http断点续传简单实现（java)

/* S/ibb&  
**SiteFileFetch.java WKSPBT;  
*/ "]\+?  
package NetFox; mA{~PpSb  
import java.io.*; [xKd7"d/n  
import java.net.*; iPrLwheb  
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public class SiteFileFetch extends Thread { 2ZQ}7`Y  
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SiteInfoBean siteInfoBean = null; //文件信息Bean aj}(E+  
long[] nStartPos; //开始位置 ek N'k  
long[] nEndPos; //结束位置 |`jjHuQ;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度 l{D'uI[&  
boolean bFirst = true; //是否第一次取文件 M2U&?V C!  
boolean bStop = false; //停止标志 ;}'D16`j  
File tmpFile; //文件下载的临时信息 *cO sv  
DataOutputStream output; //输出到文件的输出流 5 QO34t2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a/< Csad  
public SiteFileFetch(SiteInfoBean bean) throws IOException f0T,ul,  
{ rSYi<ku  
siteInfoBean = bean; b?eu jxqg  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @}:uu$OH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]@Sj`J[fd  
if(tmpFile.exists ()) y7
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{  kQ  
bFirst = false; `ImE% r!  
read_nPos(); 'fL"txW  
} 5MS
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else ce6__f5?  
{ CR|lt  
nStartPos = new long[bean.getNSplitter()]; ,$eK-w  
nEndPos = new long[bean.getNSplitter()]; <`0h|m'U  
} i9=&;_z  
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} C XHy.&Vt  
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public void run() <?D\+khlq  
{ xB !6_VlB  
//获得文件长度 w
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//分割文件 C4NTh}6tT  
//实例FileSplitterFetch tBc
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//启动FileSplitterFetch线程 t R6 +G  
//等待子线程返回 'u` .P:u?  
try{ {%#)5l
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if(bFirst) 7G)H.L)$m"  
{ PoIl>c1MS  
nFileLength = getFileSize(); 8KH\`
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if(nFileLength == -1) $\k0Nup}  
{ =rR~`  
System.err.println("File Length is not known!"); WF\)fc#;_o  
} ZR\VCVH\^  
else if(nFileLength == -2) $fgf Y8  
{ #);[mW{F  
System.err.println("File is not access!"); WYc7aciJ  
} d`1I".y  
else b]a@  
{ "U\JV)N  
for(int i=0;i<nStartPos.length;i++) p^iRPI  
{ RQFI'@Ks  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0KD]j8^  
} . <tq61  
for(int i=0;i<nEndPos.length-1;i++) P+)DsZ0ig  
{ 2[gFkyqe  
nEndPos = nStartPos[i+1]; y
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} ujJI 1I  
nEndPos[nEndPos.length-1] = nFileLength; 4ikdM/  
} "YB**Y  
} ?3O9eZY@  
i>[_r,-\[  
V i&*&"q  
//启动子线程 7$rjlVe  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |X`/  
for(int i=0;i<nStartPos.length;i++) +7
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{ !pJeA)W;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *9p |HX=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VACiVKk  
nStartPos,nEndPos,i); +1~Z#^{&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K\)Td+~jc  
fileSplitterFetch.start(); kg`.[{k  
} >Yt/]ta4+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %0Y=WYUH>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KLX/O1B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z5bo_Eq  
nEndPos = " + nFileLength); "@9?QI}  
// fileSplitterFetch[nPos.length-1].start(); <9sO  
&P,^.'  
*.&HD6Qr  
//等待子线程结束 CU7F5@+  
//int count = 0; ^2wLxXO6  
//是否结束while循环 VxzkQ}o  
boolean breakWhile = false; 6'W[{gzl  
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while(!bStop) }KD;
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{ StI1){Wf  
write_nPos(); a=T
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Utility.sleep(500); $F.kK%-*  
breakWhile = true; GjB]KA^  
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for(int i=0;i<nStartPos.length;i++) rfw-^`&{  
{ wC-Rr^q  
if(!fileSplitterFetch.bDownOver) !K?qgM  
{ y&_m4Zw"  
breakWhile = false; B??J@+Nf  
break; _hG;.=sr  
} r ]>\~&?^F  
} R4Rb73o  
if(breakWhile) k-*Mzm]kb  
break; yFhB>i  
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//count++; W9oAjO NE  
//if(count>4) 8^B;1`#  
// siteStop(); ,_ag;pt
9)  
} an2AX%u  
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System.err.println("文件下载结束！"); 8q)=  
} -A-tuyIsh"  
catch(Exception e){e.printStackTrace ();} t4K~cK  
} 'lZ.j&  
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//获得文件长度 U.T|   
public long getFileSize() XR0O;JN  
{ S-+M;@'Rl  
int nFileLength = -1; gK|R =J  
try{ O--7<Q\  
URL url = new URL(siteInfoBean.getSSiteURL()); IaFr&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;W:6{9m ze  
httpConnection.setRequestProperty("User-Agent","NetFox"); oVCmI"'  
I?Q+9Rmm`J  
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int responseCode=httpConnection.getResponseCode(); F>gmj'-^  
if(responseCode>=400) V^Rkt%JY  
{ tZ2e!<C  
processErrorCode(responseCode); D@X+{  
return -2; //-2 represent access is error /XS&d%y  
} /(t sb  
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String sHeader; 2i|B=D(  
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for(int i=1;;i++) hY<{t.ws  
{ 2=ztKfsBhE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  8RwX=  
//Utility.log(in.readLine()); t5 a7DD  
sHeader=httpConnection.getHeaderFieldKey(i); @tRMe64  
if(sHeader!=null) a <X0e>  
{ u&QKwD Uh  
if(sHeader.equals("Content-Length")) ngi<v6i  
{ e~v(eK_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); l0tYG[  
break; z(c9,3  
} b]gY~cbI8  
} #~qAHJ<  
else f+vVR1  
break; 3]JZu9#  
} /)uM[ dnai  
} u}6v?!  
catch(IOException e){e.printStackTrace ();} w?csV8ot  
catch(Exception e){e.printStackTrace ();} !p 8psi0  
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Utility.log(nFileLength); #G3N(wV3  
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return nFileLength; Gt/4F-Gn  
} TOI4?D]  
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//保存下载信息（文件指针位置） |sgXh9%x<  
private void write_nPos() 5nCu~<uJ  
{ bdh(WJh%  
try{ 6-,m}Ce\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); PI5j"u UO  
output.writeInt(nStartPos.length); wz -)1!  
for(int i=0;i<nStartPos.length;i++) TF
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{ E@ h y7X  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); 1K|@h&@  
output.writeLong(fileSplitterFetch.nEndPos); g?qKNY  
} %Ny) ?B  
output.close(); \Mi#{0f+q  
} #I`ms$j%  
catch(IOException e){e.printStackTrace ();} iRmQ5ezk  
catch(Exception e){e.printStackTrace ();} CBD_
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} 0o&}mKe  
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//读取保存的下载信息（文件指针位置） s ?l%L!  
private void read_nPos() =;c_} VY  
{ B!aK  
try{ a}.Y!O&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :\V,k~asl  
int nCount = input.readInt(); ]@xL=%  
nStartPos = new long[nCount]; m[2'd  
nEndPos = new long[nCount]; S-E++f9D~  
for(int i=0;i<nStartPos.length;i++) 6 o[/F3`  
{ 2f:Mm'XdB  
nStartPos = input.readLong(); =g@9>3~{!  
nEndPos = input.readLong(); nbvkP  
} V"d=.Hb>  
input.close(); Pl~P-n  
} &+nRIv S_`  
catch(IOException e){e.printStackTrace ();} J l7z|QS
 
catch(Exception e){e.printStackTrace ();} H)JS0 G0  
} =L0fZf  
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private void processErrorCode(int nErrorCode) &^ I+s^\=  
{ lQt% Qx  
System.err.println("Error Code : " + nErrorCode); vrrt@y  
} ^GXEJU7U  
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oP$kRfXS!<  
//停止文件下载 Z}cIA87U  
public void siteStop() k7bl'zic  
{ .`LgYW  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) A1JzW)B  
fileSplitterFetch.splitterStop(); _dmL}t-  
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} Q(\ wx
 
} $@87?Ab  
//负责部分文件的抓取 WL~`u  
**FileSplitterFetch.java 0
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*/ B3L4F"  
package NetFox; XNmQ?`.2'  
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import java.io.*; 8j\d~Lw=  
import java.net.*; g{DFS[h  
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public class FileSplitterFetch extends Thread { ^LO]Z  
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String sURL; //File URL 8gpBz'/,  
long nStartPos; //File Snippet Start Position 2lz {_9  
long nEndPos; //File Snippet End Position G\/IM  
int nThreadID; //Thread's ID nu 7lh6o=  
boolean bDownOver = false; //Downing is over Wu{&;$  
boolean bStop = false; //Stop identical =WRO\lgv.  
FileAccessI fileAccessI = null; //File Access interface 3hJH(ToO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  <qn,  
{ H'Iq~Ft1  
this.sURL = sURL; HU[oR4E  
this.nStartPos = nStart; i=da,W=0  
this.nEndPos = nEnd; 5^|"_Q#:
 
nThreadID = id; LkaG[^tfN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rUFFF'm\*a  
} "#XtDpGk  
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public void run() QeK{MF  
{ P7>IZ >bw  
while(nStartPos < nEndPos && !bStop) .wri5  
{ H0tF  
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try{ Kfd_uXL>  
URL url = new URL(sURL); =L16hDk o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E(/ sXji!  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8|vld3;  
String sProperty = "bytes="+nStartPos+"-"; #`58F
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httpConnection.setRequestProperty("RANGE",sProperty); qhwoV4@f  
Utility.log(sProperty); V#H8d_V  
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InputStream input = httpConnection.getInputStream(); ^teaJy%  
//logResponseHead(httpConnection); gD5P!}s[u0  
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byte[] b = new byte[1024]; ??+:vai2  
int nRead; X4 Y
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $/.<z(F  
{ ULTNhq R*n  
nStartPos += fileAccessI.write(b,0,nRead);
#'g^Za  
//if(nThreadID == 1) e7's)C>/'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eRVY.E<  
} |=,83,a  
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Utility.log("Thread " + nThreadID + " is over!"); _]EyEa  
bDownOver = true; B{=009.  
//nPos = fileAccessI.write (b,0,nRead); 2mLUdx~c  
} Z{#"-UG  
catch(Exception e){e.printStackTrace ();} NJ>,'s  
} Za9$Hh/X  
} :r^klJ(m  
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@jKDj]\  
//打印回应的头信息 ~ ;XYwQ"  
public void logResponseHead(HttpURLConnection con) >Pyc[_j  
{ @bY?$fj_u  
for(int i=1;;i++) ,P!D-MN$V  
{ 1M=   
String header=con.getHeaderFieldKey(i); C;%Y\S  
if(header!=null) ~r PYJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lJlZHO  
Utility.log(header+" : "+con.getHeaderField(header)); &h\CS8nT%  
else V 1*Ad  
break; 44Q9*."  
} U~CdU  
} ki`8(u6l  
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public void splitterStop() J2'W =r_#  
{ ,y{0bq9*2  
bStop = true; _o&94&  
} {&0mK"z_  
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} %`
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/Ht/F)&P  
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/* **.:)  
**FileAccess.java h)^dB,~  
*//文件访问(定位，写) RA}U#D:$i  
package NetFox; wLpkUa  
import java.io.*; 8H7O/n  
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public class FileAccessI implements Serializable{ 6<<'bi  
5cgo)/3M@}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ))p$v
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RandomAccessFile oSavedFile; -.^
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long nPos; &;Ed*OJ  
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public FileAccessI() throws IOException zuk"  
{ cxY$LY!zX  
this("",0); pXve02b1B  
} (1rJFl!  
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public FileAccessI(String sName,long nPos) throws IOException qw5&Y$((  
{ % Oz$_Xe  
oSavedFile = new RandomAccessFile(sName,"rw"); ^Wif!u/HM  
this.nPos = nPos; VccM=w%*  
oSavedFile.seek(nPos); 3mk=ZWwv  
} Jc`Rs"2  
8^8>qSD1  
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public synchronized int write(byte[] b,int nStart,int nLen) J6eJIKK  
{ r|*:9|y{"/  
int n = -1; R$Zv0a&  
try{ |MR%{ZC^i  
oSavedFile.write(b,nStart,nLen); O%fUm0O d  
n = nLen; qZXyi'(d  
} zIP[R):3&U  
catch(IOException e) P87ld._  
{ "\4]X"3<+  
e.printStackTrace (); `'kc|!%MUq  
} mm_^gQ,`  

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return n; qx Wgt(Os  
} IY V-*/ |  
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}
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f( ]R/'o  
/* ]}p2Tp;1  
**SiteInfoBean.java RV( w%g  
*/ %I_&Ehu  
package NetFox; ,c@r` x  
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public class SiteInfoBean { Hr /W6C  
#!w:_T%  
{An8/"bv}  
private String sSiteURL; //Site's URL 4sj9Z:  
private String sFilePath; //Saved File's Path +Y^-e.UO  
private String sFileName; //Saved File's Name ~^^!"-  
private int nSplitter; //Count of Splited Downloading File Rl y jOf{0  
l?})_1v,R  
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public SiteInfoBean() `oB'(  
{//nSplitter的缺省值为5 tceIA8d6  
//default value of nSplitter is 5 FTbT9   
this("","","",5); ;:AG2z
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} / c+,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DhY;pG,t  
{ jAA'hA  
sSiteURL= sURL; kSLSxfR  
sFilePath = sPath; I h5/=_n  
sFileName = sName; :|?~B%-p[  
this.nSplitter = nSpiltter; 5OPS&:  
qRgK_/[]  
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} p^p'/$<6_  
2
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public String getSSiteURL() hCU)W1q#  
{ p#ZMABlE,P  
return sSiteURL; K.:6YXVs<  
} Z|]l"W*w  
\B*k_W/r@  
#rh0r`  
public void setSSiteURL(String value)
{fAh@:{@  
{ (jp1; #P!  
sSiteURL = value; gUksO!7^1  
} Rg%R/p)C  
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public String getSFilePath() O{;M6U8C\  
{ M\:"~XW  
return sFilePath; ?whRlh  
} 3c1o,2  
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public void setSFilePath(String value) #nU@hOfg  
{ Wwn5LlJ^  
sFilePath = value; 0z#l0-NdQ  
} k$9Gn9L%  
2N6Pa(6  
&M!4]pow
 
public String getSFileName() nG&w0de<>  
{ T+&x{+gZ  
return sFileName; Jm{As*W>  
} I T*fjUY&  
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, I[^3Fn  
public void setSFileName(String value) 27h/6i3  
{ t9KH|y  
sFileName = value; Up]VU9z  
} 5*G8W\ $  
]=$-B  
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public int getNSplitter() f)&`mqeE  
{ r?Ev.m  
return nSplitter; dg!1wD  
} J ,Qy`Y B  
]pM5?^<~  
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public void setNSplitter(int nCount) b?+Yo>yF8  
{ w]]x[D]L  
nSplitter = nCount; sqq/b9 uL/  
} &(z8GYBr  
} x9XGCr  
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u
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/* Apw-7*/  
**Utility.java 18[?dV  
*/ Nlf&]^4(0  
package NetFox; [)b/uR  
[T$$od[.  
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public class Utility { 0ER6cTo-t  
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public Utility() a9mr-`<  
{ T }8r;<P6  
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} Ggxrj'r  
%8z+R m,Ot  
//线程睡眠 37ri b  
public static void sleep(int nSecond) 8V53+]c$Y  
{ ek+8hnkh  
try{ ~'PS|  
Thread.sleep(nSecond); K>DnD0  
} z
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catch(Exception e) `*uuB;  
{ I?:+~q}lZr  
e.printStackTrace (); %(O^as  
} n WO~v{h3J  
} cwDD(j  
4`^TC[
  
//日志 {~B4F}ES  
public static void log(String sMsg) TZ[Fu{gZ  
{ c'wU O3S  
System.err.println(sMsg); U4mh!  
} duiKFNYN  
c,[qjr#\>  
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public static void log(int sMsg) #h5Hi9LKf  
{ ]i_):@  
System.err.println(sMsg); <R]Wy}2-  
} $F /p8AraK  
} Y GcY2p<  
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tM?I()Y&P  
/* FdK R{dX}  
**TestMethod.java :,J86#S)  
*/ |L~gNC
  
package NetFox; w~
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public class TestMethod { ve_4@J)  
9iN!hy[  
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public TestMethod() }O-%kl  
{ ///xx/weblogic60b2_win.exe fxf GJNR  
try{ 5G]#'tu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ">4[+'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kH
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SiteFileFetch fileFetch = new SiteFileFetch(bean); 94>7-d  
fileFetch.start(); ^Qb!k/$3y  
} e\bF_ N2VA  
catch(Exception e){e.printStackTrace ();} qz_TcU'  
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56~da ){gd  
} CBgFB-!qpe  
khO<Z^wi[  
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public static void main(String[] args) ?_h#>  
{ FL_ arhrqD  
new TestMethod(); k3htHCf*G$  
} mrBhvp""  
} 7E84@V[\  
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