http断点续传简单实现（java)

/* pwl7aC+6d  
**SiteFileFetch.java L(}/W~En  
*/ 8COGe=+o  
package NetFox; Wqe0
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import java.io.*; AIw~@*T  
import java.net.*; -ug-rdXV  
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public class SiteFileFetch extends Thread { "sed{?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ckbD/+  
long[] nStartPos; //开始位置 ,<;.'r  
long[] nEndPos; //结束位置 cUwR6I9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nbBox,zW  
long nFileLength; //文件长度 Q7_#k66gb7  
boolean bFirst = true; //是否第一次取文件 wvH*<,8Vq  
boolean bStop = false; //停止标志 6\x/Z=}L  
File tmpFile; //文件下载的临时信息 q5.5%W  
DataOutputStream output; //输出到文件的输出流 h4c4!S  
}sM_^&e4X  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zS `>65}e  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3*e )D/lm  
{ ~uuM
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siteInfoBean = bean; $Q`\-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~'LoIv20j)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k!!d2y6  
if(tmpFile.exists ()) L7N>p4h]Xj  
{ #^w8Y'{?  
bFirst = false; *-@@t+3  
read_nPos(); ;MW=F9U*  
} 87hU#nVYh  
else QLZ%m$Z  
{ -IL' (vx  
nStartPos = new long[bean.getNSplitter()]; /?S,u,R  
nEndPos = new long[bean.getNSplitter()]; ,1i
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} Lp{/  
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} $ 3R5p  
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public void run() G4"[ynlWV  
{ Kj+TPqXb  
//获得文件长度 [UB]vPXm$  
//分割文件 ]GzfU'fOn|  
//实例FileSplitterFetch r,ep{ p  
//启动FileSplitterFetch线程 <KZ J  
//等待子线程返回 tS[@?qP  
try{ "O%xQ N  
if(bFirst) 0~cbB  
{ 67wq8|  
nFileLength = getFileSize(); .;37 e  
if(nFileLength == -1) 1
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{ t8Giv89{  
System.err.println("File Length is not known!"); - S%8  
} Y%8[bL$ d  
else if(nFileLength == -2) a7e.Z9k!  
{ 8o,"G}Hjk  
System.err.println("File is not access!"); vVH*\&H\T  
} XI5q>cd\Sz  
else D__*?frWpW  
{ BtKbX)R$J  
for(int i=0;i<nStartPos.length;i++) _8OSDW*D5t  
{ Bmi9U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Wp
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} A@n//AZM  
for(int i=0;i<nEndPos.length-1;i++) FMAt6HfU  
{ UvVq#<-  
nEndPos = nStartPos[i+1]; rq^VOK
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} t<znz
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nEndPos[nEndPos.length-1] = nFileLength; ^vo]bq7  
} |3 v+&eVi  
} E^t}p[s  
D<xDj#Z~1  
]PZ\N~T
 
//启动子线程 ~Q5 i0s%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _E xd:  
for(int i=0;i<nStartPos.length;i++) q%MLj./?[  
{ rTM0[2N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jUy$aGX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G!w?\-  
nStartPos,nEndPos,i); *@[+C~U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d]Mjr2h  
fileSplitterFetch.start(); ~9dAoILrl  
} mf)E%qo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _eMY?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |1Pi`^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O:W4W=K  
nEndPos = " + nFileLength); <k-hRs2d  
// fileSplitterFetch[nPos.length-1].start(); e"voXe  
TAZ+2S##7  
Mt+ggF.  
//等待子线程结束 Q#*Pjl  
//int count = 0; firiYL"=44  
//是否结束while循环 )n17}Qm`V  
boolean breakWhile = false; CFiO+p&  
p`{| [<  
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while(!bStop) =j S  
{ '1Q [&  
write_nPos(); VtJyE}  
Utility.sleep(500); pN7 v7rs  
breakWhile = true; ,
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]
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for(int i=0;i<nStartPos.length;i++) t+Hx&_pMj  
{ ajALca4  
if(!fileSplitterFetch.bDownOver) E>O1dPZcM  
{ Q1
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breakWhile = false; z+%74O"c  
break; (TFo]c  
} hDHIi\%  
} cp<jwcc!  
if(breakWhile) 4+15`  
break; `d.4L.],  
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//count++; ,7|Wf %X  
//if(count>4) B5fF\N^  
// siteStop(); 6$6Qk !%  
} u3@v  
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System.err.println("文件下载结束！"); ;#Pc^Yzc1  
} caC(KK#<  
catch(Exception e){e.printStackTrace ();} (YH/#n1"{  
} [*AWCV  
LX_{39?<{  
SebJ}P1x  
//获得文件长度 uw`fC%-xh  
public long getFileSize() p$*;>YKO  
{ u.Z,HsEOb  
int nFileLength = -1; S2*ER  
try{ bem-T`>'  
URL url = new URL(siteInfoBean.getSSiteURL()); T&PLvyBL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XT0:$0F  
httpConnection.setRequestProperty("User-Agent","NetFox"); [.`%]Z(  
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int responseCode=httpConnection.getResponseCode(); zm('\KvT  
if(responseCode>=400) EU"J'?  
{ I~.d/!
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processErrorCode(responseCode); K:g:GEDgf  
return -2; //-2 represent access is error wz(D }N5  
} yL>wCD,L  
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String sHeader; X0"f>.Lg  
b[_${in:  
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for(int i=1;;i++) Vdz(\-}ao  
{ g2'Q
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Pqm)OZE?  
//Utility.log(in.readLine()); +\O[)\  
sHeader=httpConnection.getHeaderFieldKey(i); b-XC\  
if(sHeader!=null) bn$}U.m$-  
{ :&oUI&(o  
if(sHeader.equals("Content-Length")) GXE6=B
O  
{ +$x;FT&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); A->y#KQ  
break; Y4B<]C4  
} 6b8@6;&LI  
} 3]9twfF 'J  
else FTg4i\Wp  
break; fx783  
} l6S6Y  
} yU@~UCmja  
catch(IOException e){e.printStackTrace ();} U5z}i^8a  
catch(Exception e){e.printStackTrace ();} U8b1 sz  
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Utility.log(nFileLength); (cj3[qq  
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return nFileLength; /@.c 59r  
} OZ$"P<X_"  
h!*++Y?&0  
BI\+NGrB  
//保存下载信息（文件指针位置） ffQ%GV_  
private void write_nPos() /Lc= K<  
{ _0rHxh7}q
 
try{ P~+?:buqc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZQ^kS9N i  
output.writeInt(nStartPos.length); i~IQlyGr.  
for(int i=0;i<nStartPos.length;i++) a#0GmK  
{ r $du-U  
// output.writeLong(nPos); wnE c   
output.writeLong(fileSplitterFetch.nStartPos); y%H;o?<WX  
output.writeLong(fileSplitterFetch.nEndPos); B=;pyhc  
} 4pF U`g=  
output.close(); mF>CH]k3  
} 3"gifE  
catch(IOException e){e.printStackTrace ();} bw7!MAXd  
catch(Exception e){e.printStackTrace ();} :{9|/a  
} ~?}/L'q!b  
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I_yIVw;  
//读取保存的下载信息（文件指针位置） gkpNT)  
private void read_nPos() 0;)6ZU  
{ ~^.&nph  
try{ (oxe\Qk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Siw9_c  
int nCount = input.readInt(); We]X+>BlO  
nStartPos = new long[nCount]; @"s\eL,r  
nEndPos = new long[nCount]; KrkZv$u,  
for(int i=0;i<nStartPos.length;i++) e![Q1!r  
{ e76@-fg  
nStartPos = input.readLong(); \i-jME(sN  
nEndPos = input.readLong(); ?E2k]y6<  
} %:o@IRTRU  
input.close(); Ut-6!kAm  
} DuvP3(K  
catch(IOException e){e.printStackTrace ();} =] 5;=>(  
catch(Exception e){e.printStackTrace ();} fnnwe2aso  
} oQ;f`JC^  
@\l> <R9V  
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private void processErrorCode(int nErrorCode) |/
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{ b+p!{  
System.err.println("Error Code : " + nErrorCode); &`L5UX  
} Dlj=$25  
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E2*"~gL^,  
//停止文件下载 ~vl:Tb  
public void siteStop() !v;r3*#Nky  
{ h.=B!wKK  
bStop = true; N~>?w#?J  
for(int i=0;i<nStartPos.length;i++) Rg[e~##  
fileSplitterFetch.splitterStop(); {t/!a0\HS  
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} wCt+{Y3T  
} T (2,iG8  
//负责部分文件的抓取 Zc4hjg  
**FileSplitterFetch.java |C&eH$?~=R  
*/ 3+|6])Hi1  
package NetFox; _&%!4n#>  
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import java.io.*; dY-a,ch"8p  
import java.net.*; FY|x<-f  
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public class FileSplitterFetch extends Thread { I(<G;ft<}  
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String sURL; //File URL k
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long nStartPos; //File Snippet Start Position QNJG}Upl  
long nEndPos; //File Snippet End Position `2fuV]FW  
int nThreadID; //Thread's ID f.P( {PN  
boolean bDownOver = false; //Downing is over &"
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boolean bStop = false; //Stop identical <C>i~<`d  
FileAccessI fileAccessI = null; //File Access interface " }ZD)7K  
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*(scSC>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \fKE~
61  
{
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this.sURL = sURL; l46F3C|  
this.nStartPos = nStart; zc1Zuco| R  
this.nEndPos = nEnd; $($SQZK&  
nThreadID = id; 8 Kk
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 F:@Ixk?E  
} UJH{vjIv  
:9YQX(l8  
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public void run() `SwnKg  
{ lewDR"0Kx  
while(nStartPos < nEndPos && !bStop) +n,BD C;  
{ |i`@!NrFL  
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try{ u7=[~l&L  
URL url = new URL(sURL); LNZ#%R~r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~tLR  
httpConnection.setRequestProperty("User-Agent","NetFox"); +Y~+o-_  
String sProperty = "bytes="+nStartPos+"-"; eFio,  
httpConnection.setRequestProperty("RANGE",sProperty); 1pb;A;F,A  
Utility.log(sProperty); x]ti3?w  
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InputStream input = httpConnection.getInputStream(); &FrB6y  
//logResponseHead(httpConnection); `0^i #  
/=@vG Vp6  
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byte[] b = new byte[1024]; j1F+,   
int nRead; V)2_T!e%*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V8yX7yx  
{ \Wc/kY3&  
nStartPos += fileAccessI.write(b,0,nRead); s.sy7%{  
//if(nThreadID == 1) TyWy5J< :+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k^pu1g=6I  
} (@E#O$'  
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Utility.log("Thread " + nThreadID + " is over!"); h`]/3Ma*:  
bDownOver = true; I
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//nPos = fileAccessI.write (b,0,nRead); =BS'oBn^6  
} !)3s <{k#  
catch(Exception e){e.printStackTrace ();} ['emP1g~  
} UWp8I)p!\O  
} txo?k/w  
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//打印回应的头信息 *'YNRM\}  
public void logResponseHead(HttpURLConnection con)  -C  ON  
{ LDEt.,6i  
for(int i=1;;i++) %"Q!5
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{ IKDjatn  
String header=con.getHeaderFieldKey(i); T(UYlLe  
if(header!=null) 3Z

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//responseHeaders.put(header,httpConnection.getHeaderField(header)); &PuJV +y  
Utility.log(header+" : "+con.getHeaderField(header)); R6Mxdm2P}  
else `U_>{p&x  
break; HoE
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} ev%
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} hav?mnVJ  
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= )l:^+q  
public void splitterStop() 'Y{ux>  
{ 'eDgeWt/CQ  
bStop = true; .cS,T<$  
} M(zY[O
 
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} Usf"K*A  
J s<MJ4r>/  
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/* |vDoqlW  
**FileAccess.java RrU~"P1C  
*//文件访问(定位，写) y8*@dRrq  
package NetFox; K'5sn|)  
import java.io.*; _2X6
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public class FileAccessI implements Serializable{ '"]>`=R  
f+TBs_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2}`Vc{\  
RandomAccessFile oSavedFile; 9g&)6,<  
long nPos; 76_8e{zbr  
v(@+6#&  
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public FileAccessI() throws IOException .`Old{<  
{ OwiWnS<  
this("",0); <W=[ sWJ  
} O{ %A&Ui  
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public FileAccessI(String sName,long nPos) throws IOException |
6(qg5"  
{ t`8e#n 9  
oSavedFile = new RandomAccessFile(sName,"rw"); dy6F+V\DG  
this.nPos = nPos; 4&]To@>  
oSavedFile.seek(nPos); AYPf)K;%  
} 'tV"^KQHI  
z@%/r~?|  
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public synchronized int write(byte[] b,int nStart,int nLen) 7\0|`{|R@  
{ 01-\:[{  
int n = -1; wwK~H  
try{ =JbdsYI(  
oSavedFile.write(b,nStart,nLen); ?`T6CRZ
hr  
n = nLen; r>Qyc  
} m
.HX2(&\3  
catch(IOException e) 59Tg"3xB<  
{ $ g

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e.printStackTrace (); cFI7}#,5  
} >G4HZE  
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return n; @wEKCn|}o  
} gf3u0' $  
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} k}I5x1>&  
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/* i)@U.-*5m  
**SiteInfoBean.java X]zCTY=l  
*/ {m_A1D/_  
package NetFox; >Bh)7>`3c  
r}_Lb.1]  
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public class SiteInfoBean { ;<bj{#mMv  
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private String sSiteURL; //Site's URL a%MzNH  
private String sFilePath; //Saved File's Path so?pA@O
 
private String sFileName; //Saved File's Name TdNuD V  
private int nSplitter; //Count of Splited Downloading File -!'Oy%a#  
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{2}tPT[a(  
public SiteInfoBean() R "/xne  
{//nSplitter的缺省值为5 Wz6]*P`qv  
//default value of nSplitter is 5 "t(1tWO1o  
this("","","",5); 5YTb7M  
} !q~X*ZKse  
R/ALR
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >u9id>+  
{ PtVo7zOye  
sSiteURL= sURL; F:[7^GQZ{  
sFilePath = sPath; u#a%(  
sFileName = sName; jgo e^f  
this.nSplitter = nSpiltter; %|:;Ti  
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r.^0!(d  
} T7>48
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public String getSSiteURL() M(n<Iu4^_  
{ 4o1Q7  
return sSiteURL; Ez06:]Jd  
} +Od1)_'\D3  
~pHJ0g:t  
)LkM,T  
public void setSSiteURL(String value) /_NkB$&  
{ r+imn&FK8  
sSiteURL = value;  =3h+=l[  
} =]=B}L`  
??%)|nj.  
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public String getSFilePath() [MV`pF)x  
{ T{_1c oL  
return sFilePath; Jz~+J*r;]A  
} ShC_hi  
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public void setSFilePath(String value) 0L!er%GM  
{ ?cqicN.+6  
sFilePath = value; *<B)Z  
} Na\3.:]z  
L@7Qs6G2u  
5,F;j<F  
public String getSFileName() ^H'hD  
{ <\>+~p,  
return sFileName; aXRv}WO$>k  
} f&6w;T=  
/0Z|+L9Jo  
IO}+[%ptc*  
public void setSFileName(String value) *6NO-T; -  
{ `-~`<#E[  
sFileName = value;
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} #0}Ok98P  
>g>?Y G  
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public int getNSplitter() nHrP>zN  
{ ^gd<lo g  
return nSplitter; [6O04"6K  
} $2Kau 1  
:aHcPc:  
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public void setNSplitter(int nCount) aD+0\I[x  
{ ]
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nSplitter = nCount; X2i*iW<  
} f(!E!\
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} FH4u$g+  
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/* Dzo{PstM%  
**Utility.java 'c#IMlv  
*/ dl:-k r8  
package NetFox; Jth=.9mrM  
3u*82s\8T  
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public class Utility { 4e}{$s$Xx  
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#h
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public Utility() 10?qjjb&  
{ #^Ys{  
n"iNKR>nW  
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} U7E  
J,RDTXqn  
//线程睡眠 \<X2ns@Tf  
public static void sleep(int nSecond) GYd]5`ri  
{ eI0F!Yon  
try{ YwGHG{?e  
Thread.sleep(nSecond); @^'$r&M  
} RE 9nU%!  
catch(Exception e) ka#K [qI  
{ {8 N=WZ  
e.printStackTrace (); Rnr#$C%  
} ;@9e\!%  
} t-!m vx9Z  
iTu0T!4F  
//日志 '#A:.P  
public static void log(String sMsg) #sZIDn J#  
{ [A]Ca$':  
System.err.println(sMsg); Y87XLvig}  
} Sl"BK0:%7  
qi&D+~Gv!  
'PpZ/ry$  
public static void log(int sMsg) FN!1|'VK  
{ wdwp9r  
System.err.println(sMsg); E?cZbn*>`  
} uH\w.  
} #]y5zi  
ZE rdt:w  
nv)))I\  
/* Oc~aW3*A(  
**TestMethod.java &\^rQi/tf  
*/ 7}%H2$Do  
package NetFox; `
|EH[W&y  
(sCAR=5v\  
Xu#:Fe}:  
public class TestMethod { AkA!:!l  
B.*"Xfr8  
`%=<R-/#7S  
public TestMethod() G6Nb{m  
{ ///xx/weblogic60b2_win.exe $P nLG]X  
try{ .$0Pr%0pWI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Kam]Mn'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =|,A%ZGF$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YB5dnS"n  
fileFetch.start(); \|t{e8}  
} `WnQ  
catch(Exception e){e.printStackTrace ();} 'zxoRc-b@N  
 iSiDSeW8  
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} bX2"89{  
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6Dst;:  
public static void main(String[] args) :1;Q(9:v  
{ !ni>\lZ  
new TestMethod(); 7
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} cAEokP  
} Mu2`ODe]  
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