http断点续传简单实现（java)

/* UPH#~D!  
**SiteFileFetch.java 5az%yS  
*/ QVjHGY*R  
package NetFox; `%Fp'`ZM$8  
import java.io.*; {($bzT7c  
import java.net.*; z)T-<zWO;  
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public class SiteFileFetch extends Thread { Q# hRnM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7RT{RE  
long[] nStartPos; //开始位置  ]~;*9`:  
long[] nEndPos; //结束位置 !l*A
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 -f|/#1  
long nFileLength; //文件长度 d.f0OhQ  
boolean bFirst = true; //是否第一次取文件 yu6~:$%H  
boolean bStop = false; //停止标志 W|2^yO,dX  
File tmpFile; //文件下载的临时信息 GXZ="3W |  
DataOutputStream output; //输出到文件的输出流 *z[vp2 TN  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w9Yx2  
public SiteFileFetch(SiteInfoBean bean) throws IOException +jE)kaV%  
{ uL)MbM]  
siteInfoBean = bean; A'w+Lc.2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eP~
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }#1.$a  
if(tmpFile.exists ()) L9/'zhiZBx  
{ #)S}z+I  
bFirst = false; b_Y+XXb<  
read_nPos(); SLuQv?R}9  
} Z kw-a  
else -}m  
{ q-t%spkl  
nStartPos = new long[bean.getNSplitter()]; 1tXc7NA<  
nEndPos = new long[bean.getNSplitter()]; r^"o!,H9q  
} 4AhFE@  
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} *?Eu{J){7%  
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public void run() !}c D e12  
{ HV!P]82Pa  
//获得文件长度 Jha*BaD~N  
//分割文件 U+VJiz<!  
//实例FileSplitterFetch <@`K^g;W  
//启动FileSplitterFetch线程 ~6#mVP5sU)  
//等待子线程返回 s;h`n$  
try{ f@Mku0VT  
if(bFirst) PE7V1U#$o,  
{ '0 Ys`Qo  
nFileLength = getFileSize(); +]t9kr  
if(nFileLength == -1) K/(LF}  
{ =O8YU)#  
System.err.println("File Length is not known!"); #~j$J  
} QqL?? p-S>  
else if(nFileLength == -2) ~oOv/1v},  
{ 2h5T$[f
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System.err.println("File is not access!"); (a!E3y5,  
} e~QLzZ3  
else D+_PyK~jc  
{ Z@iMG  
for(int i=0;i<nStartPos.length;i++) 0H.B>:pv  
{ kqAQrg]n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); c9E9Rx  
} T{K+1SPy4  
for(int i=0;i<nEndPos.length-1;i++) aEZn6k1  
{ p|
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nEndPos = nStartPos[i+1]; 7e#|=e *I!  
} H"?-&>V-  
nEndPos[nEndPos.length-1] = nFileLength; z
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} cfe[6N  
} =Jl1D*B*  
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//启动子线程 zsRN\U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R}+/jh2O|  
for(int i=0;i<nStartPos.length;i++) zZh`go02E  
{ M!6bf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z8"=W,2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |V~P6o(/  
nStartPos,nEndPos,i); *&2
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qV$',U*+T  
fileSplitterFetch.start(); $X&OGTlw^  
} E.% F/mM  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :* /``  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C1rCKKh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d`n
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nEndPos = " + nFileLength); r@<;  
// fileSplitterFetch[nPos.length-1].start(); 6nSk,yE'hE  
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//等待子线程结束 ~ pdf'  
//int count = 0; K6oXnz}  
//是否结束while循环 @x J^JcE  
boolean breakWhile = false; !V-SV`+X  
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while(!bStop) (1}Ndo^;w  
{ `y6l^
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write_nPos(); m<f{7]fi5  
Utility.sleep(500); d<b,LD^  
breakWhile = true; E:E&Wv?r  
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for(int i=0;i<nStartPos.length;i++) YV940A-n  
{ K+$c,1wb  
if(!fileSplitterFetch.bDownOver) {4m"S7O  
{ a&ByV!%%+_  
breakWhile = false; ft6^s(t  
break; A0X0t  
} O}D
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}
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if(breakWhile) n*6s]iG V  
break; 7Y*m_AhxJ  
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//count++; DVcu*UVw  
//if(count>4) n)7icSc  
// siteStop(); v_@_J!s  
} 6uXYZ.A
  
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System.err.println("文件下载结束！"); qtH&]Suu,  
} pz IMj_  
catch(Exception e){e.printStackTrace ();} yl 8v&e{  
} 4F4u1r+  
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//获得文件长度 # |I@`#O  
public long getFileSize() Wkk Nyg,  
{ MHYf8HN  
int nFileLength = -1; ,< icW&a  
try{ (}}8
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URL url = new URL(siteInfoBean.getSSiteURL()); 6qJB"_.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bw=[g&+o1@  
httpConnection.setRequestProperty("User-Agent","NetFox"); `j<tI6[e  
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int responseCode=httpConnection.getResponseCode(); KUyJ"q<W  
if(responseCode>=400) V6{xX0'b*m  
{ k0IU~y%  
processErrorCode(responseCode); JAz;_wS(k  
return -2; //-2 represent access is error Wu&Di8GhP  
} Z
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String sHeader; U}0/V c
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for(int i=1;;i++) NLGr=*dq  
{ .Cus t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s-V$N  
//Utility.log(in.readLine()); k>CtWV5B  
sHeader=httpConnection.getHeaderFieldKey(i); P.B'Gh#^  
if(sHeader!=null) >[@d&28b%  
{ y21uvp'  
if(sHeader.equals("Content-Length")) 5UjQLB  
{ ACYn87tq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TMCA?r%Y\  
break; |pR$' HO  
} B
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} <R>ZG"m{  
else <;e#"(7  
break; hob$eWgr  
} n5/Tn7hY  
} ?|GxVOl  
catch(IOException e){e.printStackTrace ();} Dg+d=I?  
catch(Exception e){e.printStackTrace ();} J"%}t\Q  
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Utility.log(nFileLength); CWQ2iu<_0  
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return nFileLength; k&s7-yY  
} Fd&!-`T?  
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//保存下载信息（文件指针位置） ]Hy PJ  
private void write_nPos() ]/Qy1,  
{ MwqT`;lb  
try{ veg!mY2&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /$,=>  
output.writeInt(nStartPos.length); Z<<gz[$+p  
for(int i=0;i<nStartPos.length;i++) f {Z%:H  
{ ja- ~`  
// output.writeLong(nPos); b_Jq=Gk`  
output.writeLong(fileSplitterFetch.nStartPos); -z$2pXT ^  
output.writeLong(fileSplitterFetch.nEndPos); HbfB[%  
} a BH1J]_  
output.close(); S{T d/1}  
} jY+S,lD  
catch(IOException e){e.printStackTrace ();} yKEFne8^  
catch(Exception e){e.printStackTrace ();} ,D2_Z]  
} gCr|e}w-  
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//读取保存的下载信息（文件指针位置） bK8F |  
private void read_nPos() rOb"S*  
{ :yjK*"T|OD  
try{ F(~_L.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /&as)  
int nCount = input.readInt(); rE `}?d  
nStartPos = new long[nCount]; E0^%|Mh]b  
nEndPos = new long[nCount]; dHF$T33It  
for(int i=0;i<nStartPos.length;i++) cievC,3*  
{ Y*cJ4hQ  
nStartPos = input.readLong(); >-5Gt  
nEndPos = input.readLong(); SuH.lCF-g  
} ?VP!1O=J  
input.close(); / &D$kxz  
} \R\@t]>Y  
catch(IOException e){e.printStackTrace ();} L2.`1Aag  
catch(Exception e){e.printStackTrace ();} .`>
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} Ij}F<ZgZG  
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private void processErrorCode(int nErrorCode) F*JvpI[7n  
{ (2bZ]  
System.err.println("Error Code : " + nErrorCode); !aw#',r8m  
} N^(lUba  
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//停止文件下载 o?mXxL)  
public void siteStop() N46$EsO!h  
{ vd7N&c9  
bStop = true; Gh[`q7B Q  
for(int i=0;i<nStartPos.length;i++) _OU.JrqC  
fileSplitterFetch.splitterStop(); ;i9<y8Dha  
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} ~J>gVg%66  
} =Cy>$/H64  
//负责部分文件的抓取 tK|9qs<%  
**FileSplitterFetch.java 1m<?Q&|m$  
*/ !H|82:`t+  
package NetFox; Ryba[Fz4Di  
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import java.io.*; DxKfWb5 R  
import java.net.*; .d~]e2x  
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public class FileSplitterFetch extends Thread { d9-mWz(V+  
'*N9"C  
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String sURL; //File URL |[owNV>  
long nStartPos; //File Snippet Start Position 7XVzd]jH  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID yI.}3y{^5  
boolean bDownOver = false; //Downing is over nJ
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boolean bStop = false; //Stop identical '`]n_$f'  
FileAccessI fileAccessI = null; //File Access interface H/Ec^Lc+_  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \YlF>{LVe  
{ -M:hlwha  
this.sURL = sURL; q]N?@l]  
this.nStartPos = nStart; }>;ht5/i/  
this.nEndPos = nEnd; wHOlj)CZ  
nThreadID = id; o\]:!#r{T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HLSfoQ&)v  
} juCG?}di;  
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public void run()  H\=LE  
{ i'Y'H
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while(nStartPos < nEndPos && !bStop) cNuHXaWp  
{ k~1j/VHv  
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try{ C'-zh\a  
URL url = new URL(sURL); Cv>yAt.3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3_L1Wm  
httpConnection.setRequestProperty("User-Agent","NetFox"); xz"Z3B  
String sProperty = "bytes="+nStartPos+"-"; ke}Y
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httpConnection.setRequestProperty("RANGE",sProperty); ,ykPQzO  
Utility.log(sProperty); WO.0K5nfk  
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InputStream input = httpConnection.getInputStream(); lk[G;=K:.  
//logResponseHead(httpConnection); B0)`wsb_  
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byte[] b = new byte[1024]; -v;n"Zy1  
int nRead; F<yy>Wf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q}<.x8\  
{ 1iNsX\M  
nStartPos += fileAccessI.write(b,0,nRead); oNuPP5d[]  
//if(nThreadID == 1) \6SMn6a4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6.U"_%  
} )@Zc?Da  
/`+Hwdk  
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Utility.log("Thread " + nThreadID + " is over!"); 8ji^d1G,  
bDownOver = true; v}F4R $  
//nPos = fileAccessI.write (b,0,nRead); 7_Ba3+9jpa  
} *?_qE  
catch(Exception e){e.printStackTrace ();} y@o9~?M  
} QFW0KD`5  
} w0Fwd  
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//打印回应的头信息 r]k*7PK  
public void logResponseHead(HttpURLConnection con) Kajkw>z  
{ y)3~]h\a  
for(int i=1;;i++) 4? m/*VV  
{ 5Noe/6  
String header=con.getHeaderFieldKey(i); ^oQekga\l  
if(header!=null) Dq/3E-y5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8W~lU~-  
Utility.log(header+" : "+con.getHeaderField(header)); O9t=lrYV!  
else N@Xg5huO  
break; DeOXM=&z  
} '8)Wd"[  
} 9?uqQ  
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public void splitterStop() C(-[ Y!  
{ aG
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bStop = true; Q0V^PDF  
} 0jR){G9+  
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} [O^}rUqq  
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/* f%2%T'Q  
**FileAccess.java hzaLx8L  
*//文件访问(定位，写) :3*`IB !  
package NetFox; )fNGB]%  
import java.io.*; q}>M& *  
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public class FileAccessI implements Serializable{ !L4dUMo  
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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 H}vn$$ O  
RandomAccessFile oSavedFile; " Wp   
long nPos; <O;&qT*b  
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public FileAccessI() throws IOException 7egq4gN]2Y  
{ lZ}P{d'f.  
this("",0); Js/N()X  
} 6hZ.{8e0  
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public FileAccessI(String sName,long nPos) throws IOException p` $fTgm  
{ Jf2e<?`  
oSavedFile = new RandomAccessFile(sName,"rw"); mv{<'  
this.nPos = nPos; s~L`53A
 
oSavedFile.seek(nPos); $( S*GF$S  
} .+OB!'dDK^  
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public synchronized int write(byte[] b,int nStart,int nLen) 8Bq-0=E  
{ 8+9\7*  
int n = -1; TZe+<~4*i%  
try{ wY/bA}%  
oSavedFile.write(b,nStart,nLen); JlUb0{8PE  
n = nLen; vyE{WkZxR  
} 5\WUoSgy  
catch(IOException e)
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{ N8VVGPa  
e.printStackTrace (); hje! w`  
} /w0
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return n; 22z1g(;@  
} DacN{r"3  
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} n[|6khOL-  
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/* 6.[)`iF+#  
**SiteInfoBean.java ?H`j>]%&  
*/ 6F(hY !}5  
package NetFox; wZQ)jo7*g  
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public class SiteInfoBean { sdrWOq  
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private String sSiteURL; //Site's URL syRN4  
private String sFilePath; //Saved File's Path iA9 E^  
private String sFileName; //Saved File's Name J smB^  
private int nSplitter; //Count of Splited Downloading File ;`+`#h3-V  
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public SiteInfoBean() _B3zRO  
{//nSplitter的缺省值为5 TKo<~?  
//default value of nSplitter is 5 #ra*f~G  
this("","","",5); i3P9sdTD  
} Hs$'0:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BKay*!'PX  
{ ~ltg  
sSiteURL= sURL; `]jqQr97  
sFilePath = sPath; \%TyrY+`K  
sFileName = sName; \^0!|  
this.nSplitter = nSpiltter; J1X~vQAe  
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} nM8[  
*GJ:+U&m[  
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public String getSSiteURL() U7h(-dV   
{ a~opE!|m  
return sSiteURL; w^Ag]HZN  
} 6Hk="$6K  
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public void setSSiteURL(String value) RkA8  
{ WI&lj<*  
sSiteURL = value; u h)o  
} CW p#^1F  
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public String getSFilePath() FY4T(4#  
{ y^R4I_* z  
return sFilePath; ezUQ> e  
} RYy,wVh}  
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public void setSFilePath(String value) UV@0gdy[  
{ G?xJv`"9iC  
sFilePath = value; [Gtb+'8  
} O,'#C\   
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public String getSFileName() C6]OAUXy:F  
{ $gvr -~  
return sFileName; ?:uNN  
} nQ-mmY>#  
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public void setSFileName(String value) :h*a rT4{  
{ Jzex]_:1~  
sFileName = value; 50$W0L$  
} Q4Q pn  
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public int getNSplitter() 8:dQ._#v  
{ 5FOqv=6S  
return nSplitter; jDX>izg;V  
} -[heV|$;  
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public void setNSplitter(int nCount) Ej"u1F14J  
{ !YE zFU`L  
nSplitter = nCount; 3i=Iu0
 
} WU)Ss`s \  
} gKi{Y1
 
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/* r4Q|5kT*i  
**Utility.java zK;XFN#U^  
*/  e;(  
package NetFox; ?fK1  
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public class Utility { q-_' W,  
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public Utility() 6gU{(H   
{ z7T0u.4Ss  
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} |5MbAqjzC  
N+g@8Q2s;5  
//线程睡眠 6q/?-Qcy  
public static void sleep(int nSecond) :dwt1>  
{ e.vtEQV9  
try{ {vVTv SC  
Thread.sleep(nSecond); z]@6fM[  
} q.V-LXM  
catch(Exception e) wT_h!W  
{ ]Kh2;>= Xj  
e.printStackTrace (); ]l;*$2w)  
} `JURQ:l)3^  
} A)NkT`<)  
'EhBRU%  
//日志 l"pN90B4  
public static void log(String sMsg) i.y)mcB4  
{ vHKlLl>*2  
System.err.println(sMsg); ,o#kRWRG  
} bGmx7qt#  
,r^"#C0J}  
h~}.G{"  
public static void log(int sMsg) A9:NKY{z  
{ iK;opA"  
System.err.println(sMsg); Xm!-~n@-m7  
} k%81f'H  
} NXk!qGV2  
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/* l=m(mf?QBg  
**TestMethod.java ^{yk[tHpS  
*/ g@
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package NetFox; 8Ogv9  
CA s>AXbs  
!CY&{LEYn0  
public class TestMethod { aX6}6zubr  
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public TestMethod() $j
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{ ///xx/weblogic60b2_win.exe nv/[I,nw  
try{ <[~,uR7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F7}-!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iz[gHB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); MgMD\  
fileFetch.start(); lS5ny  
} <i. apBH  
catch(Exception e){e.printStackTrace ();} {S.>B
XX  
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} Ctu?o+^;z  
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public static void main(String[] args) x!<yT?A  
{ |V,<+BEi  
new TestMethod(); t*S." q  
} hGTV;eU  
} *C

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