http断点续传简单实现（java)

/* Mw"[2P
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**SiteFileFetch.java JiO8EIM  
*/ <;'{Tj-"  
package NetFox; wq,&0P-v  
import java.io.*; 7cWeB5e?O  
import java.net.*; [i.c;'Wy/  
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public class SiteFileFetch extends Thread { R,["w98a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6d6Dk>(V  
long[] nStartPos; //开始位置 K7.a
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long[] nEndPos; //结束位置 3-6M
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 "L`BuAB  
long nFileLength; //文件长度 {O).!  
boolean bFirst = true; //是否第一次取文件 2L[!~h2  
boolean bStop = false; //停止标志 9z{g3m70@  
File tmpFile; //文件下载的临时信息 b<#zgf  
DataOutputStream output; //输出到文件的输出流 SK&1l`3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） iPY)Ew`Im  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]dl.~;3~~  
{ "PWGtM:L8Y  
siteInfoBean = bean; -P-8D6   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0u&x%c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); RRYcg{g  
if(tmpFile.exists ()) ut]UU*g^$  
{ fv+d3s?h  
bFirst = false; X2;72  
read_nPos(); m\CU,9;;(  
} 6R8>w,  
else :;hX$Qz  
{ !>ZBb\EyK  
nStartPos = new long[bean.getNSplitter()]; fx4#R(N  
nEndPos = new long[bean.getNSplitter()]; g:xg ~H2  
} $%!06w#u  
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} 6I=xjgwvf  
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public void run() N?#L{Yt  
{ Zn40NKYc  
//获得文件长度 $I/ !vV  
//分割文件 4 #KC\C  
//实例FileSplitterFetch ^_V0irv  
//启动FileSplitterFetch线程 .I]v D#o  
//等待子线程返回 Mae2L2vc  
try{ d(d3@b4Ta  
if(bFirst) z.\\m;s  
{ y!
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nFileLength = getFileSize(); zFipuG0
2  
if(nFileLength == -1) \L$]2"/v-  
{ 8tf>G(I{  
System.err.println("File Length is not known!"); ]]`[tVaFr  
} {R[V  
else if(nFileLength == -2) R
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{ K4E
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System.err.println("File is not access!"); #lSGH 5Fp?  
} >gq=W5vN(  
else 8'zfq ]g  
{ &U=_:]/  
for(int i=0;i<nStartPos.length;i++) lX/7  
{ h
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); W!kF(O NA  
} ._;It198f  
for(int i=0;i<nEndPos.length-1;i++) Xt:j~cVA  
{ lA4J#  
nEndPos = nStartPos[i+1]; $Jn.rX0}$  
}  xiQc\k$  
nEndPos[nEndPos.length-1] = nFileLength; OEzSItAI/[  
} xO%yjG=  
} `WxGU  
N>sT@ > )  
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//启动子线程 X|g5tnsj`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1cMdoQ  
for(int i=0;i<nStartPos.length;i++)
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{ Dp#27Yzc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s(s_v ?k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y,KZp2 j  
nStartPos,nEndPos,i); 1rue+GL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CN-4FI)1D9  
fileSplitterFetch.start(); ?}W#j  
} &`>dY /Y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bd;EI)J
T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $:-C9N29  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,,IK}  
nEndPos = " + nFileLength); 'cIFbjJ
 
// fileSplitterFetch[nPos.length-1].start(); _U*1D*kLI[  
6 !fq658  
kf~>%tES]  
//等待子线程结束 9!2$?xqym  
//int count = 0; jE5=e</  
//是否结束while循环 zH~g5xgh  
boolean breakWhile = false; c$u#U~~  
6"rS?>W/mO  
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while(!bStop) |\"%Dy[m  
{ i*
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write_nPos(); \Km+>G  
Utility.sleep(500); 7<2?NLE8*  
breakWhile = true; eCg|@d%D  
j *N^.2  
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for(int i=0;i<nStartPos.length;i++) 3z#
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{ AI9=?X<kh  
if(!fileSplitterFetch.bDownOver) -A:'D8o#f  
{ z|S4\Ae  
breakWhile = false; 7-9HCP  
break;  Bv%dy[I  
} 5$$]ZMof  
} s <$*A;t  
if(breakWhile) qe0ZM-C_  
break; '=(yh{W  
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//count++; : 9zEne4  
//if(count>4) k9\n='OI  
// siteStop();  M[R'  
} 1JI7P?\B  
$"=0{H.?  
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System.err.println("文件下载结束！"); Fy_~~nI0  
} d+8|aS<A  
catch(Exception e){e.printStackTrace ();} [t5Dd  
} )hK;27m4  
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H a`V"X{}  
//获得文件长度 f-}_  
public long getFileSize() B|;?#okx  
{ 9!D c=  
int nFileLength = -1; :{Iv ]d  
try{ mT1Q7ta*P  
URL url = new URL(siteInfoBean.getSSiteURL()); n{c-3w.uD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o
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httpConnection.setRequestProperty("User-Agent","NetFox"); $'
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#N\<(SD/  
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int responseCode=httpConnection.getResponseCode(); HuD~(CI.  
if(responseCode>=400) *NIhYg6  
{ 5*$z4O:Aa  
processErrorCode(responseCode); [{+ZQd  
return -2; //-2 represent access is error lJ4/bL2I/  
} MPsm)jq
X  
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String sHeader; h&bs`  
$[(FCS  
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for(int i=1;;i++) %Vsg4DRy  
{ H<`7){iG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); M;@/697G  
//Utility.log(in.readLine()); o1<Z;2#  
sHeader=httpConnection.getHeaderFieldKey(i); Xkp`1UTH  
if(sHeader!=null) ]#$rTWMl'  
{ 0Jm)2@  
if(sHeader.equals("Content-Length")) k@2@%02o9C  
{ NX<Q}3cC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n(Ry~Xu_  
break; 9z?B@;lMc  
} FzFP

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} o7:"Sl2AD  
else ~T'$gl  
break; AiV1 vD`  
} Mj |"+(  
} :DBJ2n  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} sH)40QmO{  
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Utility.log(nFileLength); |\q@XCGei  
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return nFileLength; ,V=]QHcg  
} 95 X6
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//保存下载信息（文件指针位置） Cqw`K P  
private void write_nPos() 0J9Ub   
{ YoRD9M~iG~  
try{ =xHzhh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7C^W<SUo  
output.writeInt(nStartPos.length); dv\aP  
for(int i=0;i<nStartPos.length;i++) 'ewVn1ME[  
{ #K[6Ai=We}  
// output.writeLong(nPos); VK$s+"  
output.writeLong(fileSplitterFetch.nStartPos); ,6^V)F  
output.writeLong(fileSplitterFetch.nEndPos); e&XJK*Wf   
} ~
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output.close(); )%(H'omvl  
} NE!]  
catch(IOException e){e.printStackTrace ();} uB3Yl
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catch(Exception e){e.printStackTrace ();} n'Z5rXg  
} --|L?-2k,  
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//读取保存的下载信息（文件指针位置） 17;qJ_T)  
private void read_nPos() 4ew#@  
{ iJ~e8l0CA  
try{ x?-kt.M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;!/g`*?  
int nCount = input.readInt(); @RVj~J.A  
nStartPos = new long[nCount]; UNKXfe(X9  
nEndPos = new long[nCount]; CKRnkTTiV  
for(int i=0;i<nStartPos.length;i++) F%e5j9X`  
{ P}bwEj  
nStartPos = input.readLong(); tp=/f !bv  
nEndPos = input.readLong(); /hbdQm  
} Ng<oz*>U  
input.close(); H}&4#CQ'!  
} 6ALUd^  
catch(IOException e){e.printStackTrace ();} AG<TY<nqL  
catch(Exception e){e.printStackTrace ();} W!WeYV}kb  
} '9q:gFO  
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,L7:3W  
private void processErrorCode(int nErrorCode) bmGtYv  
{ GxcW^{;  
System.err.println("Error Code : " + nErrorCode); 8AVG pL  
} ALnE[}N6,  
5Lm<3:7Q+  
"+KAYsVtU  
//停止文件下载 /s~&$(d59o  
public void siteStop() c9N5c  
{ V(6ovJpA0  
bStop = true; sD`OHV:  
for(int i=0;i<nStartPos.length;i++) UG<`m]  
fileSplitterFetch.splitterStop(); S.A|(?x  
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} cu$i8$?t  
} $79-)4;z4  
//负责部分文件的抓取 *Wz\FixP0  
**FileSplitterFetch.java bR;Wf5  
*/ LuW^Ga"E  
package NetFox; ,Taq~  
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import java.io.*; d<B=p&~  
import java.net.*; K_E- Hgg_  
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public class FileSplitterFetch extends Thread { hO}nc$S  
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String sURL; //File URL $>y   
long nStartPos; //File Snippet Start Position '2.11cM3  
long nEndPos; //File Snippet End Position dX:#KdK  
int nThreadID; //Thread's ID :*{\oqFn~$  
boolean bDownOver = false; //Downing is over _Zs]za.#)|  
boolean bStop = false; //Stop identical
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FileAccessI fileAccessI = null; //File Access interface rCdf*;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException n^Sc*7  
{ uA2-&smw  
this.sURL = sURL;
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this.nStartPos = nStart; Q.Ljz Z  
this.nEndPos = nEnd; i@XFnt  
nThreadID = id; 5!)_"u3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 oc3}L^aD  
} b5Pakz=jNM  
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public void run() a2N4Jg@  
{ @ag*zl  
while(nStartPos < nEndPos && !bStop) mrz@Y0mgL  
{ ngHPOI16  
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try{ ,HM~Zs  
URL url = new URL(sURL); GBsM?A:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t
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httpConnection.setRequestProperty("User-Agent","NetFox"); *X4$'LSx1  
String sProperty = "bytes="+nStartPos+"-"; |]9Z#lv+I  
httpConnection.setRequestProperty("RANGE",sProperty); YKsc[~ h  
Utility.log(sProperty); S0<m><|kl  
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InputStream input = httpConnection.getInputStream(); lm;G8IP`  
//logResponseHead(httpConnection); 15^5yRXC  
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byte[] b = new byte[1024]; ep3iI77/  
int nRead; /4Lmu+G4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?nAKB5=  
{ 9&`ejeD  
nStartPos += fileAccessI.write(b,0,nRead); 2i3& 3oz]O  
//if(nThreadID == 1) pD>^Dfd  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ma`Goi\vFk  
} ?hQ,'M2  
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Utility.log("Thread " + nThreadID + " is over!"); Z/ypWoV(  
bDownOver = true; _("&jfn  
//nPos = fileAccessI.write (b,0,nRead); ?w[M{  
} g$f;  
catch(Exception e){e.printStackTrace ();} 8>|@O<2\  
} = 5E:CP  
} =':,oz^|  
}@V,v[&e  
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//打印回应的头信息 'Na/AcRdg  
public void logResponseHead(HttpURLConnection con) .{|AHW&0<  
{ !cWnQRIt_F  
for(int i=1;;i++) j>0~"A  
{ 9#;UQ.qA  
String header=con.getHeaderFieldKey(i); igW>C2J  
if(header!=null) 3[jk}2R';p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^:RDu q  
Utility.log(header+" : "+con.getHeaderField(header)); Nh[{B{k  
else Uieg4Iro  
break; UT9=S21  
} j;k(AM<  
} 92k}ON  
-~HlME*~f  
[[[QBplJ  
public void splitterStop() c[Mz#BWG  
{ (Rc0l;  
bStop = true; U "qO&;m  
} ]PnE%  
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} r]=3aebR.  
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/* diLjUC`69  
**FileAccess.java ,QpDz{8  
*//文件访问(定位，写) d\ &jl`8*  
package NetFox; +(3PY e\  
import java.io.*; ]rh)AE!Y(  
"iof -b=ys  
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public class FileAccessI implements Serializable{ n]B)\D+V^  
sv^;nOAc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 mP)<;gm,  
RandomAccessFile oSavedFile; pr-{/6j6  
long nPos; Z6b3gV  
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public FileAccessI() throws IOException K6,5C0  
{ Oed&B  
this("",0); 7#,
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} (WW,]#^  
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public FileAccessI(String sName,long nPos) throws IOException |7zm!^t$  
{ ]sjOn?YA+  
oSavedFile = new RandomAccessFile(sName,"rw"); 2="C6 7TK  
this.nPos = nPos; tE{7S/?h  
oSavedFile.seek(nPos); l!ye\
 
} O'."ca]:5  
?.A6HrAPB  
'ce9v@(0  
public synchronized int write(byte[] b,int nStart,int nLen) $`'^&o;&f  
{ <,0&Ox  
int n = -1; 4(JxZ49  
try{ >?e*;f$VdJ  
oSavedFile.write(b,nStart,nLen); e_6 i896  
n = nLen; JoZC+G  
} 0;TMwE  
catch(IOException e) sZ'3PNpCP  
{ ?NI)3-l  
e.printStackTrace (); %!rsu-W:Y  
} ,XP9NHE  
i=2+1;K  
#U/B,`= >  
return n; 2$NP46z}  
} V!KtF  
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}qz58]fyx  
} % wRJ"T`Tt  
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WaMn
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/* +N4h Q"  
**SiteInfoBean.java 9Zrn(D  
*/ *8XGo  
package NetFox; .^kTb2$X  
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public class SiteInfoBean { m Xw1%w[*  
!9)*.9[8  
n? s4"N6  
private String sSiteURL; //Site's URL 1xtbhk]D  
private String sFilePath; //Saved File's Path Vxgc|E^J  
private String sFileName; //Saved File's Name ^U_jeAuk8[  
private int nSplitter; //Count of Splited Downloading File kLD)<D  
&2\.6rb.  
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public SiteInfoBean() %n}]$ d  
{//nSplitter的缺省值为5 M(3E b;`  
//default value of nSplitter is 5 R1q04Zj{2  
this("","","",5); gieX`}  
} :,VyOmf  
3YT _GW{  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Dkdm~~Rr  
{ \aW5V:?  
sSiteURL= sURL; Hh@mIusj  
sFilePath = sPath; v5$zz w  
sFileName = sName; -=qmY
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this.nSplitter = nSpiltter; fCV
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} H{GbOI.  
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public String getSSiteURL() uPp(l4(+  
{ 0^[$0]Mt[  
return sSiteURL; fg1 zT~  
} 03#_ (  
yz+r@I5  
?)PcYrV  
public void setSSiteURL(String value) Aqm0|GlJ  
{ L"b5P2{c  
sSiteURL = value; j/Kw-h ,5"  
} Kc{wv/6}T  
uuC/F_='B  
iCEX|Tj;  
public String getSFilePath() n+i}>3'A  
{ FP\[7?ZLn  
return sFilePath; ?
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} -zTeIvcy5  
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kdo)y(fn@  
public void setSFilePath(String value) FVpe*]  
{  3sw1y  
sFilePath = value; ~|!lC}!IKL  
} eeX>SL5'i  
0!zWXKX  
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public String getSFileName() JL$RBr  
{ O,;SA  
return sFileName; M>^IQ  
} G dooy~cn  
AUq?<Vg\  
/;>EyWW  
public void setSFileName(String value)  6$Dbeb  
{ PQs9@]w[  
sFileName = value; 2KX *x_-  
} }$UFc1He\J  
P6?Q;-\q0  
w7W-=\Hvh  
public int getNSplitter() #nd,cn  
{ #*`|}_6L  
return nSplitter; 8_LDS  
} r#j*vO '  
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RU'J!-w{  
public void setNSplitter(int nCount) HvngjP{>  
{ _1Eyqh`oh  
nSplitter = nCount; ls5S9R 5  
} Cm&itG  
} Tv KX8m"  
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/* 'F~
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**Utility.java g?`J,*y  
*/ I F@M  
package NetFox; Nf~<xK  
$OO[C={v[  
g=%&p?1@E  
public class Utility { ^Ve^}|qPc  
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<vrx8Q*6  
public Utility() (AS%P?  
{ nZ*P:K t:  
nGt8u4gcP  
MoA{ /{  
} g,;MV7yE  
JB|I/\(A  
//线程睡眠 tX_eN  
public static void sleep(int nSecond) (!b: gG  
{ 6IX!9I\sT  
try{ 8+u8piG  
Thread.sleep(nSecond); gM*s/,;O"  
} Vh<`MS0X  
catch(Exception e) JjmL6(*ui  
{ (X9V-4  
e.printStackTrace (); g DhwJks  
} A"'MRYT`  
} { nV zN(  
>&VL2xLy  
//日志 %L/=heBBd  
public static void log(String sMsg) (pmo[2kg  
{ 6~}H
3rvO}  
System.err.println(sMsg); EDo (  
} |h7v}Y  
A=$oYBB  
W)#`4a^xj7  
public static void log(int sMsg) 5c"kLq
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{ E;q
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System.err.println(sMsg); VC.?]'OqD  
} qEAF!iB]L  
} 5-OvPTY`M  
HZ}*o%O  
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/* <%z/6I Af|  
**TestMethod.java B4}XK=)  
*/ q :bKT#\  
package NetFox; ]Q3Gj@6  
8VZ-`?p  
zCHr  
public class TestMethod { p{rS -`I  

xeI{i{8  
"YL-!P  
public TestMethod() :3B\,inJ  
{ ///xx/weblogic60b2_win.exe /Uc*7Y5j  
try{ _#C}hwOR>X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Xo`1#6xsE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L,6Y=?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v\Ljm,+  
fileFetch.start(); |
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} FT~^$)8=  
catch(Exception e){e.printStackTrace ();} 4i,SiFKB  
Bu1z$#AC  
#lF<="y%X  
} K(gj6SrjV  
*3$,f>W^  
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public static void main(String[] args) {<kG{i/  
{ z(3"\ ^T  
new TestMethod(); 8|({ _Z
 
} MxRU6+a  
} D@^ZpN8r  
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