http断点续传简单实现（java)

/* u] b6>  
**SiteFileFetch.java )9->]U@  
*/ (*]Y<ve  
package NetFox; \O~P !`  
import java.io.*; `#bcoK5  
import java.net.*; WGn1pW  
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public class SiteFileFetch extends Thread { CcQ|0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -:q7"s-}b  
long[] nStartPos; //开始位置 /[M~##%:  
long[] nEndPos; //结束位置 ,\7okf7H,-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?`$4ZDM  
long nFileLength; //文件长度 7;{F"/A  
boolean bFirst = true; //是否第一次取文件 [R$4n-$  
boolean bStop = false; //停止标志 G1|:b-C  
File tmpFile; //文件下载的临时信息 COafVlJ,l  
DataOutputStream output; //输出到文件的输出流 *XuzTGa"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） cW\7yZh  
public SiteFileFetch(SiteInfoBean bean) throws IOException C{-pVuhK+  
{ m" GrpE3  
siteInfoBean = bean; hSmM OS{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @z.!Dby  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Cpl)byb  
if(tmpFile.exists ()) YeVhWPn@  
{ M=%p$\x
  
bFirst = false; sQw-#f7t  
read_nPos(); tp7fmn*  
} A|^?.uIM  
else
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{ [Pay<]c6g  
nStartPos = new long[bean.getNSplitter()]; cQjJ9o7  
nEndPos = new long[bean.getNSplitter()]; &oBJY'1  
} d hy=x  
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} 7^1ikmYY
 
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public void run() ^VQiq7 xm  
{ eUl[gHP  
//获得文件长度 IKt9=Tx  
//分割文件 KvgZx(.  
//实例FileSplitterFetch ;Zw28!#Rt  
//启动FileSplitterFetch线程 |67UN
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//等待子线程返回 cWi2Sls  
try{ +{s^"M2`  
if(bFirst) "H({kmR  
{ R$\ieNb  
nFileLength = getFileSize(); -Bc.<pFqp  
if(nFileLength == -1) \%K6T)9  
{ L.5GX 29  
System.err.println("File Length is not known!"); y Le5,  
} lm+wjhkN  
else if(nFileLength == -2) _&T$0SZco  
{ }.
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System.err.println("File is not access!"); E^rN)  
} Ruf*aF(  
else >+1bTt/-F  
{ tlW}lN}  
for(int i=0;i<nStartPos.length;i++) }"szL=s  
{ aW"BN 5eM>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); yVW)DQ4?  
} )t|M)zJ  
for(int i=0;i<nEndPos.length-1;i++) Ft07>E$/Q^  
{ J[^-k!9M  
nEndPos = nStartPos[i+1]; !#'*@a  
} 8r~4iVwg  
nEndPos[nEndPos.length-1] = nFileLength; y+c+/L8  
} 8garRB{  
} cc@y  
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//启动子线程 OH&&d=~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Cjw|.c`  
for(int i=0;i<nStartPos.length;i++) NpSS/rd $  
{ 3t8VH`!mL{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &L_(
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?(E$|A  
nStartPos,nEndPos,i); `CRW2^g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0;
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fileSplitterFetch.start(); SoCa_9*X  
} emTqbO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6<gh:vj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); P#iBwmwN+.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -2f_e3jF  
nEndPos = " + nFileLength); g$uj<"^  
// fileSplitterFetch[nPos.length-1].start();
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+dlN^P647  
L,BuzU[1S  
//等待子线程结束 Uh{|@D  
//int count = 0; "1Vuf<
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//是否结束while循环 a:C
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boolean breakWhile = false; ?nE<Aig  
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while(!bStop) !ouJ3Jn   
{ ~8Z)e7j  
write_nPos(); ,-D3tleu`  
Utility.sleep(500); Zh,(/-XN;  
breakWhile = true; ]U82A**n  
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for(int i=0;i<nStartPos.length;i++) x:4:G(  
{ qi!+Ceo}  
if(!fileSplitterFetch.bDownOver) ,Tjc\;~%  
{ ,:;ZzHzR0  
breakWhile = false; jY
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break; '| WY 2>/(  
} JYc;6p$<i  
} @p"m{  
if(breakWhile) ?cF`T/z]"  
break; j"1#n? 0  
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//count++; B)*?H=f/  
//if(count>4) OO#_0qK  
// siteStop(); F!ZE4S_  
} \SKobO?qI  
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System.err.println("文件下载结束！"); m) QV2n  
} _Fkz^B*  
catch(Exception e){e.printStackTrace ();} t\S=u y  
} UB^OMB-W.m  
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maTQ0G
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//获得文件长度 )xm[mvt  
public long getFileSize() gxPu/VD
4  
{ gv\WI4"n  
int nFileLength = -1; As{"B  
try{ A1g.ww:  
URL url = new URL(siteInfoBean.getSSiteURL()); [3D*DyQt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Cg_9V4h.C  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?*LVn~y  
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int responseCode=httpConnection.getResponseCode(); zCji]:  
if(responseCode>=400) nEHmiG  
{ 4g+Dp&U  
processErrorCode(responseCode); ^m Ua5w  
return -2; //-2 represent access is error uo9FLm  
} 7D&O5Z=%+  
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}i$ER,hXh  
String sHeader; k@Qd:I;;  
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8B!MgNKV  
for(int i=1;;i++) ,J(shc_F  
{ L8,/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;W{2\ Es  
//Utility.log(in.readLine()); wU
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sHeader=httpConnection.getHeaderFieldKey(i); "O~7s}  
if(sHeader!=null) zb3,2D+P  
{ >=1Aa,_tc  
if(sHeader.equals("Content-Length")) #$X _,+<HZ  
{ XFSHl[uS1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 
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break; Z H2   
} nvB<pSm  
} nc3u
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else !?)aZ |r  
break; *b7evU *1  
}
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} `y>BbJqy  
catch(IOException e){e.printStackTrace ();} KwNOB _  
catch(Exception e){e.printStackTrace ();} :.=#U  
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[]
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Utility.log(nFileLength); |?v .5|1  
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return nFileLength; iD.p KG  
} uuQsK. S  
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//保存下载信息（文件指针位置） c*r@QmB:  
private void write_nPos() L|8&9F\  
{ g_@b- :$Yq  
try{ $F1Am%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Yyw9IYB;  
output.writeInt(nStartPos.length); nub!*)q  
for(int i=0;i<nStartPos.length;i++) `YY07(%  
{ `_sKR,LhB  
// output.writeLong(nPos); >`^;h]Q  
output.writeLong(fileSplitterFetch.nStartPos); w\M"9T  
output.writeLong(fileSplitterFetch.nEndPos); dXPTW;w  
} tkmzOc H  
output.close(); )Fw#]~Z  
} ;Fd1:"1pP  
catch(IOException e){e.printStackTrace ();} L#WGOl  
catch(Exception e){e.printStackTrace ();} dkW7k^g  
} R[kF(C&  
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//读取保存的下载信息（文件指针位置） 8?rq{&$t  
private void read_nPos() ['Qh#^p  
{ s)Xz}QPK.  
try{ `4e| I.`^r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (Q.tH  
int nCount = input.readInt(); h7 mk<  
nStartPos = new long[nCount]; EN__C$  
nEndPos = new long[nCount]; <nK@+4EH"o  
for(int i=0;i<nStartPos.length;i++) #=72/[  
{ nkz<t   
nStartPos = input.readLong(); >}/T&S  
nEndPos = input.readLong(); P`S'F_I
N  
} AF,;3G  
input.close(); J\N&u#  
} 5=fS^]- F  
catch(IOException e){e.printStackTrace ();} eep/96G ?  
catch(Exception e){e.printStackTrace ();} }S4+1 U3  
} ;&!QN#_  
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private void processErrorCode(int nErrorCode) xTqP`ljX  
{ 6W~JM^F  
System.err.println("Error Code : " + nErrorCode); GnCs_[*&r  
} 7<(kvE*x  
}2^qM^,0  
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//停止文件下载 Q(R-8"  
public void siteStop() MwL!2r  
{ =`2jnvx  
bStop = true; ?T,a(m<i{  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); `uqe[u;`6  
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} uz:r'+v  
} 9H53H"5q  
//负责部分文件的抓取 *|cs_,3  
**FileSplitterFetch.java b(adM3MP  
*/ #Fgybokm  
package NetFox; dz/3=0  
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import java.io.*; %`s1 Ocvp  
import java.net.*; +:/.\3v71  
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public class FileSplitterFetch extends Thread { 9lkl-b6xG  
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String sURL; //File URL Q91mCP~$  
long nStartPos; //File Snippet Start Position D+w?  
long nEndPos; //File Snippet End Position J/rF4=j%xy  
int nThreadID; //Thread's ID X@/wsW(kM\  
boolean bDownOver = false; //Downing is over A6xN6{R!  
boolean bStop = false; //Stop identical n"vO?8Sx  
FileAccessI fileAccessI = null; //File Access interface q6o}2<T@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cet|k!   
{ c'Q.2^w^  
this.sURL = sURL; K]^Jl0  
this.nStartPos = nStart; %wGQu;re  
this.nEndPos = nEnd; -AQ 7Bd  
nThreadID = id; =`!#V/=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n8q%>.i7  
} |T*t3}  
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public void run() J6nH|s8  
{ >QBDxm
  
while(nStartPos < nEndPos && !bStop) ^~3{n  
{ /1hcw|cfC  
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try{ /~g.j1g  
URL url = new URL(sURL); `R-VJR 2"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 461p4)  
httpConnection.setRequestProperty("User-Agent","NetFox"); #BI6+rfv|  
String sProperty = "bytes="+nStartPos+"-"; .|y{1?f_  
httpConnection.setRequestProperty("RANGE",sProperty); 4EhWK;ra  
Utility.log(sProperty); JNI&]3[C>?  
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InputStream input = httpConnection.getInputStream(); j^Ln\N]^  
//logResponseHead(httpConnection); LEAU3doK;  
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byte[] b = new byte[1024]; |+1k7S,  
int nRead; ?u{D-by%&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) y*lAmO  
{ mvyOwM  
nStartPos += fileAccessI.write(b,0,nRead); T6=~vOzTJ  
//if(nThreadID == 1) "ZG2olOqLI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sv#/78~|  
} oho~?.F  
?1H>k<Jp  
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Utility.log("Thread " + nThreadID + " is over!"); vARZwIu^D  
bDownOver = true; aY%{?8PsB  
//nPos = fileAccessI.write (b,0,nRead); '~pZj"uy  
} .j`8E^7<  
catch(Exception e){e.printStackTrace ();} -M-y*P
)  
} 1tH#QZIT  
} pF:C  
U> {CG+X  
.X6V>e)(3  
//打印回应的头信息 ?xo<Fv  
public void logResponseHead(HttpURLConnection con) "IoY$!Hk  
{ S@C"tHD  
for(int i=1;;i++) XQj+]-m  
{ 9<*<-x{A17  
String header=con.getHeaderFieldKey(i); Cx8  H  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header));  83:qIfF  
Utility.log(header+" : "+con.getHeaderField(header)); &-ZRS/_d>  
else {ALOs^_-  
break; ~#iAW@  
} CdiL{zH\3  
} P/8z  
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public void splitterStop() ~;nW+S$o  
{ ,CnUQx0  
bStop = true; W7 9.,#  
} q^b_'We_9  
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} hFt~7R  
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/* )jN fQ!?/  
**FileAccess.java bl;v^HR0)  
*//文件访问(定位，写) D{s4Bo-  
package NetFox; vX}mwK8  
import java.io.*; AmT*{Fz8  
+@K8:}lOW
 
" qrL:,  
public class FileAccessI implements Serializable{ =_H)5I_\  
Cl3hpqv1I  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?C9>bKo*2H  
RandomAccessFile oSavedFile; |)u|@\{  
long nPos; DX#F]8bWl  
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public FileAccessI() throws IOException VEg/x z4c  
{ UHUO9h  
this("",0); 9TW  
} .[#bOp*  
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jRIm_)  
public FileAccessI(String sName,long nPos) throws IOException Yg14aKZl  
{ 98eS f  
oSavedFile = new RandomAccessFile(sName,"rw"); VR0#"  
this.nPos = nPos; esQRg~aCGy  
oSavedFile.seek(nPos); \78kShx  
} prg8Iq'w  
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public synchronized int write(byte[] b,int nStart,int nLen) R!LKGiN  
{ )hai?v~g  
int n = -1; 1 +'HKT}  
try{ r#[YBaCZJ  
oSavedFile.write(b,nStart,nLen); 1)m&6:!b  
n = nLen; OT5'cl  
} vmXY}Ul  
catch(IOException e) "A?_)=zZ  
{ 9#@CmiIhy  
e.printStackTrace (); D`^9 u K  
} +C !A@  
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return n; XOy#?X/`  
} ~ Qt$)  
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} jP";ll|c  
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/* wFaWLC|&  
**SiteInfoBean.java G#4cWn'  
*/ VmB/X))  
package NetFox; qEpP%p  
VRoeq {  
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public class SiteInfoBean { FBPT@`~v  
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private String sSiteURL; //Site's URL 5aTyM_x  
private String sFilePath; //Saved File's Path 5\tYs=>b<  
private String sFileName; //Saved File's Name QE5 85s5  
private int nSplitter; //Count of Splited Downloading File ";
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>}/"gx  
public SiteInfoBean() ^dP@QMly6  
{//nSplitter的缺省值为5 I=^%l7  
//default value of nSplitter is 5 p$@=N6)I.k  
this("","","",5); qhpq\[U6in  
} @11voD  
^ :Q |,oy  
b\?#O}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N1(}3O  
{ W.n@  
sSiteURL= sURL; wy_TFV  
sFilePath = sPath; s:cS 9A8  
sFileName = sName; ~%Yh`c EP  
this.nSplitter = nSpiltter; Ye!=  
#D+Fq^="P  
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} ^O\tN\g;c  
q
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public String getSSiteURL() jO:<"l^+u  
{ Q:VD2<2  
return sSiteURL; L +.K}w  
} D?5W1m]E,s  
4b3p,$BWS  
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public void setSSiteURL(String value) eB$v'9S8/  
{ 2 >xV&  
sSiteURL = value; NnHM$hEI"U  
} rzaEVXbz1  
bJB:]vs$  
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public String getSFilePath() a/)TJv  
{ (%+DE4?  
return sFilePath; F/EHU?_EI  
} vW)GUAF[  
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4?yc/F=kI  
public void setSFilePath(String value) ]r"{G*1Q 9  
{ \HK#d1>ox  
sFilePath = value; l3iL.?&Pa  
} [sKdIw_  
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public String getSFileName() ^*{xTB57  
{ (J^ Tss  
return sFileName; O&w$  
} ? ! 1uw  
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public void setSFileName(String value) 1@nR.v"$  
{ G0]n4"~+?  
sFileName = value; ]7u8m[@  
} +j@|D@z  
[#9ij3vxd  
)Y *?VqZn  
public int getNSplitter() ;D^)^~7dh  
{ %r
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return nSplitter;
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} +qz)KtJS  
+tV(8h4  
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public void setNSplitter(int nCount) n~)Y%xe[U  
{ +pcj8K%  
nSplitter = nCount; \ qs6%  
} Y?5yzD:  
} _E30t( _.  
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v;RQVH;,  
/* f<}!A$wd  
**Utility.java AQiP2`?  
*/ <7jb4n<  
package NetFox; ?\O+#U%W  
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v =?V{"wk!  
public class Utility { 9nG] .@H  
"yz\p,  
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public Utility() eN-{  
{ 8uGPyH  
LN
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ILO+=xU  
} G4{qWa/  
#y*=UV|h  
//线程睡眠 8;!Eqyt  
public static void sleep(int nSecond) hv"toszj\  
{ 1`}fbX;"m)  
try{ >C-_Zv<!T\  
Thread.sleep(nSecond); _5K_YhT  
} vV[dJ%  
catch(Exception e) =k*0O_  
{ #VOjnc/rW  
e.printStackTrace (); qE`=^  
} #pe{:f?  
} QB.'8B_  
9kF#*  
//日志 Ds G *  
public static void log(String sMsg) !U#++Zig%  
{ a`-hLX)~Z  
System.err.println(sMsg); %)/f; T6  
} I1myuZ  
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@*DIB+K  
public static void log(int sMsg) |x6mkSf]ke  
{ Z8&C-yCC  
System.err.println(sMsg); 2&Byq  
} Ft7a\vn*B  
} F3Y>hs):7  
}K>HS\e  
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/* X}*o[;2G  
**TestMethod.java y^AA#kk  
*/  4Z}bw#  
package NetFox; S(J\<)b  
\u]CD}/  
MA+-2pMc|7  
public class TestMethod { :6u3Mj{  
cY2-T#rL  
~+#--BhV  
public TestMethod() g&4~nEp  
{ ///xx/weblogic60b2_win.exe eUkoVr   
try{ s1vrzze  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %EGr0R(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]VWfdG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 16QbB;  
fileFetch.start(); vSYKe  
} eFSC^  
catch(Exception e){e.printStackTrace ();} nuQ6X5>.=  
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} jBv$^L  
4$aO;Z_  
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public static void main(String[] args) z9 w&uZzi  
{ s$Zq/l$1x  
new TestMethod(); ZB[(Tv1  
} y5/6nvH_6  
} <{/;1Dru  
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