http断点续传简单实现（java)

/* 9BB<. p  
**SiteFileFetch.java xI'<4lo7Z  
*/ \/4ipU.  
package NetFox; &|P@$O>  
import java.io.*; N]: "3?%  
import java.net.*; v,r}q1.E}  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1Nx.
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long[] nStartPos; //开始位置 vTjgW?9  
long[] nEndPos; //结束位置 R|H9AM ~E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "!XeK|Wi  
long nFileLength; //文件长度 m}0US;c#f  
boolean bFirst = true; //是否第一次取文件 OlhfBu)~  
boolean bStop = false; //停止标志 NAhV8  
File tmpFile; //文件下载的临时信息 ed*Cx~rT  
DataOutputStream output; //输出到文件的输出流 'nI2RX  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @lAOi1m,,  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?HVsIAU  
{ ]CH@T9d5V  
siteInfoBean = bean; v vlfL*f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {6)fZpd)@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S5d:?^PGg  
if(tmpFile.exists ()) RH ow%2D  
{ 3tI=?E#  
bFirst = false; sj2v*tFb  
read_nPos(); l.1)%q&@^  
} @``kt*+K+  
else +Uq9C-Iu  
{ g~.,
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nStartPos = new long[bean.getNSplitter()]; uOc>~ITPS  
nEndPos = new long[bean.getNSplitter()]; MQE=8\  
} ,T"pUeVJ  
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}  m3 ;  
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public void run() (p
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{ YS,kjL/  
//获得文件长度 v83uGEq(  
//分割文件 shxr^  
//实例FileSplitterFetch KSVIX!EsX  
//启动FileSplitterFetch线程 (}O)pqZ>  
//等待子线程返回 a*CP1@O  
try{ 3/:O8H  
if(bFirst) 0~A<AF*t  
{ UA{sUj+?  
nFileLength = getFileSize(); # j*$ `W;  
if(nFileLength == -1) >OE.6)'Rm  
{ [Z,AquCU(  
System.err.println("File Length is not known!"); r\vB-nJ  
} yk#yrxM
 
else if(nFileLength == -2) qyUcjc%[  
{ p*!@z|F>U  
System.err.println("File is not access!"); Vv' e,m  
} MTb}um.($  
else PTA;a0A  
{ n)} J<  
for(int i=0;i<nStartPos.length;i++) y4
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{ >NB}Bc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CSc*UX+  
} l}335;(  
for(int i=0;i<nEndPos.length-1;i++) W)^:*z  
{ 0ang~_  
nEndPos = nStartPos[i+1]; /OgXNIl]  
} r4JXbh6Tt  
nEndPos[nEndPos.length-1] = nFileLength; 3k;U#H  
}  vi4 1`  
} )&+_T+\  
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//启动子线程 7EY~5U/4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \bQ|O7s  
for(int i=0;i<nStartPos.length;i++) 7;;W{W%  
{ zA&0H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,M7sOp6}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f Otrn  
nStartPos,nEndPos,i); fj0+a0h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i0-!!  
fileSplitterFetch.start(); j6Jz  
} =t@m:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~0ZEnejy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D\(,:_ge  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 78+H|bH8  
nEndPos = " + nFileLength); MP[v 9m@  
// fileSplitterFetch[nPos.length-1].start(); \*LMc69  
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//等待子线程结束 sl6p/\_w  
//int count = 0; v7
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//是否结束while循环 <ofXNv;`  
boolean breakWhile = false; E=~H,~  
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while(!bStop) +n,8o:fU:  
{ ~Zl`Ap  
write_nPos(); r4+w?=`  
Utility.sleep(500); )@eBe^  
breakWhile = true; |r}%AN6+  
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for(int i=0;i<nStartPos.length;i++) +D?d)lK  
{ YtW#MG$f  
if(!fileSplitterFetch.bDownOver) @kvp2P+O  
{ ez(4TtT  
breakWhile = false; bIp;$ZHy`K  
break; `6~*kCj5  
} t)cG_+rJ  
} G]P4[#5  
if(breakWhile) :U)e 8  
break; Lom%eoH)  
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//count++; eoEb\zJ  
//if(count>4) ujz %0Mq;  
// siteStop(); + W@r p#  
} $nn~K  
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System.err.println("文件下载结束！"); ?b
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} 7IK<9i4O  
catch(Exception e){e.printStackTrace ();} ++&F5'?
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} $)n
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//获得文件长度 @;rVB  
public long getFileSize() ykM#EyN  
{ N"r ;d+LTL  
int nFileLength = -1; _'I9rGlx3  
try{ m9L+|r  
URL url = new URL(siteInfoBean.getSSiteURL()); H~ks"D1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M<ad>M  
httpConnection.setRequestProperty("User-Agent","NetFox"); l$zNsf.  
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int responseCode=httpConnection.getResponseCode(); bzJKoxU  
if(responseCode>=400) 6:B5PJq  
{ A:D\!5=  
processErrorCode(responseCode); *s%s|/  
return -2; //-2 represent access is error 6,@M0CX  
} N.64aL|1  
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String sHeader; J&3;6
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for(int i=1;;i++) aLsGden|  
{ Ev^Xs6 }"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^k_!+8"q{  
//Utility.log(in.readLine()); k&~vVx  
sHeader=httpConnection.getHeaderFieldKey(i); R +\y".  
if(sHeader!=null) 4k#B5^iJ  
{ "Y%\qw/wq  
if(sHeader.equals("Content-Length")) 2X*epU_1h  
{ xDQ$Ui.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8vT:icl  
break; 2sU
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} }s)Z:6;(,q  
} #e|eWi>  
else {xH \!!"T  
break; /ZzlC#`  
} %kcg#p+tE  
} 3R{-\
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catch(IOException e){e.printStackTrace ();} ;zCHEz  
catch(Exception e){e.printStackTrace ();} qnA:[H;F  
#-@{rgH  
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Utility.log(nFileLength); .1pEq~>  
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return nFileLength; "|Pl(HX  
} /C(L(
X  
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//保存下载信息（文件指针位置） sW]n~
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private void write_nPos() nuCK7X  
{ \O0fo^+U,,  
try{ r[,KE.^6~#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); uZYeru"w  
output.writeInt(nStartPos.length); <]9MgfAe  
for(int i=0;i<nStartPos.length;i++) lyi}q"Kn*;  
{ G{"1I
 
// output.writeLong(nPos); %b*%'#iK  
output.writeLong(fileSplitterFetch.nStartPos); JJ+<?CeHD  
output.writeLong(fileSplitterFetch.nEndPos); c8'8DM  
} I#Bz UF  
output.close(); Ym6ec|9;  
} (8*lLZ  
catch(IOException e){e.printStackTrace ();} `j(+Y  
catch(Exception e){e.printStackTrace ();} T2->  
} asF-mf;D  
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//读取保存的下载信息（文件指针位置） c !;wp,c  
private void read_nPos() x:bYd\ EJ[  
{ 3Yf$WE8#l  
try{ gON6jnDO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {c1qC zM4  
int nCount = input.readInt(); O-B3@qQ. h  
nStartPos = new long[nCount]; Q?tV:jogY  
nEndPos = new long[nCount]; G8&'*7Bb  
for(int i=0;i<nStartPos.length;i++) Yn#8uaU  
{ PWmz7*/  
nStartPos = input.readLong(); ,qfa,O  
nEndPos = input.readLong(); y{"E)YY  
} 7*5ctc!dG  
input.close(); I,S'zH
R  
} dL
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catch(IOException e){e.printStackTrace ();} K
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catch(Exception e){e.printStackTrace ();} &Ch)SD  
} J)G3Kq5>:b  
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private void processErrorCode(int nErrorCode) l<HRD  
{ U<t-LF3  
System.err.println("Error Code : " + nErrorCode); em]K7B=  
} K$ &wO.  
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//停止文件下载 -hzza1DP  
public void siteStop() 4 * OU  
{ S3_4i;K\  
bStop = true; HDEG/k/~m  
for(int i=0;i<nStartPos.length;i++) +doT^&2u*  
fileSplitterFetch.splitterStop(); br;G5^j3?  
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} ]/bE${W*]  
} i#lo?\PO>  
//负责部分文件的抓取 HZm i?  
**FileSplitterFetch.java 4yA`);r62  
*/ 6+5Catsn  
package NetFox; V!P3CNK  
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import java.io.*; |z'?3?,~  
import java.net.*; j+9 S  
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public class FileSplitterFetch extends Thread { V\"5<>+O  
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String sURL; //File URL sV<4^n7  
long nStartPos; //File Snippet Start Position wb[(_@eZ  
long nEndPos; //File Snippet End Position k)s 7Ev*  
int nThreadID; //Thread's ID =5`@:!t7  
boolean bDownOver = false; //Downing is over /)1-
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boolean bStop = false; //Stop identical TJpv"V  
FileAccessI fileAccessI = null; //File Access interface gp)ds^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S:YL<_oI|  
{ j 7URg>i0  
this.sURL = sURL; nrIL_  
this.nStartPos = nStart; !cb#fl  
this.nEndPos = nEnd; ?~.&Y  
nThreadID = id; {wP|b@(1t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BcLt95;.\  
} Y+GeT#VHe  
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public void run() _zh5KP[{  
{ ku?_/-ko]  
while(nStartPos < nEndPos && !bStop) ]e.+u  
{ E<uOk  
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try{ h*UUtLi%WU  
URL url = new URL(sURL); P;%QA+%7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MPbPq3an  
httpConnection.setRequestProperty("User-Agent","NetFox"); (OB8vTRXP  
String sProperty = "bytes="+nStartPos+"-"; r6JkoPMh  
httpConnection.setRequestProperty("RANGE",sProperty); 8>q%1]X  
Utility.log(sProperty); P@YL.'KU)  
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InputStream input = httpConnection.getInputStream(); Y}uQ`f  
//logResponseHead(httpConnection); 4P!DrOB  
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byte[] b = new byte[1024]; M7R&J'SAY  
int nRead; t3$gwO$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) JF%=Bc$C  
{ io7U[#  
nStartPos += fileAccessI.write(b,0,nRead); C-u/{CP  
//if(nThreadID == 1) kA!(}wRL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K<6x4ha  
} ':D&c  
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Utility.log("Thread " + nThreadID + " is over!"); \!Zh="hN  
bDownOver = true; a~F@3Pd  
//nPos = fileAccessI.write (b,0,nRead); ;J-Ogt@d7  
} V2{#<d-T!  
catch(Exception e){e.printStackTrace ();} xsDa!  
} <C%-IZv$  
} (V.,~t@
  
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//打印回应的头信息 j9ta0~x1*6  
public void logResponseHead(HttpURLConnection con) 4V|z)=)A  
{ yM:~{;HLF  
for(int i=1;;i++) h#>L:Wf5E  
{ Hu8atlpo  
String header=con.getHeaderFieldKey(i); F.pHL)37  
if(header!=null) *}ee"eHs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AH'4H."o/9  
Utility.log(header+" : "+con.getHeaderField(header)); A}bHfn|  
else eD{ @0&
 
break; 8='21@wrN  
} <nTmZ-;  
} ef}E.Bl  
3 9{"T0  

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public void splitterStop() lzs(i2pA  
{ *rcuhw"^b#  
bStop = true; S"TMsi  
} OI_/7@L  
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} }&T<wm!  
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/* >'-w%H/  
**FileAccess.java ix7 e])m(  
*//文件访问(定位，写) ]9&q'7*L  
package NetFox; `3y!XET  
import java.io.*; (_qBsng:  
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public class FileAccessI implements Serializable{ @=NVOJy}c  
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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 (Ef2 w['  
RandomAccessFile oSavedFile; f:[d]J|  
long nPos; w}W@M,.^  
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public FileAccessI() throws IOException YNC0Z'c9  
{
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this("",0); dD^_^'i  
} j&[.2PW\  
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public FileAccessI(String sName,long nPos) throws IOException / }XsuH  
{ r($_>TS&"  
oSavedFile = new RandomAccessFile(sName,"rw"); `@$"L/AJ  
this.nPos = nPos; B}
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oSavedFile.seek(nPos); X}j'L&{F@  
} 0?F@iB~1F  
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public synchronized int write(byte[] b,int nStart,int nLen) noaN@K[GO  
{ RZd4(7H=q  
int n = -1; 7"n1it[RJ8  
try{ sh !~T<yy  
oSavedFile.write(b,nStart,nLen); W?^8/1U  
n = nLen; qXB03}] G  
} VX!Y`y^a  
catch(IOException e) ~*mOt7G  
{ %<w
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e.printStackTrace (); u3M`'YCb  
} y4/>Ol]  
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return n; WAwfL?  
} 9xK4!~5V  
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} F9k I'<Q  
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/* T6R7,Vt'v  
**SiteInfoBean.java EtR@sJ<  
*/ })zB".  
package NetFox; /OhaERv  
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public class SiteInfoBean { iM?I /\  
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private String sSiteURL; //Site's URL 9{O2B5u1  
private String sFilePath; //Saved File's Path KH2F#[ !Lw  
private String sFileName; //Saved File's Name ol?z<53X]  
private int nSplitter; //Count of Splited Downloading File {+C%D'  
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public SiteInfoBean() r,u<y_YW  
{//nSplitter的缺省值为5 (o x4K{  
//default value of nSplitter is 5 2vqmsl?  
this("","","",5); *Z]5!$UpC  
} mJ8{lXq3!  
:]B% >*;}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VY+(,\)U  
{ e;A^.\SP  
sSiteURL= sURL; sR"zRn  
sFilePath = sPath; "pSH!0Ap\  
sFileName = sName; |D;_:x9
 
this.nSplitter = nSpiltter; 9N~8s6Ob  
$
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wJ80};!
  
} vQ-i
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public String getSSiteURL() =bs.2aN&^  
{ {BFT  
return sSiteURL; F5N>Uqr*oN  
} n!0${QVnS  
2Vz'n@g=  
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public void setSSiteURL(String value) jIAW-hc]  
{ -`zG_]=-  
sSiteURL = value; 0Jm]f/iZ  
} do:QH.q8)  
CS~=Z>6EjA  
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public String getSFilePath() Cz'xGW{  
{ !lR0w|  
return sFilePath; KWFyw>*)  
} ftYR,!&  
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public void setSFilePath(String value) gB(9vhj$  
{ Eyr5jXt%;  
sFilePath = value; {E!$ xY8  
} _:wZmZU}  
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public String getSFileName() !"g=&Uy&  
{ VDB$"T9#  
return sFileName; a`7%A H)  
} OOCQsoN
  
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public void setSFileName(String value) q<-%L1kc1  
{ d32@M~vD  
sFileName = value; >$2E1HW.  
} |'ZN!2u  
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Px'R`1^  
public int getNSplitter() &g*klt'B  
{ j.k@6[R>?  
return nSplitter; jmkRP"ZnA  
} C=>B_EO
 
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public void setNSplitter(int nCount) (l Lu?NpIi  
{ ^fkCyE;=  
nSplitter = nCount; M6# \na  
} )yHJ[  
} @(Z( /P;:  
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/* jyNb(Z  
**Utility.java ?#?e(mpo  
*/ g<f
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package NetFox; $np=eT)  
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public class Utility { P?uf?{  
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public Utility() O'fk&&l  
{ |-|jf  
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} ;vMn/  
. =&Jo9  
//线程睡眠 ,aI,2U91  
public static void sleep(int nSecond) d;{y`4p)s  
{ (/'h4KS@  
try{  KZ]r8  
Thread.sleep(nSecond); .%_)*NUZ  
} $)Wb#B  
catch(Exception e) @\ }sb]  
{ TfL4_IAG.  
e.printStackTrace (); X&s7%]n+  
} -)X{n?i  
} w5,6$#  
RYt6=R+f  
//日志 J=):+F=  
public static void log(String sMsg) }f0u5:;Zth  
{ JfkTw~'R  
System.err.println(sMsg); q'.;W@m  
} (]OFS;%  
f7Zf}1|  
?!H)zz6y  
public static void log(int sMsg) YX_vv!-]  
{ A]j}'  
System.err.println(sMsg); u)7*Rj^  
} Hr6wgYPi  
} H"O$&  
B3Mx,uXT\  
f4 Q( 1(C  
/* [g+y_@9s  
**TestMethod.java mk\i}U>`  
*/ _e_4Q)z-a  
package NetFox; x:qr\Rz  
H-Pq!9[DB  
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public class TestMethod { 2% %
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l]$40 j  
}%+qP+O\  
public TestMethod() Y[?`\c|  
{ ///xx/weblogic60b2_win.exe WV2~(/hX&  
try{ v{.\iIg N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
66 N)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YwXXXh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N#UXP5
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fileFetch.start(); %[XY67A3I  
} ?I\v0H*  
catch(Exception e){e.printStackTrace ();} t=i/xG:5  
qC..\{z  
V}SyD(8~  
} ?ql2wWsQO  
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public static void main(String[] args) 9Eg&CZ,9$D  
{ JR)/c6
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new TestMethod(); 7G"7wYc>R  
} ,%Z&*n  
} SW#BZ
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