http断点续传简单实现（java)

/* `eWcp^|  
**SiteFileFetch.java |Hm'.-   
*/ iXm||?Rnx  
package NetFox; ^0|NmMJ]  
import java.io.*; 7 h1"8#X  
import java.net.*; NslA/"*  
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public class SiteFileFetch extends Thread { 9$,gTU_a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean V0 F30rK  
long[] nStartPos; //开始位置 _o?(t\B9{  
long[] nEndPos; //结束位置 c9uT`h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !~N4}!X3du  
long nFileLength; //文件长度 w~U`+2a3  
boolean bFirst = true; //是否第一次取文件 rc$!$~|I3Z  
boolean bStop = false; //停止标志 mVK9NK  
File tmpFile; //文件下载的临时信息 v|I5Gz$qpa  
DataOutputStream output; //输出到文件的输出流 k4$q|x7+%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <VU4rk^=  
public SiteFileFetch(SiteInfoBean bean) throws IOException y,&M\3A  
{ hcgc =$^  
siteInfoBean = bean; o1WidJ"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yOK])&c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =]QH78\3  
if(tmpFile.exists ()) 7Hl_[n|  
{ ^CPfo/!  
bFirst = false; i"]8Zw_D  
read_nPos(); K~8tN,~&  
} mrC+J*  
else @6co\.bv  
{ @5jG
  
nStartPos = new long[bean.getNSplitter()]; B#6pQp$  
nEndPos = new long[bean.getNSplitter()]; G\+nWvV7  
} yJ8}*Gj&  
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} 1 j12Qn@]  
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public void run() (Q5@MfK`  
{ T#n1@FgC  
//获得文件长度 3EVC8ue  
//分割文件 Ke?gz:9j  
//实例FileSplitterFetch 0BCGJFZ{  
//启动FileSplitterFetch线程 OJsd[l3xR  
//等待子线程返回 <i'u96  
try{ ),]2`w&k  
if(bFirst) N+M&d3H`  
{ n<:d%&^n  
nFileLength = getFileSize(); vaR
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if(nFileLength == -1) "'!%};  
{ @qPyrgy  
System.err.println("File Length is not known!"); NVJ&C]H6  
} Nr24[e G>d  
else if(nFileLength == -2) sk ?'^6Xh  
{ {?/8jCVd  
System.err.println("File is not access!"); `GQiB]Z  
} ,![Du::1  
else ZJ9Jf2 c  
{ ,B%fjcn  
for(int i=0;i<nStartPos.length;i++) t\pK`DM-[  
{ 
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); So=nB} b[?  
} oKYhE  
for(int i=0;i<nEndPos.length-1;i++) aw/7Z`
 
{ @mx$sNDkL  
nEndPos = nStartPos[i+1]; \$'m^tVU  
} 7y)=#ZG'R  
nEndPos[nEndPos.length-1] = nFileLength; x$n~f:1Y  
} 7<:Wq=e!r  
} 3_MS'&M  
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//启动子线程 u\XkXS`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8pPC 9ew\=  
for(int i=0;i<nStartPos.length;i++) ^.#X<8hr  
{ 3kiE3*H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9Yl8ndP^E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /S]:dDY9K  
nStartPos,nEndPos,i); [vWkAJ'K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `pi-zE)  
fileSplitterFetch.start(); t0bhXFaiE  
} abo>_"9-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y|6@-:B.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b0YiQjS6>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E69:bQ94u  
nEndPos = " + nFileLength); PZuq'^p  
// fileSplitterFetch[nPos.length-1].start(); i Y*o;z,~  
U|J$?aFDr  
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//等待子线程结束 *:\:5*SY  
//int count = 0; GsIwY {d  
//是否结束while循环 DB`$Ru@  
boolean breakWhile = false; 9q1HSJ1)  
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]
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while(!bStop) ]$~Fzs  
{ _ktK+8*6`  
write_nPos(); zb;(?!Bd#  
Utility.sleep(500); Q(|PZng  
breakWhile = true; =#i4MXRZ{  
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for(int i=0;i<nStartPos.length;i++) !%c{+]g  
{ o_Jn_3=  
if(!fileSplitterFetch.bDownOver) [DZqCo  
{ b0@>xT  
breakWhile = false; b4Z`y8=  
break; Ot`LZ"H:  
} F qeV3N  
} {f+N]Oo*  
if(breakWhile) v2hZq-q  
break; *jM_
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//count++; b , juF2  
//if(count>4) M{?zvq?d  
// siteStop(); C.J`8@a]?  
} Oj4v#GK]  
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System.err.println("文件下载结束！"); o84UFhm  
} 3CR@' qG-  
catch(Exception e){e.printStackTrace ();} [%@2
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} 4_PCqEp)  
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//获得文件长度 Deg!<[Nw  
public long getFileSize() aUH\Ee^M:R  
{ B7!<{i  
int nFileLength = -1; _u&>&,:q  
try{ /g_9m  
URL url = new URL(siteInfoBean.getSSiteURL()); %#~((m1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X E|B)Q(  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZgV~W#t  
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int responseCode=httpConnection.getResponseCode(); yND"bF9  
if(responseCode>=400) %35L=d[  
{ D.'h?^kA  
processErrorCode(responseCode); JD6aiI!Su  
return -2; //-2 represent access is error ]N*L7AVl  
} E{tx/$f  
v" }WP34  
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String sHeader; 1/B]TT  
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for(int i=1;;i++) <W>++< -  
{ *7ZGq(O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); dj'm, k b  
//Utility.log(in.readLine()); GCDwWCxh  
sHeader=httpConnection.getHeaderFieldKey(i); Sw~(uH_l  
if(sHeader!=null) #j;Tb2&w  
{ |% z^N*  
if(sHeader.equals("Content-Length")) X1+wX`f  
{ J/2j;,8D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :Sr?6FPc  
break; 96d~~2p  
} 1y J5l,q  
} /~De2mq1  
else bEm7QgV{X  
break; *?/tO, R?  
} BZK2$0  
} C5xag#Z1  
catch(IOException e){e.printStackTrace ();} zh\p  
catch(Exception e){e.printStackTrace ();} :0$a.8Y\++  
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Utility.log(nFileLength); ,57$N&w  
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return nFileLength; \v+u;6cx_  
} rQ/,XH  
"#yJHsu]  
E@-ta):  
//保存下载信息（文件指针位置） bLzs?eos  
private void write_nPos() &-%>qB|*  
{ 1B|8ZmFJj  
try{ Z$p0&~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b
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output.writeInt(nStartPos.length); 8)N@qUV  
for(int i=0;i<nStartPos.length;i++) a5@z:i  
{ >nzu],U  
// output.writeLong(nPos); UiH!Dl}<  
output.writeLong(fileSplitterFetch.nStartPos); oH^(qZ8W  
output.writeLong(fileSplitterFetch.nEndPos); %Y]=1BRk}  
} (D<(6?  
output.close(); #2RiLht  
} /kgeV4]zR  
catch(IOException e){e.printStackTrace ();} G O{.9_2  
catch(Exception e){e.printStackTrace ();} *wuqa)q2  
} W+Xz$j/u  
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-&|:0#@P  
//读取保存的下载信息（文件指针位置） {`(>O"_[Q  
private void read_nPos() {o0qUX>[  
{ pd3,pQ  
try{ Y4E/?37j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $<nCXVqL,  
int nCount = input.readInt(); %@Oma  
nStartPos = new long[nCount]; Rx7X_A}  
nEndPos = new long[nCount]; V8WFQdXc  
for(int i=0;i<nStartPos.length;i++) uI~s8{0T6  
{ Yw'NX5#)g  
nStartPos = input.readLong(); ).5RPAP  
nEndPos = input.readLong(); qnM|w~G  
} :`\) P,  
input.close(); BecPT  
} :u6JjW[a)  
catch(IOException e){e.printStackTrace ();} PRkSQ4  
catch(Exception e){e.printStackTrace ();} b&#DnZcf  
} MZ
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private void processErrorCode(int nErrorCode) %c|UmKKi  
{ b0v:12q  
System.err.println("Error Code : " + nErrorCode); =w$tvo/  
} /J3ZL[o?Q  
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 /ASaB  
//停止文件下载 E<E3&;qD  
public void siteStop() HDVW0QaMu  
{ 0v)bA}k  
bStop = true; %zBCq"y  
for(int i=0;i<nStartPos.length;i++) JhHWu<  
fileSplitterFetch.splitterStop(); 7 <9yH:1  
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} >&,[H:Z  
} 4dawg8K`9  
//负责部分文件的抓取 #3$\Iu  
**FileSplitterFetch.java K+Y^>N4m  
*/ -d+aV1n  
package NetFox; oVvc?P  
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import java.io.*;
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import java.net.*; \Q~8?p+  
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public class FileSplitterFetch extends Thread { {ZU1x C  
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String sURL; //File URL 5U`ZbG  
long nStartPos; //File Snippet Start Position /./"x
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long nEndPos; //File Snippet End Position [AU II*:}  
int nThreadID; //Thread's ID j.e0;! (L}  
boolean bDownOver = false; //Downing is over uo\ .7[1  
boolean bStop = false; //Stop identical F&RgT1*  
FileAccessI fileAccessI = null; //File Access interface L<
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }`(N:p  
{ ;0rGiWC#  
this.sURL = sURL; ;-P)
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this.nStartPos = nStart; ,`D~py,  
this.nEndPos = nEnd; t.
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nThreadID = id; H}hFFI)#Oo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3_Cp%~Gi-_  
} !Ucjax~  
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public void run() O.aG[wm8  
{ kOOGw:/  
while(nStartPos < nEndPos && !bStop) -l~Z0U>^  
{ Vj<:GRNQ,d  
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try{ 6!x&LoM  
URL url = new URL(sURL); {]_uMg#
!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;~fT,7qBah  
httpConnection.setRequestProperty("User-Agent","NetFox"); [.se|]t7X  
String sProperty = "bytes="+nStartPos+"-"; Od+6 -J  
httpConnection.setRequestProperty("RANGE",sProperty); PZxAH9 S?  
Utility.log(sProperty); <+MyZM(z>  
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InputStream input = httpConnection.getInputStream(); U,#yqER'r  
//logResponseHead(httpConnection); o#) {1<0vg  
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byte[] b = new byte[1024]; T|J9cgtS  
int nRead; pl@O N"=[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2M#M"LHo  
{ OsBo+fwT  
nStartPos += fileAccessI.write(b,0,nRead); <,o>Wx*1C  
//if(nThreadID == 1) Z;9>S=w!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^b:(jI*l  
} ;!:U((wv  
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Utility.log("Thread " + nThreadID + " is over!"); ojYbR<jn9  
bDownOver = true; J
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//nPos = fileAccessI.write (b,0,nRead); sn7AR88M;  
} |*Z$E$k:  
catch(Exception e){e.printStackTrace ();} Lg8nj< TF  
} zp\8_U@  
} |,9JNm$  
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//打印回应的头信息 5T sUQc  
public void logResponseHead(HttpURLConnection con) J+rC
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{ V5+SWXZ  
for(int i=1;;i++) "$s~SIUB  
{ A-:O`RK  
String header=con.getHeaderFieldKey(i); 5F`;yh+e  
if(header!=null) oFjIA!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;&H4u)  
Utility.log(header+" : "+con.getHeaderField(header)); z/i+EE  
else 21k5I #U  
break; r0p w_j  
} YK|bXSA[  
} [MuEoWrq(}  
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public void splitterStop() 8XbA'% o  
{ @lJzr3}WZ  
bStop = true; {vAE:W.s  
} $w"$r$K9K  
/cc\fw1+  
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}  hi
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*#TUGfwy  
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/* KNH1#30 K  
**FileAccess.java v<Bynd-  
*//文件访问(定位，写) EC
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package NetFox; l5L.5$N  
import java.io.*; E=){K  
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public class FileAccessI implements Serializable{ cuOvN"nuNj  
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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 =8U&[F  
RandomAccessFile oSavedFile; R<B7K?SxV~  
long nPos; 7G
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public FileAccessI() throws IOException JN7k2]{  
{ !^Q.VYY  
this("",0); 1q;#VS/D;H  
} @A)R_p  
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public FileAccessI(String sName,long nPos) throws IOException )BRKZQN  
{ j0@[Br%7  
oSavedFile = new RandomAccessFile(sName,"rw"); RT%pDym\  
this.nPos = nPos; Ivb4P`{  
oSavedFile.seek(nPos); b(9FZ]7S  
} _{M\Bs2<  
.^b;osAU  
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public synchronized int write(byte[] b,int nStart,int nLen) 5xii(\lC  
{   zxp`  
int n = -1; "s\L~R.&  
try{ 3"F`ZJ]=  
oSavedFile.write(b,nStart,nLen); ak:c rrkx  
n = nLen; 6Zn @2PGEl  
} 4b:s<$TZ  
catch(IOException e) 2B,] -Mu)  
{ F{ELSKcp.  
e.printStackTrace (); ;'-olW~  
} D-,L&R!`  
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return n; : }`-B0  
} -,["c9'3  
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} ]THPSw_y8  
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 x]z2Z*  
/* @BNEiOAZ#  
**SiteInfoBean.java p019)X|vx  
*/ r7Ya\0gU  
package NetFox; GtwT  
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, lJv  
public class SiteInfoBean { JsotO
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private String sSiteURL; //Site's URL HI@syFaJM  
private String sFilePath; //Saved File's Path DLCkM*'  
private String sFileName; //Saved File's Name b"TjGE  
private int nSplitter; //Count of Splited Downloading File {aM<{_v  
\lSU  
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public SiteInfoBean() 6)BR+U  
{//nSplitter的缺省值为5 MCdx?m3]  
//default value of nSplitter is 5 p6vKoI#T  
this("","","",5); /y>>JxAEb  
} pAk/Qxl3eo  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G}9=)  
{ n#iwb0-  
sSiteURL= sURL; Oez>X=Xf  
sFilePath = sPath; Ye.r
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sFileName = sName; SRSvot};C  
this.nSplitter = nSpiltter; 57 #6yXQ  
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} 1@lJonlF  
:\=CRaA  
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public String getSSiteURL() ~.!c~fke  
{ r:]1O*  
return sSiteURL; @9&P~mo/  
} Y \:0Ev  
HE
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P bQk<"J1  
public void setSSiteURL(String value) PdVfO8-  
{ GHmv} Z  
sSiteURL = value; c,*9K/:  
} B7z -7&TE  
^H6<Km l/V  
V=1Bo~  
public String getSFilePath() hxS 6:5Uc  
{ R-P-i0~  
return sFilePath; K+6e?5t  
} TB;o~>9U  
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public void setSFilePath(String value) "al`$%(
 
{ _$>pw<  
sFilePath = value; yOvm`9  
} lq"f[-8a2q  
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public String getSFileName() XQ*eP?OS{  
{ |{@FMxn|q  
return sFileName; B*gdgM*`  
} O=9-Qv|  
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public void setSFileName(String value) F H1Z2  
{ ]#.]/f >-  
sFileName = value; R CkaJ3  
} { m|pl  
7G)H.L)$m"  
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public int getNSplitter() 8KH\`
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{ $\k0Nup}  
return nSplitter; =rR~`  
} DvM5 k  
ZR\VCVH\^  
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public void setNSplitter(int nCount) sFBneBub  
{ 1[]&(Pa  
nSplitter = nCount; 0D8K=h&e  
} #b7$TV  
} wR{'y)$  
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/* 3R&lqxhg  
**Utility.java ( 9]_ HW[  
*/ &5L<i3BX  
package NetFox; cv/_r#vN  
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public class Utility { _{|D  
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|7#[ (%D!  
public Utility() P4Th_B7  
{ jzK5-;b  
[le)P$#z  
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} Ssk}e=]  
V i&*&"q  
//线程睡眠 7$rjlVe  
public static void sleep(int nSecond) |X`/  
{ +7
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try{ *|_"W+JC  
Thread.sleep(nSecond); Z/ Tm)Xd
 
}
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catch(Exception e) 9 fMau  
{ 2!Bd2  
e.printStackTrace (); n$[f94d=  
} w}{5#  
} 5Q=P4w!'  
Pf F=m'  
//日志 ]x&u`$F  
public static void log(String sMsg) V)P&Zw  
{ s :`8ZBz~  
System.err.println(sMsg); Cg616hyut  
}
3v")J*t  
}$\M{#C~  
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public static void log(int sMsg) MC,>pR{  
{ u`(- -  
System.err.println(sMsg); .Gcy>Av  
} +`uY]Q,O  
} ^;c16  
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/* B>Wu;a.:L  
**TestMethod.java j|tC@0A  
*/ `nO71mo  
package NetFox;
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fw;rbP!  
public class TestMethod { r 6eb}z!i  
v=95_l  
 8L*GE  
public TestMethod() 8J)xzp`*)  
{ ///xx/weblogic60b2_win.exe VxFOYC>p  
try{ $F.kK%-*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GTv#nnC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bJ_cId8+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V]S1X^
 
fileFetch.start(); OMk5{-8B  
} 0[<~?`:)  
catch(Exception e){e.printStackTrace ();} oQ=>'w  
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U}$DhA"r"  
} 4'p=p#o  
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public static void main(String[] args) irk*~k ?  
{ {7MjP+\  
new TestMethod(); ]B=C|usJ  
} 1
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} +u'I0>)S  
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