http断点续传简单实现（java)

/* ~e 6yaX8S  
**SiteFileFetch.java K[~Wj8W0  
*/ g#9w5Q  
package NetFox; pqMvYF  
import java.io.*; nI2}E  
import java.net.*; 0WF(Ga/o  
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public class SiteFileFetch extends Thread { n
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SiteInfoBean siteInfoBean = null; //文件信息Bean *VHBTO9  
long[] nStartPos; //开始位置 4TwU0N+>  
long[] nEndPos; //结束位置 rJ\A)O+Mq(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "*+epC|ks  
long nFileLength; //文件长度 *9j9=N?  
boolean bFirst = true; //是否第一次取文件 *uA?}XEfi  
boolean bStop = false; //停止标志 <e/O"6='Z  
File tmpFile; //文件下载的临时信息 ?=r!b{9  
DataOutputStream output; //输出到文件的输出流 GVn
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1yX&iO^d  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;4 ?%k )  
{ 7w>"M  
siteInfoBean = bean; ,yV pB)IQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oYJ&BPuA'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \lKQDct. -  
if(tmpFile.exists ()) LaN4%[;X1-  
{ ]3d&S5zU  
bFirst = false; a Q`a>&R0  
read_nPos(); mNb+V/*x3  
} <i]%T~\Af)  
else m+OR W"o  
{ $XyGCn  
nStartPos = new long[bean.getNSplitter()]; }Lb];hww1  
nEndPos = new long[bean.getNSplitter()]; Wv=L_E_  
} Z]w_2- -  
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} ;Jx ^  
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public void run() ni~45WX3  
{ oC4rL\d
{  
//获得文件长度 (/k,q  
//分割文件 (]7@0d88  
//实例FileSplitterFetch e% 5!  
//启动FileSplitterFetch线程 B2845~\.  
//等待子线程返回 zh/+1  
try{ Bj@&c>  
if(bFirst) 
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{ ARQ1H0_B  
nFileLength = getFileSize(); 8$G$Rdn  
if(nFileLength == -1) i3e|j(Gs4  
{ *,'"\n  
System.err.println("File Length is not known!"); t8?+yG;  
} []dRDe;#  
else if(nFileLength == -2) QtN0|q{af  
{ 3>L1}zyM]  
System.err.println("File is not access!"); L {B#x@9tQ  
} L"}@>&6  
else lPFMNRt~8  
{ _I$]L8hC  
for(int i=0;i<nStartPos.length;i++) <7PtC,74  
{ A)`M*(~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ][?GJ"O+U  
} Z<&: W8n  
for(int i=0;i<nEndPos.length-1;i++) {<kl)}  
{ .-W
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nEndPos = nStartPos[i+1]; 8V}c(2m  
} |ZZ3Qr+%S  
nEndPos[nEndPos.length-1] = nFileLength; &Q&$J )0  
} )9<)mV*EB(  
} "UAW  
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//启动子线程 !0fK*qIL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \[D"W{9l  
for(int i=0;i<nStartPos.length;i++) Q45rP4mQ  
{ 6b]vHT|p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pn =S%Qf]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pAa{,,Qc  
nStartPos,nEndPos,i); \{UiGCK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l
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fileSplitterFetch.start(); 0j_!)B  
} {?m',sG;&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w^ DAu1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :$}67b)MO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _FVIN;!  
nEndPos = " + nFileLength); *{
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// fileSplitterFetch[nPos.length-1].start(); ~V./*CQ\c  
.5I1wRN49  
a\%g_Q){  
//等待子线程结束 0e}LZ,9e  
//int count = 0; kXOlZC  
//是否结束while循环 SQz>e  
boolean breakWhile = false; ]I}' [D  
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while(!bStop) 5,mb]v0k  
{ (TY^ kySr  
write_nPos(); ](a<b@p  
Utility.sleep(500); BRW   
breakWhile = true; wiFckF/  
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for(int i=0;i<nStartPos.length;i++) `[:f;2(@  
{  Ng-3|N  
if(!fileSplitterFetch.bDownOver) Pd@?(WQ  
{ ml3]CcKn  
breakWhile = false; EL+}ab2S  
break; M@gm.)d  
} z{%G  
} c3Mql+@  
if(breakWhile) s\KV\5\o  
break; -bs~{  
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//count++; y\@XW*_?  
//if(count>4) 0<P -`|X  
// siteStop(); R"82=">v  
} @,s[l1P  
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System.err.println("文件下载结束！"); 2} T"|56
 
} r?Z8_5Y  
catch(Exception e){e.printStackTrace ();} &]ImO RN  
} IRcZyry  
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//获得文件长度 g@S"!9[;U  
public long getFileSize() G_X'd  
{ X"[c[YT!%[  
int nFileLength = -1; Y=Bk;%yT=  
try{ HZM&QZHx)`  
URL url = new URL(siteInfoBean.getSSiteURL()); 2>UyA.m0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,rG$JCS'KQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); (A?e}M^}  
>S!QvyM(V  
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int responseCode=httpConnection.getResponseCode(); jT'1k[vJj  
if(responseCode>=400) hDfsqSK0 /  
{ j[c|np4k\  
processErrorCode(responseCode); SFh6'v'1N@  
return -2; //-2 represent access is error @y}1%{,%  
} =m1B1St2  
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,!Q2^R  
String sHeader; CM~)\prks  
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for(int i=1;;i++) d7l0;yR&+  
{ r0hu?3u1?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F7L+bv   
//Utility.log(in.readLine()); b^FB[tZ\x  
sHeader=httpConnection.getHeaderFieldKey(i); :~g=n&x  
if(sHeader!=null) 0h$23.  
{ mNs&*h}  
if(sHeader.equals("Content-Length")) 7zy6`OP  
{ uZg Kex;c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =cg0o_q8  
break; 1'Kn:I  
} A<AZs~f  
} Cg-khRgLS  
else friNo^v&  
break; Rsqb<+7  
} 4WDh8U  
} nV GrW#'E  
catch(IOException e){e.printStackTrace ();} 3C2L _ K3  
catch(Exception e){e.printStackTrace ();} RV7l=G9tq  
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Utility.log(nFileLength); ] S]F&B M|  
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return nFileLength; ^P\(IDJCo  
} l *.#g  
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//保存下载信息（文件指针位置） Xk
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private void write_nPos() 2
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{ wjQu3 ,Cj  
try{ hH|3s-o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $_% a=0  
output.writeInt(nStartPos.length); ,;hIyT  
for(int i=0;i<nStartPos.length;i++) 6:#zlKYJ  
{ i4&"-ujrm  
// output.writeLong(nPos); G2zfdgW${/  
output.writeLong(fileSplitterFetch.nStartPos); @9-z8PyF  
output.writeLong(fileSplitterFetch.nEndPos); !A,]  
} +A3@{2  
output.close(); ON\_9\kv  
} '
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catch(IOException e){e.printStackTrace ();} AWc7TW  
catch(Exception e){e.printStackTrace ();} YrL:!\p.  
} ,QdUfM  
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//读取保存的下载信息（文件指针位置） j"9bt GX  
private void read_nPos() nYLq%7}k  
{ u4, p.mZtb  
try{ kW3V"twx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #\_N-bVu  
int nCount = input.readInt(); a4Fe MCvV9  
nStartPos = new long[nCount]; S{7A3 x'B  
nEndPos = new long[nCount]; k$j>_U? P  
for(int i=0;i<nStartPos.length;i++) 6DD"Asi+  
{ nM>oG'm[n  
nStartPos = input.readLong(); sjvlnnO  
nEndPos = input.readLong(); ]ECzb/  
} @~qlSU&  
input.close(); n&jfJgD&g  
} *?VbN}g2  
catch(IOException e){e.printStackTrace ();} q okgu$2  
catch(Exception e){e.printStackTrace ();} L Me{5H  
} z}&?^YU*)`  
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private void processErrorCode(int nErrorCode) =c"`>Vi@d  
{ -1;BwlL  
System.err.println("Error Code : " + nErrorCode); uckag/tv  
} yF8 av=<{  
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//停止文件下载 hOx'uO`x(  
public void siteStop() & gnE"  
{ ,`ST Va-  
bStop = true; *BF5B\[r?  
for(int i=0;i<nStartPos.length;i++) uQ=p }w  
fileSplitterFetch.splitterStop(); dgh)Rfp3  
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} (sHqzWh  
} y0k*iS e  
//负责部分文件的抓取 )7l+\t  
**FileSplitterFetch.java e)]9u$x  
*/ k7z;^:  
package NetFox; *NHBwXg+  
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import java.io.*; /7/d u[P6  
import java.net.*; OXd617  
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public class FileSplitterFetch extends Thread { "l&=a1l  
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String sURL; //File URL r BQFC4L  
long nStartPos; //File Snippet Start Position 7=(rk  
long nEndPos; //File Snippet End Position rJ|Q%utYz  
int nThreadID; //Thread's ID DN3#W w2[r  
boolean bDownOver = false; //Downing is over BQu_)@  
boolean bStop = false; //Stop identical kclClB:PS  
FileAccessI fileAccessI = null; //File Access interface W ZdEfY{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException N3nFE:`u]  
{ mrX 2w  
this.sURL = sURL; Cgq/#2BM  
this.nStartPos = nStart; C8 9c2  
this.nEndPos = nEnd; 1
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nThreadID = id; ?^t"tY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 of
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} PeT _Ty  
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public void run() g`I`q3EF)  
{ yV[9 (  
while(nStartPos < nEndPos && !bStop) "Ah (EZAR  
{ J/X{ Y2f  
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try{ &.J8O+  
URL url = new URL(sURL); INtt0Cm9"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cVya~ *  
httpConnection.setRequestProperty("User-Agent","NetFox"); *y<Ru:D  
String sProperty = "bytes="+nStartPos+"-"; __o`+^FS  
httpConnection.setRequestProperty("RANGE",sProperty); ]wFKXZeK  
Utility.log(sProperty); ?@8[1$1a  
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InputStream input = httpConnection.getInputStream(); {@, } M  
//logResponseHead(httpConnection); ^wNx5t  
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byte[] b = new byte[1024]; =%P'?(o|  
int nRead; acr@erk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^PA[fL"  
{ o>*vG  
nStartPos += fileAccessI.write(b,0,nRead); .#0),JJZ[  
//if(nThreadID == 1) FYq]-k{\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9ZFvN*Zf'  
} 7fRL'I#[@  
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Utility.log("Thread " + nThreadID + " is over!"); ]AkHNgW  
bDownOver = true; >`L)E,=/  
//nPos = fileAccessI.write (b,0,nRead); ."b=dkx  
} $Lg%CY  
catch(Exception e){e.printStackTrace ();} %{qJkjG  
} NJK?5{H'  
} %.^8&4$+  
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//打印回应的头信息 N5 ITb0Tv  
public void logResponseHead(HttpURLConnection con) *I,3,zO  
{ 8&snLOU -Q  
for(int i=1;;i++) E/ %S0  
{ tk3%0XZH  
String header=con.getHeaderFieldKey(i); P5M+usx  
if(header!=null) zWvG];fsN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R{{d4=:S  
Utility.log(header+" : "+con.getHeaderField(header)); n.zVCKNH  
else iC- ?F cA  
break; 5c6CH k`:  
} gNkx]bm  
} Y^5X>  
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public void splitterStop() 4
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{ &X0/7)*"v  
bStop = true; nsR^TD;  
} uV1H iv-  
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} Vlb L p;  
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7+]T}4;  
/* T3 xr Ua&  
**FileAccess.java ;-84
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*//文件访问(定位，写) N,v4SIC@  
package NetFox; *;A I0  
import java.io.*; ,])@?TJb@  
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public class FileAccessI implements Serializable{ %-"?  
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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 pAg;Rib  
RandomAccessFile oSavedFile; *0bbSw1kc  
long nPos; "aNl2T  
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public FileAccessI() throws IOException W"9iFj X  
{ N{n}]Js1D-  
this("",0); 6_/oVvd  
} !ZP1?l30  
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public FileAccessI(String sName,long nPos) throws IOException pJ7wd~wF*  
{ B.f
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oSavedFile = new RandomAccessFile(sName,"rw"); FxOhF03\=[  
this.nPos = nPos; }%k,PYe/  
oSavedFile.seek(nPos); :@g@jcbYq`  
} #$V`%2>  
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public synchronized int write(byte[] b,int nStart,int nLen) aM'0O![d  
{ ,-u | l  
int n = -1; =!NYvwg6;o  
try{ I%xrDiK97  
oSavedFile.write(b,nStart,nLen); QI>yi&t  
n = nLen; QC>I<j&`!  
} 'qLk"   
catch(IOException e) j9C=m"O  
{ =0xuH>WY}w  
e.printStackTrace (); b!hxx Z  
} 6$wS7Cu  
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}]sI?&xB  
return n; ><iEVrpN  
} UNocm0!N'  
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} QQ@, v@j5  
]!H*oP8a*  
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/* [ANit0-~  
**SiteInfoBean.java 1DcYc-k#  
*/ SqY;2:  
package NetFox; jM J[6qj  
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public class SiteInfoBean { 6, ag\  
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;}K1c+m!5V  
private String sSiteURL; //Site's URL !$h%$se  
private String sFilePath; //Saved File's Path 18w[T=7)  
private String sFileName; //Saved File's Name Zx25H"5j  
private int nSplitter; //Count of Splited Downloading File Faa:h#  
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public SiteInfoBean() sAk~`(:4!  
{//nSplitter的缺省值为5 Bt,qG1>$-  
//default value of nSplitter is 5 dv4)fG]W;_  
this("","","",5); IC[SJVH;  
} &dvJg  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [.<nt:  
{ $Z10Zf=  
sSiteURL= sURL; -a3+C,I8g  
sFilePath = sPath; fh$U
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sFileName = sName; F~a5yW:R=)  
this.nSplitter = nSpiltter; O|,+@qtH  
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} )Tng
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public String getSSiteURL() : ` F>B  
{ eHv~?b5l  
return sSiteURL; KGi@H
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} ~2@U85"o  
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public void setSSiteURL(String value) UkNC|#l)  
{ #CV(F$\1{  
sSiteURL = value; 2)RW*Qu;+  
} e_]1e7t  
i )3Y\u  
i[3$Wi$  
public String getSFilePath() y(.WK8  
{ qCgP8U/jv  
return sFilePath; /7S]%UY  
} |BH, H  
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public void setSFilePath(String value) c'`7p/l.  
{ q(.%f
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sFilePath = value; ]CC~Eo-%-  
} f+xGf6V  
86%weU/*  

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public String getSFileName() Rz=]K
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{ fY%Sw7ql<  
return sFileName; W\~ZmA.  
} @D"|Jq=6P  
"6KOql3  
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public void setSFileName(String value) L6 _Sc-sU  
{ I}:>M!w  
sFileName = value; 3;:xEPb._6  
} {7/6~\'/@  
$ @1&G~x  
Q ;k_q3  
public int getNSplitter() APc@1="#J  
{ +'#d*r91@  
return nSplitter; 9oq(5BG,  
} }f-rWe{gs>  
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public void setNSplitter(int nCount) ^Ws~h\{%  
{
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nSplitter = nCount; ~{NDtB)  
} {?L}qV   
} [e^i".  
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A,=l9hE'  
/* ,*lK4?v  
**Utility.java 5cE[s<=  
*/ ]B7t9l  
package NetFox; Bf* F^  
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public class Utility { x)Th2es\  
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public Utility() X0P$r6 ;  
{ ]D]K_`!K  
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9,>M/_8>  
} &a(w0<  
7SM/bJ-M#  
//线程睡眠 LaIif_fie^  
public static void sleep(int nSecond) @v'<~9vG  
{ #]'V#[;~  
try{ p,0 \NUC  
Thread.sleep(nSecond); (J;?eeP  
} JH5])i0  
catch(Exception e) So 5{E4[  
{ He@= bLLa  
e.printStackTrace (); *>#cs#)  
} @]7\.>)  
} df)1}/*L  
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//日志 ^49moC-  
public static void log(String sMsg) FPMk&  
{ 0jS/U|0  
System.err.println(sMsg); N?Z?g_a8  
} t2gjhn^p  
WT)")0)[  
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public static void log(int sMsg) 'GyPl  
{ -I*A `M  
System.err.println(sMsg); PLyu1{1"z  
} _aGdC8%[  
} {+EPE2X=C  
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c%dy$mkqgK  
/* b(VU{cf2d  
**TestMethod.java ~_&.A*Jh  
*/ +!Ltn  
package NetFox; P&YaJUq.u  
Y^G3<.B  
IO'Q}bU4vs  
public class TestMethod { ^`7t@G$ D  
t<7WM'2<y  
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public TestMethod() n\YxRs7 hF  
{ ///xx/weblogic60b2_win.exe `3KprpE8v  
try{ )X/Faje  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N'1~wxd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >KPJ74R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]4yvTP3[Rm  
fileFetch.start(); O+$70  
} l_%~X9"  
catch(Exception e){e.printStackTrace ();} l.juys8s  
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} o~K2K5I  
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public static void main(String[] args) }}_uN-m  
{ o0L#39`'g  
new TestMethod(); ar|[D7Xrq\  
} qrc/Q;$  
} aAM UJk  
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