http断点续传简单实现（java)

/* h*w9{[L  
**SiteFileFetch.java A;AQw  
*/ =NB[jQ :(  
package NetFox; *^>" h@J  
import java.io.*; An2>]\L  
import java.net.*;  Y@,iDQ  
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public class SiteFileFetch extends Thread { @]uqC~a^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "Eh=@?]S_  
long[] nStartPos; //开始位置 ZL|aB886  
long[] nEndPos; //结束位置 8SRR)O[)}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n 0!8)Sth  
long nFileLength; //文件长度 N8A)lYT]_u  
boolean bFirst = true; //是否第一次取文件 IjI'Hx  
boolean bStop = false; //停止标志 Nd8>p.iqO  
File tmpFile; //文件下载的临时信息 8/e-?2l  
DataOutputStream output; //输出到文件的输出流 C'R9Nn'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +n^M+ea;  
public SiteFileFetch(SiteInfoBean bean) throws IOException -()WTdIy  
{ ;m7V]h? R  
siteInfoBean = bean; zt.kNb  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 17hoX4T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]545:)Q1  
if(tmpFile.exists ()) @9/I^Zk  
{ @3`5(xwzm  
bFirst = false; x0j5D  
read_nPos(); c^}G=Z1@  
} O|Uz)Y94  
else y2W+Y
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{ OG$n C  
nStartPos = new long[bean.getNSplitter()]; `[H^`  
nEndPos = new long[bean.getNSplitter()]; \,R;  
} _CD~5EA:  
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} s|C[{n<_  
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public void run() 1UP {j`-K|  
{ i'fw>-0  
//获得文件长度 HZ3;2k  
//分割文件 I`_2Q:r  
//实例FileSplitterFetch 0zW*JJxV  
//启动FileSplitterFetch线程 FjCGD4x1N  
//等待子线程返回 ~5 6&!4  
try{ BU -;P  
if(bFirst) bEcs(Mc~  
{ |[],z 8  
nFileLength = getFileSize(); t/ \S9  
if(nFileLength == -1) WI\a  
{ @$ 7 GrT  
System.err.println("File Length is not known!"); kf@JEcKV  
} UL[,A+X8D  
else if(nFileLength == -2) rrL.Y&DTK  
{ (xgw';g  
System.err.println("File is not access!"); l~Jd>9DwY  
} |WB-Ng  
else luP;P&  
{ U7WYS8  
for(int i=0;i<nStartPos.length;i++) (d4btcg
 
{ xPZ>vCg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V$ZclV2:Ih  
} @c^ Dl  
for(int i=0;i<nEndPos.length-1;i++) #mV2VIX#Jv  
{ AM+5_'S,  
nEndPos = nStartPos[i+1]; m%0-3c(  
} jPSVVOG  
nEndPos[nEndPos.length-1] = nFileLength; ^ ]9K>}  
} Pn!~U] A$%  
} !Cgj >=  
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//启动子线程 xMr,\r'+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "$(+M t^  
for(int i=0;i<nStartPos.length;i++) tWn dAM(U7  
{ !(lcUdBd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y w0,K&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xhP~]akHN7  
nStartPos,nEndPos,i); %`F;i)Zz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ki><~!L  
fileSplitterFetch.start(); X&9:^$m  
} ",,#q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZVgfrvZP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )- W1Wtom  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >!Yuef <P  
nEndPos = " + nFileLength); t5{P'v9J  
// fileSplitterFetch[nPos.length-1].start(); ^;EhKG  
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//等待子线程结束 w(@r-2D"  
//int count = 0; nJe}U#  
//是否结束while循环 6qT@M0)i  
boolean breakWhile = false; N,TV?Q5l7  
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while(!bStop) -'Z Gc8)  
{ %mC@}  
write_nPos(); Om*QN]lGq  
Utility.sleep(500); m?(8T|i  
breakWhile = true; [rx9gOOa&  
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for(int i=0;i<nStartPos.length;i++) t^'nh 1=  
{ 2u$-(JfoS  
if(!fileSplitterFetch.bDownOver) HJ&P[zV^  
{ IHTimT?  
breakWhile = false; `O6#-<>  
break; ]c>@RXY
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} L3{(Bu  
} P}4&J ^  
if(breakWhile) |mtW)  
break; ?L }>9$"  
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//count++; S1$^ _S =  
//if(count>4) l>\EkUT  
// siteStop(); Xmr}$<<=  
} FQ>$Ps*a[  
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System.err.println("文件下载结束！"); 7 z   
} ]({-vG\m  
catch(Exception e){e.printStackTrace ();} SRfh{u  
} QVjHGY*R  
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//获得文件长度 :[<Y#EX.  
public long getFileSize() _s;y0$O  
{ ^8&}Nk[j  
int nFileLength = -1; 0~U0s3  
try{ =%|`gZ  
URL url = new URL(siteInfoBean.getSSiteURL()); wNi%u{T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P|Aac,nE+^  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,g?ny<#o  
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int responseCode=httpConnection.getResponseCode(); ]\yB,  
if(responseCode>=400) \oPe"k=  
{ Qm[((6}  
processErrorCode(responseCode); 9i\}^s2  
return -2; //-2 represent access is error |it*w\+M  
} k*A(7qQA`4  
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String sHeader; h.tj8O1  
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for(int i=1;;i++) oVw4M2!"K  
{ {APfSD_4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U
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//Utility.log(in.readLine()); 4&NB xe  
sHeader=httpConnection.getHeaderFieldKey(i); SLuQv?R}9  
if(sHeader!=null) Qb@j8Xa4[  
{ DAq H  
if(sHeader.equals("Content-Length")) W^elzN(  
{ Q3>qT84  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r^"o!,H9q  
break; :fmV||Q  
} MLr L"I"  
} .g/!u(iy  
else VQ!4( <XD  
break; ^:?z7m  
} No\#N/1@P  
} 9y\nO)\Tv  
catch(IOException e){e.printStackTrace ();} s-*N_Dv  
catch(Exception e){e.printStackTrace ();} }|h-=T '  
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Utility.log(nFileLength); +]t9kr  
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return nFileLength; ,dba:D=l  
} NZ`6iK-V_  
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//保存下载信息（文件指针位置） 0D:uM$ i]  
private void write_nPos() ' Sd&I:
?  
{ I-.?qcy~  
try{ [9?
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output = new DataOutputStream(new FileOutputStream(tmpFile)); yq3"VFh3d  
output.writeInt(nStartPos.length); &\?{%xj  
for(int i=0;i<nStartPos.length;i++) :%Z)u:~':  
{ j,,#B4b  
// output.writeLong(nPos); $.DD^ "9  
output.writeLong(fileSplitterFetch.nStartPos); "~C\Z} ;  
output.writeLong(fileSplitterFetch.nEndPos); BvlY\^  
} 6:r1^q6A9L  
output.close(); /x-tl)(s=  
} ICoZ<;p  
catch(IOException e){e.printStackTrace ();} FlS)m`  
catch(Exception e){e.printStackTrace ();} #oGvxc7  
} -NG9?sI\U  
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//读取保存的下载信息（文件指针位置） K6<1&  
private void read_nPos()
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{ Vfw +m1sS  
try{ f2|On6/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 
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int nCount = input.readInt(); jM@@N.  
nStartPos = new long[nCount]; 43J8PMY  
nEndPos = new long[nCount]; JvUHoc$sI  
for(int i=0;i<nStartPos.length;i++) A&'HlI%J  
{ 9.goO|~B~  
nStartPos = input.readLong(); OQX ek@~2  
nEndPos = input.readLong(); ;+qP
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} N~arxe(K  
input.close(); ,KibP_<%&P  
} \b88=^  
catch(IOException e){e.printStackTrace ();} 8&f"")

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catch(Exception e){e.printStackTrace ();} I|[aa$G  
} ^_ZQf  
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private void processErrorCode(int nErrorCode) H+2J.&Ch  
{ ~pSD|WX  
System.err.println("Error Code : " + nErrorCode); b_Ky@kp  
} f4T-=` SO  
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//停止文件下载 TAJ9Y<  
public void siteStop() 4_I,wG@  
{ Iei4yDv ;  
bStop = true; J&:0ytG  
for(int i=0;i<nStartPos.length;i++) +TX p;6pA  
fileSplitterFetch.splitterStop(); !xqG-rd '  
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} <db/. A3  
} t_VHw'~"  
//负责部分文件的抓取 fW}H##b  
**FileSplitterFetch.java ?R{?
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*/ a m 
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package NetFox; $BBfsaJPT  
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import java.io.*; <,hBoHZSL  
import java.net.*; ?h3Ow`1G  
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public class FileSplitterFetch extends Thread { YV940A-n  
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String sURL; //File URL Gf]s?J^a  
long nStartPos; //File Snippet Start Position Pd;ClMa%  
long nEndPos; //File Snippet End Position |f}NO~CA  
int nThreadID; //Thread's ID &lS0"`J=  
boolean bDownOver = false; //Downing is over tx1jBh:e=  
boolean bStop = false; //Stop identical z|?R=;,u`  
FileAccessI fileAccessI = null; //File Access interface I2DmM"-|  
7VXeu+-P  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !^fJAtCN]  
{ ipp_?5TL  
this.sURL = sURL; pz IMj_  
this.nStartPos = nStart; C;) xjZiR  
this.nEndPos = nEnd; 0amz#VIB<u  
nThreadID = id; rlIEch^wZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 udZ: OU<  
} E$>e< T  
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public void run() _Usg`ax-  
{ 85{vz|(':  
while(nStartPos < nEndPos && !bStop) )x7hhEk=^  
{ piFQ
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try{ WO9/rF_  
URL url = new URL(sURL); E\S&} K,s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NFc8"7Mz}  
httpConnection.setRequestProperty("User-Agent","NetFox"); r*wKYb  
String sProperty = "bytes="+nStartPos+"-"; !~l%6Z5  
httpConnection.setRequestProperty("RANGE",sProperty); z.^ )r  
Utility.log(sProperty); ~QcKW<bz  
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InputStream input = httpConnection.getInputStream(); 0cUt"(]  
//logResponseHead(httpConnection); ]c2| m}I{:  
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byte[] b = new byte[1024]; ,GnU]f  
int nRead; 3pW MS&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;/T-rVND  
{ UYOn p7R<  
nStartPos += fileAccessI.write(b,0,nRead); 2oG|l!C  
//if(nThreadID == 1) hFfaaB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); se HbwO3 b  
} *KH@u  
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Utility.log("Thread " + nThreadID + " is over!"); [Mc5N  
bDownOver = true; =+S3S{\CK  
//nPos = fileAccessI.write (b,0,nRead); 9nS!  
} am+mXb  
catch(Exception e){e.printStackTrace ();} Jk`)`94I  
} D#1~]d  
} m@u`$rOh  
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D])YP0|}  
//打印回应的头信息 ld}$Tsy0  
public void logResponseHead(HttpURLConnection con) (x0*(*A}  
{ 8I0Tu  
for(int i=1;;i++) gCr|e}w-  
{ E2H
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String header=con.getHeaderFieldKey(i); O:tX0<6  
if(header!=null) ko2j|*D6@~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 89#0vG7m  
Utility.log(header+" : "+con.getHeaderField(header)); 6n\z53Mk  
else /JubiLEK  
break; fR%1FXpK&  
} Wd56B+  
} SuH.lCF-g  
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public void splitterStop() G? gXK W  
{ ~!:Sp_y  
bStop = true; ~uR6z//%  
} 56SS >b  
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} L\wpS1L(  
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/* "E)++\JL  
**FileAccess.java AYA&&b  
*//文件访问(定位，写) Oqpl2Y"/  
package NetFox; A9l})_~i  
import java.io.*; \y H3Y  
' q<EZ{  
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public class FileAccessI implements Serializable{ G9n /S=R?  
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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 SAG`^
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RandomAccessFile oSavedFile; (21 W6  
long nPos; tdnXPxn[  
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public FileAccessI() throws IOException Ly)(_Tp@+  
{ nJ
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this("",0); Z#F,y)YiO  
} (!VMnLlXRK  
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public FileAccessI(String sName,long nPos) throws IOException }>;ht5/i/  
{ ..q63dr  
oSavedFile = new RandomAccessFile(sName,"rw"); 6/mkJj+"  
this.nPos = nPos; <cDKGd  
oSavedFile.seek(nPos); B]|6`UfB  
} 6i]
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public synchronized int write(byte[] b,int nStart,int nLen) oF;%^XFp  
{ fys5-1@-p  
int n = -1; xi?P(sA  
try{ r}oURy,5  
oSavedFile.write(b,nStart,nLen); WjY{rM,K  
n = nLen; bvipbf[m<  
} 0Oc}rRH(C  
catch(IOException e) ~IlF*Zz#}6  
{ _oJ2]f6KX  
e.printStackTrace (); F<yy>Wf  
} }{&ln  
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return n; iY ^{wi~?  
} =de<WoKnu2  
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^  
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} (VYR
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/* ]{IR&{EI-  
**SiteInfoBean.java :cc[Jco@w  
*/ zBk_-'z  
package NetFox; ~~C6)N~1  
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public class SiteInfoBean { ${hyNt  
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private String sSiteURL; //Site's URL L]k*QIn:h  
private String sFilePath; //Saved File's Path gB]C&Q  
private String sFileName; //Saved File's Name RVc)") hQj  
private int nSplitter; //Count of Splited Downloading File m_Mwg  
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public SiteInfoBean() 9v~1We;{$  
{//nSplitter的缺省值为5 [O=W>l  
//default value of nSplitter is 5 r_Lu~y|  
this("","","",5); Ur^YG4(  
} KHvIN}V5?3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Dba+z-3Nzy  
{ AK6=Ydu  
sSiteURL= sURL; hIR
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sFilePath = sPath; @. "
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sFileName = sName; 7egq4gN]2Y  
this.nSplitter = nSpiltter; Q"A_bdg5  
,# ]+HS^B  
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} X$/E>I  
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public String getSSiteURL() 'r~8  
{ P"b8!k?  
return sSiteURL; C?,*U  
} !6lOIgn  
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public void setSSiteURL(String value) R6 ;jY/*#  
{ }@wVW))6$  
sSiteURL = value; k!&:(]  
} &1P(O\d  
-!l^]MU  

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public String getSFilePath() OZ=Cp$  
{ (i\)|c/a7  
return sFilePath; $|k%@Q>  
} sMP:sCRC  
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public void setSFilePath(String value) )T9~8p.  
{ [P{a_(
 
sFilePath = value; rkq#7  
} <KX&zi<L)  
teAukE=}  
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public String getSFileName() n&$/Q$d&  
{ uxb:^d?D!  
return sFileName; >VP5vkv=  
} #ra*f~G  
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public void setSFileName(String value) `Ug tvo  
{ h/HHKn  
sFileName = value; "TNVD"RLY  
} myIe_k,F  
CcY7$D  
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public int getNSplitter() WqE '(  
{ f0DK>L  
return nSplitter; ^&Q<tN7  
} B$?^wo  
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public void setNSplitter(int nCount) s1bU  
{ L=]p_2+  
nSplitter = nCount; u h)o  
} O%&cE*eX  
} 6]n/+[ ks  
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/* D:9 2\l  
**Utility.java Juu+vMn1  
*/ G?xJv`"9iC  
package NetFox; Om9jtWk  
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public class Utility { y
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:$%>4+l  
public Utility() J+ts  
{ t7*#[x)a  
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I 8zG~L%"  
} jn=:G+0  
g`[$XiR  
//线程睡眠 o\!qcoE2W  
public static void sleep(int nSecond) rt}^4IqL  
{ 5JSrrpGr
 
try{ %\6Q .V#s  
Thread.sleep(nSecond); Ej"u1F14J  
} h/m6)m.D  
catch(Exception e) !%[S49s  
{ #|f~s  
e.printStackTrace (); 6Hf,6>  
} BJy;-(JP  
} :NE/Ddgc'  
;gB`YNL  
//日志 KY.ZT2k  
public static void log(String sMsg) ,Eu?JH&}u  
{ (MLhaux-  
System.err.println(sMsg); 7lA:)a_!]  
} m3 -9b"  
/X#z*GX  
~x]9SXD%  
public static void log(int sMsg) G;1?<3
 
{ 7x k|+!  
System.err.println(sMsg); ^+/kr/  
} [Qj;/  
} @Rq}nq=k  
nc?B6IV  
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/* $[ z y  
**TestMethod.java rRb+_]Lg  
*/ ^3~e/PKM  
package NetFox; | C+o;  
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public class TestMethod { ^%<pJMgdF  
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8@\7&C(g17  
public TestMethod() [hh/1[   
{ ///xx/weblogic60b2_win.exe vHKlLl>*2  
try{ o\=n4;S  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #wR;|pN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D4u%6R|F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q
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fileFetch.start(); TqAPAHg  
} N4!<Xj  
catch(Exception e){e.printStackTrace ();} z`3( ,V  
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} I4c!m_sr  
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public static void main(String[] args) 27Emm
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{ md Gwh7/3  
new TestMethod(); EbQa?  
} EqB)sK/3  
} +j/~Af p5f  
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