http断点续传简单实现（java)

/* ft$!u-`  
**SiteFileFetch.java BD [<>Wm  
*/ s8;*Wt  
package NetFox; A$rCo~E
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import java.io.*; ]f6,4[  
import java.net.*; 1]"S?  
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public class SiteFileFetch extends Thread { ;pqS|ayl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w& )ApfL  
long[] nStartPos; //开始位置 i^)JxEPr w  
long[] nEndPos; //结束位置 4Mox
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 mOJ-M@ME  
long nFileLength; //文件长度 bUe6f,8,  
boolean bFirst = true; //是否第一次取文件 19i=kdH  
boolean bStop = false; //停止标志 4$+/7I \  
File tmpFile; //文件下载的临时信息 R]l2,0:  
DataOutputStream output; //输出到文件的输出流 or(P?Ro  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QzY5S0  
public SiteFileFetch(SiteInfoBean bean) throws IOException (8(P12l  
{ <m*j1|^{t  
siteInfoBean = bean; `We?j7O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ZQyXzERp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B;t{IYhq{  
if(tmpFile.exists ()) (d['f]S+&  
{ Wu)An  
bFirst = false; SqVh\Nn  
read_nPos(); [j?<&^SW  
} lt%9Zgr[u  
else ctR^"'u  
{ 7)BK&kpVr  
nStartPos = new long[bean.getNSplitter()]; fr&K^je\  
nEndPos = new long[bean.getNSplitter()]; Sc:)H2k`$  
} 1cV0TUrz  
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} =<Ss&p>  
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public void run() a``
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{ VqS1n  
//获得文件长度 VP^{-mDph  
//分割文件 awSi0*d~  
//实例FileSplitterFetch vb$i00?  
//启动FileSplitterFetch线程 _xM3c&VeG  
//等待子线程返回 7b(r'b@N  
try{ $Zj3#l:rK  
if(bFirst) @eP(j@(^  
{ 8aVj@x$'  
nFileLength = getFileSize(); w}?,N  
if(nFileLength == -1) 1~S''[  
{ fz  rH}^  
System.err.println("File Length is not known!"); :MGIp%3  
} oTveY  
else if(nFileLength == -2) ;oOv~YB7H  
{ Mlo:\ST
|  
System.err.println("File is not access!"); )Mh5q&ow  
} {"_V,HmEF+  
else Is!+`[ma  
{ 7TA&u'  
for(int i=0;i<nStartPos.length;i++) [pSQ8zdF"  
{ ,S1'SCwVdJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7e Hj
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} Fu65VLKh  
for(int i=0;i<nEndPos.length-1;i++) v
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{ -pQ0,/}K  
nEndPos = nStartPos[i+1]; pEY zB;  
} =91f26c!~  
nEndPos[nEndPos.length-1] = nFileLength; A s8IjGNs{  
} k>#-NPU$  
} u+ 8wBb5!  
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//启动子线程 UZo[]$"Q`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8< z  
for(int i=0;i<nStartPos.length;i++) \j0016;  
{ nr%P11U\c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c22L]Sxo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dl+c+
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nStartPos,nEndPos,i); O`.IE? h#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l?KP/0`  
fileSplitterFetch.start(); $Q`\-  
} ~'LoIv20j)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R".*dC,0'B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4TcW%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tw<}7l_>Au  
nEndPos = " + nFileLength); Q.SqOHeJ  
// fileSplitterFetch[nPos.length-1].start(); JiGS[tR  
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[
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//等待子线程结束 BUXlHh%<R  
//int count = 0; C`\yc_b9Pf  
//是否结束while循环 -IL' (vx  
boolean breakWhile = false; {%z
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while(!bStop) @XH@i+{B  
{ Gk)6ljL  
write_nPos(); ,DCrhk
 
Utility.sleep(500); &izk$~  
breakWhile = true; SKVQ !^o  
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for(int i=0;i<nStartPos.length;i++) Y~UWUF%aK  
{ ORt)sn&~d  
if(!fileSplitterFetch.bDownOver) U-#vssJhk  
{ ]u%Y8kBe  
breakWhile = false; FZ
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break; ^Fwdi#g  
} `12Y2W 9  
} D`PA
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if(breakWhile) K# h7{RE  
break; RYM[{]4b5F  
/[|A(,N}{  
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//count++; =@.5J'!  
//if(count>4) 2~@Cj@P]  
// siteStop(); mnM$#%q;%  
} =Ct$!uun  
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System.err.println("文件下载结束！"); VpB+|%@p  
} *m&(h@l  
catch(Exception e){e.printStackTrace ();} jk5C2dy  
} $wqi^q*)  
m[A$Sp_"-h  
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//获得文件长度 - S%8  
public long getFileSize() {?]&P  
{ Sp@{5  
int nFileLength = -1; eit%U  
try{ f:h<tlob  
URL url = new URL(siteInfoBean.getSSiteURL()); !3Q^oR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2bTM0-  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3NrWt2?  
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int responseCode=httpConnection.getResponseCode(); `YK#m4gc  
if(responseCode>=400) 0|~3\e/QV  
{ m"~),QwF9  
processErrorCode(responseCode); ptTp63+  
return -2; //-2 represent access is error I>@Qfc bG  
} 9S{0vc/2@  
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String sHeader; - s0QEQ  
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for(int i=1;;i++) g;!,2,De}  
{ L_fiE3G|>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X1GM\*BE  
//Utility.log(in.readLine()); nY_+V{F  
sHeader=httpConnection.getHeaderFieldKey(i); >\>!Q V1@  
if(sHeader!=null) k E-+#p  
{ RGLi#:0_.x  
if(sHeader.equals("Content-Length")) c4L++
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{ |3 v+&eVi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yo#fJ`  
break; Ufe@G\uyI  
} >2K:O\&  
} >~\CiV4^  
else 7
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break; 8#15*'Y  
} _E xd:  
} CI@qT}Y_  
catch(IOException e){e.printStackTrace ();} ?.,2EC=+  
catch(Exception e){e.printStackTrace ();} W.  p'T}2  
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7)y +QU]  
Utility.log(nFileLength); .0]Odf:@  
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return nFileLength; #l_hiD`;r  
} /` 4B-Y4M4  
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//保存下载信息（文件指针位置） G1/  
private void write_nPos() <84d Vg  
{ }G1hB#j  
try{ XN~r d,MZ%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5w@Q %'o`I  
output.writeInt(nStartPos.length); rfhvdwwD  
for(int i=0;i<nStartPos.length;i++) };]f 3  
{ 4GqE%n+ta~  
// output.writeLong(nPos); W>rx:O+  
output.writeLong(fileSplitterFetch.nStartPos); }B2qtb3  
output.writeLong(fileSplitterFetch.nEndPos); |BA<> WE  
} >y iE}  
output.close(); L@8C t  
}  WfkP  
catch(IOException e){e.printStackTrace ();} X1Y+ao1)  
catch(Exception e){e.printStackTrace ();} $Z4IPs  
} `i3fC&?C  
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//读取保存的下载信息（文件指针位置） @3I/57u<  
private void read_nPos() \k*h& :$  
{ lcEin*Oc  
try{ IT\ x0b cv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O_y?53X  
int nCount = input.readInt(); w1 tg7^(@  
nStartPos = new long[nCount]; Q)}z$h55  
nEndPos = new long[nCount]; 5tl uS  
for(int i=0;i<nStartPos.length;i++) HDT-f9%}<4  
{ D^\2a;[AxA  
nStartPos = input.readLong(); 2V=bE-  
nEndPos = input.readLong(); "3:TrM$|A  
} ]
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input.close(); f)!7/+9>  
} %R LGO&  
catch(IOException e){e.printStackTrace ();} P};GcV-  
catch(Exception e){e.printStackTrace ();} uM('R;<^  
} g'1ASMuR  
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private void processErrorCode(int nErrorCode) z+%74O"c  
{ qn|~z@"  
System.err.println("Error Code : " + nErrorCode); nV&v@g4Tt  
} z7um
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//停止文件下载 ?<-ins  
public void siteStop() o
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{ f3HleA&&  
bStop = true; xEvm>BZi  
for(int i=0;i<nStartPos.length;i++) T&~7*j(|e  
fileSplitterFetch.splitterStop(); xl;0&/7e  
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} lT~A~O  
} ;OfZEy>7  
//负责部分文件的抓取 wQ/Z:  
**FileSplitterFetch.java 088"7 s  
*/ u3@v  
package NetFox; e&J_uG  
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import java.io.*; %t<ba[9F  
import java.net.*; UV8K$n<  
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public class FileSplitterFetch extends Thread { (YH/#n1"{  
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String sURL; //File URL !E|k#c9
 
long nStartPos; //File Snippet Start Position Wg ?P"  
long nEndPos; //File Snippet End Position iHL`r1I!  
int nThreadID; //Thread's ID rYw
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boolean bDownOver = false; //Downing is over cJ!C=J  
boolean bStop = false; //Stop identical CxRhMhvP  
FileAccessI fileAccessI = null; //File Access interface Y;6%pm$  
7O.{g  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kw.IVz<  
{ mFXkrvOf,  
this.sURL = sURL; K7N.gT*4  
this.nStartPos = nStart; q^k]e{PD  
this.nEndPos = nEnd; Ps_q\R  
nThreadID = id; Z-B b,8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K{x FhdW  
} ~^R?HS  
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public void run() -*r]9f6x  
{ jJDYl([  
while(nStartPos < nEndPos && !bStop) s55t>t,g6  
{ @"E{gM@B  
>hbT'Or@  
^HasT4M+x  
try{ Ee?+IZ H7|  
URL url = new URL(sURL); 'fkaeFzOl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ie%_-  
httpConnection.setRequestProperty("User-Agent","NetFox"); lSk<euCYs  
String sProperty = "bytes="+nStartPos+"-"; czv )D\*  
httpConnection.setRequestProperty("RANGE",sProperty); 3JR1If  
Utility.log(sProperty); ^#A[cY2eM  
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InputStream input = httpConnection.getInputStream(); t@O4!mFH  
//logResponseHead(httpConnection); 9M$N>[og  
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byte[] b = new byte[1024]; (66DKG   
int nRead; 1KtPq
,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (ATCP#lF  
{ U DC>iHt  
nStartPos += fileAccessI.write(b,0,nRead); mC}!;`$8p  
//if(nThreadID == 1) >7^
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "Nn+Zw43  
} )QvuoaJQ  
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Utility.log("Thread " + nThreadID + " is over!"); T|&2!Sh  
bDownOver = true; 4:
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//nPos = fileAccessI.write (b,0,nRead); :<$IGzw}.  
} X&qa3C})  
catch(Exception e){e.printStackTrace ();} a|v}L,  
} Jqt&TqX@s  
} >`@yh-'r  
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//打印回应的头信息 M"t=0[0DM:  
public void logResponseHead(HttpURLConnection con) yU@~UCmja  
{ ^QKL}xiV:  
for(int i=1;;i++) &MlBpI  
{ <.h\%&'U  
String header=con.getHeaderFieldKey(i); i;Y@>-[e<  
if(header!=null) j_r7oARL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7q] @Jx9  
Utility.log(header+" : "+con.getHeaderField(header)); k9^Vw+$m  
else X}5a
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break; d$G<g78D  
} @}e'(ju%R  
} DB>Y#2j4h  
{&Bpf K;`)  
;\$P;-VY  
public void splitterStop() ,OQ!lI_`R  
{ XT|!XC!|  
bStop = true; ~BVK6  
} !j3V'XU#Zn  
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} r12{XW?~  
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/* GD$jP?  
**FileAccess.java 28j=q-9Z  
*//文件访问(定位，写) `37GVo4  
package NetFox; | 3`qT#p{  
import java.io.*; A!kNqJ2  
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public class FileAccessI implements Serializable{ $J |oVVct  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xmDX1sL**  
RandomAccessFile oSavedFile; I>27
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long nPos; >t"]gQHtx  
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public FileAccessI() throws IOException X'&$wQ6,K  
{ TgaDzF,j{A  
this("",0); {tE/Jv $  
} %(-YOTDr  
-%=StWdb   
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public FileAccessI(String sName,long nPos) throws IOException f$E66yG
 
{ ~PNO|]8j  
oSavedFile = new RandomAccessFile(sName,"rw"); ."Yub];H  
this.nPos = nPos; xrT_ro8  
oSavedFile.seek(nPos); 6Upg\(  
} wE75HE`gW  
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public synchronized int write(byte[] b,int nStart,int nLen) J{mP5<8>b  
{ 7[-jr;v  
int n = -1; v.1= TBh  
try{ (oxe\Qk  
oSavedFile.write(b,nStart,nLen); rI}E2J  
n = nLen; ~zz
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} ru`;cXa,  
catch(IOException e) T^a {#B  
{ B-[SUmHr  
e.printStackTrace (); s\&_Kbw]c  
} Q
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return n; 9ok|]d P  
} R7KQ-+Zb  
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} 'w%N(Ntq  
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/* .Qh8I+Q%  
**SiteInfoBean.java dITnPb)i  
*/ e#^|NQ<'A  
package NetFox; Z"?AaD[  
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public class SiteInfoBean { BH0rT})  
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private String sSiteURL; //Site's URL (?\ZN+V)  
private String sFilePath; //Saved File's Path gE=~.P[Z
X  
private String sFileName; //Saved File's Name U>;itHW/  
private int nSplitter; //Count of Splited Downloading File ?<frU ,{  
T *t$   
~DZ;l/&Mz7  
public SiteInfoBean() UKK}$B  
{//nSplitter的缺省值为5 M{kPEl&Z  
//default value of nSplitter is 5 6sy%KO*A  
this("","","",5); F'CUkVC0~P  
} >2syF{`j  
&up/`8  
;oFaDTX]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X}zKV  
{ <(p1 j0_Q  
sSiteURL= sURL; K=5_jE^e  
sFilePath = sPath; vB4cdW 2#3  
sFileName = sName; ap%o\&T;  
this.nSplitter = nSpiltter; ]bnxOk  
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} 3}:pD]`h  
e3>Re![_.  
-N\{QX1Yd  
public String getSSiteURL() K[sM)_I  
{ ?XOeMI  
return sSiteURL; T%a]3  
} j|G-9E  
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public void setSSiteURL(String value) gy =`cMS@  
{ 4}LF>_+=  
sSiteURL = value; @B9|{[P  
} !RcAJs'  
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}BogE$tc  
public String getSFilePath() pO+1?c43
 
{ d7^XP  
return sFilePath; Jj6kZK  
} tiE+x|Ju"  
$m=z87hX  
\[oHt:$do  
public void setSFilePath(String value) C]=E$^|{  
{ <dYk|5AdLF  
sFilePath = value; ;5|EpoM  
} &yA<R::o  
(x^|  
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public String getSFileName() ONGe/CEXT  
{ mW-@-5Wda  
return sFileName; I(<G;ft<}  
} u3. PHZ  
>rFvT>@NU  
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public void setSFileName(String value) /3TorB~Y  
{ I@S<D"af  
sFileName = value; xRY
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} \QM
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?@#}%<yEq  
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public int getNSplitter() P~qVr#eU  
{ &"
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return nSplitter; 0 j.Sb2  
} JZXc
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public void setNSplitter(int nCount) .E}});l  
{ aXJe"IT.u  
nSplitter = nCount; Y@4vQm+  
} XP`kf]9  
} v4zd x)  
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/* >ATW/9r  
**Utility.java y^A$bTQq  
*/ QLUe{@ivc  
package NetFox; $($SQZK&  
6'%]6"&M4  
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public class Utility { +-nQ, fOV  
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public Utility() Ji!-G4.n"  
{ 1%@~J\qF  
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0\#Q;Z2  
} % *G)*n  
`@eH4}L*  
//线程睡眠 ( 7?%Hg  
public static void sleep(int nSecond) fA8
+SaXW%  
{
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try{ 3-R3Qlr  
Thread.sleep(nSecond); 0hkuBQb\  
} 3PA'Uk"5Z  
catch(Exception e) >" .qFn g  
{ m%V[&"5%e  
e.printStackTrace (); UH.cn|R  
} bevT`D  
} }m H>lN  
\$C4H  
//日志 SHk[X ]Uo  
public static void log(String sMsg) +Y~+o-_  
{ W =zG  
System.err.println(sMsg); g=C<E2'i*  
} |u{QI3#'  
+mA=%?l  
g,:Nzb  
public static void log(int sMsg) CP#79
=1  
{ eC$v0Gtq  
System.err.println(sMsg); F&*M$@u5  
} &FrB6y  
} 9^ r  
C'._}\nX  
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/* 1,j9(m2  
**TestMethod.java QP B"EW  
*/ !T*B{+|  
package NetFox; <yS"c5D6  
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m=MT`-:  
public class TestMethod { BB.TrQM.#  
\Wc/kY3&  
>y9o&D  
public TestMethod() \`zG`f  
{ ///xx/weblogic60b2_win.exe w4'K2 7  
try{ MI(i%$R-A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^I{]Um:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Fw9``{4w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nEm7&Gb  
fileFetch.start(); g8+,wSE  
} zb/Xfu.)?6  
catch(Exception e){e.printStackTrace ();} @W
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} > bF!Y]H  
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i8YgG0[)  
public static void main(String[] args) d&bc>Vt  
{ Z]TVH8%|k  
new TestMethod(); ]7t\%_  
} DH9?2)aR  
} ? SP7vQ/  
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