http断点续传简单实现（java)

/* 7>m#Y'ppl@  
**SiteFileFetch.java YtrMJ"  
*/ oB$D&  
package NetFox; rkl/5z??  
import java.io.*; |7I.DBjR;  
import java.net.*; Bv |Z)G%RR  
|JL47FR  
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public class SiteFileFetch extends Thread { \0pJ+@\T9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean mYk5f_}  
long[] nStartPos; //开始位置 4>^ %_Xj[  
long[] nEndPos; //结束位置 2g^Kf,m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E}qeh"sJt  
long nFileLength; //文件长度 -K/' }I  
boolean bFirst = true; //是否第一次取文件 mHox  
boolean bStop = false; //停止标志 d}',Bl+u{$  
File tmpFile; //文件下载的临时信息 /=\__$l)  
DataOutputStream output; //输出到文件的输出流 !+H=e>Y6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） I=^%l7  
public SiteFileFetch(SiteInfoBean bean) throws IOException )[)-.{q  
{ 4f"a
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siteInfoBean = bean; ]IJ.}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b,G+=&6u  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Bd"7F{H  
if(tmpFile.exists ()) FO}4~_
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{ D@Fa~O$75  
bFirst = false; k 9Kv  
read_nPos(); 3<msiCP  
} {R,rc!yF  
else %2oLND}?z  
{ h{ce+~X  
nStartPos = new long[bean.getNSplitter()]; H$ xSl1>E  
nEndPos = new long[bean.getNSplitter()]; tO?*x/XC{  
} cVn7
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} !HDk]  
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public void run() >KH4X:  
{ fC%;|V'Nd  
//获得文件长度 q
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//分割文件 EGGy0ly  
//实例FileSplitterFetch XW]|Mv[M  
//启动FileSplitterFetch线程 8yFD2(#  
//等待子线程返回 ?-\KVha  
try{ 8N-~.p  
if(bFirst) kC9A  
{ `Xmpm4 ]  
nFileLength = getFileSize(); O t`}eL-  
if(nFileLength == -1) T:.J9  
{ n3b@6V1_  
System.err.println("File Length is not known!"); cX.v^9kuX  
} q}BQu@'H  
else if(nFileLength == -2) 2 >xV&  
{ 6x/ X8zu  
System.err.println("File is not access!"); 6nGDoW#  
} rzaEVXbz1  
else web&M!-  
{ bJB:]vs$  
for(int i=0;i<nStartPos.length;i++) =AcbX
_[  
{ KS(T%mk\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sQihyq6U;  
} J;q3 fa  
for(int i=0;i<nEndPos.length-1;i++) ]P<&CEk  
{ /e{Oqhf[n  
nEndPos = nStartPos[i+1]; ( v ~/glf  
} Z^GriL  
nEndPos[nEndPos.length-1] = nFileLength; A7b7IM
[  
} )cs y^-qw  
} QTn-n)AE  
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sCRBKCR?  
//启动子线程 <U,T*Ql1x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s^KxAw_IV  
for(int i=0;i<nStartPos.length;i++) |+`hS
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{ W+K=M*^D;c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &*)tqQeQf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BTd'bD~EA  
nStartPos,nEndPos,i); LK:|~UV?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6gR=e+  
fileSplitterFetch.start(); [[s k  
} Y?%6af+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @MB;Ez v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >9u6@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5E!|-xD  
nEndPos = " + nFileLength); ^jmnE.8R  
// fileSplitterFetch[nPos.length-1].start(); / V{w<  
0U/:Tpyr  
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//等待子线程结束 B-&J]H  
//int count = 0; Cq(Xa-  
//是否结束while循环 Y6D=tb  
boolean breakWhile = false; ryn)  
[Z5x_.k"I  
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while(!bStop) W>DpDrO4ml  
{ +j@|D@z  
write_nPos(); M2zfN ru  
Utility.sleep(500); dU&.gFw1  
breakWhile = true; >$Fc=~;Ba  
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for(int i=0;i<nStartPos.length;i++) dl":?D4H  
{ 'g=yJ  
if(!fileSplitterFetch.bDownOver) RD_;us@&&*  
{ -dvDAs{X  
breakWhile = false; `jZX(H  
break; MZd\.]G@  
} 'Vrev8D  
} /e7'5#v  
if(breakWhile) /t9w%Y  
break; q/B+F%QiMQ  
+pcj8K%  
HRb_ZJz  
//count++; Txfb-f!mv\  
//if(count>4) (bo bKr  
// siteStop(); 1I@4xC #X  
} M5x!84  
pz$$K?  
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System.err.println("文件下载结束！"); [{{?e6J  
} 3,F/i+
@  
catch(Exception e){e.printStackTrace ();} mm{U5
  
} +I Ze`M%n  
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//获得文件长度 <#s-hQ  
public long getFileSize() O?2
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{ _+Q$h4t   
int nFileLength = -1; c'|MC[^A  
try{ MV/~Rmd.  
URL url = new URL(siteInfoBean.getSSiteURL()); cUm9s>^)/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7GIv3Dc  
httpConnection.setRequestProperty("User-Agent","NetFox"); v:HgpZo+  
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int responseCode=httpConnection.getResponseCode(); I?Zs|A  
if(responseCode>=400) ^6LFho4  
{ n5JB'F)  
processErrorCode(responseCode); -E500F*
b  
return -2; //-2 represent access is error ,m"ztu-  
} G4{qWa/  
!:n),sFv45  
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String sHeader; aW6+Up+G*  
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for(int i=1;;i++) RYV6hp)|  
{ *3ne(c
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L
|2COX  
//Utility.log(in.readLine()); dikWk  
sHeader=httpConnection.getHeaderFieldKey(i); Vd/S81/  
if(sHeader!=null) 6_y|4!,:W  
{ 3'"M31iA  
if(sHeader.equals("Content-Length")) op|mRJBq;  
{ ~4>Xi* B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &53#`WgJ  
break; V-cuG.  
} #pe{:f?  
} @\DD|o67  
else Ad,r(0a LZ  
break; qbEj\ b[  
} 9V66~Bf5  
} hY1|qp  
catch(IOException e){e.printStackTrace ();} AslH V@K  
catch(Exception e){e.printStackTrace ();} L@z !,r,  
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Utility.log(nFileLength); E?XCL8NC  
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return nFileLength; y\_S11{v  
} "pZ3  
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//保存下载信息（文件指针位置） 8Wj=|Ow-q  
private void write_nPos() fMQ*2zGu95  
{ UC1!J =f  
try{ +r0eTP=zf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4{DeF@@  
output.writeInt(nStartPos.length); bS<@Rd{g  
for(int i=0;i<nStartPos.length;i++) K7hf m%`N  
{ }R1`ThTM  
// output.writeLong(nPos); gr 5]5u   
output.writeLong(fileSplitterFetch.nStartPos); rEhf_[Dv  
output.writeLong(fileSplitterFetch.nEndPos); j&/.[?
K  
} 99!{[gOv  
output.close(); 3] qlz?5  
} O&,O:b:@  
catch(IOException e){e.printStackTrace ();} xploFw~  
catch(Exception e){e.printStackTrace ();} s
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} x ctU.)p  
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//读取保存的下载信息（文件指针位置） A(n=k
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private void read_nPos() :6u3Mj{  
{ e9W7ke E*  
try{ IMGqJc,7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); d# 3tQ*G/  
int nCount = input.readInt(); -m160k3  
nStartPos = new long[nCount]; QklNw6,  
nEndPos = new long[nCount]; s1vrzze  
for(int i=0;i<nStartPos.length;i++) Z) Xs;7  
{ TJXraQK-=  
nStartPos = input.readLong(); <KwK tgzs  
nEndPos = input.readLong(); Uk:.2%S2  
} cU*lB!  
input.close(); H\I!J@6g  
} #Q3PzDfj  
catch(IOException e){e.printStackTrace ();} VK'T[5e  
catch(Exception e){e.printStackTrace ();} u7"Ve
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} ;x-H$OZX  
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2 1~7{#  
private void processErrorCode(int nErrorCode) P!y`$Ky&  
{ ?Y{^un  
System.err.println("Error Code : " + nErrorCode); U+;>S$  
} .NkAD-k`  

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//停止文件下载 ,iVPcza  
public void siteStop() l
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{ Lq-33#n/  
bStop = true; 9U)t@b  
for(int i=0;i<nStartPos.length;i++) cVay=5].  
fileSplitterFetch.splitterStop(); 8*yo7q&  
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} MdH97L)L.0  
} `4%;qLxngP  
//负责部分文件的抓取 D;zWksq  
**FileSplitterFetch.java ESMG<vW&f  
*/ =dM.7$6) R  
package NetFox; poD\C;o"  
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import java.io.*; 8PBU~mr  
import java.net.*; >`89N'lZBm  
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public class FileSplitterFetch extends Thread { e3eVvl5]  
t'R':+0Vf  
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String sURL; //File URL H#L#2M%  
long nStartPos; //File Snippet Start Position IyS"  
long nEndPos; //File Snippet End Position -|}%~0)/bH  
int nThreadID; //Thread's ID 0/\PZX+  
boolean bDownOver = false; //Downing is over 't(}Rq@  
boolean bStop = false; //Stop identical 'Y!pY]Z  
FileAccessI fileAccessI = null; //File Access interface A XBkJ'jd  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gF[6c`-s  
{ M!
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this.sURL = sURL; hr
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this.nStartPos = nStart; ?j/kOD0  
this.nEndPos = nEnd; u 1ZJHry  
nThreadID = id; mX&xn2}qZ"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h2wN<dJCM  
} JI"/N`-?;b  
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public void run() 6F`qi:a+  
{ #JA}LA"l  
while(nStartPos < nEndPos && !bStop) 5"JU?e59M  
{ F7{R~mS;  

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try{ dEASvD'  
URL url = new URL(sURL); lC#RNjDp/~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G02ox5X  
httpConnection.setRequestProperty("User-Agent","NetFox"); !4R>O6k  
String sProperty = "bytes="+nStartPos+"-"; 74K)aA  
httpConnection.setRequestProperty("RANGE",sProperty); X JY5@I.  
Utility.log(sProperty); ^qxdmMp)l  
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InputStream input = httpConnection.getInputStream(); &%^K,Q"  
//logResponseHead(httpConnection); 6eQsoKK  
\M5P+Wk'  
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byte[] b = new byte[1024]; Y@Y`gF6F  
int nRead; Ic'Q5kfM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R]u (l+`  
{ lv4(4$T  
nStartPos += fileAccessI.write(b,0,nRead); ]cIu|bRO  
//if(nThreadID == 1) P##Z[$IJ3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W h| L  
} <uZPqi||  
!@u&{"{`  
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Utility.log("Thread " + nThreadID + " is over!"); &p5&=zV}  
bDownOver = true; {j?7d; 'j  
//nPos = fileAccessI.write (b,0,nRead); P5xI  
} ]pnYvXf>!  
catch(Exception e){e.printStackTrace ();} v~"Ef_`  
} k6@b|  
} &Yp+k}XU  
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vMhYpt?7\  
//打印回应的头信息 :BZMnCfA  
public void logResponseHead(HttpURLConnection con) R2w`Y5#`  
{ GR%{T'ZD`  
for(int i=1;;i++) mDfwn7f  
{ #vQ?  
String header=con.getHeaderFieldKey(i); P@gtdi(Q  
if(header!=null) Ep mJWbU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cC%j!8!  
Utility.log(header+" : "+con.getHeaderField(header)); R
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else "tL2F*F"6X  
break; 7 _g+^e-"  
} x;j{} %  
} ==N` !+  
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(SF1y/g@=  
public void splitterStop() Z:@6Lv?CN  
{ _gW{gLYyJ  
bStop = true; )lh8 k{  
} IaLMWoh  
V&i2L.{G)  

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} ?*H9-2W@  
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/* txq~+'A:+  
**FileAccess.java G2]^F Y  
*//文件访问(定位，写) /s|{by`we4  
package NetFox; :
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import java.io.*; R"+wih  
+K^h!d]  
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public class FileAccessI implements Serializable{ ~*}$>@f{[X  
WPo:^BD   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =&7@<vBpy  
RandomAccessFile oSavedFile; =i>\2J%'R  
long nPos; +tt9R_S  
zAs&%OjG  
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public FileAccessI() throws IOException 9tK>gwb  
{ KE.Dt  
this("",0); NZk&JND  
} ]JjK#eh  
/v#)f-N%zs  
#cU^U#;=r  
public FileAccessI(String sName,long nPos) throws IOException AW~"yI<  
{ sDC*J\X  
oSavedFile = new RandomAccessFile(sName,"rw"); eA=WGy@IcN  
this.nPos = nPos; 5G(E&>~  
oSavedFile.seek(nPos); t> . Fl-  
} x<ax9{  
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public synchronized int write(byte[] b,int nStart,int nLen) |QMA@Mx  
{ +Ok%e.\ZM  
int n = -1; 6|!NLwa  
try{ {38\vX,I(w  
oSavedFile.write(b,nStart,nLen); Z\? E3j  
n = nLen; aV6#t*\J  
} KX3KM!*  
catch(IOException e) `8:Kp  
{ $`ztiVu3  
e.printStackTrace (); ?6P.b6m}0  
} *(QH{!-$s  
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return n; WV
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} Qi9-z'
 
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} A:# k  
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/* g"hJ{{<  
**SiteInfoBean.java vl:J40Kfn  
*/ s8<gK.atl  
package NetFox; ,^$
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(\,BxvhG=  
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public class SiteInfoBean { #0"~G][#  
+(?>-3_z  
U \oy8FZ  
private String sSiteURL; //Site's URL kV&9`c+  
private String sFilePath; //Saved File's Path aeP[+I9  
private String sFileName; //Saved File's Name cpZc9;@IC  
private int nSplitter; //Count of Splited Downloading File nJZ6? V  
"y;bsZBd"  
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public SiteInfoBean() !EBY@ Y1  
{//nSplitter的缺省值为5 0Scm?l3  
//default value of nSplitter is 5 \9{F5Sz  
this("","","",5); 6GL=)0Ah  
} T!2=*~A  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4Ysb5m
)u  
{ 3x@<Z68S  
sSiteURL= sURL; )9v`f9X){  
sFilePath = sPath; Q2|p\rO  
sFileName = sName; _\8qwDg"#e  
this.nSplitter = nSpiltter; aP-<4u
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7 sFz?`-  
} y$W
|~ H   
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public String getSSiteURL() HU;#XU1  
{ {~Tg7<\L  
return sSiteURL; , YW|n:X  
} ;xYNX  
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%O[N}_XHEh  
public void setSSiteURL(String value) JXqr3Np1  
{ c64v,Hj9  
sSiteURL = value; ,'fxIO  
} )_7>nuQ6  
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public String getSFilePath() 2 QTZwx  
{ wBSQ:f]g  
return sFilePath; MGpt}|t-  
} ;#/@+4@a&  
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'lz"2@4{  
public void setSFilePath(String value) kOL'|GgK  
{ DKL@wr}8  
sFilePath = value; ]0V}D,V($  
} 'jg3  
#Pk$L+C
 
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public String getSFileName() Z.PBu|Kx  
{ *fMpZ+;[m  
return sFileName; AyKMhac  
} NAC_pM&B  
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public void setSFileName(String value) ,:2'YB  
{ =+:{P?*}  
sFileName = value; :mppv8bh  
} -
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~&dyRtW
4  
public int getNSplitter() feM6K!fL`  
{ ZP\M9Ja  
return nSplitter; bm~W EX  
} C4$:mJ>y  
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public void setNSplitter(int nCount) }L=/A7Nk>  
{ N"tFP9;K  
nSplitter = nCount; BR`ygrfe  
} f|7\DeY9U  
} #N(= 3Cj  
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/* }|OaL*|u  
**Utility.java >SF Uy\3  
*/ =ac_,]z  
package NetFox; enS}A*Io  
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public class Utility { u7%D6W~m0  
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public Utility() hg.#DxRi{  
{ Qj{8?lew  
|~`as(@Ih  
+d}E&=p_  
} kl!wVLE  
p@!nYPr.  
//线程睡眠 Z%zj";C G  
public static void sleep(int nSecond) AN:sQX`  
{ !%+2Yifna  
try{ z}QwP~Z  
Thread.sleep(nSecond); (/d5UIM{&  
} 94uNI8  
catch(Exception e) }"vW4   
{ vy2Q g  
e.printStackTrace (); N[]Hc  
} 1d"Z>k:mn  
} XgN` 7!Z  
h+p*=|j`  
//日志 K%<j=c  
public static void log(String sMsg) g6@Fp7T  
{ c .3ZXqpI;  
System.err.println(sMsg); 6fH@wQ"wN  
} q\Q{sv_  
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d<!3`qe  
public static void log(int sMsg) l&4,v  
{ <U5wB]]  
System.err.println(sMsg); uzmk6G v  
} ]wT 7*( Y  
} nkxzk$  
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/* >z;[2n'  
**TestMethod.java fH`P[^N  
*/ =ph&sn$;L  
package NetFox; CTt vyr  
6
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public class TestMethod { K8n4oz#z  
>EL)X #e  
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public TestMethod() bmNq[}  
{ ///xx/weblogic60b2_win.exe 7{e{9QbJ4  
try{ H gTUy[(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >_rha~   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [b%:.bjY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B\J^=W+`  
fileFetch.start(); 9TF f8'?d  
} bfB\h*XO  
catch(Exception e){e.printStackTrace ();} '1,,)U#6E  
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} {Q+gZcu  
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public static void main(String[] args) R
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{ }kw/W#)J  
new TestMethod(); 4h5g'!9-g  
} b'VV'+|  
} {o5V7*P;_  
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