http断点续传简单实现（java)

/* jQz^)8)B  
**SiteFileFetch.java g3vbskY|  
*/ `ba<eT':  
package NetFox; >op/<?<  
import java.io.*; NR&a er  
import java.net.*; X`v6gv5qj  
(/&ht-~EL  
@o@SU"[?_  
public class SiteFileFetch extends Thread { SK/}bZ;f  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -KbO[b\V  
long[] nStartPos; //开始位置 8Dxg6>  
long[] nEndPos; //结束位置 [Z'4YXS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2>x[
_  
long nFileLength; //文件长度 /^{Q(R(X<  
boolean bFirst = true; //是否第一次取文件 *a_QuEw_k  
boolean bStop = false; //停止标志 .'+JA:3R  
File tmpFile; //文件下载的临时信息 b)X
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DataOutputStream output; //输出到文件的输出流 ZA_~o#0%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >>R)?24,<  
public SiteFileFetch(SiteInfoBean bean) throws IOException  ;1,#rTs  
{ ZFX}=?+  
siteInfoBean = bean; :+^`VLIf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WH $*\IGJL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *x#5S.i1  
if(tmpFile.exists ()) ?OO
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{ `ALQSo~l  
bFirst = false; u0+<[Ia'q  
read_nPos(); 2"xhFxoD7  
} _6nza)OFH  
else 
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{ hI<$lEB  
nStartPos = new long[bean.getNSplitter()]; c&RiUU7  
nEndPos = new long[bean.getNSplitter()]; R 'mlKe x  
} RvVF^~u  
@*T8>  
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} aeLIs SEx  
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public void run() s5d[sx  
{ 9%P$e=Ui#  
//获得文件长度 '+^XL6$L  
//分割文件 -Vg0J6x  
//实例FileSplitterFetch UU =,Brb  
//启动FileSplitterFetch线程 pek5P4W_  
//等待子线程返回 sh<JB`^$(?  
try{ 8p~[8}  
if(bFirst) tnmz5Q  
{ ac4dIW{$3  
nFileLength = getFileSize(); y(K:,CI  
if(nFileLength == -1) b$Bq#vdg:  
{ <C*%N;F5R  
System.err.println("File Length is not known!"); P!~&Ei  
} 2)^T[zHe  
else if(nFileLength == -2) [S`Fm>,  
{ h2]GV-  
System.err.println("File is not access!"); 
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} 7x |Pgu(  
else P/9|mYmsq  
{ !G~\9  
for(int i=0;i<nStartPos.length;i++) {\!@k\__  
{ ol4!#4Y&{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oB}rd9  
} \H
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for(int i=0;i<nEndPos.length-1;i++) G!ryW4  
{ zgpvI~Ck  
nEndPos = nStartPos[i+1]; ~]K<Vh`  
} 37,)/8]lG  
nEndPos[nEndPos.length-1] = nFileLength; /z,+W9`  
} oP<E)  
} eY$Q}BcW  
0ipYXbC  
<_Po/a!c3  
//启动子线程 W.b?~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U./1OZ&  
for(int i=0;i<nStartPos.length;i++) %eqL)pC]  
{ z?_5fte`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .Wci@5:3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kObgo
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nStartPos,nEndPos,i); b9Ix*
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5adB5)`  
fileSplitterFetch.start(); 1Yv#4t  
} _{?/4ZhA\+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), obIYC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h@?BA<'S  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RE:$c!E!  
nEndPos = " + nFileLength); Riz!HtyR  
// fileSplitterFetch[nPos.length-1].start(); &4l>_  
9=^4p=1J  
.l&<-l;UQ  
//等待子线程结束 </d&bS  
//int count = 0; Rh#TR"  
//是否结束while循环 EabZ7zFoN  
boolean breakWhile = false; ~rU{Q>c  
(svd~he2  
Y{#m=-h  
while(!bStop) nR~L$Wu5_a  
{ (hX}O>  
write_nPos(); & 5YI!; q,  
Utility.sleep(500); al\ R(\p|  
breakWhile = true; cvf#^Cu   
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ep"54o5=d  
for(int i=0;i<nStartPos.length;i++) C,m o4,Q  
{ 4q5bW+$Xj  
if(!fileSplitterFetch.bDownOver) ?l<u%o  
{ n
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breakWhile = false;
hG!"e4  
break; ((%g\&D  
} ^t\AB)(8  
} rRZ ,X%  
if(breakWhile) sh"\ kk9  
break; 7e-l`]  
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mM7S9^<UH  
//count++; !M&B=vk4  
//if(count>4) G(~"Zt}?  
// siteStop(); (yel  
} Ea*Jl<  
V qW(S1w  
GzUgzj|BN~  
System.err.println("文件下载结束！"); 3l@={Ts  
} 0zAj.iG  
catch(Exception e){e.printStackTrace ();} L);kwx7{LW  
} /TgG^|  
.sDVBT'%  
9f4#b8  
//获得文件长度 ~?{"H<  
public long getFileSize() B/CP/Pfb  
{ ;2;Kq)j_=  
int nFileLength = -1; ' RjFWHAp  
try{ <4Jo1  
URL url = new URL(siteInfoBean.getSSiteURL()); 8BZDaiE"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S|%f<zAtJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); "syf@[tz7  
/\KB*dX  
MW+]w~7_Q  
int responseCode=httpConnection.getResponseCode(); b|*A%?m  
if(responseCode>=400) |3MqAvPJ  
{ i.Qy0  
processErrorCode(responseCode); ` 0k  
return -2; //-2 represent access is error LPk85E  
} \TrhJ  
~WJEH#  
B/Lx,

 
String sHeader; _6 ~/`_(KP  
vxo iPqo  
/*lSpsBn  
for(int i=1;;i++) &6E^<v?]  
{ Gu:aSb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s3G3_&  
//Utility.log(in.readLine()); Q[y75 [  
sHeader=httpConnection.getHeaderFieldKey(i); g9;}?h  
if(sHeader!=null) }_L@CpG  
{ v:<UbuJw  
if(sHeader.equals("Content-Length")) KPUc+`cN%  
{ &k?Mt#J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <c{RY.1[  
break; -_ [Z5%B  
} #$Z|)i]w  
} 94F9f^ L  
else j%KLp4J/e  
break; SA|f1R2uS  
} -<i&`*zG  
} fV_(P_C  
catch(IOException e){e.printStackTrace ();} , c/\'k\K)  
catch(Exception e){e.printStackTrace ();} _Ucj)Ud k  
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Utility.log(nFileLength); 9frS!AQ  
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return nFileLength; q7wd96G:  
} Tp`by 1s  
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Au"[2cG  
//保存下载信息（文件指针位置） -iS\3P.  
private void write_nPos() u[^(s_  
{ ?iUAzM8  
try{ Y2w 9]:J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M*E4:A9_M  
output.writeInt(nStartPos.length); ZSMOq4Y 9  
for(int i=0;i<nStartPos.length;i++) #oi4!%*M  
{ fdCsn:  
// output.writeLong(nPos); .c+RFX@0  
output.writeLong(fileSplitterFetch.nStartPos); LeY\{w  
output.writeLong(fileSplitterFetch.nEndPos); HT5G HkT  
} ])a?ri  
output.close(); ]RQQg,|D  
} A[ZJS  
catch(IOException e){e.printStackTrace ();} _#e
='~;  
catch(Exception e){e.printStackTrace ();} bI=\n)sEz  
} z1F[okLA  
-rlxxLT+  
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//读取保存的下载信息（文件指针位置） s&M6DFlA  
private void read_nPos() Q/=L(_1l  
{ pP)0 l  
try{ /H,!7!6>?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j+J)S1  
int nCount = input.readInt(); Zi2NgVF  
nStartPos = new long[nCount]; C 9,p-  
nEndPos = new long[nCount];  vu YH+  
for(int i=0;i<nStartPos.length;i++) t4UKG&[a  
{ iR(A^  
nStartPos = input.readLong(); {`~{%2ayq7  
nEndPos = input.readLong(); ts%@1Y?  
} S0g5Ym ia  
input.close(); Ps.O.2Z5ZB  
} uyxU>yHV<g  
catch(IOException e){e.printStackTrace ();} 4fZ$&)0&  
catch(Exception e){e.printStackTrace ();} yc4mWB~gyU  
} rG
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private void processErrorCode(int nErrorCode) yGH'|`  
{ ZqkP# ]+Y'  
System.err.println("Error Code : " + nErrorCode); JQE^ bcr  
} .7Ys@;>B  
@=b0>^\m  
As1Er[>  
//停止文件下载 #* 
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public void siteStop() )AqM?FE4R  
{
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bStop = true; r&xqsZ%R  
for(int i=0;i<nStartPos.length;i++) #v')iR"  
fileSplitterFetch.splitterStop(); {`KgyCW:  
pR&cdORsP  
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} <Ky\^  
} s+tS4E?  
//负责部分文件的抓取 I1&Z@[  
**FileSplitterFetch.java <k5FlvE2  
*/ $ZXy&?4  
package NetFox; _W]2~9  
AzN.vA)q  
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import java.io.*; bu%@1:l  
import java.net.*; )Bl% {C  
(Y'rEc#H&z  
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public class FileSplitterFetch extends Thread { [t<^WmgtxL  
#'^p-Jdm  
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String sURL; //File URL Q9 kKk  
long nStartPos; //File Snippet Start Position ^;NM'Z  
long nEndPos; //File Snippet End Position 1
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int nThreadID; //Thread's ID ;MCv  
boolean bDownOver = false; //Downing is over dj?.Hc7od  
boolean bStop = false; //Stop identical u-pE ;|  
FileAccessI fileAccessI = null; //File Access interface _w^p~To^  
C\.?3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5gGYG]*l  
{ v.cB3/$z  
this.sURL = sURL; Nb#E+\q  
this.nStartPos = nStart; c"H4/,F  
this.nEndPos = nEnd; GfJm&'U&  
nThreadID = id; U-3KuR+0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &EXql']  
} .pi#Z/v  
lV`y6{o#T  
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public void run() 2j4VW0:  
{ X||oiqbY  
while(nStartPos < nEndPos && !bStop) v=i[s  
{ .+ai dWd  
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/Rx%}~x/m  
try{ cpFw]w%]  
URL url = new URL(sURL); kdQ=%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E^1uZI\z  
httpConnection.setRequestProperty("User-Agent","NetFox"); o,D>7|h  
String sProperty = "bytes="+nStartPos+"-"; {^"c>'R  
httpConnection.setRequestProperty("RANGE",sProperty); }N2T/U  
Utility.log(sProperty); nrwb6wj  
A7+eWg{  
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InputStream input = httpConnection.getInputStream(); 6peO9]Zy  
//logResponseHead(httpConnection); Nh]eZ3O  
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byte[] b = new byte[1024]; OjE wJ$$  
int nRead; !z(POK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bW3e*O$V  
{ Bu>srX9f  
nStartPos += fileAccessI.write(b,0,nRead); )f(#Fn  
//if(nThreadID == 1) ;'}1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4rwfY<G  
} @ L%3}  
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/Kw
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Utility.log("Thread " + nThreadID + " is over!"); &UbNp8h  
bDownOver = true; exTpy  
//nPos = fileAccessI.write (b,0,nRead); eO(VSjo'`  
} @5acTYQ  
catch(Exception e){e.printStackTrace ();} 9!_`HE+(XJ  
} Z\(+a
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} D gY2:&0  

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N:d`L+tcc  
//打印回应的头信息 GLnj& Ve  
public void logResponseHead(HttpURLConnection con) %Ofa
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{ w;}P<K
 
for(int i=1;;i++) ztgSd8GGE  
{ yew9bn0a=  
String header=con.getHeaderFieldKey(i); B\KvKT|\  
if(header!=null) 3UslVj1u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1f~unb\Gg  
Utility.log(header+" : "+con.getHeaderField(header)); o`M7:8G  
else Xy_+L_h^  
break; Z7K;~*  
}  #XQEfa  
} C[& \Xq  
Et
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public void splitterStop() b0PF7PEEQ  
{ {]Nvq9?  
bStop = true; x}AWWmXv  
} y*vs}G'W  
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} 1q}iUnR  
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/* Iy8Ehwejd  
**FileAccess.java \uQ(-ji  
*//文件访问(定位，写) 2e/ JFhA  
package NetFox; DFVaZN?~  
import java.io.*; r*&gd|sn  
-PBm@}*  
yJppPIW^  
public class FileAccessI implements Serializable{ dE
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flVQG@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
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RandomAccessFile oSavedFile; 9Fv1D  
long nPos; XBF#ILJ  
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1  
|@sUN:G4k  
public FileAccessI() throws IOException CS:j->  
{ k9.@S  
this("",0); vCFMO3  
} ^UEI`_HO0  
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6  
public FileAccessI(String sName,long nPos) throws IOException )ra_`Qdcf  
{ Q
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oSavedFile = new RandomAccessFile(sName,"rw"); O:{I9V-=>s  
this.nPos = nPos; k_ UY^vz.  
oSavedFile.seek(nPos); c/^} =t(  
} CDK0 $W n  
|bQKymS  
i!*w'[G->Y  
public synchronized int write(byte[] b,int nStart,int nLen) q}*(rR9/Br  
{ jdK~]eld=  
int n = -1; )c^Rc9e/  
try{ 8uP,#D<wZ  
oSavedFile.write(b,nStart,nLen); GXr9J rs.e  
n = nLen; K#%L6=t$<  
} :p;!\4)u  
catch(IOException e) Ew*_@hVC  
{ Oq7M1|{  
e.printStackTrace (); V\W?@V9g-  
} x{*g^f  
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return n; 4`I2tr  
} FDbb/6ku  
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} Y}&//S A  
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/* f7Y0L8D  
**SiteInfoBean.java ZgP=maQk  
*/ s )POtJ<  
package NetFox; +0{m(
%i  
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public class SiteInfoBean { $]2srRA^A  
Q>8F&p?R  
6}6;%{p"Gu  
private String sSiteURL; //Site's URL
Oh3AbpTT  
private String sFilePath; //Saved File's Path @%d g0F}h  
private String sFileName; //Saved File's Name 'Ybd'|t{}  
private int nSplitter; //Count of Splited Downloading File t3|If@T  
k@L},Td  
/BjM&v(5/  
public SiteInfoBean() lr'h  
{//nSplitter的缺省值为5 !8lG"l|,l  
//default value of nSplitter is 5 cfBq/2I  
this("","","",5); AyKvh  
} 0"
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;R|i@[(J  
J3fk3d`2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) = NHuj.  
{ )_k"_VVcC  
sSiteURL= sURL; IppzQ0'=y1  
sFilePath = sPath; }TY}sr  
sFileName = sName; b#`XmB  
this.nSplitter = nSpiltter; VkTdpeBV  
*1"xvle  
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} S96H`kedZo  
x' >Nz{B,P  
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public String getSSiteURL() BgRfy2:  
{ $&&mGD;?K  
return sSiteURL; {; #u~e(W  
} H=Scrvfx  
}{T9`^V:h  
%sxLxx_x!  
public void setSSiteURL(String value) 7r;7'X5  
{ Jmrs@  
sSiteURL = value; W; yNg  
} "O{j}QwY  
rH*1bDL  
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public String getSFilePath() HK&Ul=^VN|  
{ .B?6  
return sFilePath; 3<}\{jT  
} +Ysm6n '  
5pSo`)  
-AnQZy  
public void setSFilePath(String value) wNo2$>*  
{ Q6blX
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sFilePath = value; -FQ!  
} Ne<={u%  
x\PZ.o  
%LyZaU_sB  
public String getSFileName() OAJGwm  
{ rQmDpoy
=  
return sFileName; FvYgpbEZ  
} |osu4=s|  
XJg8-)T#  
rPhx^ QKH2  
public void setSFileName(String value) PD #9Z=Hj  
{ Dl=9<:6FW  
sFileName = value; Lzmdy0!'  
} Vw-,G7v&E  
,LI$
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tfB}U.  
public int getNSplitter() q^!_jMN5  
{ Y-2IAJHS8  
return nSplitter; 0lpkG ="&r  
} NSe Huk  
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public void setNSplitter(int nCount) pH&*
5=t}  
{ d*qb^C{'"  
nSplitter = nCount; 7~b=G  
} <P
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} #IJm*_J<  
4
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/* /{1sU}k-  
**Utility.java yyPQ^{zD  
*/ A]0A
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package NetFox; 9NF2a)&~  
_{j'` #  
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public class Utility { k+9*7y8w  
/q|r!+  
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public Utility() BF^dNgn+%K  
{
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YnR8mVo5Q  
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} %G0J]QY{(x  
;R5@]Hg6q  
//线程睡眠 ~7p!t%;$  
public static void sleep(int nSecond) G)|Xj70  
{ *y+N-uq  
try{ 1G}f83yR  
Thread.sleep(nSecond); I+oe{#
:.  
} [8C|v61Y  
catch(Exception e) vHJOpQmt~  
{ IRhi1{K$"  
e.printStackTrace (); * 'eE[/K  
} &}'FC7}  
} $>JfLSyC  
5)5$h]Nz>  
//日志 uzoI*aqk-s  
public static void log(String sMsg) J.EBt3  
{ G]]"Jc  
System.err.println(sMsg); n!aA<  
} P"(VRc6x  
45.<eWH$*(  
}Q2v~eD  
public static void log(int sMsg) 7xF)\um  
{ 18^#:
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System.err.println(sMsg); U g:  
} ?F6L,  
} r` B(ucE  
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$e~MKLd  
/* N#``(a  
**TestMethod.java ?rm3Iac0S  
*/ M)F_$ ICE-  
package NetFox; c,2OICj  
tJG+k)EE  
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public class TestMethod { mjQZ"h0  
3S5`I9I  
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public TestMethod() gt(^9t;  
{ ///xx/weblogic60b2_win.exe Pz^C3h$5_  
try{ b(IZ
:ekZ5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O~Jm<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u^O!5 'D%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X-=4Z
9  
fileFetch.start(); 57fl<IM  
} 4wMZNa<S
x  
catch(Exception e){e.printStackTrace ();} y Nc@K|  
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j.&Y'C7GOC  
} o%b6"_~%3  
bm*.*A]  
&6^ --cc  
public static void main(String[] args) oVTXn=cYDp  
{ E^
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new TestMethod(); C'y4 ~7  
} `fuQt4  
} s=e`}4  
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