C  
{ QE7V. >J_p  
System.err.println("File Length is not known!");
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}
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else if(nFileLength == -2) ge8/``=  
{ W5R\Q,x6  
System.err.println("File is not access!"); K<>sOWZ'S  
} @e{^`\l=<  
else W6Y@U$P#G  
{ D+>1]ij  
for(int i=0;i<nStartPos.length;i++) 0iJue&  
{ yq$,,#XDD=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tor!Dl@Mo  
} aM;W$1h  
for(int i=0;i<nEndPos.length-1;i++) A~mum+[5  
{ #Skv(IL  
nEndPos = nStartPos[i+1]; M'/aZ# b  
} 4"Hye&O  
nEndPos[nEndPos.length-1] = nFileLength; Q`D_|L  
} N?.%?0l  
} 9+pmS#>_  
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//启动子线程 )RcL/n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yxc=Z0~1  
for(int i=0;i<nStartPos.length;i++) V(E/'DR  
{ ccL~#c0P7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9H%X2#:fH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h;0S%ZC  
nStartPos,nEndPos,i); /soKucN"h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #BSTlz  
fileSplitterFetch.start(); )(@Hd  
} 7hcNf,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e#k<d-sf6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zLJ/5&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1m.W<  
nEndPos = " + nFileLength); 3g6j?yYqb  
// fileSplitterFetch[nPos.length-1].start(); Ox@P6|m  
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> %KuNy{  
//等待子线程结束 +}a ]GTBgA  
//int count = 0; e$pMsw'MJ  
//是否结束while循环 BXyo  
boolean breakWhile = false; y.q(vzg\_  
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while(!bStop) `ta7Gc/:UY  
{ *Aa?yg:=  
write_nPos(); M8TSt\  
Utility.sleep(500); -neKuj  
breakWhile = true; uAWM\?  
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for(int i=0;i<nStartPos.length;i++) LupkrxV  
{ ]EpWSs!"g  
if(!fileSplitterFetch.bDownOver) LWt&3  
{ 1w&!H]%{  
breakWhile = false; n-@j5w+k4  
break; <=,6p>Eo[  
} 71{p+3Z&  
} 2j&AiD  
if(breakWhile) cSm%s  
break; B9J&=6`)  
;"m ,:5%  
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//count++; jfqopiSi  
//if(count>4) ~appY Av  
// siteStop(); P$-X)c$&  
} DX|# gUAm  
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System.err.println("文件下载结束！"); Alxx[l\<J  
} eD#hpl  
catch(Exception e){e.printStackTrace ();} :*2ud(  
} (!zy{;g|  
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//获得文件长度 ]S5JUAGkE*  
public long getFileSize() icgSe:Ci  
{ F
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int nFileLength = -1; }:~x7|~s:  
try{ ze]h..,]K  
URL url = new URL(siteInfoBean.getSSiteURL()); yiA<,!;4P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _:"<[ >9  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dv/WE>?Aw  
D N*t~Z3[  
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int responseCode=httpConnection.getResponseCode(); _Wa.JUbv  
if(responseCode>=400) (/j); oSK  
{ ^R@j=_8}  
processErrorCode(responseCode); Jtk|w[4L  
return -2; //-2 represent access is error aX}P|l  
} |x-S&-  
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String sHeader; 82DmG@"s2  
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for(int i=1;;i++) PxS8 n?y  
{ !dC<4qZ\C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x3"#POp  
//Utility.log(in.readLine()); |1>*;\o-  
sHeader=httpConnection.getHeaderFieldKey(i); JC3m.)/  
if(sHeader!=null) >L 0_dvr  
{ 1OF& *  
if(sHeader.equals("Content-Length")) E3iW-B8u8  
{ A`}rqhU.{-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^:Gie  
break; \<)9?M
:  
} 4zo5}L`Y  
} %V ;?  
else E!P yL>){  
break; y7i*s^ys{  
} KPj\-g'A  
} =HlQ36;*  
catch(IOException e){e.printStackTrace ();} 7fba-7-P  
catch(Exception e){e.printStackTrace ();} w2'f/  
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hBX!iukT|{  
Utility.log(nFileLength); Pw61_ZZ4B\  
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return nFileLength; "PpN0Rr  
} c. 2).Jt,  
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//保存下载信息（文件指针位置） k|H:  
private void write_nPos() 9c6gkt9eB  
{  #c66)  
try{ |YY_^C`"-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &E=>Hj(dTG  
output.writeInt(nStartPos.length); UaB @  
for(int i=0;i<nStartPos.length;i++) 0ok-IHE<  
{ 3^6 d]f  
// output.writeLong(nPos); ikSt"}/hd  
output.writeLong(fileSplitterFetch.nStartPos); -xA2pYz"  
output.writeLong(fileSplitterFetch.nEndPos); PJL=$gBgKk  
} Rw:*'1  
output.close(); HEM9E&rL  
} }=]M2}  
catch(IOException e){e.printStackTrace ();} 3S}Pm2D2  
catch(Exception e){e.printStackTrace ();} tyqT  
} ?pB>0b~3-  
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//读取保存的下载信息（文件指针位置） bq:(
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private void read_nPos() I\$X/t +dH  
{ J\M>33zu  
try{ %s(k_|G+4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "pRtczxOgR  
int nCount = input.readInt(); b7p@Dn?E  
nStartPos = new long[nCount]; ,^. 88<  
nEndPos = new long[nCount]; ZGKu>yM  
for(int i=0;i<nStartPos.length;i++) uW}s)j.  
{ !*%WuyCgr4  
nStartPos = input.readLong(); ZP\-T*)l$  
nEndPos = input.readLong(); mh{1*T$fP  
} -K3^BZHI  
input.close(); ^>hWy D  
} ='
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catch(IOException e){e.printStackTrace ();} zp%Cr.)$  
catch(Exception e){e.printStackTrace ();} c
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} "$N+"3I  
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private void processErrorCode(int nErrorCode) r 0iK  
{ l)&X$3?tz  
System.err.println("Error Code : " + nErrorCode); esMX-.8Cx  
} ap+JQ@b  
Z*= $8e@  
~2QR{; XQ  
//停止文件下载 O4V.11FnW  
public void siteStop() KQg]0y d  
{ 9|gr0&#~j  
bStop = true; 2h1vVF3  
for(int i=0;i<nStartPos.length;i++) t_$2CRG#  
fileSplitterFetch.splitterStop(); Pn>Xbe  
'
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} G#u6Am)T  
} e3nYbWBy]  
//负责部分文件的抓取 !FElW`F  
**FileSplitterFetch.java [k;\SXDZo  
*/ AN/;)wc  
package NetFox; :lPb.UCY  
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import java.io.*; < v@9#c  
import java.net.*; BlA_.]Sg$  
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public class FileSplitterFetch extends Thread { YH\O
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String sURL; //File URL z4jR[x,  
long nStartPos; //File Snippet Start Position %B5wH_p  
long nEndPos; //File Snippet End Position }:KEj_~.  
int nThreadID; //Thread's ID b2OQtSr a  
boolean bDownOver = false; //Downing is over =IQ5<;U3  
boolean bStop = false; //Stop identical #AL=f'2=f  
FileAccessI fileAccessI = null; //File Access interface AK*LyR?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I uMQ9&  
{ Tk:h@F|B.|  
this.sURL = sURL; `\#B18eU  
this.nStartPos = nStart; `OXpU,Z 6U  
this.nEndPos = nEnd; B1>/5hV}  
nThreadID = id; [d1mLJAR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &h^9}>rVjV  
} "NXB$
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public void run() D*gFV{Ws  
{ ;U.hxh;+  
while(nStartPos < nEndPos && !bStop) ]%wVHC  
{ N`L0Vd  
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try{
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URL url = new URL(sURL); :7!0OVQla\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z7hgA-t  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7b;I+q  
String sProperty = "bytes="+nStartPos+"-"; $m].8?  
httpConnection.setRequestProperty("RANGE",sProperty); 7Z\--=;|[:  
Utility.log(sProperty); --%N8L;e  
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InputStream input = httpConnection.getInputStream(); K1\a#w  
//logResponseHead(httpConnection); p~BRh  
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byte[] b = new byte[1024]; LYz.Ci}  
int nRead; ly
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QgU8s'e  
{ $o0iLFIX/  
nStartPos += fileAccessI.write(b,0,nRead); jv%kOovj  
//if(nThreadID == 1) :y%/u%L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q@<S[Qh[.  
} S+atn]eU@  
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Utility.log("Thread " + nThreadID + " is over!"); YaKeq5%y  
bDownOver = true; TgmnG/Z  
//nPos = fileAccessI.write (b,0,nRead); ;CmS ~K:  
} QS` PpyBkd  
catch(Exception e){e.printStackTrace ();} G~2jUyv  
} B8V>NvE~o  
} 4E]l{"k<  
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mKL<<L[  
//打印回应的头信息 Li/O  
public void logResponseHead(HttpURLConnection con) toya fHf  
{ Mc09ES  
for(int i=1;;i++) 5Iy;oZ  
{ K]s[5  
String header=con.getHeaderFieldKey(i); C":32_q  
if(header!=null) Gb#Cm]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F+,~v-  
Utility.log(header+" : "+con.getHeaderField(header)); }z _  
else "$ Y_UJT7  
break; jkiFLtB@V  
} bx{$Y_L+p  
} ![YX]+jqNp  
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public void splitterStop() pQ=>.JU  
{ h|VeG3H  
bStop = true; Pe3@d|-,MU  
} XC0bI,Fu,  
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} %Y<|;0v  
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)
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/* ,2j&ko1  
**FileAccess.java ?Z Rs\+{vG  
*//文件访问(定位，写) 7 %Oa;]|  
package NetFox;  [F0s!,P  
import java.io.*; ~$:|VHl  
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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 D
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RandomAccessFile oSavedFile; =vQcYa  
long nPos; HJXT9;w  
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public FileAccessI() throws IOException
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{ Sp@^XmX(S  
this("",0); [ oL.+  
} hU`wVy  
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public FileAccessI(String sName,long nPos) throws IOException s}UjGFP  
{ UDL!43K  
oSavedFile = new RandomAccessFile(sName,"rw"); +Z7th7W/,  
this.nPos = nPos; Hyb3 ;yQ  
oSavedFile.seek(nPos); iVp,e  
} z.$4!$q  
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public synchronized int write(byte[] b,int nStart,int nLen) WG N=Y~E  
{ d F9!G;V  
int n = -1; CdasP9"1  
try{ P<l&0dPO8  
oSavedFile.write(b,nStart,nLen); t]y D-3'l&  
n = nLen; {5%5}[/x  
} %\D)u8}  
catch(IOException e)  ud xZ0  
{ ^B(V4-|  
e.printStackTrace (); Bt>}rYz1  
} LJk@Vy <?  
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return n; <(-= 'QA  
} $FlW1E j  
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} l)Pu2!Ic  
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/* ;3d"wW]}7K  
**SiteInfoBean.java (g[h 8 c  
*/ _A+s)]}  
package NetFox; v1BDP<qU2  
w.H%R-Be  
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public class SiteInfoBean { RIb4!!',c  
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private String sSiteURL; //Site's URL /4a._@1h[y  
private String sFilePath; //Saved File's Path (8Bk;bd  
private String sFileName; //Saved File's Name x^kp^ /f  
private int nSplitter; //Count of Splited Downloading File &xa(BX%,c  
.q%WuQw  
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public SiteInfoBean() 0J?~N`#O|  
{//nSplitter的缺省值为5 Y' %^NP}o  
//default value of nSplitter is 5 G?EoPh^m  
this("","","",5); (yF:6$:#  
} zA$k0p  
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&>%T^Y|J4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SnE(o)Q  
{ aa>xIW,u  
sSiteURL= sURL; >#hO).`C  
sFilePath = sPath; FN\E*@>X=  
sFileName = sName; CjlKMbnBH  
this.nSplitter = nSpiltter; h3bff#<K  
cWi}V  
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} Po ZuMF  
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@!`Xl*l  
public String getSSiteURL() }dp=?AFg  
{ 2.%.Z_k)  
return sSiteURL; ^C_#<m_k  
} ppZDGpp  
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public void setSSiteURL(String value) o$w_Es]Ma  
{ Z&|Kki*  
sSiteURL = value; n^z]q;IN2.  
} {B[=?6tQ  
8-BflejX  
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public String getSFilePath() &;+-?k|  
{ KVD8YfF  
return sFilePath; [-\%4  
} 4:|S` jm  
D@Vt^_  
>sK!F$  
public void setSFilePath(String value) f>W-  
{ U-IpH+E  
sFilePath = value; fjU8gV  
} $lLz3YS  
'R c,Mq'  
lEhk'/~  
public String getSFileName() R $&o*K`?  
{ *Eo?k<:zPm  
return sFileName; Pb?$t  
} Olh<,p+x  
/4g1zrU
  
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public void setSFileName(String value) AS\F{ !O  
{ BaSZ71>9]r  
sFileName = value; 4WJ.^(  
} cFeXpj?GV  
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public int getNSplitter() 7T1=q{#M  
{ z"0I>gl  
return nSplitter; 8Le||)y,\  
} (>r[-Bft  
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public void setNSplitter(int nCount) D|Q#gcWpo  
{ ,6om\9.E@  
nSplitter = nCount; 3wC' r  
} :.$3vaZ@  
} }[4r4 1[  
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/*  !"\80LP  
**Utility.java J[4mLU  
*/ w]]8dz  
package NetFox; UPG9)aF  
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public class Utility { 8xccp4  
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public Utility() Y*H|?uNF
 
{ wS%Q<uK  
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} vvKEv/pN7
 

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//线程睡眠 zmSUw}-4N  
public static void sleep(int nSecond) _Em.
 
{ {=F/C,-  
try{ QNpqdwu%h  
Thread.sleep(nSecond); S/4^ d &Gr  
} %?p1d!  
catch(Exception e) ~v6OsH%vx  
{ =Ur}~w&H8  
e.printStackTrace (); a
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} ][?G/*k  
} Ry%Mej:  
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//日志 @wE5S6! B\  
public static void log(String sMsg) (X?%^^e!  
{ 4}4Pyjh  
System.err.println(sMsg); A29gz:F(  
} |j#C|V%kV  
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F.w5S!5Q  
public static void log(int sMsg) .HkL2m  
{ ?TU}~}  
System.err.println(sMsg); t.`@{R$hoA  
} 9J9)AV  
} fjs [f'L  
f"qga/  
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/* !f&Kf,#b`  
**TestMethod.java :=wTvz  
*/ }j*KcB_  
package NetFox; N6 (  
(^u1~1E 5  
>(?
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public class TestMethod { p;t
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mR}6r2O2\Q  
DGAX3N;r6{  
public TestMethod() c6X}2a'  
{ ///xx/weblogic60b2_win.exe lzYnw)Pv  
try{ = c>Qx"Sw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?34 e-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iVy7elT;R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V`bi&1?6\  
fileFetch.start(); ^(|vsFz
n  
} `"&da#N]  
catch(Exception e){e.printStackTrace ();} h $L/<3oP6  
(UU(:/  
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} UG'9*(*  
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public static void main(String[] args) uWM{JEOl  
{ 8;Yx<woR  
new TestMethod(); b+f'[;  
} Gcig*5   
} BbgnqzU  
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