http断点续传简单实现（java)

/* 4
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**SiteFileFetch.java .9g :-hv  
*/ g2LvojR  
package NetFox; wk
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import java.io.*; +@8, uL  
import java.net.*; I3x+pa^]2  
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public class SiteFileFetch extends Thread { 0lYP!\J3]%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ix?Z:pIS0  
long[] nStartPos; //开始位置 Ly v"2P  
long[] nEndPos; //结束位置 G$Fo*;Fl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Jzy:^PObT  
long nFileLength; //文件长度 g}9heR  
boolean bFirst = true; //是否第一次取文件 [6.<#_~{  
boolean bStop = false; //停止标志 km lb,P  
File tmpFile; //文件下载的临时信息 h.- o$+Sa  
DataOutputStream output; //输出到文件的输出流 =
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vt(n: Xk  
public SiteFileFetch(SiteInfoBean bean) throws IOException PT&qys2k  
{ @&Yl'&pn-R  
siteInfoBean = bean; !>K=@9NC|.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v6x jLP;O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~\u>jel  
if(tmpFile.exists ()) Z~|%asjFE  
{ ~WB-WI\  
bFirst = false; yC|odX#  
read_nPos(); w`#9Re  
} UA0( cK  
else k4:=y9`R}$  
{ bsI?=lO  
nStartPos = new long[bean.getNSplitter()]; YVz,P_\(m  
nEndPos = new long[bean.getNSplitter()]; SST@   
} ^tjM1uaZ5(  
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} lqAv  
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public void run() 1mfB6p1Z(  
{ 'Q*lp!2>  
//获得文件长度 XwU1CejP0  
//分割文件 n4+^f~Y  
//实例FileSplitterFetch _71I9V&  
//启动FileSplitterFetch线程 8N#.@\'kz.  
//等待子线程返回 >7W8_6sC<  
try{ Gh%dVP9B@P  
if(bFirst) 8<EU|/O  
{ f=4q]y#& X  
nFileLength = getFileSize(); 6"+bCx0:  
if(nFileLength == -1) Zjc0R   
{ !|"LAr9u  
System.err.println("File Length is not known!"); "QtkNy%E  
} `<R^ZL,  
else if(nFileLength == -2) -b  )~  
{ }Q,BI*}*  
System.err.println("File is not access!"); r6 pz(rCs}  
} SvQj'5~<  
else ^Ri ; vM  
{ A_J!VXq  
for(int i=0;i<nStartPos.length;i++) Nlm3RxSn  
{ }:b) =fs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); c^,8eb7c  
} Y#U0g|UDn  
for(int i=0;i<nEndPos.length-1;i++) W[73q>'  
{ 7Uh/Gl  
nEndPos = nStartPos[i+1]; D;DI8.4`N  
} h>|IA@;|f  
nEndPos[nEndPos.length-1] = nFileLength; P>*`<$FR  
} `DP4u\6_  
} 6:G::"ew  
+/#Lm#*nu%  
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//启动子线程 I
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; anUH'mcK*  
for(int i=0;i<nStartPos.length;i++) <a D}Ko(  
{ 0INlo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M8FC-zFs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), RUV:  
nStartPos,nEndPos,i); F @Wb<+0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {w9GMqq  
fileSplitterFetch.start(); 3 k)P*ME#  
} YJ01-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >#xIqxV,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0VI[6t@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E-$N!KY  
nEndPos = " + nFileLength); "Za
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// fileSplitterFetch[nPos.length-1].start(); 2wYY0=k2  
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//等待子线程结束 {
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//int count = 0; ;J?zD9  
//是否结束while循环 .+`Z:{:BC&  
boolean breakWhile = false; >=L<3W1  
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while(!bStop) m<:g\_<  
{ J|WkPv2  
write_nPos(); ~5_>$7L>  
Utility.sleep(500); }& e#b]&:*  
breakWhile = true; (d=knoo7A  
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for(int i=0;i<nStartPos.length;i++) uhr&P4EW  
{ t|k-Bh:x  
if(!fileSplitterFetch.bDownOver) 2?9gf,U  
{ Y:K1v:Knw  
breakWhile = false; f}zv@6#&  
break; qMmhmH)Gp  
} 1n+JHXR\  
} l Gy`{E|  
if(breakWhile) 7E)*]7B%  
break; { daEKac5  
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//count++; J[4IO  
//if(count>4) >^+c s^jCM  
// siteStop(); xw83dQ]}^  
} !" 7ip9a  
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4.i< `'  
System.err.println("文件下载结束！"); WH0$v#8`v  
} .^JsnP  
catch(Exception e){e.printStackTrace ();} )R9QJSe  
} `1U?^9Nf  
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//获得文件长度 1 c4I`#_v  
public long getFileSize() ~z*A%vp6ER  
{ T
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int nFileLength = -1; t(.xEl;Ma  
try{ $_&g
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URL url = new URL(siteInfoBean.getSSiteURL()); VA@t8H,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |H@1g=q  
httpConnection.setRequestProperty("User-Agent","NetFox"); *D$Hd">X  
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int responseCode=httpConnection.getResponseCode(); N'e3<  
if(responseCode>=400)
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{ m}>#s3KPA  
processErrorCode(responseCode); zD}2Zh]  
return -2; //-2 represent access is error D= LLm$y  
} [(4s\c  
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String sHeader; *[O)VkL\%i  
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for(int i=1;;i++) >z1q\cz  
{ k_%"#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d(8X?k.S  
//Utility.log(in.readLine()); Y1h)0_0  
sHeader=httpConnection.getHeaderFieldKey(i); x5)YZ~5  
if(sHeader!=null) h`%}5})=  
{ ^SH8*7l7  
if(sHeader.equals("Content-Length")) Dwp-*QK^G  
{ O!#bM< *  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ()I';o  
break; 3Zeh$DZ  
} ,Z6\%:/  
} @{y[2M} %]  
else ley:=(  
break; auV<=1<zJ  
} pSlosv(6  
} bB`p-1  
catch(IOException e){e.printStackTrace ();} MZInS:Vj  
catch(Exception e){e.printStackTrace ();} @u}1
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Utility.log(nFileLength); GH!Lu\y\  
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return nFileLength; Qt+;b  
} XrD@q  
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//保存下载信息（文件指针位置） S;]][h=  
private void write_nPos() /kKF|Hg`c  
{ 'qT[,iQ  
try{ 9EqU 2~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?$&iVN^UA  
output.writeInt(nStartPos.length); iO_6>&(  
for(int i=0;i<nStartPos.length;i++) kX)Xo`^Ys  
{ 2PrUI;J$  
// output.writeLong(nPos); .W)%*~ O!;  
output.writeLong(fileSplitterFetch.nStartPos); /
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output.writeLong(fileSplitterFetch.nEndPos); J$X
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} {"x8q  
output.close(); K~B@8az  
} I"<ACM  
catch(IOException e){e.printStackTrace ();} -*I
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catch(Exception e){e.printStackTrace ();} ;j]-;wg-;  
} & NO:S  
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//读取保存的下载信息（文件指针位置） =6N%;2`84  
private void read_nPos() N4JJA+  
{ {BA1C (  
try{ K4\#b}P!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); aV9QIH~  
int nCount = input.readInt(); k;bdzcMkQ  
nStartPos = new long[nCount]; z|:3,$~sN  
nEndPos = new long[nCount]; j~@Hj$APa`  
for(int i=0;i<nStartPos.length;i++) IyfhVk?  
{ 1\'zq;I~  
nStartPos = input.readLong(); !jeoB  
nEndPos = input.readLong(); !^:)zORYR  
} E 9LKVs}  
input.close(); D[5Qd)PIL  
} wgb e7-{  
catch(IOException e){e.printStackTrace ();} a*4l!-7  
catch(Exception e){e.printStackTrace ();} mDT"%I"4j  
} <:rbK9MIl  
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private void processErrorCode(int nErrorCode) O*8.kqlgt  
{ `Z3p( G  
System.err.println("Error Code : " + nErrorCode); np#RBy  
} &2EimP  
k1
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//停止文件下载 M@=eWZ<  
public void siteStop() !\ckUMZ\  
{ )_\ZUem  
bStop = true; 6ofi8(n[  
for(int i=0;i<nStartPos.length;i++) tXgsWG?v[H  
fileSplitterFetch.splitterStop(); 3{wmKo|_X  
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} -t:~d:  
} GV1SKa  
//负责部分文件的抓取 eiJ13`T  
**FileSplitterFetch.java )S;pYVVAl  
*/ hrRkam!y  
package NetFox; Ob"48{w$  
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import java.io.*; ,'E+f%  
import java.net.*; Sl?@c/Ng  
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public class FileSplitterFetch extends Thread { 2Bf]#l{z  
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String sURL; //File URL Sas&P:#r  
long nStartPos; //File Snippet Start Position $i^#KZ}-WK  
long nEndPos; //File Snippet End Position 2th>+M~A  
int nThreadID; //Thread's ID M:4N'
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boolean bDownOver = false; //Downing is over dZ1/w0<M2  
boolean bStop = false; //Stop identical rX-V0  
FileAccessI fileAccessI = null; //File Access interface 0pYCh$TL1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t=IpVl!  
{ S8{Sb>  
this.sURL = sURL; Aw38Tw  
this.nStartPos = nStart; nsRZy0@$t  
this.nEndPos = nEnd; wstH&^  
nThreadID = id; O$2= Z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Oc|`<^m  
} `H:5D5]  
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public void run() Y0f"}A1  
{ vUX(h.}8  
while(nStartPos < nEndPos && !bStop) \ nIz5J}3  
{ OqaVp/,  
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try{ 4!%TY4bJ  
URL url = new URL(sURL); HR/"Nwr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "o=*f/M  
httpConnection.setRequestProperty("User-Agent","NetFox"); A1mxM5N  
String sProperty = "bytes="+nStartPos+"-"; )@X `B d  
httpConnection.setRequestProperty("RANGE",sProperty); X/5\L.g2  
Utility.log(sProperty); Z`?Z1SBt  
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InputStream input = httpConnection.getInputStream(); ^sWsP`DV  
//logResponseHead(httpConnection); 9q##)  
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byte[] b = new byte[1024]; M=mzl750M  
int nRead; C Rd1zDB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BRTM]tRZ  
{ F)W7,^=X>-  
nStartPos += fileAccessI.write(b,0,nRead); VUo7Evc:.P  
//if(nThreadID == 1) _o 2pyV&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kiW|h)w_,v  
} ]/o0p  
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Utility.log("Thread " + nThreadID + " is over!"); bD&^-& G  
bDownOver = true; Qj?qWVapA  
//nPos = fileAccessI.write (b,0,nRead); -FAAP&LG  
} Auq)  
catch(Exception e){e.printStackTrace ();} QWo_Zg0"  
} xHA6  
} b"au9:F4@7  
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//打印回应的头信息 1@ e22\  
public void logResponseHead(HttpURLConnection con) ux[h\Tp  
{ rNdeD~\  
for(int i=1;;i++) 0I8w'/s_g9  
{ pwiXA{  
String header=con.getHeaderFieldKey(i); y?ps+ce93  
if(header!=null) OZ/P@`kN.f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Pl@3=s!~>~  
Utility.log(header+" : "+con.getHeaderField(header)); f{b$Y3  
else Z*Sa%
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break; c k$ > yk  
} aR iD}P*V  
} '8auj  
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public void splitterStop() ;3nR_6\  
{ q'07  
bStop = true; BCw5.@HK*  
} x1gfo!BN  
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} B,@<60u  
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/* (QO8_  
**FileAccess.java gUfLw  
*//文件访问(定位，写) nLA8Hy"8z  
package NetFox; %n^jho5  
import java.io.*; /M:R|91:_  
%0>DjzYt  
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public class FileAccessI implements Serializable{ X1A~#w>  
9@nDXZPY&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QY]^^f  
RandomAccessFile oSavedFile; 'T(7EL3$}  
long nPos; !+&Rn\e%7  

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public FileAccessI() throws IOException C q/936`O  
{ Q7 dXTS4H  
this("",0); [k"@n+%  
} Ig9gGI,  
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*rY@(|  
public FileAccessI(String sName,long nPos) throws IOException  aOS:rC  
{ + _=&7  
oSavedFile = new RandomAccessFile(sName,"rw"); $ekB+ t:cj  
this.nPos = nPos; Lo'P;Sb4<}  
oSavedFile.seek(nPos); =}:9y6QR.  
} Y9b|lP7!  
uQ^r1 $#  
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public synchronized int write(byte[] b,int nStart,int nLen) &P+7U
m(  
{ E%R^ kqqr  
int n = -1; >~;MQDU5*Y  
try{ Kq`C5  
oSavedFile.write(b,nStart,nLen); y^7ol;t  
n = nLen; {Vc%ga|E  
} dQ4VpR9|;  
catch(IOException e) %J*z!Fe8s  
{ 6} DGEHc1  
e.printStackTrace (); CM}1:o<
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} fl{wF@C6  
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return n; M;
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} >^cP]gGY  
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} ;Up'+[Vj'C  
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/* )!h(oR  
**SiteInfoBean.java `rt  
*/ |5uvmK  
package NetFox; ;Z\1PwT  
jOJ$QT  
X!}
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public class SiteInfoBean { w"s;R8  
%M=[h2SN  
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private String sSiteURL; //Site's URL v/n4Lp$W^  
private String sFilePath; //Saved File's Path \a:#e%]qz9  
private String sFileName; //Saved File's Name &RRHmJI:  
private int nSplitter; //Count of Splited Downloading File g7($lt>  
|}~2=r z  
7H$0NMP  
public SiteInfoBean() TU6e,G|t  
{//nSplitter的缺省值为5 ^;";fr Vw  
//default value of nSplitter is 5 4)L(41h  
this("","","",5); nXgnlb=
 
} Yp_ L.TTb  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nz72w_  
{ hE|Z~5\Y,>  
sSiteURL= sURL; p.{M sn  
sFilePath = sPath; V3%"z  
sFileName = sName; 3;M7^DM  
this.nSplitter = nSpiltter; <eU1E}BDQ  
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t')47k\  
} i$~2pr  
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public String getSSiteURL() ao4"=
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{ >s 4"2X  
return sSiteURL; U(lcQC`$  
} ~U] "
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public void setSSiteURL(String value) T&M*sydA  
{ ?C(' z7  
sSiteURL = value; ) >_xHc?  
} Vu @2  
&`#k1t'  
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public String getSFilePath() -^ )0c  
{ y v6V1gK  
return sFilePath; ws"{Y+L  
} ~}uv4;0l]  
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public void setSFilePath(String value) do {E39  
{ #nK38W#  
sFilePath = value; -6 WjYJx  
} P$YY4|`  
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public String getSFileName() []i/\0C^  
{ {FYWQ!L  
return sFileName; ;E Z5/"T  
} 9YpgzCx Z  
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public void setSFileName(String value) =mVWfFL  
{ 7_OC&hhL  
sFileName = value; ^!Y]l  
} y^PQgzm]  
d:Y!!LV-@L  
UL9
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public int getNSplitter() @vsgm
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{ nWfzwXP>_  
return nSplitter; oXC|q-(C
 
} CSKOtqKQ)  
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public void setNSplitter(int nCount) 9((B
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{ ~m/nV81  
nSplitter = nCount; Xk9mJ]31LC  
} A -C.Bi;/  
} ew13qpt)<L  
x)35}mi){L  
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/* $|kq{@<  
**Utility.java "_LDs(&  
*/ zKh^BwhO|X  
package NetFox; i-.]on
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public class Utility { Ro}7ERA  
~]sj.>P  
nt 9LBea  
public Utility() zd%n)jlwR  
{ :B^YK].  
X;e=d+pw  
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} 7aF'E1e'3  
U yb-feG  
//线程睡眠 ,/fB~On-  
public static void sleep(int nSecond) FUt
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{ YC!IIE_  
try{ .<m${yU{3  
Thread.sleep(nSecond); fL^$G;_?3  
} !.2tv  
catch(Exception e) =3h?!$#?  
{ DOaTp f  
e.printStackTrace (); C VXz>oM  
} d4ga6N3'  
} 9
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//日志 O{vVW9Q  
public static void log(String sMsg) ~U;M1>  
{ YkN0,6  
System.err.println(sMsg); ftb .CPWI  
} T!f+H?6  
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public static void log(int sMsg) Vn=K5nm  
{ ?[Sac]h ys  
System.err.println(sMsg); 0~a9gBG  
} 009[`Z  
} XRl!~Y|  
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/* T'ko
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**TestMethod.java +g9CklJ  
*/ Exb?eHO  
package NetFox; q`Rc \aWB%  
.](~dVp%~  
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public class TestMethod { gzMp&J  
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public TestMethod() 1 $m[#3  
{ ///xx/weblogic60b2_win.exe +L\Dh.Ir  
try{ gmqL,H#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [PIh^DhK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @<TC+M5!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M?S&@\}c  
fileFetch.start(); im-XP@<  
} Z[ 53cVT^  
catch(Exception e){e.printStackTrace ();} LJgGX,Kp  
v:IpZ;^  
iW?z2%#  
} p!o?2Lbiw  
F
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public static void main(String[] args) NiSybyR$  
{ _x`oab0@  
new TestMethod(); 8{- *Q(=/  
} <WiyM[ep  
} 3/{,}F$  
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