http断点续传简单实现（java)

/* `3kE$h#  
**SiteFileFetch.java &/=>:ay+#  
*/ (p
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package NetFox; C=@BkneQ  
import java.io.*; zy4AFW  
import java.net.*; &d`Umm]  
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public class SiteFileFetch extends Thread { Km]N scq1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I!jSAc{  
long[] nStartPos; //开始位置 - t4"BD  
long[] nEndPos; //结束位置 :q~qRRmjBe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "$+naY{w  
long nFileLength; //文件长度 '0X!_w6W  
boolean bFirst = true; //是否第一次取文件 Ql%7wrK  
boolean bStop = false; //停止标志 F^_d8=67h  
File tmpFile; //文件下载的临时信息 /V~L:0%  
DataOutputStream output; //输出到文件的输出流 P~_CDh.N  
0{v?  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {b^naE  
public SiteFileFetch(SiteInfoBean bean) throws IOException [ar:zlV8  
{ xj{X#[q):  
siteInfoBean = bean; "Na9Xea  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O 4N_lr~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J><O 51  
if(tmpFile.exists ()) lZ0+:DaP2  
{ 52m^jT Sx  
bFirst = false; ?Li^XONz  
read_nPos(); a%tm[Re  
} `NXyzT`:K  
else dpZ7eJ  
{ sxgR;gf6  
nStartPos = new long[bean.getNSplitter()]; _XXK1H x  
nEndPos = new long[bean.getNSplitter()]; 7EY~5U/4  
} \bQ|O7s  
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} !/< 5.9!9r  
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public void run() vc6UA%/f  
{ tt[P{mMQ  
//获得文件长度 [2
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//分割文件 ="@W)"r  
//实例FileSplitterFetch 1?(BWX)7  
//启动FileSplitterFetch线程 Qu!\Cx@  
//等待子线程返回 ZyCAl9{p  
try{ P.qD,$-  
if(bFirst) ;DC0LJ  
{ au"HIyi?k  
nFileLength = getFileSize(); "c!s\iuBU  
if(nFileLength == -1) kSU5  }  
{ KrMIJA4>  
System.err.println("File Length is not known!"); dwrc"GK!o  
} bw%1*;n)  
else if(nFileLength == -2) T 6QnCmB4  
{ >]:R{1h  
System.err.println("File is not access!"); a
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} /T#<g:   
else x)"=*Jj  
{ bQXxb(^  
for(int i=0;i<nStartPos.length;i++) 6$ IXER  
{ t vk^L3=<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [7<X&Q  
} zmr=iK  
for(int i=0;i<nEndPos.length-1;i++) ^+`vh0TPQ  
{ t)cG_+rJ  
nEndPos = nStartPos[i+1]; ,Lv}Xku  
} c::x.B"w  
nEndPos[nEndPos.length-1] = nFileLength; Lom%eoH)  
}  @KOa5-u  
} 82$By]Y9  
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{6 #3`  
//启动子线程 x ?^c:`.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $nn~K  
for(int i=0;i<nStartPos.length;i++) m*i~Vjxj-m  
{ R%#c~NOO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =v:_N.Fh-c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 07(E/A]  
nStartPos,nEndPos,i); ++&F5'?
g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $)n
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fileSplitterFetch.start(); ]2h[.qa  
} ~%#?;hJ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n:wn(BC3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T"QY@#
E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", I,YGm  
nEndPos = " + nFileLength); tH_#q"@)  
// fileSplitterFetch[nPos.length-1].start(); IE_@:]K}Ja  
v/m`rc
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jQb=N%5s  
//等待子线程结束 IC}zgvcW  
//int count = 0; LrPDpTd  
//是否结束while循环 @b>]q$)(}  
boolean breakWhile = false; 5&}icS  
{_q2kk  
46XB6z01  
while(!bStop) T&R`s+7  
{ n|,Es!8:o  
write_nPos(); XX6&%7(  
Utility.sleep(500); #m$H'O[WG\  
breakWhile = true; xje{kx#  
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for(int i=0;i<nStartPos.length;i++) ;euWpE;E\#  
{ `/HygC6  
if(!fileSplitterFetch.bDownOver) 3_h%g$04s  
{ PA,j;{,(b  
breakWhile = false; _I8-0DnOM  
break; *k
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} Rw/G =zV@2  
} ED?s[K  
if(breakWhile) E_H1X'|qS4  
break; qL'3MY.!  
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//count++; c<H4rB  
//if(count>4) 3zl!x  
// siteStop(); rW`F|F%  
} UoLO#C0i  
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System.err.println("文件下载结束！"); ze4/XR  
} ,7QnZ=F  
catch(Exception e){e.printStackTrace ();} ]-}a{z  
} NGze: gPmO  
"q(&<+D@  
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//获得文件长度 [=9R5.)c  
public long getFileSize() ^M80 F7  
{ t%TZu>(1O  
int nFileLength = -1; t =*K?'ly  
try{ c^bA]l^a  
URL url = new URL(siteInfoBean.getSSiteURL()); 3%P?1s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "(xS  
httpConnection.setRequestProperty("User-Agent","NetFox");
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int responseCode=httpConnection.getResponseCode(); 4/h2_  
if(responseCode>=400) Gt1Up~\s  
{ t]` 2f3UO  
processErrorCode(responseCode); jNyC%$  
return -2; //-2 represent access is error .Yf h*  
} 9.@(&  
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String sHeader; RhJ<<T.2  
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for(int i=1;;i++) {10ms_s  
{ tS9m8(Hr%Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [qXpi'q[  
//Utility.log(in.readLine()); 7d<v\=J
}  
sHeader=httpConnection.getHeaderFieldKey(i); z=fag'fzM  
if(sHeader!=null) -?]ltn9!  
{ 9F-k:hD |  
if(sHeader.equals("Content-Length")) W+eN%w5  
{ ms{R|vU%b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); oF>GWstTR  
break; =QC^7T  
} e"2QV vB  
} FjydEV
 
else zm"\D vN)  
break; J{Ay(  
} 7 dzE"m  
} \%C[l  
catch(IOException e){e.printStackTrace ();} 68)^i"DM<  
catch(Exception e){e.printStackTrace ();} l6WcnJ  
{L=[1  
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Utility.log(nFileLength); <-?B#  
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return nFileLength; |-mazvA  
} jgstx3  
Jt)~h,68  
<2Q@^  
//保存下载信息（文件指针位置） em]K7B=  
private void write_nPos() K$ &wO.  
{ gP<_DEd^`  
try{ f8 jaMn9o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -hzza1DP  
output.writeInt(nStartPos.length); C
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for(int i=0;i<nStartPos.length;i++) S3_4i;K\  
{ HDEG/k/~m  
// output.writeLong(nPos); Z~uKT n  
output.writeLong(fileSplitterFetch.nStartPos); br;G5^j3?  
output.writeLong(fileSplitterFetch.nEndPos); ]M2<I#hF.  
} md`ToU  
output.close(); ]/bE${W*]  
} 8F* WT|]  
catch(IOException e){e.printStackTrace ();} HZm i?  
catch(Exception e){e.printStackTrace ();} X2`>@GR/>  
} ]R@G5d  
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//读取保存的下载信息（文件指针位置） [1*/lt|+p  
private void read_nPos() -1:Z^&e/  
{ $imx-H`|  
try{ c{Kl?0#[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _E;Y ~I,i  
int nCount = input.readInt(); r83~o/T@  
nStartPos = new long[nCount]; `@M4THt  
nEndPos = new long[nCount]; Wa(S20yF  
for(int i=0;i<nStartPos.length;i++) ]'Yw#YB  
{ 2X*<Fma3C  
nStartPos = input.readLong(); V.#8-?z  
nEndPos = input.readLong(); FT;JYkO  
} 
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input.close(); G|lI=Q3f  
} !_) ^bRd  
catch(IOException e){e.printStackTrace ();} 4I*Mc%dD  
catch(Exception e){e.printStackTrace ();} Q.1ohj0)  
} z
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private void processErrorCode(int nErrorCode)
? st#6=M  
{ 0I((UA/7Zs  
System.err.println("Error Code : " + nErrorCode); fYy.>m+P1  
} 5B 7*Z  
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@>5<m'}2  
//停止文件下载 }^[@m#  
public void siteStop() zRu`[b3u<  
{ dLf8w>i`T  
bStop = true; tTH%YtG  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); >n~p1:$  
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} $0}bi:7  
} rb
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//负责部分文件的抓取 H4NEB1TO>  
**FileSplitterFetch.java )F9r?5}v4x  
*/ #&83;uys  
package NetFox; .,Qnn}:l  
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import java.io.*; A#S:_d  
import java.net.*; Qiw4'xQm  
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public class FileSplitterFetch extends Thread { f9UaAdJ(  
"5:f{GfO#v  
lM^!^6=v0l  
String sURL; //File URL A.9'pi'[9Q  
long nStartPos; //File Snippet Start Position /\cu!yiX  
long nEndPos; //File Snippet End Position oh~ vo!  
int nThreadID; //Thread's ID _a$DY,;  
boolean bDownOver = false; //Downing is over I&8SP$S>J  
boolean bStop = false; //Stop identical HFuaoS+b*  
FileAccessI fileAccessI = null; //File Access interface MuV0;K\  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @z
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{ JjLyV`DJ  
this.sURL = sURL; >
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this.nStartPos = nStart; "jO3Y/>S  
this.nEndPos = nEnd; @O}j:b  
nThreadID = id; sLdUrD%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o?K|[gNi  
} 6bKO;^0  
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public void run() ll\^9 4]Q  
{ no
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while(nStartPos < nEndPos && !bStop) AH'4H."o/9  
{ A}bHfn|  
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|vN@2h(|"  
try{ /lB0>Us  
URL url = new URL(sURL); F[D0x26^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XYHCggy  
httpConnection.setRequestProperty("User-Agent","NetFox"); eM=)>zl  
String sProperty = "bytes="+nStartPos+"-"; uuYH6bw*d  
httpConnection.setRequestProperty("RANGE",sProperty); c48J!,jCd'  
Utility.log(sProperty); *C@[5#CA2z  
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InputStream input = httpConnection.getInputStream(); mERrcYY{  
//logResponseHead(httpConnection); h2"|tTm,a  
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O {6gNR,*  
byte[] b = new byte[1024]; !N8)C@=  
int nRead; {IPn\Bka  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uxC   
{ S2ppKlVv  
nStartPos += fileAccessI.write(b,0,nRead); =HV-8C]  
//if(nThreadID == 1) bI]UO)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \As oeeF  
} HS
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Utility.log("Thread " + nThreadID + " is over!"); y|;8:b32  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); dD^_^'i  
} j&[.2PW\  
catch(Exception e){e.printStackTrace ();} u1)TG"+0  
} W]D`f8r9  
} {nPkb5xbW  
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=F
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//打印回应的头信息 YKe0:cWc  
public void logResponseHead(HttpURLConnection con) Z0"&  
{ Naf`hE9  
for(int i=1;;i++) 9U7Mu;4  
{ 1(?CNW[  
String header=con.getHeaderFieldKey(i); }^pQ
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if(header!=null) O
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~*mOt7G  
Utility.log(header+" : "+con.getHeaderField(header)); ,dZ#,<  
else fmnRUN=  
break; ,"N3k(g  
} +f\pk \Ith  
} RUS7Z~5  
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public void splitterStop() @0vC v
 
{ F9k I'<Q  
bStop = true; Q"OV>klk  
} kj{rk^x  
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} P34LV+e  
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_b!;(~@p  
/* CRc!|?  
**FileAccess.java xH"W}-#[  
*//文件访问(定位，写) ?GUz?'d  
package NetFox; eg$5z Z  
import java.io.*; kMl@v`  
6+Wr6'kuH  
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public class FileAccessI implements Serializable{ Sv7>IVC?@  
1H&?UP4=(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `z-H]fU  
RandomAccessFile oSavedFile; P~Te+ -jX}  
long nPos; BrNG%
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public FileAccessI() throws IOException iot.E%G  
{ RwAbIXG{0  
this("",0); Yg=E@F   
} $[
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public FileAccessI(String sName,long nPos) throws IOException fa!3/X+  
{ lFp!XZ!  
oSavedFile = new RandomAccessFile(sName,"rw"); f MY;  
this.nPos = nPos; ).0V%}>  
oSavedFile.seek(nPos); *? K4!q'  
} /S7+B]  
1<LC8?wt  
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public synchronized int write(byte[] b,int nStart,int nLen) , @%C8Z  
{ -H1"OJ2aF  
int n = -1; &YT_#M  
try{ ?ID* /u|X  
oSavedFile.write(b,nStart,nLen); v!<PDw2'  
n = nLen; hmK8jl<6  
} j+_S$T8w  
catch(IOException e) \6`v.B&v  
{ 2 ) TG  
e.printStackTrace (); -"~
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} j~,h)C/v  
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return n; l `fW{lh  
} <@u0.-]  
/]ku$.mr\  
//\ds71h  
} y#]}5gJ  
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6#E]zmXO2  
/* K#GXpj  
**SiteInfoBean.java |7rR99  
*/ P['X<
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package NetFox; Bz~ -2#l  
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public class SiteInfoBean { \e?.hmq  
2Ryp@c&r^  
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private String sSiteURL; //Site's URL ;EK(b  
private String sFilePath; //Saved File's Path -L@]I$Yo  
private String sFileName; //Saved File's Name e{,!|LhpQ  
private int nSplitter; //Count of Splited Downloading File s{yJ:WncI  
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public SiteInfoBean() |WB"=PE  
{//nSplitter的缺省值为5 WI,40&<  
//default value of nSplitter is 5 0(wf{5  
this("","","",5); uVN.=  
} j h; 9 [  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @Ppo &>  
{ N g58/}zO  
sSiteURL= sURL; y&7YJx  
sFilePath = sPath; .j:i&j(  
sFileName = sName; q#;BhPc  
this.nSplitter = nSpiltter; :FnOS<_B  
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} 'KSa8;:=C  
.FuA;:@%\  
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public String getSSiteURL() CNut{4  
{ }.'Z=yy  
return sSiteURL; F#6cF=};@  
} DYX-5~;!  
/E)9v$!  
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public void setSSiteURL(String value) <lFdexH"T  
{ ]x2Jpk99a  
sSiteURL = value; ~NxEc8Y  
} l$M$o(  
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public String getSFilePath() h9)RJSF4  
{ F@9Y\. ,  
return sFilePath; pqJ)G;%9  
} 5)mVy?Z
  
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public void setSFilePath(String value) 4KE)g  
{ |B eA
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sFilePath = value; d^tVD`Fm  
} C(s\LI!r  
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public String getSFileName() 2sUbiDe-  
{ )i @1XH"D  
return sFileName; &RWM<6JP  
} KCD5*xH  
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P 4QkY#v  
public void setSFileName(String value) QskUdzQ=  
{ NS Np  
sFileName = value; >=Jsv  
} b7!UZu]IEv  
85} ii{S  
Bq *[c=(2  
public int getNSplitter() Q? qjWZY  
{ xo(k?+P>.  
return nSplitter; IQIbz{bMx  
} $Buf#8)F*  
%bXsGPB  
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public void setNSplitter(int nCount) 2hy NVG&$  
{ sYW[O"oNi  
nSplitter = nCount; [7RheXO<  
} gGmxx,i  
} ~Zmi(Ra  
)=Zsv40O  
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/* uWTN2jr
 
**Utility.java '6X%=f'^b  
*/ <PioQ>~  
package NetFox; z>|)ieL  
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*="m3:c'J  
public class Utility { 9\>sDSCx  
iD<6t_8),  
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public Utility() izf~w^/  
{ fe';b[q)#  
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j  
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} .EG*+,  
odpUM@OAW  
//线程睡眠 H*rx{F?  
public static void sleep(int nSecond) )tD6=Iz^5  
{ "XhOsMJ  
try{ *> KHRR<N  
Thread.sleep(nSecond); jN6b*-2  
} y AOg\+  
catch(Exception e) 6JH56  
{ YDFCGA  
e.printStackTrace (); XVF^,Yf  
} \TUE<<?1s  
} +zsZNJ(U  
w" JGO  
//日志 zKxvN3!  
public static void log(String sMsg) O3Uh+gKQ  
{ 1ef'7a7e8  
System.err.println(sMsg); w;+ br  
} +T2HE\  
Qci$YTwl>  
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public static void log(int sMsg) o%`npi1y  
{ ik5|,#}m&  
System.err.println(sMsg); q^*6C[G B  
}
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} `hzrfum4  

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VFSz-<L  
/* 5m7b\Mak  
**TestMethod.java QrC/ssf}  
*/ k_?~<vTM  
package NetFox; Hbk&6kS  
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_]=9#Fg7
{  
public class TestMethod { CZ3].DA|z  
.45^=2NGmQ  
+j[`,5oS  
public TestMethod() :Q-oV8t{  
{ ///xx/weblogic60b2_win.exe d0 -~|`5  
try{ HH8;J66I&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2]2H++  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8a>SC$8"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %hINpZMr  
fileFetch.start(); M4?8xuC  
} gvyT-XI  
catch(Exception e){e.printStackTrace ();} >'`Sf ?+|  
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} 2+'|kt2  
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public static void main(String[] args) RtC'v";6  
{ [M:S`{SbY  
new TestMethod(); :c7CiP  
} ?2ItB`<(  
} ntGq" o  
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