http断点续传简单实现（java)

/* Fb9!x/$tGV  
**SiteFileFetch.java Z 361ko}  
*/ \w\{x0u  
package NetFox; E8s&.:;+  
import java.io.*; yUzpl[*e^o  
import java.net.*; 2[R{IV8e  
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public class SiteFileFetch extends Thread { s j{i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z}:|is)?  
long[] nStartPos; //开始位置 W4~:3Sk  
long[] nEndPos; //结束位置 yC]X&1,:z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T,eP&IN  
long nFileLength; //文件长度 w0iv\yIRQ  
boolean bFirst = true; //是否第一次取文件 }- P ='AyL  
boolean bStop = false; //停止标志 }+4^ZbX+:  
File tmpFile; //文件下载的临时信息 WfDpeXdO  
DataOutputStream output; //输出到文件的输出流 Eax^1 |6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }+1Y>W7q  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y}pCBw  
{ ~@wM[}ThP$  
siteInfoBean = bean; |nFg"W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }+fMYgw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); uYv"5U]MFv  
if(tmpFile.exists ()) |3A/Og  
{ G$B( AWL  
bFirst = false; &eHhj9  
read_nPos(); 8(EK17rE`  
} D+ )R_  
else SXW8p>1Jw  
{ 30fsVwE2  
nStartPos = new long[bean.getNSplitter()]; 1dy>a=W  
nEndPos = new long[bean.getNSplitter()]; _*I@ J/  
} } :@s  
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} F(w  
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.
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public void run() #=G[~m\  
{ $H9+>Z0(  
//获得文件长度 wm$1LZ8o-`  
//分割文件 c<`Z[EY(t  
//实例FileSplitterFetch i+2fWi6Z+  
//启动FileSplitterFetch线程 Z*}5M4  
//等待子线程返回 =X0"!y"  
try{ q^e
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if(bFirst) 0 s
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{ Y 7a<3>  
nFileLength = getFileSize(); YR2Q6}xR  
if(nFileLength == -1) L|7F%oR  
{ +$hqwNh@Z@  
System.err.println("File Length is not known!"); LG0z|x(  
} bvf}r ,`Q7  
else if(nFileLength == -2) Jzg>Y?jN R  
{ J;K-Pv+  
System.err.println("File is not access!"); |hp_<F9.  
} Kd?TIeFE  
else #+vIq?  
{ = h _>OA  
for(int i=0;i<nStartPos.length;i++) f__r" N  
{ yA8e"$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y|BRAk&n  
} 'w?*4H  
for(int i=0;i<nEndPos.length-1;i++) 9!u=q5+E  
{ DriJn`vtzq  
nEndPos = nStartPos[i+1]; Oie0cz:>:  
} qP"+SVqC  
nEndPos[nEndPos.length-1] = nFileLength; !$/1Q+  
} ? 1OZEzA!  
} l(EDe  
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//启动子线程 ionFP
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) 0w0\TWz*  
{ mgIB8D+6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wA+QUN3#n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7oj ^(R,  
nStartPos,nEndPos,i); G:W4<w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u&q RK>wLa  
fileSplitterFetch.start(); .?L&k|wX-  
} .eg?FB'7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d|^cKLu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); uSeRn@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h]wahExYP  
nEndPos = " + nFileLength); ]SqLF!S(=  
// fileSplitterFetch[nPos.length-1].start(); ,]1oG=`3v  
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//等待子线程结束 pzX684  
//int count = 0; =K
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//是否结束while循环 3?x4+b  
boolean breakWhile = false; [0M2`x4`  
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while(!bStop) ^6tcB* #A  
{ l98.Hb7  
write_nPos(); huMNt6P[  
Utility.sleep(500); fOE8{O^W  
breakWhile = true; X2X.&^  
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for(int i=0;i<nStartPos.length;i++) |T!^&t  
{ 9ANC,+0p  
if(!fileSplitterFetch.bDownOver) aq'dC=y  
{ ikr|P&e#u  
breakWhile = false; qH3<,s*  
break; G+k[.  
} mN5`Fct*A>  
} W
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if(breakWhile) <78]OZ] Z  
break; 'S_kD! BO  
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//count++; aNZJs<3;'D  
//if(count>4) mcbr3P  
// siteStop(); / v";u)  
} aBo8?VV]8  
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System.err.println("文件下载结束！"); PV_E3,RY  
} q1:Y]Rbe  
catch(Exception e){e.printStackTrace ();} G~,K$z/-l  
} (~YFm"S  
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$ O1w6\}_  
//获得文件长度 I\NiA>c  
public long getFileSize() Q.5C
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{ h'{}eYb+   
int nFileLength = -1; +&LzLF.bK  
try{ pEUbP,3M:  
URL url = new URL(siteInfoBean.getSSiteURL());
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VieX5  
httpConnection.setRequestProperty("User-Agent","NetFox"); O>zPWVwa  

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int responseCode=httpConnection.getResponseCode(); 7qfo%n"  
if(responseCode>=400) X!+#1NPM  
{ vmI2o'zi  
processErrorCode(responseCode); h@
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return -2; //-2 represent access is error MA\^<x_?L}  
} 71AR)6<R  
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String sHeader; E,6(/`0H*  
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for(int i=1;;i++) 2ckAJcpEb/  
{ d/Q}I[J.u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J(BtGGU'  
//Utility.log(in.readLine()); 19 h7 M  
sHeader=httpConnection.getHeaderFieldKey(i); A>;Q<8rh  
if(sHeader!=null) *?/9lAm  
{ ^i3~i?\,P  
if(sHeader.equals("Content-Length")) K".\QF,:  
{ +Eil:Jz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~n)!e#p  
break; C$X )I~M  
} +\SNaq~&  
} OiB*,TWV  
else ;#np~gL  
break; zd)2@jX=  
} %w <59d6  
} E?c)WA2iH  
catch(IOException e){e.printStackTrace ();} Da#|}m0>  
catch(Exception e){e.printStackTrace ();} (*63G4Nz\  
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Utility.log(nFileLength); Lod$&k@@  
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return nFileLength; Dq/ _#&S  
} FA 1E`AdU  
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//保存下载信息（文件指针位置） 3y!yz3E  
private void write_nPos() ;Qpp`  
{ S~WsGLF s  
try{ P0m;AqS#R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]h0Fv-[A  
output.writeInt(nStartPos.length); b6Jv|1w'  
for(int i=0;i<nStartPos.length;i++) z/bJDSQ  
{ #u8|cs!  
// output.writeLong(nPos); 
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output.writeLong(fileSplitterFetch.nStartPos); )|>LSKTEl  
output.writeLong(fileSplitterFetch.nEndPos); gi::?ET/.  
} \>0F{-cR$  
output.close(); pdnkHR$  
} Xg*IOhF6x  
catch(IOException e){e.printStackTrace ();} lk $S"OH!  
catch(Exception e){e.printStackTrace ();} A1xY8?#?~c  
} )A]
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//读取保存的下载信息（文件指针位置） 0{ovLzW  
private void read_nPos() *uYnu|UQH  
{ q2VQS1R`8  
try{ 'jp nQcwxx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OtuOT=%  
int nCount = input.readInt(); H-%)r&"vn  
nStartPos = new long[nCount]; MF>1u%  
nEndPos = new long[nCount]; ?>lvV+3^`  
for(int i=0;i<nStartPos.length;i++) u@SE)qg  
{ ajy.K'B*  
nStartPos = input.readLong(); >SJ# rZ  
nEndPos = input.readLong(); 8Rq+eOP=S  
} <fX]`57Dc`  
input.close(); }{*((@GY
}  
} Wx}+Vq<q  
catch(IOException e){e.printStackTrace ();} Lu&2^USTO  
catch(Exception e){e.printStackTrace ();} &wj;:f  
} ,RFcR[ak  
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private void processErrorCode(int nErrorCode) m ys5B}  
{ =re1xR!E5  
System.err.println("Error Code : " + nErrorCode); YH`/;H=$G/  
} Gy36{*  
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z
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//停止文件下载 x1)G!i  
public void siteStop() O`e0r%SJ  
{ DJ"O`qNV3  
bStop = true; t?^C9(;6  
for(int i=0;i<nStartPos.length;i++) sMAc+9G9k  
fileSplitterFetch.splitterStop(); htbN7B(  
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} \nV|Y=5  
} t5h]]TOz  
//负责部分文件的抓取 %-@`|  
**FileSplitterFetch.java Wt+aW  
*/ PezUG{q(  
package NetFox; Yck(Fl  
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import java.io.*; B\&;eZY'G  
import java.net.*; Vm]ltiTVk  
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public class FileSplitterFetch extends Thread { 8XwAKN:f  
u
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String sURL; //File URL G.K3'^_  
long nStartPos; //File Snippet Start Position <Gzy*1Q&  
long nEndPos; //File Snippet End Position @L|X('i  
int nThreadID; //Thread's ID 'UO,DFq[Fl  
boolean bDownOver = false; //Downing is over ywlN4=  
boolean bStop = false; //Stop identical 7G}vQO  
FileAccessI fileAccessI = null; //File Access interface 0N.tPF}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1E!0N`E  
{ N$J)Ow
 
this.sURL = sURL; T{u!4Yu  
this.nStartPos = nStart; dwks"5l  
this.nEndPos = nEnd; }*l
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nThreadID = id; ~I6Er6$C^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >jAr9Blz]  
} NUBzmnA>8  
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public void run() D1bS=> ;,"  
{ #V[?puE@  
while(nStartPos < nEndPos && !bStop) POTW+Zq]  
{ |E-0P=h  
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try{ ~*-ar
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URL url = new URL(sURL); UwY<3ul  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'X{cDdS^  
httpConnection.setRequestProperty("User-Agent","NetFox"); L'4o
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String sProperty = "bytes="+nStartPos+"-"; F.?
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httpConnection.setRequestProperty("RANGE",sProperty); Oy[1_qfP  
Utility.log(sProperty); }.|\<8_  
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InputStream input = httpConnection.getInputStream(); ^pMjii8IZ  
//logResponseHead(httpConnection); _GK^7}u  
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byte[] b = new byte[1024]; &|P@$O>  
int nRead; N]: "3?%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) v,r}q1.E}  
{ XhFa9RC  
nStartPos += fileAccessI.write(b,0,nRead); ke|v|@  
//if(nThreadID == 1) 94%gg0azp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IjN3 jU  
} ';??0M  
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Utility.log("Thread " + nThreadID + " is over!"); bJe*J\){  
bDownOver = true; <5/r  
//nPos = fileAccessI.write (b,0,nRead); h{.KPK\  
} qie7iE`o  
catch(Exception e){e.printStackTrace ();} AY:3o3M  
} 8 f%@:}H  
} ` 1DJwe2  
2
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//打印回应的头信息 =If% m9  
public void logResponseHead(HttpURLConnection con) C1P{4 U  
{ 7P9n. [  
for(int i=1;;i++) 1N
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{ ?UQVmE&  
String header=con.getHeaderFieldKey(i); ^4]#Ri=U  
if(header!=null) *x[B g]/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N+l~r]: &  
Utility.log(header+" : "+con.getHeaderField(header)); 0.O pgv2K  
else JY0t H
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break; Jl&bWp^3  
} `|wH=  
} 0IBVR,q  
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public void splitterStop() F1R91V|  
{ 5/DTE:M<  
bStop = true; k);z}`7  
} 8,YF>O&  
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} UT [7 J  
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/* WM: ~P$%cx  
**FileAccess.java 28SlFu?  
*//文件访问(定位，写) rui}a=rs  
package NetFox; [e3|yE6  
import java.io.*; -'JTVfm.  
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public class FileAccessI implements Serializable{ \^;Gv%E  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F^_d8=67h  
RandomAccessFile oSavedFile; /V~L:0%  
long nPos; mLk@&WxG  
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9 f-T>}  
public FileAccessI() throws IOException swG^L$r`  
{ xj{X#[q):  
this("",0); "Na9Xea  
} O 4N_lr~  
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public FileAccessI(String sName,long nPos) throws IOException 52m^jT Sx  
{ ?Li^XONz  
oSavedFile = new RandomAccessFile(sName,"rw"); a%tm[Re  
this.nPos = nPos; `NXyzT`:K  
oSavedFile.seek(nPos); dpZ7eJ  
} sxgR;gf6  
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public synchronized int write(byte[] b,int nStart,int nLen) \bQ|O7s  
{ 7;;W{W%  
int n = -1; ro@Zbm;P  
try{ #i ?@S$  
oSavedFile.write(b,nStart,nLen); N$pwTyk  
n = nLen; H24g+<Tv  
} POH>!lHu  
catch(IOException e) qS&PMQ"$  
{ U`FybP2R~  
e.printStackTrace (); WeuV+}\b  
} `m3@mJ!>\  
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return n; FtM7+>Do
.  
} z"}k\B-5  
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} Lj*FKP\{  
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/* kjaz{&P  
**SiteInfoBean.java n#z^uq|v  
*/ |GK [I  
package NetFox; ^eM=h
 
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public class SiteInfoBean { \^Y#"zXo1  
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private String sSiteURL; //Site's URL (n" )  
private String sFilePath; //Saved File's Path P7egT,Z  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File ]~?k%Mpw  
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public SiteInfoBean() ~pzaX8!  
{//nSplitter的缺省值为5 W:(:hT6`j9  
//default value of nSplitter is 5 MF 5w.@62X  
this("","","",5);  @KOa5-u  
} 82$By]Y9  
yl 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x ?^c:`.  
{ $nn~K  
sSiteURL= sURL; <g*rTqT'  
sFilePath = sPath; M|n)LyL  
sFileName = sName; %M}zi'qQ?  
this.nSplitter = nSpiltter; rFx2S  
/4_}wi\  
*N>Qj-KAM_  
} =7e8N&-nv  
.Z_U]_(  
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public String getSSiteURL() /2FX"I[0V%  
{ P?9CBhN  
return sSiteURL; EHzZ9zH\  
} '/sc `(`:0  
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public void setSSiteURL(String value) _Fz)2h,3  
{ Ku&(+e  
sSiteURL = value; e3S6+H),I  
} ++dV5  
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public String getSFilePath() @J
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{ #m$H'O[WG\  
return sFilePath; G!rcY5!J  
} \&TTe8  
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public void setSFilePath(String value) 3_h%g$04s  
{ z? {#/  
sFilePath = value; z9D2,N.  
} (XW#,=rYk  
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public String getSFileName() Ey6K@@%  
{ %1=W#jz  
return sFileName; 2X*epU_1h  
} xDQ$Ui.  
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Yt#($}p  
public void setSFileName(String value) ko5\*!|:lj  
{ 8p5'}Lq  
sFileName = value; VqbiZOZ@  
} +\W"n_PPy  
>^Y9p~  

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public int getNSplitter() RF;N]A?*  
{ yjSN;3t71  
return nSplitter; -"cN9RF  
} Ee|@l3)  
>N,G@{FR  
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public void setNSplitter(int nCount) VLO>{"{'  
{ :?p{ga9  
nSplitter = nCount; ScTqnY$v  
} \;?\@vo<  
} t{7l.>kf  
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/* R80R{Ze  
**Utility.java y&CU
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*/ 9.@(&  
package NetFox; jqLyX  
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public class Utility { O[`Ob6Q{F  
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public Utility() -m@s 9k  
{ 1]<!Xuk^f  
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} ms{R|vU%b  
oF>GWstTR  
//线程睡眠 E??%)q  
public static void sleep(int nSecond) C=]3NB>Jc  
{ =;`YtOL  
try{ w %zw+
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Thread.sleep(nSecond); 6,7omYof  
} U=t'>;(g  
catch(Exception e) VsmL#@E  
{ +sI.GWQ_:  
e.printStackTrace (); 3K{8sFDO  
} P$QjDu-  
} x3P@AC$\  
_kd
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//日志 *Q>:|F[vM  
public static void log(String sMsg) "5YdmBy  
{
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System.err.println(sMsg); k|_2aQ02  
} $"i690  
vqs~a7E-P  
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public static void log(int sMsg) C1/jA>XW  
{ O<3,n;56Z  
System.err.println(sMsg); Y;w]u_  
} }-vBRY  
} y(dS1.5F  
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\PFx# :-c  
/* |W <:r
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**TestMethod.java /Ow?nWSt  
*/ k$c j|-<  
package NetFox; 'l:2R,cP  
"uCQm '  
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public class TestMethod { -b$OHFL  
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public TestMethod() j+9 S  
{ ///xx/weblogic60b2_win.exe 64lEB>VNm  
try{ eTc`FXw`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); v2{O67j} o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !.9vW&t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =F&RQ}$  
fileFetch.start(); <C77_t  
} Q7r,5w&cm  
catch(Exception e){e.printStackTrace ();} 7j:{rCp3J  
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} ?a%i|Z7!  
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public static void main(String[] args) 62jA  
{ wDO5Zew!  
new TestMethod(); q?L
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} _);Kb/  
} Elp!,(+&6  
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