http断点续传简单实现（java)

/*
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**SiteFileFetch.java }qfr&Ffh@  
*/ 8Ml&lfn_8  
package NetFox; 'Z2:u!E  
import java.io.*; r})2-3ZA9  
import java.net.*; f@l6]z{.L  
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public class SiteFileFetch extends Thread { uY0V!W  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .4={K)kz|F  
long[] nStartPos; //开始位置 5zJkPki  
long[] nEndPos; //结束位置 VlW#_.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Hv%(9)-8  
long nFileLength; //文件长度 `NA[zH,w3  
boolean bFirst = true; //是否第一次取文件 Cpa
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boolean bStop = false; //停止标志 Vzy]N6QT{  
File tmpFile; //文件下载的临时信息 C%d 4ItB >  
DataOutputStream output; //输出到文件的输出流 -oq!zi4:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PpMZ-f@  
public SiteFileFetch(SiteInfoBean bean) throws IOException '|^LNAx  
{ dJ\6m!Mp  
siteInfoBean = bean; A9PXu\%y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q0WW^jwQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PJj{5,#@3  
if(tmpFile.exists ()) =/=x"q+X  
{ Ab7hW(/  
bFirst = false; /uI/8>p(  
read_nPos(); b~06-dk1  
} ulFU(%&  
else o;Ijv\Em  
{ 4W8rb'B!Ay  
nStartPos = new long[bean.getNSplitter()]; w?ssV  
nEndPos = new long[bean.getNSplitter()]; IV
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} dsD
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} "@B!5s0  
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public void run() Ku LZg  
{ wo2^,Y2z+  
//获得文件长度 OXDlwbwL  
//分割文件 Y~1}B_  
//实例FileSplitterFetch i=_leC)rl  
//启动FileSplitterFetch线程 A{h hnrr8  
//等待子线程返回 Z_' %'&Y  
try{ T\c;Ra  
if(bFirst) Qpd-uC_Ni  
{ yp5*8g5  
nFileLength = getFileSize(); 3M{!yPlj  
if(nFileLength == -1) rP ;~<IxEr  
{ (Wr;:3i  
System.err.println("File Length is not known!"); 'R_U,9y`  
} D,xWc|V  
else if(nFileLength == -2) qt]QO1pAd  
{ v,vTRrpK  
System.err.println("File is not access!"); 0!=e1_  
} .Q"3[  
else OdQ>h$ gZ  
{ o0-e,F>u  
for(int i=0;i<nStartPos.length;i++) XBhWj\`(T  
{ QOuy(GY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "W6nW  
} +WPi}  
for(int i=0;i<nEndPos.length-1;i++) V.WfP*~NJ  
{ /6{`6(p  
nEndPos = nStartPos[i+1]; <6/XE@"  
} q<>2}[W  
nEndPos[nEndPos.length-1] = nFileLength; UEo,:zeN[  
} }SitT\%  
} w%S<N  
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//启动子线程 @usQ*k  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +azPpGZ=  
for(int i=0;i<nStartPos.length;i++) PB>p"[ap4  
{ ~b\7qx_a9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JoW*)3Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p8s2#+/  
nStartPos,nEndPos,i); O
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {\|? {8f  
fileSplitterFetch.start(); u-U
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} ?^BsR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1@)]+* F*z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gbpm::  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", SNvK8,"g  
nEndPos = " + nFileLength); $pk3d+0B  
// fileSplitterFetch[nPos.length-1].start(); i`&yPw  
]kb%l"&  
vzi=[A  
//等待子线程结束 b]RCe^E1  
//int count = 0; 344,mnAd  
//是否结束while循环 j,/o0k,  
boolean breakWhile = false; W\.f:"2qr  
>[|:cz  
#*S/Sh?Q  
while(!bStop) 1bzPBi  
{ ;ok];4`a  
write_nPos(); 5B'-&.Aj+  
Utility.sleep(500); 4L!{U@'  
breakWhile = true; IUd>jHp`6  
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for(int i=0;i<nStartPos.length;i++) KXw \N!  
{ um,/^2A  
if(!fileSplitterFetch.bDownOver) N)poe2[  
{ ]`m|A1(  
breakWhile = false; nr&G4t+%Hv  
break; z*yN*M6t  
} u"T5m  
} ls*^3^O  
if(breakWhile) @TgCI`E  
break; e}[$ =  
4] ?  
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//count++; )W57n)]  
//if(count>4) d1y(Jt  
// siteStop(); 8
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} J=zZGd%  
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System.err.println("文件下载结束！"); yv3myaS  
} &)s A(  
catch(Exception e){e.printStackTrace ();} 1pzU=!R?-O  
} D%^EG8i n.  
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//获得文件长度 t9m`K9.\  
public long getFileSize() s ^)W?3t]  
{ )%^oR5W  
int nFileLength = -1; O')Ivm,E  
try{ Kq{s^G  
URL url = new URL(siteInfoBean.getSSiteURL()); ~S-x-cZ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?WAlW,H>  
httpConnection.setRequestProperty("User-Agent","NetFox"); $%1[<}<  
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}  
U +mx@C_  
int responseCode=httpConnection.getResponseCode(); ' J-(v  
if(responseCode>=400) _|A)ueY  
{ Z]SCIU @+  
processErrorCode(responseCode); Nm,vE7M  
return -2; //-2 represent access is error <[~x]-  
} Hlz4f+#I  
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String sHeader; !5A nr  
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for(int i=1;;i++) v11mu2  
{ H[>_LYZ8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }Bc6:a
  
//Utility.log(in.readLine()); -CL
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sHeader=httpConnection.getHeaderFieldKey(i); '|FM|0~-J  
if(sHeader!=null) c7iu[vE'+  
{ J=\Y4- "  
if(sHeader.equals("Content-Length")) E0)v;yRcw  
{ ie$=3nZJ}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'kh%^_FH7  
break; ahV_4;
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} (b{ {B$O  
} {.!:T+'Xi\  
else  bM-Y4[  
break; }*R"yp  
} -Q$$2QW!  
} 5n9F\T5  
catch(IOException e){e.printStackTrace ();} sWX  
catch(Exception e){e.printStackTrace ();} %< W1y  
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Utility.log(nFileLength); ]AHUo;(f%  
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return nFileLength; B]Zsn`n  
} LG,RF:
 
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//保存下载信息（文件指针位置） Xp{gh@#dr  
private void write_nPos() JGO>X|T  
{ $~:hv7%  
try{ 4uu*&B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wPc,FH+y  
output.writeInt(nStartPos.length); }XXE hOO  
for(int i=0;i<nStartPos.length;i++) k"sL.}$  
{ QY^ y(I49  
// output.writeLong(nPos); 
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output.writeLong(fileSplitterFetch.nStartPos); IsRsjhg8x  
output.writeLong(fileSplitterFetch.nEndPos); @ym7hk.  
} SA/0Z=  
output.close(); ,U2D&{@  
} \/$v@5  
catch(IOException e){e.printStackTrace ();} F(XWnfUv  
catch(Exception e){e.printStackTrace ();} ,U7hzBj8k  
} hqBwA1](a  
|RjjP 7  
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//读取保存的下载信息（文件指针位置） :ZzG5[o3  
private void read_nPos() ?&X6VNbU  
{ sP+S86 u  
try{ BFEo:!'F  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); buhxC5i%  
int nCount = input.readInt(); ]Ny]Ox<  
nStartPos = new long[nCount]; I9u=RIs  
nEndPos = new long[nCount]; Jz|(B_U  
for(int i=0;i<nStartPos.length;i++) xv%}xeEV  
{ RV($G8U  
nStartPos = input.readLong(); o3W5FHFAv  
nEndPos = input.readLong(); u#P7~9ZG-  
} 'PO1{&M  
input.close(); 4o=G) KO{  
} t6"4+:c!>  
catch(IOException e){e.printStackTrace ();} t*<c+Ixu  
catch(Exception e){e.printStackTrace ();} 'rF TtT  
} 9<YB&:<  
)8k6GO8|  
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private void processErrorCode(int nErrorCode) Kp&d9e{ Yc  
{ ?_^9e  
System.err.println("Error Code : " + nErrorCode); X
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} 5$#<z1M.&  
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T }8aj  
//停止文件下载 $`5DGy?RU  
public void siteStop() A9R}74e4g  
{ 3n/L;T,X  
bStop = true; Jg Xbs+.  
for(int i=0;i<nStartPos.length;i++) '+eP%Y[W%  
fileSplitterFetch.splitterStop(); h]=chz  
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} C4
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} '*-SvA\Cx  
//负责部分文件的抓取 L{Th>]X  
**FileSplitterFetch.java 4Cfwz-Qo  
*/ /;lk.-yU  
package NetFox; l9jcoVo.  
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import java.io.*; 2MC\~"
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import java.net.*; 81n%2G  
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public class FileSplitterFetch extends Thread { dqkkA/1  
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String sURL; //File URL $wN.~"T  
long nStartPos; //File Snippet Start Position !kIw835U  
long nEndPos; //File Snippet End Position 4v!@9.!vQ  
int nThreadID; //Thread's ID 6JL 7ut  
boolean bDownOver = false; //Downing is over |-R::gm  
boolean bStop = false; //Stop identical f>'7~69  
FileAccessI fileAccessI = null; //File Access interface =?2y <B  
c]LH.  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L"Gi
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{ *[U:'o`67  
this.sURL = sURL; Po_9M4kU  
this.nStartPos = nStart; 4H,DG`[Mo  
this.nEndPos = nEnd; z_H2L"Z  
nThreadID = id; 2Fh_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &p%,+|  
} jmb\eOq+~V  
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public void run() G'epsD,.bX  
{ b'&pJ1]]}  
while(nStartPos < nEndPos && !bStop) j NY8)w_  
{ ]@f6O*&=  
i" )_M|   
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try{ mSzwx/3"  
URL url = new URL(sURL); :X!(^a;]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UtutdkaS  
httpConnection.setRequestProperty("User-Agent","NetFox"); GGBe/X  
String sProperty = "bytes="+nStartPos+"-"; MPB6  
httpConnection.setRequestProperty("RANGE",sProperty); )FP|}DCxQ  
Utility.log(sProperty); 0L1P'*LRU  
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4/jY;YN,2  
InputStream input = httpConnection.getInputStream(); J!H5{7.efN  
//logResponseHead(httpConnection); pFK |4
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byte[] b = new byte[1024]; RpXQi*c0  
int nRead; l=oVC6C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OBl8kH(b>  
{ ZMe|fn  
nStartPos += fileAccessI.write(b,0,nRead); 3x'30  
//if(nThreadID == 1) X+3)DE\2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )&9=)G  
} N!v@!z9Mu  
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Utility.log("Thread " + nThreadID + " is over!"); !G,$:t1-=V  
bDownOver = true; ^Pf&C0xXv  
//nPos = fileAccessI.write (b,0,nRead); Fv: %"P^  
} h<M7[p=  
catch(Exception e){e.printStackTrace ();} =6dKC_Q  
} xsvs3y|  
} 7L]?)2=  
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`SW " RLS3  
//打印回应的头信息 !$?@;}=  
public void logResponseHead(HttpURLConnection con) KFhn}C3 i  
{ YfalsQ8  
for(int i=1;;i++) q!TbM"  
{ =4D_-Q  
String header=con.getHeaderFieldKey(i); $P-m6  
if(header!=null) =, 0a3D6b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;!}SgzSH}  
Utility.log(header+" : "+con.getHeaderField(header)); v;Dcq  
else z]YhQIU4n8  
break; ob7_d
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} 'k67$H  
} J*Hn/m  
5:d2q<x:{  
5
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public void splitterStop() vw]nqS~N  
{ ##@#:B  
bStop = true; 5%`Ul  
} ~ t H s+  

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} jq]"6/xxb  
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/* ?>8zU;Aj  
**FileAccess.java #[W[|m  
*//文件访问(定位，写) )r i

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package NetFox; 713M4CtJ  
import java.io.*; qlJOb}$ I  
lnWiE}F  
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public class FileAccessI implements Serializable{ Uq.~3V+u  
N]}+F w\5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \Sby(l  
RandomAccessFile oSavedFile; gJxVU41  
long nPos; c.Y8CD.tqL  
;8T=uCi  
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public FileAccessI() throws IOException KaE;4gwM  
{ %m) h1/
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this("",0); )JQQ4D  
} {Yk20Zn  
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public FileAccessI(String sName,long nPos) throws IOException J\+gd%  
{ b6Hk20+B;  
oSavedFile = new RandomAccessFile(sName,"rw"); <M?#3&5A  
this.nPos = nPos; mtQ{6u  
oSavedFile.seek(nPos); $jm<' 4  
} 1!wEXH(  
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yn[ZN-H~
  
public synchronized int write(byte[] b,int nStart,int nLen) bDS1'Ce  
{ ^(JHRH~=h  
int n = -1; YiuOu(X  
try{ 9:i,WJO  
oSavedFile.write(b,nStart,nLen); (y=o]Vy  
n = nLen; FqxOHovE  
} VQ<i$ I  
catch(IOException e) TDE1z>h+"  
{ X&?lDL7?  
e.printStackTrace (); T\!SA  
} T;r];Y(b*  
(OcNC/9  
)v{41sM+  
return n; -xu.=n@,  
} R(83E B~_  
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} K_|~3g  
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/* s|j<b#<xQ  
**SiteInfoBean.java &9_\E{o%]  
*/ <o7#?AcPu  
package NetFox; yXV|
4  
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public class SiteInfoBean { 50GYL5
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private String sSiteURL; //Site's URL zO5u{  
private String sFilePath; //Saved File's Path $
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private String sFileName; //Saved File's Name vZeYp  
private int nSplitter; //Count of Splited Downloading File $`5lvy^  
I,<54?vS  
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public SiteInfoBean() +F~0\#d  
{//nSplitter的缺省值为5 &<V_[Wh"  
//default value of nSplitter is 5 ;#yu"6{  
this("","","",5); QS [B  
} "gvw0)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nN`Z0?  
{ NVc!g  
sSiteURL= sURL; X'#$e{  
sFilePath = sPath; }\939Y  
sFileName = sName; ]]=-AuV.  
this.nSplitter = nSpiltter; U 'CfP9=  
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} !jnqA Z  
[Ql?Y$QB`4  
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public String getSSiteURL() h lkvk]v  
{ (}FW])y  
return sSiteURL; +dgo-)kP(_  
} v*H &F  
h*#2bS~nl-  
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public void setSSiteURL(String value) [CDXCV-z  
{ hX8gV~E=y  
sSiteURL = value; 1t[;`iZ  
} f
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public String getSFilePath() YQ@dl
 
{ \)otu\3/  
return sFilePath; uRm_  
} >'ksXA4b  
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public void setSFilePath(String value) Oj"pj:fB  
{ !u53 3  
sFilePath = value; {\svV 0)~  
} -7k|6"EwM  
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5%QC ][,  
public String getSFileName() 4+5OR&kxZ  
{ }$Hs;4|  
return sFileName; \[[TlB>  
} d=t}T6.|  
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public void setSFileName(String value) @.Z
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{ +~w?Xw,  
sFileName = value; <V$Y6(uMs  
} :dY.D|j*  
f@! fW&  
i
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public int getNSplitter() <78$]Z2we  
{ Ha)3i{OM  
return nSplitter; qe5tcv}u  
} stg30><  
>'} Y1_S5  
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public void setNSplitter(int nCount) T_
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{ p.rdSv(8'  
nSplitter = nCount; mUrS&&fu8  
} ?w]"~   
} A6^p}_  
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/* |rE!   
**Utility.java n|70x5Z?}J  
*/ $` Z>Lm*  
package NetFox; S'Z70 zJ  
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public class Utility { {D_++^  
a>o"^%x  
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public Utility() z5XYpi_;[  
{ _M8G3QOx  
:3KO6/+  
r{t.c?/  
} MV"E?}0  
@sc8}"J]#  
//线程睡眠 <i\UMrD]`:  
public static void sleep(int nSecond) &mN'Tk  
{ pU?{0xZH  
try{ wGEWr2$  
Thread.sleep(nSecond); /=8O&1=D  
} dtB[m^$  
catch(Exception e) ==%`e/~Y  
{ .S~@BI(|<  
e.printStackTrace (); L;/9L[s,  
} LP.HS'M~u  
} T;i?w  
Uc_jQ4e_  
//日志 +7| [b  
public static void log(String sMsg) zP_]  
{ E]?)FH<oP  
System.err.println(sMsg); ppAmN0=G  
} l6iw=b[?  
8)L'rW{q#  
EzR%w*F>Q  
public static void log(int sMsg) B$cOssl  
{ 89hF)80  
System.err.println(sMsg); 2dHM  
} u?Fnlne4@  
} Oo FgQEr@  
>vUB%OLyP  
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/* #v{Y=$L  
**TestMethod.java T"n{WmVQ  
*/ -glugVq  
package NetFox; Rw{$
L~\
 
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public class TestMethod { U z"sdi  
?n)Xw)]  
}1 $hxfb  
public TestMethod() ARPKzF`Wq  
{ ///xx/weblogic60b2_win.exe z)}3**3'y  
try{ j7K5SS_]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k/%#>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ZAMeqP
t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); DW#
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fileFetch.start(); ,Kuk_@(}5~  
} >9ob*6q,  
catch(Exception e){e.printStackTrace ();} 1Fv8T'  
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%B@!  
} 
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$0_^=DEW  
&,J*_F<s2<  
public static void main(String[] args) M|d={o9Hp  
{ *RBV'b  
new TestMethod(); (B@X[
~  
}
)T9;6R$b  
} bG"HD?A_  
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