http断点续传简单实现（java)

/* uX[O,l^}  
**SiteFileFetch.java c8#T:HM|`  
*/ GFdZ`i  
package NetFox; ZR/R'prW  
import java.io.*; 5mI?p
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import java.net.*; 6Cl+KcJH  
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public class SiteFileFetch extends Thread { rD0k%-{{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _Fy4DVCg  
long[] nStartPos; //开始位置 #04{(G|~+E  
long[] nEndPos; //结束位置 5R,la\!bQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h`?y2?O  
long nFileLength; //文件长度 E7rX1YdR  
boolean bFirst = true; //是否第一次取文件 o-SRSu  
boolean bStop = false; //停止标志 C!!mOAhJ
 
File tmpFile; //文件下载的临时信息 T(Y}V[0+  
DataOutputStream output; //输出到文件的输出流 [urH a  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #mgA/q?A  
public SiteFileFetch(SiteInfoBean bean) throws IOException KU+( YF$1
 
{ d@-wi%,^  
siteInfoBean = bean; YO)')&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Sdgb#?MR|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %S{o5txo  
if(tmpFile.exists ()) :~t<L%tYF  
{ qPsyqn?Y|  
bFirst = false; d4d\0[  
read_nPos(); xe(MHNrj  
} oz%h)#;  
else  ;e&
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{ wX-RQ[2X  
nStartPos = new long[bean.getNSplitter()]; {V[Ha~b%*  
nEndPos = new long[bean.getNSplitter()]; ;US83%*  
} 5\VxXiy0  
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} c`-YIz)W  
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public void run() >RM 0=bO  
{ [/?c@N,  
//获得文件长度 w3<Z?lj:  
//分割文件 EtGH\?d~]  
//实例FileSplitterFetch ?Rlgv5P!  
//启动FileSplitterFetch线程 2[.5oz`  
//等待子线程返回 R @"`~#$$  
try{ )j\r,9<K+5  
if(bFirst) 9#u}^t  
{ {U(Bfe^a,  
nFileLength = getFileSize(); PM@XtL7J  
if(nFileLength == -1) j\
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{ f](I.lm:  
System.err.println("File Length is not known!"); Z%Vr+)!4  
} ?hKm&B;d  
else if(nFileLength == -2) 6%>/og\%  
{ {n\6BT
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System.err.println("File is not access!"); !2(.$}E  
} ;JYoW{2  
else m6-76ma,hi  
{ ]+
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for(int i=0;i<nStartPos.length;i++) 9KXym
}  
{ QS\Uq(Ja\  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} 60'6/3  
for(int i=0;i<nEndPos.length-1;i++) L5
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{ s){Q&E~X  
nEndPos = nStartPos[i+1]; 7O:"~L  
} 5KK{%6#f\  
nEndPos[nEndPos.length-1] = nFileLength; "rVU4F)  
} @Eo4U]-  
} kr#I{gF  
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//启动子线程 .M8=^,h^K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B0v|{C   
for(int i=0;i<nStartPos.length;i++) C]/&vh7ta  
{ FK6K6wU52m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D
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nStartPos,nEndPos,i); #aa1<-&H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); B9}E {)T?  
} 0EyAMu  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 691G15  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]s_@n!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X\kjAMuW/*  
nEndPos = " + nFileLength); NK~PcdGl  
// fileSplitterFetch[nPos.length-1].start(); wajZqC2yg  
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//等待子线程结束 +SyUWoM  
//int count = 0; b]w[*<f?  
//是否结束while循环 )XpVu  
boolean breakWhile = false; /V#7=,,  
#J\s%60pt  
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while(!bStop) ~zMDY F"&  
{ *(icR  
write_nPos(); Z&A0hI4d  
Utility.sleep(500); >zFD$  
breakWhile = true; B_cgWJ*4  
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for(int i=0;i<nStartPos.length;i++) k
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{ 5\&]J7(  
if(!fileSplitterFetch.bDownOver) Uh}+"h5  
{ nW11wtiO.  
breakWhile = false; T RDxT  
break; 3
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} !x8kB Di,  
} L$SMfx  
if(breakWhile) x df?nt  
break; GoazH?%  
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//count++; t?HF-zQ  
//if(count>4) }YRO'Q{  
// siteStop(); hox< vr4  
} K>$qun?5  
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System.err.println("文件下载结束！"); IhfZLE.,  
} HJ",Sle  
catch(Exception e){e.printStackTrace ();} =6
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} ~{$L
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//获得文件长度 %7 /,m  
public long getFileSize() ]=|P<F  
{ [8TS"ph>  
int nFileLength = -1; <cj}:H *  
try{ B2Z0  
URL url = new URL(siteInfoBean.getSSiteURL()); }qL~KA{&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >;7a1+`3  
httpConnection.setRequestProperty("User-Agent","NetFox"); $cu]_gu  
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int responseCode=httpConnection.getResponseCode(); pjdo|  
if(responseCode>=400) d+e0;!s~O  
{ ni<[G0#T  
processErrorCode(responseCode); ++0rF\&  
return -2; //-2 represent access is error ZL,8,;]  
} >MPa38  
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String sHeader; 6#v
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for(int i=1;;i++) ]);NnsG  
{ ^obC4(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +!><5  
//Utility.log(in.readLine()); op.d;lO@  
sHeader=httpConnection.getHeaderFieldKey(i); ly=a>}F_  
if(sHeader!=null) w,/6B&|  
{ mqw 84u  
if(sHeader.equals("Content-Length")) '-.
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{ zIm-X,~I$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h1*FPsc  
break; 5VZjDg?  
} 7DZTQUb"  
} w&5/Zh[~~L  
else ntZ~m  
break; ]w-.|vx  
} F 3s?&T)[G  
} Mt=R*M}D0  
catch(IOException e){e.printStackTrace ();} ?<6@^X"  
catch(Exception e){e.printStackTrace ();} c$A@T~$  
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Utility.log(nFileLength); b`zET^F  
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return nFileLength; x)5LT}p  
} ]Zk}ZG>6  
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o} {-j  
//保存下载信息（文件指针位置） t#~XLCE  
private void write_nPos() _*n)mlLln  
{ 7@3sUA_Go  
try{ \XDmK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [8z&-'J=  
output.writeInt(nStartPos.length); H?{MRe  
for(int i=0;i<nStartPos.length;i++) a'A s
 
{ QF&6?e06p0  
// output.writeLong(nPos); ]
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output.writeLong(fileSplitterFetch.nStartPos); NNp}|a9  
output.writeLong(fileSplitterFetch.nEndPos); _#vGs:-x&  
} wASX\D }  
output.close(); GFt1  
} gyFr"9';c  
catch(IOException e){e.printStackTrace ();} \Z'/+}^h  
catch(Exception e){e.printStackTrace ();} aj v}JV&:  
} tah
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//读取保存的下载信息（文件指针位置） S<pk
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private void read_nPos() 2vvh|?M  
{ C`EY5"N r  
try{ 
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tR;{.  
int nCount = input.readInt(); R\y'_S=#a  
nStartPos = new long[nCount]; O5OXw]  
nEndPos = new long[nCount]; [xf$VkjuF  
for(int i=0;i<nStartPos.length;i++) IM]h*YV'  
{ ( OXY^iq  
nStartPos = input.readLong();  p[Hr39o  
nEndPos = input.readLong(); ~ k<SbFp  
} 6klD22b2$  
input.close(); HzEGq,.  
} y]^#$dK(z  
catch(IOException e){e.printStackTrace ();} &?r*p0MQC  
catch(Exception e){e.printStackTrace ();} p&O8qAaO  
} L#!$hq9{_  
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private void processErrorCode(int nErrorCode) > Y]_K  
{ `)2[ST  
System.err.println("Error Code : " + nErrorCode); oLw|uU-
|  
} mw
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//停止文件下载 dQK`sLChv  
public void siteStop() f:XfAH3R{  
{ 5zVQ;;9  
bStop = true; 0e\y~#-  
for(int i=0;i<nStartPos.length;i++) j/' g$  
fileSplitterFetch.splitterStop(); ;h9W\Se  
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} xU:4Y0y8  
} `0z/BCNB  
//负责部分文件的抓取 ^9=4iXd  
**FileSplitterFetch.java om>VQ3  
*/ Ko+al{2  
package NetFox; :cdQ(O.m  
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import java.io.*; IX.sy  
import java.net.*; {lMqcK  
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public class FileSplitterFetch extends Thread { k% NrL@z  
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String sURL; //File URL LyV#j>gD  
long nStartPos; //File Snippet Start Position q}sK  
long nEndPos; //File Snippet End Position &rP~`4Mkp  
int nThreadID; //Thread's ID @Kp1k> ov  
boolean bDownOver = false; //Downing is over w?S8@|MK  
boolean bStop = false; //Stop identical |@ *3^'  
FileAccessI fileAccessI = null; //File Access interface #'8)u)!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F3 Y<ZbxT  
{ {6:& %V  
this.sURL = sURL; .*:h9AE7vo  
this.nStartPos = nStart; |,{+;:  
this.nEndPos = nEnd; PqI![KxZW  
nThreadID = id; %z2oDAjX  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RQ|?Ce",  
} 6&mWIk^VC  
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public void run() &1~Re.*B  
{ V(Dj
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while(nStartPos < nEndPos && !bStop) F^xaz^=`u  
{ !]G jIT]Oh  
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try{ Kk`<f d  
URL url = new URL(sURL); RyE_|]I62u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,8~dz  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]`K[W&  
String sProperty = "bytes="+nStartPos+"-"; <ZV7|'^  
httpConnection.setRequestProperty("RANGE",sProperty); WSS(Bm|B  
Utility.log(sProperty); ExQ--!AC=  
w~]}
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InputStream input = httpConnection.getInputStream(); Txu>/1N,  
//logResponseHead(httpConnection); `BpCRKTG  

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byte[] b = new byte[1024]; t"tNtLI  
int nRead; q 7`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =O,e97  
{ gkLr]zv  
nStartPos += fileAccessI.write(b,0,nRead); E}t-N  
//if(nThreadID == 1) OoSa95#x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *5^ze+:  
} `u$24h'!  
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Utility.log("Thread " + nThreadID + " is over!"); f)WPOTEY  
bDownOver = true; /CbkqNV  
//nPos = fileAccessI.write (b,0,nRead); r&=r/k2  
} ;=#qHo9k1%  
catch(Exception e){e.printStackTrace ();} Xz" JY
 
} 9'l.TcVm`,  
} kr6:{\DU:B  
$sM]BE:  
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//打印回应的头信息 4">84,-N  
public void logResponseHead(HttpURLConnection con) eZ[#+
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{ iKY-;YK  
for(int i=1;;i++) =qan%=0"h  
{ Of!|,2`(  
String header=con.getHeaderFieldKey(i); 7;~2e  
if(header!=null) ~;` fC|)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f&f[La  
Utility.log(header+" : "+con.getHeaderField(header)); wH#Lb@cfZ0  
else JLt{f=`%F  
break; L-SdQTx_  
} ]2g5Ka[>w  
} 3EO#EYAHiM  
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public void splitterStop() S`fu+^cv  
{ hY)YX,f=S  
bStop = true; \A~4\um  
} jjNxatAN  
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} g}^4^88=a  
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/* ^j1Gmv)  
**FileAccess.java 3huzz<n3  
*//文件访问(定位，写) CRP
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package NetFox; [@jp9D H  
import java.io.*; iFY]0@yt  
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public class FileAccessI implements Serializable{ dV'6m@C
 
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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 I):m6y@  
RandomAccessFile oSavedFile; _$~ex ~v  
long nPos; 34HFrMi  
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public FileAccessI() throws IOException uHTKo(NG  
{ `Nc`xO?  
this("",0); 9*"[pt+tA  
} + ?[ ACZF  
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public FileAccessI(String sName,long nPos) throws IOException # r2$ZCo3o  
{ %jYQ  
oSavedFile = new RandomAccessFile(sName,"rw"); 8.6no  
this.nPos = nPos; 9N`+ O  
oSavedFile.seek(nPos); yN%3w0v  
} }mkA Hmu4  
] `b<"  
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public synchronized int write(byte[] b,int nStart,int nLen) o%y+Y;|?J  
{ 
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int n = -1; ufHuI*  
try{ 6yV5Yjs  
oSavedFile.write(b,nStart,nLen); =P@M&Yy'  
n = nLen; ";%e~ =  
} :T8u?@.  
catch(IOException e) hlYS=cgY=  
{ Ih9O
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e.printStackTrace (); rcD.P?"  
} eA;j/&qH  
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return n; e)fJd*P  
} HPv&vdr3  
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f  
} $_%2D3-;D  
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/* &z{dr~  
**SiteInfoBean.java *RUd!]bh  
*/ VuYWb)@  
package NetFox; HXlr  
7M&.UzIY`  
a,F8+ Pb>  
public class SiteInfoBean { 81%qM7v9H  
w>1l@%Uo  
+?J_6Mo@X  
private String sSiteURL; //Site's URL ,4h!"c  
private String sFilePath; //Saved File's Path 8VBkIYgb  
private String sFileName; //Saved File's Name v)v{QNQp^  
private int nSplitter; //Count of Splited Downloading File a!S
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%BT)oH}  
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public SiteInfoBean() 0e7O#-  
{//nSplitter的缺省值为5  h;:Se  
//default value of nSplitter is 5 g(z#h$@S  
this("","","",5); Q}k_#w  
} 7k[`]:*o  
=]2RC1#}e  
+w_MSj#P  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J"a2 @S&  
{ @5dBb+0J  
sSiteURL= sURL; &D&5UdN x  
sFilePath = sPath; PG-cu$\??  
sFileName = sName; VygXhh^7\  
this.nSplitter = nSpiltter; c DEe?WS  
~I8"l@H>  
q^T&A[hMPx  
} ID{Pzmt-  
8O;rp(N.n  
}SJLBy0  
public String getSSiteURL() sbq44L)  
{ H8=vQy  
return sSiteURL; /(WX!EEsB  
} }AeE|RNc  
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0N} wD-  
public void setSSiteURL(String value) M25z<Y  
{ f0fqDmn  
sSiteURL = value; XyKKD&j  
} s1*WK&@  
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public String getSFilePath() gw}7%U`T9  
{ zN729wK  
return sFilePath; {) '" k6w  
} ^0,&R\e+  
d/-]y:`f`  
<|>:UGAR  
public void setSFilePath(String value) '8kL1  
{ aS1P]&  
sFilePath = value; >x_:=%Wr+  
}  +lf@O&w  
2=UTH%1D  
tr67ofld|  
public String getSFileName() /i]=ndAk  
{ F6neG~Y  
return sFileName; {H7$uiq3:B  
} dA MilTo  
7HR%rO?'  
7=M'n;!Mh  
public void setSFileName(String value) A)`fD %+  
{ ED
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sFileName = value; L}sm R,  
} H&>>]DD  
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Fy+7{=?^F  
public int getNSplitter() 3!L<=X  
{ -^nQ^Td=j  
return nSplitter; /v5g;x
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} JD\-X(O  
;]`NR  
3Jk?)Dy  
public void setNSplitter(int nCount) N6 }i>";_;  
{ kI1{>vYD  
nSplitter = nCount; vGLb2Q  
} ` a<|CcUGU  
} @0@'6J04  
"=5vgg3  
<xh'@592  
/* =ym~= S  
**Utility.java %+OPas8C  
*/ cK}  
package NetFox; 6;=wuoJi  
mYs->mg1  
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public class Utility { [8J}da}  
~Sem_U`G  
'' A[`,3  
public Utility() 1J%qbh  
{ $R#L@iL-  
8@C|exAD`  

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} $!3t$-TSD  
gSo(PW)  
//线程睡眠 I`}vdX)  
public static void sleep(int nSecond) e^fKatI1  
{
$A!h=]  
try{ v(nQd6;T  
Thread.sleep(nSecond); }T*xT>p^3  
} W;@ae,^  
catch(Exception e) R8W44I*R:  
{ l$_+WC*wp  
e.printStackTrace (); l?<z1Acd&  
} Cot\i\]jv  
} g1!L. On  
9p'J(`  
//日志 ny?m&;^r:  
public static void log(String sMsg) IF?B`TmZ  
{ N %/DN  
System.err.println(sMsg); V$F.`O!hfi  
} *gpD4c7A\  
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MldL"*HW:  
public static void log(int sMsg) 5qB=@O]|G;  
{ u#k6v\/  
System.err.println(sMsg); YbBH6RZr  
} dGW7,B~  
} u4^"E+y^S  
8}
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"9T`3cM0  
/* U4I` xw'  
**TestMethod.java Oqe.t;E 0}  
*/ >u#VHaB  
package NetFox; ~acK$.#  
B91PlM.  
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public class TestMethod { |Ie`L("  
eu|q {p  
e;u
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public TestMethod() 4W-+k  
{ ///xx/weblogic60b2_win.exe 1E_Ui1[  
try{ g~D6.OZU  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); y8n1IZ*#SZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6zZR:ej  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (eE}W~Z  
fileFetch.start(); ' 1]bjW*!  
} l%5%oN`4  
catch(Exception e){e.printStackTrace ();} [MP:Eeg  
1e| M6*  
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} /%w[q:..h  
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public static void main(String[] args) 1>{-wL4rc  
{ __%E!*m"<_  
new TestMethod(); \k-juF80  
} iC2n
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} z(68^-V=:  
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