http断点续传简单实现（java)

/* Zdv.PGn  
**SiteFileFetch.java 9">zdFC'  
*/ ioB|*D<U2  
package NetFox; q[{:  
import java.io.*; d&}pgb-
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import java.net.*; =y)p>3p}&  
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public class SiteFileFetch extends Thread { ^=eq .(>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean vOos*&  
long[] nStartPos; //开始位置 RL?u n}Qa  
long[] nEndPos; //结束位置 G{@C"H[$<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ni+3b  
long nFileLength; //文件长度 I#"t'=9H  
boolean bFirst = true; //是否第一次取文件
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boolean bStop = false; //停止标志 >Y
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File tmpFile; //文件下载的临时信息 H7{Q@D8  
DataOutputStream output; //输出到文件的输出流 cU7rq j_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T?W[Z_D  
public SiteFileFetch(SiteInfoBean bean) throws IOException nqZA|-}  
{ W3^
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siteInfoBean = bean; `d75@0:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c5X`_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q:vz?G  
if(tmpFile.exists ()) 1*Sr5N[=  
{ . _1jk  
bFirst = false; g d  z  
read_nPos(); .CVUEK@Z4  
} k1wCa^*gc  
else "e~k
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{ S3SV.C:z>  
nStartPos = new long[bean.getNSplitter()]; 'I&|1I^  
nEndPos = new long[bean.getNSplitter()]; ,`;jvY~Ec  
} RS'} nY}  
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} "kX`FaAhY  
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public void run() u FMIY(vB  
{ DC&A1I&  
//获得文件长度 /@Ez" ?V2  
//分割文件 C1V# ?03eI  
//实例FileSplitterFetch !tI=`
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//启动FileSplitterFetch线程 3DH.4@7P  
//等待子线程返回 pss6Oz8  
try{ _)Qy4[S=d  
if(bFirst) , Hn7(^t  
{ BEln6zj  
nFileLength = getFileSize(); bFSlf5*H  
if(nFileLength == -1) pFpZbU^  
{ (Up'$J}  
System.err.println("File Length is not known!"); L{=l#vu  
} N;<//,  
else if(nFileLength == -2) <D;MT96SG  
{ "LOnDa7E^  
System.err.println("File is not access!"); [#0Yt/G  
} cFLd)mt/  
else 4GVNw!V  
{ T'8RkDI}-  
for(int i=0;i<nStartPos.length;i++) YZibi  
{ X6xx2v%D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DR6]-j!FK  
} qh-[L  
for(int i=0;i<nEndPos.length-1;i++) Qu`n&  
{ tVunh3-  
nEndPos = nStartPos[i+1]; :y\09)CJK  
} ,*dzJT$k  
nEndPos[nEndPos.length-1] = nFileLength; X:Q$gO?[4  
} gA_krK,Z  
} r=qLaPG  
yIOLs}!SF  
qbXz7s*{  
//启动子线程 9mQ#L<Ps  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vXb:  
for(int i=0;i<nStartPos.length;i++) $_)=8"Sn  
{ z5 Bi=~=#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @F?=a*s"!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gv9=quG  
nStartPos,nEndPos,i); a"QU:<-v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =O,JAR"ug  
fileSplitterFetch.start(); R*yU<9Mm8  
} MHo1 lrZa+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [h4o7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k5@d! }#c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8a9RML}G<  
nEndPos = " + nFileLength); =<{ RX8  
// fileSplitterFetch[nPos.length-1].start(); %w7m\nw@  
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//等待子线程结束 u?kD)5Nk  
//int count = 0; !qA8Zky_  
//是否结束while循环 a=+T95ulDy  
boolean breakWhile = false; khAqYu")  
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v)):$s?WB  
while(!bStop) Wt J{  
{
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write_nPos(); Fd7*]a  
Utility.sleep(500); G AQ 'Ti1!  
breakWhile = true; H?uukmZl  
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for(int i=0;i<nStartPos.length;i++) [T`}yb@  
{
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if(!fileSplitterFetch.bDownOver) 8Mu;U3cIW  
{ se!mb _!  
breakWhile = false; Q.k :\m*h  
break; /s c.C  
}  ]>Si0%  
} M^6$ MMx  
if(breakWhile) W&(f&{A  
break; Ax!Gu$K2o  
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//count++; 6z?gg3GV  
//if(count>4) ~O: U|&  
// siteStop(); |)o#|Qo  
} EvE,Dm?h  
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System.err.println("文件下载结束！"); f-g1[!"F  
} 6GYtY>  
catch(Exception e){e.printStackTrace ();} ([ dT!B#aH  
} EfiU$8y  
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//获得文件长度 \Hwg) Uc{  
public long getFileSize() F98i*K`"  
{ ?t rV72D  
int nFileLength = -1; `.=sTp2rbc  
try{ Z0ReWrl;`  
URL url = new URL(siteInfoBean.getSSiteURL()); ~ y;y(4<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jxw_*^w"  
httpConnection.setRequestProperty("User-Agent","NetFox"); R8
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int responseCode=httpConnection.getResponseCode(); 8g*hvPc  
if(responseCode>=400) *7" L]6  
{ 4_LQ?U>$  
processErrorCode(responseCode); :?CQuEv-  
return -2; //-2 represent access is error Y ?'tUV  
} 9<s4yZF@x  
~]WVG@-  
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String sHeader; aMK~1]Cx  
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for(int i=1;;i++) O8|*M "  
{ b |7ja_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1
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//Utility.log(in.readLine()); =Q(vni83<  
sHeader=httpConnection.getHeaderFieldKey(i); DjHp+TyT  
if(sHeader!=null) 4vdNMV~  
{ 'iUg[{'+  
if(sHeader.equals("Content-Length")) &uM^0eM  
{ GXX+}=b7qO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (~s|=Hxq|-  
break; f9TV%fG?  
} & ,L9OU  
} 8o-bd_  
else 2~c~{ jl\  
break; ?Zz'|.l@  
} 9z ?7{2C  
} K:5eek  
catch(IOException e){e.printStackTrace ();} u&]vd /  
catch(Exception e){e.printStackTrace ();} N[U9d}Zv  
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Utility.log(nFileLength); x#8w6@iPQ  
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return nFileLength; ULBg{e?l8  
} UQT'6* !  
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//保存下载信息（文件指针位置） ijUzC>O+q  
private void write_nPos() +
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{ xxa} YIe8  
try{ qpqokK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -5>NE35Cto  
output.writeInt(nStartPos.length); =%qEf   
for(int i=0;i<nStartPos.length;i++) F#V q#|_)>  
{ p-$Cs _{Z  
// output.writeLong(nPos); \ijMw  
output.writeLong(fileSplitterFetch.nStartPos); u oVNK  
output.writeLong(fileSplitterFetch.nEndPos); Qv#]81i(1  
}
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output.close(); E9 Y\X  
} 9=+-QdX+0]  
catch(IOException e){e.printStackTrace ();} S>_27r{  
catch(Exception e){e.printStackTrace ();} :q+N&j'3  
} Imym+  
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//读取保存的下载信息（文件指针位置） BWUq%o,@g  
private void read_nPos() &ITuyGmF  
{ vRhnX  
try{ Hs?zq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F^kwdS  
int nCount = input.readInt(); &%F@O<:  
nStartPos = new long[nCount]; 30F!kP*E  
nEndPos = new long[nCount]; Y=B3q8l5  
for(int i=0;i<nStartPos.length;i++) fA^Em)cs2  
{ "="O >  
nStartPos = input.readLong(); n:#TOU1ix<  
nEndPos = input.readLong(); F0dI/+  
} 3$p#;a:=n  
input.close(); Utt>H@t[  
} i~yX tya  
catch(IOException e){e.printStackTrace ();} (#Mp 5C'X  
catch(Exception e){e.printStackTrace ();} }e{qW  
} ]/dVRkZeAE  
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private void processErrorCode(int nErrorCode) d?L
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{ .BZVX=x  
System.err.println("Error Code : " + nErrorCode); FGanxv@15  
} =Hu0v}i/  
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//停止文件下载 &0v.E"0<
 
public void siteStop()  46,j9x  
{ $k2)8#\  
bStop = true; Nhf~PO({&  
for(int i=0;i<nStartPos.length;i++) dcq#TBo8  
fileSplitterFetch.splitterStop(); Q~,YbZ-7  
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} `T WN^0!]  
} Dy9\O77>  
//负责部分文件的抓取 <8
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**FileSplitterFetch.java @LX6hm*}  
*/ M]EsS^/X  
package NetFox; )pgrl  
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>-cfZ9{!  
import java.io.*; &a)vdlZSE=  
import java.net.*; TT}]wZ  
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL s:|M].  
long nStartPos; //File Snippet Start Position JdNF-64ky  
long nEndPos; //File Snippet End Position bI ITPxz  
int nThreadID; //Thread's ID SN">g
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boolean bDownOver = false; //Downing is over vA&Vu"}S  
boolean bStop = false; //Stop identical ;5S}~+j  
FileAccessI fileAccessI = null; //File Access interface \C|cp|A*&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Wk7WK` >i  
{ %FA@)?~  
this.sURL = sURL; t9 F=^)s  
this.nStartPos = nStart; BGWAh2w6  
this.nEndPos = nEnd; <[Oo*:A!7  
nThreadID = id; < K%j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v1.*IV5Y  
} 9O98Q6-s  
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public void run() b-<HXn_Fd  
{ \U
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while(nStartPos < nEndPos && !bStop) }DIF%}UK\  
{ =_d%=m  
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try{ hx!7w}[A  
URL url = new URL(sURL); (4+1lOd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a39hP*  
httpConnection.setRequestProperty("User-Agent","NetFox"); ijYvqZ_  
String sProperty = "bytes="+nStartPos+"-"; .ER98  
httpConnection.setRequestProperty("RANGE",sProperty); N}Vn;29  
Utility.log(sProperty); _m'ysCjA  
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InputStream input = httpConnection.getInputStream(); P]6}\ ]~  
//logResponseHead(httpConnection); ([k7hUP  
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byte[] b = new byte[1024]; Fb_S&!  
int nRead; 2
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GjQfi'vCk  
{ U}AX0*S  
nStartPos += fileAccessI.write(b,0,nRead); WH$HI/%*m  
//if(nThreadID == 1) %$mjJw<|&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kBsXfVs
9  
} nX5C<Ky  
v5$s#f<   
x>3@R0A1:  
Utility.log("Thread " + nThreadID + " is over!"); ")`S0n5e  
bDownOver = true; lOerrP6f(  
//nPos = fileAccessI.write (b,0,nRead); bhg}-dto  
} 2{o10eL  
catch(Exception e){e.printStackTrace ();} zhsx&  
} ok0X<MR!I  
} |f' 8p8J  
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//打印回应的头信息 +_mr  
public void logResponseHead(HttpURLConnection con) HeIS;gfUY  
{ G$=-,6kZO  
for(int i=1;;i++) y-+G wa3  
{ @$U 
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String header=con.getHeaderFieldKey(i); ]PX}b  
if(header!=null) Z)9R9s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %e=!nRc  
Utility.log(header+" : "+con.getHeaderField(header)); T\sNtdF`:  
else (B#(Z=  
break; C0m\SNR  
} Q7a(P  
} ?q$P>guH6-  
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public void splitterStop() w|Q
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{ S+T|a:]\7  
bStop = true; X"/~4\tJ"  
} =/Juh7[C  
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} E(Gr0#8  
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/* rsxRk7s@  
**FileAccess.java _s>^?x}  
*//文件访问(定位，写) 3,$iGe  
package NetFox; WU\m^!`w=F  
import java.io.*; F`&>NQb  
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public class FileAccessI implements Serializable{ I'InZ0J2  
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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 H1T~u{8j}  
RandomAccessFile oSavedFile; KH}t:m+h  
long nPos; uPDaq ]A  
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public FileAccessI() throws IOException 0wvU?z%WK  
{ s]x2DH+_  
this("",0); j|4tiv>  
} |- OHve4A  
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e
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public FileAccessI(String sName,long nPos) throws IOException yq6LH  
{ ETelbj;0  
oSavedFile = new RandomAccessFile(sName,"rw"); ^5x4q  
this.nPos = nPos; n\>.T[$"  
oSavedFile.seek(nPos); V9{B}5KC  
} t2.juoI(  
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public synchronized int write(byte[] b,int nStart,int nLen) k?-S`o%Q  
{ @:gl:mc  
int n = -1; ^[TOZXL`:  
try{ *k6$  
oSavedFile.write(b,nStart,nLen); (Y;'[.  
n = nLen; 8IOj[&%0  
} B;c=eMw  
catch(IOException e) *vs~SzF$  
{ 3@HIpQM3  
e.printStackTrace (); Pz {Ig  
} 7'UWRRsxUF  
|"\lL9CT  
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return n; ~UW{)]_jox  
} Q9q9<J7j$  
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} =n)#!i  
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/* W_D%|Ub2X  
**SiteInfoBean.java C~_q^fXJt  
*/ hvcR.f)C>  
package NetFox; Cha?7F[xL  
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6#-Z@fz%  
public class SiteInfoBean { 1eF@_Y^a!  
,whM22Af~{  
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private String sSiteURL; //Site's URL ASM1Y]'Z  
private String sFilePath; //Saved File's Path .lG
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private String sFileName; //Saved File's Name _!;\R7]  
private int nSplitter; //Count of Splited Downloading File %\

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4sQ~&@[Q+  
public SiteInfoBean() Bf(Mot^  
{//nSplitter的缺省值为5 )w@y(;WJ  
//default value of nSplitter is 5 qIk )'!Vk  
this("","","",5); ]o!&2:'N`  
} 'F6#l"~/  
v6(,Ax&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^CX,nj_(  
{ /Sh4pu"'  
sSiteURL= sURL; {{GHzW  
sFilePath = sPath; LVWxd}0  
sFileName = sName; y
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this.nSplitter = nSpiltter; h!~|6nj  
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} <WgG=Kf)N  
6yi/&#YM  
:e52hK1[T  
public String getSSiteURL() -ca]Q|m8  
{ %pM :{Z  
return sSiteURL; @]<DR*<  
} eb(m8vLR  
>4#tkv>S.  
&a~L_`\'  
public void setSSiteURL(String value) C`z;,!58%  
{ =b|)Wnt2f  
sSiteURL = value;
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} J$<:/^t  
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public String getSFilePath() = c/3^e  
{ O]4W|WI3  
return sFilePath; #SK#k<&P  
} U8U/?zW/&  
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^JiaR)#r  
public void setSFilePath(String value) ByC1I.B`  
{ WJBW:2=;  
sFilePath = value; (#C
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} EPR(i#xU  
Qdh"X^^  
GF9ZL  
public String getSFileName() moZ)|y  
{ {lTR/  
return sFileName; H,/~=d: ^  
} /{49I,  
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public void setSFileName(String value) {Nzmb|&  
{ DKf}47y  
sFileName = value; t=AE7  
} |~Htj4K/  
LAOdH/*:  
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public int getNSplitter() W8\PCXnsfl  
{ 3T Yo  
return nSplitter; xuw//F  
} <x.]OZgO  
F%Ro98?{  
_+0uju?o}  
public void setNSplitter(int nCount) eimA *0Cq  
{ pqRO[XEp2  
nSplitter = nCount; v GulM<YY  
} N8u_=b{X  
} hXj* {vT  
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4'd;'SvF  
/* k4]R]=Fh.  
**Utility.java ksxO<Y  
*/ ]
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package NetFox; n-L]YrDPK[  
K gR1El.r  
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public class Utility { hqwz~Ky}  
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public Utility() L|dab{9  
{ WW,r9D:/  
\" 5F;J  
!nZI? z;  
} a3DoLq"/  
W]C_oh  
//线程睡眠 LRfFn^FPM  
public static void sleep(int nSecond) /It.>1~2@  
{ FE^?U%:u@  
try{ D0,o
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Thread.sleep(nSecond); }bj,&c  
} )w3XN A_V  
catch(Exception e) i2\\!s  
{ &kmd<  
e.printStackTrace (); +dPE!:  
} OsHkAI  
} PW~cqo B71  
.q~,.yI&j  
//日志 ~7eUt^SD;  
public static void log(String sMsg) qHcY 2LV  
{ q?gQ  
System.err.println(sMsg); *NX*/(Q  
} *$*nY [/5  
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o} bj!h]N  
public static void log(int sMsg) #I*ht0++  
{ 7csl1|U  
System.err.println(sMsg); /3"e3{uy  
} oIu,rjb  
} o i,
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q%)*,I<  
=~(LJ
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/* yF [@W<  
**TestMethod.java )BMWC k  
*/ l{%Op\  
package NetFox; $6]x,Ct  
m+G0<E%  
 9\W5
 
public class TestMethod { ~-o^eI4_  
:\ON+LQr  
8B% O%*5`  
public TestMethod() ^.><t+tM  
{ ///xx/weblogic60b2_win.exe `Q!FMv6Y^  
try{ o@Cn
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?><   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $`+~QR!h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F".IB^}$  
fileFetch.start(); joSr,'x  
} 1)c=15^  
catch(Exception e){e.printStackTrace ();} Vq;{+j(  
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} njx\$,ruN  
O#89M%  
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public static void main(String[] args) *T}dv)8  
{ 6nhfI\q3wY  
new TestMethod(); V~%WKQ  
} /*xmv $  
} eyl) uR  
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