http断点续传简单实现（java)

/* GVp2|\-L  
**SiteFileFetch.java TNV#   
*/ Si]8*>}-B  
package NetFox; Fu(I<o+T-  
import java.io.*; asI:J/%+2  
import java.net.*; u37@9  
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public class SiteFileFetch extends Thread { wLC|mByq  
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SiteInfoBean siteInfoBean = null; //文件信息Bean @[S\ FjI  
long[] nStartPos; //开始位置 N*My2t_+E  
long[] nEndPos; //结束位置 IXf@YV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KyAQzN9  
long nFileLength; //文件长度 /Et
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boolean bFirst = true; //是否第一次取文件 #3u;Ox  
boolean bStop = false; //停止标志 o^},L?  
File tmpFile; //文件下载的临时信息 w]\O3'0Js  
DataOutputStream output; //输出到文件的输出流 |L7 `7!Z  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NPEs0|  
public SiteFileFetch(SiteInfoBean bean) throws IOException vV|u+v{  
{ 9oY%v7  
siteInfoBean = bean; h7 >  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "Gxf[6B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q$s0
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if(tmpFile.exists ()) U:xr['  
{ lG;sDR|)(  
bFirst = false; nMXSpX>!|  
read_nPos(); [ua{qJ9  
} D{/GjFO  
else C(_xqn  
{ u*&wMR>Crf  
nStartPos = new long[bean.getNSplitter()]; 7{XI^I:n  
nEndPos = new long[bean.getNSplitter()]; f?_H02j`/E  
} nlK"2/W  
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} Wel-a< e  
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public void run() q=E<y  
{ a3037~X  
//获得文件长度 \?)<==^  
//分割文件 Pd\S{ Y~wk  
//实例FileSplitterFetch F\&R nDJ  
//启动FileSplitterFetch线程 &}%3yrU  
//等待子线程返回 B}YB%P_CWs  
try{ aBT|Q@Y.  
if(bFirst) \=4[v-3H  
{ BfIGw  
nFileLength = getFileSize(); -2mm 5E~N  
if(nFileLength == -1) q!9SANTx  
{ Ry0n_J:7  
System.err.println("File Length is not known!"); !["WnF{5eC  
} H{`S/>)[   
else if(nFileLength == -2) D'#Wc#b  
{ 5+'1 :Sa(i  
System.err.println("File is not access!"); m Fwx},dl  
} qv=i eU  
else QVI4<Rxg  
{ $GYcZN&  
for(int i=0;i<nStartPos.length;i++) ep Eg6   
{ {KE858  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $AUC#<*C  
} _bn*B$  
for(int i=0;i<nEndPos.length-1;i++) N%:QaCZKw  
{ Ylll4w62N  
nEndPos = nStartPos[i+1]; 9=~"^dp54%  
} Y_)!U`>N?  
nEndPos[nEndPos.length-1] = nFileLength; /N7j5v(  
} *K'(t  
} `$7j:<c=  
x\GCsVy  
f 6Bx>lh  
//启动子线程 InM
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +hRAU@RA  
for(int i=0;i<nStartPos.length;i++) X4lz?Y:*  
{ TP[<u-@G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Uo<d]4p $  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gEMxK2MNXj  
nStartPos,nEndPos,i); :03w k)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^N _kiSr  
fileSplitterFetch.start(); noC]&4b  
} E=3<F_3W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YUat}-S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |#Bz&T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G@ XKE17  
nEndPos = " + nFileLength); _K3?0<=4  
// fileSplitterFetch[nPos.length-1].start(); ,n}X,#]  
tpO%)*  
OW
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//等待子线程结束 gh|TlvnA  
//int count = 0; 3G dWq*  
//是否结束while循环 W
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boolean breakWhile = false; fa;\4#  
t{| KL<d]  
7/w)^&8  
while(!bStop) v{"$:Z ow  
{ [84ss;.$  
write_nPos(); r*fZS$e  
Utility.sleep(500); kqYWa`eE  
breakWhile = true; BYFvf(>  
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for(int i=0;i<nStartPos.length;i++) (PE x<r1   
{ 8hZ+[E}  
if(!fileSplitterFetch.bDownOver) @-Tt<pl'L  
{ 8<z+hWX=4  
breakWhile = false; 1~Zmc1]  
break; z;JyHC)  
} UmcPpZ  
} '.r_6X$7Jt  
if(breakWhile) <spVUp  
break; fwK5p?Xhm  
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D |kdk;Xv  
//count++; EaaQC]/OX5  
//if(count>4) `+[Ct08  
// siteStop(); Z1 %"w*U  
} gE]6]L  
kHygif !I4  
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System.err.println("文件下载结束！");  eme7y  
} nj$TdwZbK  
catch(Exception e){e.printStackTrace ();} Kur3Gf X  
} :*Lr(-N-  
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//获得文件长度 :rd{y`59>&  
public long getFileSize() D^8]+2r  
{ ^<49NUB>  
int nFileLength = -1; FD:3;nUY7  
try{ GX?R# cf  
URL url = new URL(siteInfoBean.getSSiteURL()); ZxLdh8v.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (3~h)vaJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); jR[VPm=  
82l$]W4  
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int responseCode=httpConnection.getResponseCode(); \9j +ejGf  
if(responseCode>=400) (Ild>_Tdb`  
{ 2
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processErrorCode(responseCode); f]%:.N~1w  
return -2; //-2 represent access is error =jXBF.  
} #@FMH*?xX6  
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String sHeader; LK\L}<;1V  
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for(int i=1;;i++) B;x5os  
{ pURtk-Fr2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WxLbf+0o  
//Utility.log(in.readLine()); Od_xH
 
sHeader=httpConnection.getHeaderFieldKey(i); ""$vaqt  
if(sHeader!=null) oGt,^!V1  
{ c\A 4-08  
if(sHeader.equals("Content-Length")) \PReQ|[ah  
{ +~xY}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'u@,,FFz[K  
break; K#Ia19au5  
} >T84NFdz+  
} Buc{dcL/  
else JBqL0H  
break; U'~M(9uv:  
} c12mT(+-  
} !r\u,l^
  
catch(IOException e){e.printStackTrace ();} >
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catch(Exception e){e.printStackTrace ();} >7g #e,d  
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Utility.log(nFileLength); DO*rVs3'p[  
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return nFileLength; tofX.oi+C$  
} 8XfhXm>~  
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//保存下载信息（文件指针位置） 0O>T{<
 
private void write_nPos() Qe,jK{Y< -  
{ "x1?T+j4  
try{ Me;XG?`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 75v7w  
output.writeInt(nStartPos.length); N+lhztYQ?  
for(int i=0;i<nStartPos.length;i++) DVJuX~'|!  
{ gq%U5J"x;J  
// output.writeLong(nPos); ^wass_8  
output.writeLong(fileSplitterFetch.nStartPos); qwhDv+o  
output.writeLong(fileSplitterFetch.nEndPos); mVXwU](N  
} R+sv?4k  
output.close(); }%75Wety  
} z)%Ke~)<\@  
catch(IOException e){e.printStackTrace ();} mD5Vsy{Pb  
catch(Exception e){e.printStackTrace ();} ql/K$#u  
} "L4ZE4|)  
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//读取保存的下载信息（文件指针位置） z}BuR*WSY{  
private void read_nPos() F\
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{ Z
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try{ Vh?5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SfSWjq  
int nCount = input.readInt(); L"8Z5VHA&&  
nStartPos = new long[nCount]; hTc :'vq  
nEndPos = new long[nCount]; vVhSl$mW  
for(int i=0;i<nStartPos.length;i++) mzO5&h7  
{ @`mr|-Rp@  
nStartPos = input.readLong(); J]W? Vvv  
nEndPos = input.readLong(); xe"A;6H  
} L;\f^v(  
input.close(); ]ZR}Pm/CA  
} v[~~q  
catch(IOException e){e.printStackTrace ();} U8S<wf&  
catch(Exception e){e.printStackTrace ();} t $m:  
} lvOM1I  
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private void processErrorCode(int nErrorCode) &?@gCVNO,  
{ *epK17i=  
System.err.println("Error Code : " + nErrorCode); LbkQuq/d  
} U| T}0  
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wY]ejK$0R  
//停止文件下载 `\beQ(g  
public void siteStop() -e\OF3Td  
{ ]FNe&o1zX  
bStop = true;  o,rK8x  
for(int i=0;i<nStartPos.length;i++) <=~*`eWV  
fileSplitterFetch.splitterStop(); t/lQSUip  
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} G#L6;  
} 63`5A3rii  
//负责部分文件的抓取 rF$S  
**FileSplitterFetch.java Aflf]G1  
*/ y@h v#;  
package NetFox; Xv+!)j<  
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import java.io.*; A(9$!%#+L  
import java.net.*; _RNP_$a  
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public class FileSplitterFetch extends Thread { zr ~4@JTS  
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String sURL; //File URL L)i6UAo  
long nStartPos; //File Snippet Start Position 9=J 3T66U  
long nEndPos; //File Snippet End Position rR4?*90vjj  
int nThreadID; //Thread's ID /2Z7  
boolean bDownOver = false; //Downing is over a|5<L  
boolean bStop = false; //Stop identical O]XgA0]  
FileAccessI fileAccessI = null; //File Access interface y*Gq VA[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d};[^q6X  
{ 9ec>#Vxx  
this.sURL = sURL; )gx*;z@  
this.nStartPos = nStart; t*`G@Nj  
this.nEndPos = nEnd; Z,-J tl  
nThreadID = id; UGxF}Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 EK
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} ;Kh[6{W  
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public void run()  Spw^h=o  
{ DoNN
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while(nStartPos < nEndPos && !bStop) HJ!!"  
{ 2eRv{_  
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de9e7.(2  
try{ }U
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URL url = new URL(sURL); \maj5VlJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x6Tpt^N}  
httpConnection.setRequestProperty("User-Agent","NetFox"); HqI[]T@  
String sProperty = "bytes="+nStartPos+"-"; Y=i_2R2e2  
httpConnection.setRequestProperty("RANGE",sProperty); S\ K[l/  
Utility.log(sProperty); z%]3`_I  
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InputStream input = httpConnection.getInputStream(); RT2&^9-  
//logResponseHead(httpConnection); - i{1h"  
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byte[] b = new byte[1024]; 6o^O%:0g  
int nRead; v5I5tzt*%H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L*P*^I^1  
{ )+"(7U<  
nStartPos += fileAccessI.write(b,0,nRead); NA YwuE-`  
//if(nThreadID == 1) >_#A*B|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]D^zTl3=q  
} mqBX1D`e2  
Bw<$fT`  
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Utility.log("Thread " + nThreadID + " is over!"); /GO((v+J  
bDownOver = true; qP+%ui5xR  
//nPos = fileAccessI.write (b,0,nRead); =y^g*9}_  
} S/yBr`  
catch(Exception e){e.printStackTrace ();} +O1=Ao  
} #4AqWyp#f  
} ivSpi?   
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//打印回应的头信息 AHT(Z~C  
public void logResponseHead(HttpURLConnection con) b%X<'8z9Z  
{ #bb$Icmtk  
for(int i=1;;i++) rW)}$|-Z  
{ KhPDXY]!  
String header=con.getHeaderFieldKey(i); %+dRjG~TB  
if(header!=null) 6|Crc$4l  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "Z"`X3,-z  
Utility.log(header+" : "+con.getHeaderField(header));  "2}n(8  
else Q@s G6iz  
break; )LL.fPic  
} ;`
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} ?U,XyxN  
[
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public void splitterStop() tbB.n  
{ YCBUc<)  
bStop = true; >qdRqy)DC  
} r2&/Ii+  
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} 3P
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/* InG<B,/
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**FileAccess.java ^Uldyv/  
*//文件访问(定位，写) 6a6N$v"  
package NetFox; ?YM0VB,y  
import java.io.*; g:>dF#  
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public class FileAccessI implements Serializable{ =/N0^  
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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 YY$O"!."
 
RandomAccessFile oSavedFile; hw&~OJeo  
long nPos; yiczRex%rq  
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} ejc  
public FileAccessI() throws IOException af/;Dr@  
{ ?nozB|*>ut  
this("",0); !_:|mu'  
} +s5Yg,4*  
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public FileAccessI(String sName,long nPos) throws IOException -<5H8P-  
{ HF%)ip+  
oSavedFile = new RandomAccessFile(sName,"rw"); 68!=`49r>  
this.nPos = nPos; Z15b'^)?9  
oSavedFile.seek(nPos); &&n-$WEl  
} M5B?`mTl  
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public synchronized int write(byte[] b,int nStart,int nLen) )eWg2w]  
{ t2z@"e   
int n = -1; ":^cb =  
try{ ^^(4xHN  
oSavedFile.write(b,nStart,nLen); Xx=.;FYk  
n = nLen; GnW_^$Fs  
} -KCQ!0\F  
catch(IOException e) QsPL^ Ny  
{ 4!<[5+.  
e.printStackTrace (); Oc^bbC  
} 4Bq
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return n; MtK5>mhZI`  
} -MeO|HWm  
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} 9/50+2F  
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/* yl~h `b4  
**SiteInfoBean.java $g)X,iQu  
*/ qgsKbsl  
package NetFox; 4N{^niq7  
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}MV=t7x9+  
public class SiteInfoBean { T8J[B( )L  
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private String sSiteURL; //Site's URL z,=k F I  
private String sFilePath; //Saved File's Path .JL?RH2@8  
private String sFileName; //Saved File's Name RLbxNn  
private int nSplitter; //Count of Splited Downloading File 2;=xHt  
<7sGA{  
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public SiteInfoBean() nK|WzUtp  
{//nSplitter的缺省值为5 ZIM 5$JdCv  
//default value of nSplitter is 5 ?!kPW^gD  
this("","","",5); eMDraJv@  
} vh^,8pPy  
{KalVZX2R  
fwi(qx1=}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u:D,\`;)  
{ J;7O`5J  
sSiteURL= sURL; mGqT_   
sFilePath = sPath; fRd^@@,[  
sFileName = sName; v/WvT!6V`  
this.nSplitter = nSpiltter; Gd%E337d  
nc.X+dx:  
_8"%nV  
} /0qLMlL$  
sYb(g'W*'  
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public String getSSiteURL() (lVHKg&U[  
{ !5K9L(gqb  
return sSiteURL; 9;u&,R  
} 5m&Zq_Qe  
S&YC"  
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public void setSSiteURL(String value) ]\5?E }kd  
{ r.b!3CoQ  
sSiteURL = value; \`M8Mu9~w  
} $,~D-~-  
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6S#e?>"+  
public String getSFilePath() `aW>h8$I)  
{ 11(:#4Y,  
return sFilePath; %^$7z,>;  
} %0!!998  
td#B$$[  
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public void setSFilePath(String value) N8^AH8l  
{ >ps=z$4j*  
sFilePath = value; 5J4'\M  
} hf~'EdU  
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public String getSFileName() yy%'9E ldc  
{ vC9Qe ]f  
return sFileName; %`[Oz[V  
} OF)G2>t  
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IE|$mUabm  
public void setSFileName(String value) plRBfw>]N  
{ M3U*'A\  
sFileName = value; zFqlTUD`t  
} k_hV.CV  
BB694   
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public int getNSplitter() U- UD27  
{ z_^Vgb]  
return nSplitter; l$~3_3+  
} .A. VOf_  
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public void setNSplitter(int nCount) zMf.  
{ vO#=]J8`  
nSplitter = nCount; L:ox$RU  
} $6evK~  
} M(alc9tn  
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/* [%a
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**Utility.java '518S"T @  
*/ c0
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package NetFox; .BR2pf|R  

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8tR(i[L   
public class Utility { T5g}z5~"  
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public Utility() :QGd/JX$n`  
{ 2|KgRk|!  
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} \CP)$0j-&o  
5*ip
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//线程睡眠 G>/Gw90E  
public static void sleep(int nSecond) -.>b7ui  
{ n\v;4ly^  
try{ \<}
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Thread.sleep(nSecond); v\3:R,|'  
} wE.CZ%f  
catch(Exception e) _R,VNk  
{ 3~I|KF7x  
e.printStackTrace (); M?iU$qI  
} \{HbL,s  
} rff=ud>Jf  
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//日志 >VQP,J{  
public static void log(String sMsg) Kyz!YB  
{ 
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System.err.println(sMsg); \DG 6  
} vU:FDkx*nn  
0UJ%tPS  
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public static void log(int sMsg) -K 7jigac  
{ INi9`M.h  
System.err.println(sMsg); CWP),]#n  
} o=t@83Fh5  
} yMU>vr  
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h%9>js^~  
/* p(jY2&g  
**TestMethod.java /k$h2,O"*  
*/ 0]3 ,0s $}  
package NetFox; hV(>}hb  
WF)(Q~op0U  
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public class TestMethod { yqaLqZ$  
lEcZ/  
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public TestMethod() 1S&GhJ<wJ  
{ ///xx/weblogic60b2_win.exe '
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try{ c>_tV3TDA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [Eeanl&x>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ewo]-BQS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i++a^f  
fileFetch.start(); )w?DB@Tx  
} ,buSU~c_Q  
catch(Exception e){e.printStackTrace ();} S(B$[
)(  
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#GDnV/0)  
} #41xzN  
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@/MI Oxg[  
public static void main(String[] args) /6=IL  
{ m*Zq3j  
new TestMethod(); n~1F[ *  
} 03ol6y )C  
} #ujry.m  
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