http断点续传简单实现（java)

/* w%-S5#  
**SiteFileFetch.java |IDZMd0  
*/ c^stfFE&  
package NetFox; eIQ@){lJ-]  
import java.io.*; =k5O*ql"  
import java.net.*; RLfB]\w  
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public class SiteFileFetch extends Thread { v^B2etiX_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Z29aRi  
long[] nStartPos; //开始位置 Q9i[?=F:z  
long[] nEndPos; //结束位置 Qh+zs^-?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a3L-
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long nFileLength; //文件长度 O=oIkvg  
boolean bFirst = true; //是否第一次取文件 ._q<~_~R  
boolean bStop = false; //停止标志 ~ 1~|/WG  
File tmpFile; //文件下载的临时信息 |)S*RQb\  
DataOutputStream output; //输出到文件的输出流 )FN$Jlo  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） q@1xYz:J  
public SiteFileFetch(SiteInfoBean bean) throws IOException !C ZFbz~:  
{ :QC |N@C  
siteInfoBean = bean; Y|buQQ|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u:H:N]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e m  
if(tmpFile.exists ()) *MQ`&;Qa,  
{ jZ''0Lclpc  
bFirst = false; Nh\o39=  
read_nPos(); L_o/fTz4  
} e'->Sg  
else 3i~X`@$k>  
{ i8S=uJ]n  
nStartPos = new long[bean.getNSplitter()]; )y{:Uc\4!  
nEndPos = new long[bean.getNSplitter()]; O=6[/oc '  
} W}#n.c4+  
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} BN~ndWRK  
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public void run() $hMD6<e  
{ 1 J}ML}h)  
//获得文件长度 )_Z^oH ]<  
//分割文件 hzT)5'_  
//实例FileSplitterFetch >dgz/n?:v  
//启动FileSplitterFetch线程 Hg$7[um  
//等待子线程返回 UuC-R)  
try{ `3`.usw  
if(bFirst) t7Mq>rFB  
{ 9ENI%Jz  
nFileLength = getFileSize(); .R l7,1\  
if(nFileLength == -1) `F3wO!  
{ ;e< TEs  
System.err.println("File Length is not known!"); ".2d{B  
} }kP<zvAaw  
else if(nFileLength == -2) D c;k)z=  
{ +bT[lJ2O>G  
System.err.println("File is not access!"); g@T}h[  
} (4Nj3x o  
else ,HI%ym  
{ *+nw%gZG  
for(int i=0;i<nStartPos.length;i++) H \'1.8g/  
{ >|yP`m   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0a bQY  
} PQa0m)H@  
for(int i=0;i<nEndPos.length-1;i++) (=%0$(S>  
{ klH?
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nEndPos = nStartPos[i+1]; @b,6W wc  
} Gp+\}<^Z  
nEndPos[nEndPos.length-1] = nFileLength; tP"6H-)X&  
} v1Q78P  
} s;Gg  
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//启动子线程 `( w"{8laB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xVgm 9s$"c  
for(int i=0;i<nStartPos.length;i++) vB}c6A4'U  
{ vbd)L$$20+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;8dffsyq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IvlfX`("  
nStartPos,nEndPos,i); V1pBKr)v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :0QDV~bs  
fileSplitterFetch.start(); a(=lQ(v/?  
} {dm>]@"S  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )RT?/NW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %ek0NBE7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Pq8oK'z-  
nEndPos = " + nFileLength); "qd|!:bE  
// fileSplitterFetch[nPos.length-1].start(); YB<nz<;JR  
J7^UQ  
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//等待子线程结束 >TY;l3ew  
//int count = 0; E}v8Q~A(  
//是否结束while循环 p)ig~kk`  
boolean breakWhile = false; o-7{\%+M  
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while(!bStop) C\~}ySQc.e  
{ n6+h;+8;]  
write_nPos(); Wbei{3~$Y"  
Utility.sleep(500); 8V 4e\q  
breakWhile = true; >}%#s`3W1_  
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for(int i=0;i<nStartPos.length;i++) ..X_nF  
{ =gD)j&~}_  
if(!fileSplitterFetch.bDownOver) Q;w[o
 
{ DXI4DM"15I  
breakWhile = false; t!*[nfR  
break; .P aDR |!  
} yxHo0U  
} #qYgQ<TM!  
if(breakWhile) vI0,6fOd6  
break; rKUtTj  
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//count++; (${ #l  
//if(count>4) $rmxwxz&W:  
// siteStop(); WA~[)S0
  
} Zk((VZ(y  
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System.err.println("文件下载结束！"); +]A,fmI.  
} \}v@!PQl  
catch(Exception e){e.printStackTrace ();} o>C,Db~L/  
} RQ=$, i`  
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//获得文件长度 T` h%=u|D  
public long getFileSize() z+7V}a
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{ R}gdN-941  
int nFileLength = -1; G\dPGPPM  
try{ 'g)f5n a[  
URL url = new URL(siteInfoBean.getSSiteURL()); PL{lYexJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [|oG}'Xz  
httpConnection.setRequestProperty("User-Agent","NetFox"); d{JI] !  
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int responseCode=httpConnection.getResponseCode(); \tYImh  
if(responseCode>=400) A;Y~Hu4KPZ  
{ <q$Tk,  
processErrorCode(responseCode); jH9PD8D\  
return -2; //-2 represent access is error 2|lR@L sr  
} 2PyuM=(Wt  
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String sHeader; QOkt
IH  
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]  
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for(int i=1;;i++) GqL&hbpi  
{ S/)),~`4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,.p 36ZLP  
//Utility.log(in.readLine()); [-VH%OM  
sHeader=httpConnection.getHeaderFieldKey(i); hGY-d}npAJ  
if(sHeader!=null) xaVX@ 3r.3  
{ g$Y]{VM.J  
if(sHeader.equals("Content-Length")) ]NTQF/   
{ 01-rBto$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nc:/GxP
 
break; Jw}t~m3  
} HJN GO[*g  
} /kG?I_z  
else iXo;e  
break; pP":,8Q{  
} i /[{xRXiR  
} i*N2@Z[  
catch(IOException e){e.printStackTrace ();} 'uL$j
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catch(Exception e){e.printStackTrace ();} @
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Utility.log(nFileLength); }C_g;7*  
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return nFileLength; ^2$b8]q  
} A"M;kzAfHM  
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//保存下载信息（文件指针位置） k8}fKVU;  
private void write_nPos() ];Noe9o  
{ =<HekiYM  
try{ j:1N&7<FU  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6/L[`n"G  
output.writeInt(nStartPos.length); uo]\L^j   
for(int i=0;i<nStartPos.length;i++) ;~:Z~8+{c  
{ 2EpQ(G J  
// output.writeLong(nPos); yOl
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output.writeLong(fileSplitterFetch.nStartPos); ) 6QJZ$  
output.writeLong(fileSplitterFetch.nEndPos); $!9U\Au>2  
} H4 O"^#5  
output.close(); 2*w`l|Sx  
} 
}GURq#  
catch(IOException e){e.printStackTrace ();} nw/g[/<;  
catch(Exception e){e.printStackTrace ();} >ph=?MKD  
} #@BhGB`9Qt  
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//读取保存的下载信息（文件指针位置） 9'H:pb2  
private void read_nPos() Szu@{lpP@  
{ W#g!Usf:/  
try{ ],!}&#|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a] c03$fK  
int nCount = input.readInt(); h~sTi  
nStartPos = new long[nCount];  -V2`[k  
nEndPos = new long[nCount]; OjffN'a+N  
for(int i=0;i<nStartPos.length;i++) \Kui`X  
{ WNjG/U  
nStartPos = input.readLong(); %u9Q`  
nEndPos = input.readLong(); ckFPx l.  
} |qQ6>IZ  
input.close(); fI;nVRfp  
} U+B{\38   
catch(IOException e){e.printStackTrace ();} 3;z1Hp2X  
catch(Exception e){e.printStackTrace ();} lQ^"-zO4  
} Jb> X$|N'%  
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private void processErrorCode(int nErrorCode) u{uqK7]+  
{ ^"lEa-g&  
System.err.println("Error Code : " + nErrorCode); \>oy2{=;'  
} eW<NDI&b  
Zp{K_ec{  
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//停止文件下载 8H};p
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public void siteStop() f\$_^dV  
{ !}x-o`a5  
bStop = true; Y<Ae_yLa  
for(int i=0;i<nStartPos.length;i++) -8"
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fileSplitterFetch.splitterStop(); b~<V}tJ  
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} er BerbEEH  
} t&JOASY
C  
//负责部分文件的抓取 x

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**FileSplitterFetch.java j)ln"u0R^B  
*/ (8ct'Q;  
package NetFox; ^pY8'LF6  
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import java.io.*; ep5`&g]3  
import java.net.*; %'. x vC
  
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public class FileSplitterFetch extends Thread { _I,GH{lhI  
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String sURL; //File URL ~A%+oa*2~  
long nStartPos; //File Snippet Start Position W%&s$b(  
long nEndPos; //File Snippet End Position OqH3.@eK  
int nThreadID; //Thread's ID @!ja/Y^  
boolean bDownOver = false; //Downing is over inq {" 6  
boolean bStop = false; //Stop identical M.qv'zV`xG  
FileAccessI fileAccessI = null; //File Access interface NTK9`#SA  
f#I#24)RH  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;2?fz@KZ  
{ g^po$%I '  
this.sURL = sURL; G<rAM+B*g  
this.nStartPos = nStart; plr3&T~,&S  
this.nEndPos = nEnd; )Xt#coagS  
nThreadID = id; +_*iF5\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3;uLBuZOCN  
} 64"DT3:  
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public void run() 2"}Vfy  
{ /c!^(5K fT  
while(nStartPos < nEndPos && !bStop) I 5ZDP|  
{ \?Xoa"^  
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try{ ApggTzh@  
URL url = new URL(sURL); ,j(E>g3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sUiO~<Ozpk  
httpConnection.setRequestProperty("User-Agent","NetFox"); n8\88d  
String sProperty = "bytes="+nStartPos+"-"; )@tHS-Jf  
httpConnection.setRequestProperty("RANGE",sProperty); Ui1s
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Utility.log(sProperty); y5^OD63s  
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InputStream input = httpConnection.getInputStream(); ?y"M>#  
//logResponseHead(httpConnection); :7Uv)@iUk  
f
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byte[] b = new byte[1024]; S|6i]/  
int nRead; /74h+.amg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X -=M>H^  
{ Gv#bd05X  
nStartPos += fileAccessI.write(b,0,nRead); nC?Lz1re  
//if(nThreadID == 1) 7GErh,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '9Q#%
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} oSYbx:2wo  
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Utility.log("Thread " + nThreadID + " is over!"); xBf->o S?  
bDownOver = true; D=.Ob<m`Z  
//nPos = fileAccessI.write (b,0,nRead); Ty7`&  
} $Tt.r  
catch(Exception e){e.printStackTrace ();}  #3RElI  
} sint":1FC  
} MpJ\4D5G  
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//打印回应的头信息 Yu
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public void logResponseHead(HttpURLConnection con) ,Qo:]
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{ {F\P3-ub  
for(int i=1;;i++) 6p3cMJ'8y  
{ ,":_CY4(  
String header=con.getHeaderFieldKey(i); *xj2Z,u  
if(header!=null) uz20pun4B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); T#I}w\XlhP  
Utility.log(header+" : "+con.getHeaderField(header)); Tks1gN^^  
else ,K30.E  
break; Lm1JiPs d  
} eE;j#2SEO  
} \CS4aIp  
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public void splitterStop() e5;YY  
{ y
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bStop = true; 7;r3Bxa Q  
} 5'w&M{{9  
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} 1g$xKe~]4  
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/* $?[pcgv  
**FileAccess.java nhZ/^`Y<  
*//文件访问(定位，写) ,KPrUM}  
package NetFox; _t4(H))]vG  
import java.io.*; rH\oFCzC  
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public class FileAccessI implements Serializable{ f%[xl6VE;  
*7L1SjZw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x>A[~s"|N  
RandomAccessFile oSavedFile; '9&@?P;  
long nPos; %*gg6Q  
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public FileAccessI() throws IOException }
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{ sP=^5K`g  
this("",0); V<PH5'^$j  
} [I<J6=  
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public FileAccessI(String sName,long nPos) throws IOException IfI:|w}:"r  
{ + kF%>F]  
oSavedFile = new RandomAccessFile(sName,"rw"); [W3sveqj&  
this.nPos = nPos; z|(<Co8#.  
oSavedFile.seek(nPos); !>kg:xV  
} #2Iw%H2q&  
Jv]$@>#  
#nZPnc:  
public synchronized int write(byte[] b,int nStart,int nLen) ]z#Ita;  
{ Y\4B2:Qd9  
int n = -1; %):pfM;b  
try{ dAM]ZR<  
oSavedFile.write(b,nStart,nLen); .O&YdUo  
n = nLen; taO(\FOm  
} GE!p  
catch(IOException e) t/3qD7L  
{ G)o:R iq  
e.printStackTrace (); |=:hUp Jp  
} ,*m|Lt%;R  
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return n; %8YUK/(|n  
} ^E+fmY2a  
q; C6ID`  
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} 3Jj&wHp]  
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<P]%{msGH  
/* |U$ "GI  
**SiteInfoBean.java |PGTP#O
<  
*/ 2gEF$?+q?  
package NetFox; ho^jmp  
<l eE.hhf.  
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public class SiteInfoBean { j;-2)ZLm  
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private String sSiteURL; //Site's URL |nqN95'u+]  
private String sFilePath; //Saved File's Path <B @z>V  
private String sFileName; //Saved File's Name vM:c70=  
private int nSplitter; //Count of Splited Downloading File qT#NS&T!-  
7>AMzNj  
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public SiteInfoBean() pP#|: %  
{//nSplitter的缺省值为5 q_"w,28  
//default value of nSplitter is 5 -uhVw_qq#  
this("","","",5); sJ5#
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} "QBl "<<s  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X[SIk%{D  
{ -e0?1.A$  
sSiteURL= sURL; l701$>>  
sFilePath = sPath; ]c6h'}  
sFileName = sName; 2~V"[26t
 
this.nSplitter = nSpiltter; ^a1k"|E?f  
[Ov/&jD"  
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} <5G4|l  
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public String getSSiteURL() n{M-t@r7  
{ JE<h  
return sSiteURL; [EK^0g
 
} h*3{IHAQ  
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public void setSSiteURL(String value) %:OX^^i;  
{ 5s>>] .%  
sSiteURL = value; a=6@} l1<  
} @![1W@J  
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public String getSFilePath() Cj/!m  
{ {Eqx'j  
return sFilePath; vjA!+_I6  
} BbPRPkV  
"EE(O9q  
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public void setSFilePath(String value) EZT 8^m  
{ U_Q;WPJ  
sFilePath = value; m9\~dD  
} f>&*%[fw  
{CFy %  
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public String getSFileName() ]
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{ <Ynrw4[)t  
return sFileName; ,-DU)&dF  
} }j!C+
i  
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/-(OJN5F^  
public void setSFileName(String value) voJJoy%  
{ .z*}%,G  
sFileName = value; 9hJ  a K  
} =F5zU5`i  
/_yAd,^-+  
k?1e+ \  
public int getNSplitter() -<e_^  
{ Yjl:i*u/  
return nSplitter; o"kL,&  
} h${=gSJc  
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-"XHN=H  
public void setNSplitter(int nCount) R0G!5>1i  
{ fwa*|y;  
nSplitter = nCount; czB),vooz  
} -KZ9TV # R  
} j(M.7Z7^  
/J(~NGT  
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/* $+,kibk*R  
**Utility.java i@ 86Ez  
*/ AKS. XW  
package NetFox; ( efxw  
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public class Utility { ME.!l6lm\  
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public Utility() zy|h1.gd  
{ Z!4
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}C$D-fH8sW  
} 1DN  
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//线程睡眠 Zq:c2/\c}  
public static void sleep(int nSecond) jHV) TBr  
{ X+/^s)  
try{ 7&(h_}Z  
Thread.sleep(nSecond); 4E$d"D5]>p  
} A-h[vP!v|  
catch(Exception e) ']Z%6_WF  
{ 7Jpq7;  
e.printStackTrace (); " BU4\QF-  
} Kp!A ay  
} R'oGsaPB2  
q#"lnc<S  
//日志 >x ]{cb/m  
public static void log(String sMsg) sWi4+PAM0  
{ N,*'")k9  
System.err.println(sMsg); 4.>y[_vu  
} i1GQ=@  
Q@*9|6-  
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public static void log(int sMsg) ^,J>=>,1\  
{ lXD=uRCI  
System.err.println(sMsg); t7*F,  
} *T.V5FB0S  
} di<g"8  
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/* -67!u;  
**TestMethod.java uX6rCokr  
*/ aFL<(,~r  
package NetFox; n} ]gAX  
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public class TestMethod { {J/+KK  
>;}(?+|f  
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public TestMethod() !P6?nS  
{ ///xx/weblogic60b2_win.exe GKG:iR)  
try{ 9j5B(_J^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xFA`sAucr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h|<;:o?yh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IU"8.(;o  
fileFetch.start(); Z5`V\$  
} \[/}Cy  
catch(Exception e){e.printStackTrace ();} ]
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} N1U.1~U  
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public static void main(String[] args) OK z5;#S=  
{ xJOp~fKG  
new TestMethod(); V h5\'Sn  
} sBNqg~HwB?  
} 0;w84>M  
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