http断点续传简单实现（java)

/* mzRH:HgN?  
**SiteFileFetch.java VUon>XQ G  
*/ %i6/= 'u  
package NetFox; EtnuEU  
import java.io.*; l{I.l  
import java.net.*; buldA5*!o  
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public class SiteFileFetch extends Thread { CJjT-(a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nx(jYXVT  
long[] nStartPos; //开始位置 KVevvy)W  
long[] nEndPos; //结束位置 o@m7@$7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !K-qoBqKM  
long nFileLength; //文件长度 X$Shi *U[  
boolean bFirst = true; //是否第一次取文件 c|@OD3w2lM  
boolean bStop = false; //停止标志 X?YT>+g;  
File tmpFile; //文件下载的临时信息 % *ng *  
DataOutputStream output; //输出到文件的输出流 'l<Oj&E  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -_xTs(;|8  
public SiteFileFetch(SiteInfoBean bean) throws IOException SP\s{,'F-b  
{ |No9eZ8>.  
siteInfoBean = bean; _?]W%R|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |!81M|H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U2r[.Ru  
if(tmpFile.exists ()) O1@3V/.Wu  
{ riF-9 %i  
bFirst = false; PWeWz(]0Z4  
read_nPos(); j u&v4]  
} <*I*#WI&B  
else A
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{ s{OV-H  
nStartPos = new long[bean.getNSplitter()]; `z`=!1  
nEndPos = new long[bean.getNSplitter()]; `,O"^zR)z  
} VnqcpJ  
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} r0wAh/J|  
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public void run() f9OY>|a9  
{ *kTj,&x[  
//获得文件长度 g*Pn_Yo[.  
//分割文件 EL%Pv1  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 6B]i}nFH{+  
//等待子线程返回  f
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try{ >7)Q
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if(bFirst) 7xM4=\~OG  
{ }~Do0XUH  
nFileLength = getFileSize(); &1Y7Ne
 
if(nFileLength == -1) Pc`)D:/}R  
{ KSJ+3_7]k  
System.err.println("File Length is not known!"); gil:SUW1r  
} .AQTUd(_  
else if(nFileLength == -2) /3.;sS]B  
{ He$v'87]  
System.err.println("File is not access!"); )Y&B63]B  
} RD0*]4>]  
else KMG}VG   
{ 0}YadNb7  
for(int i=0;i<nStartPos.length;i++) +U<.MVOo.  
{ belBdxa{"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); LN)yQ-  
} ]<ay_w;  
for(int i=0;i<nEndPos.length-1;i++) g6xQQ,q=l  
{
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nEndPos = nStartPos[i+1]; R5mb4  
} V6+:g=@U-l  
nEndPos[nEndPos.length-1] = nFileLength; 4jlwu0L+  
} BpGyjoJ2  
} tk)}4b^\%j  
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Sj:c {jyJd  
//启动子线程 5z_Kkf?o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @+_pj.D  
for(int i=0;i<nStartPos.length;i++) xSO5?eR"u  
{ ~[kI![  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d|`8\fq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <Fv7JPN%  
nStartPos,nEndPos,i); zsj]WP6j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z =\ENG|x#  
fileSplitterFetch.start(); 0C3Y =
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} DZ $O%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >s!k"s,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y9 Bk$$#\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xT( pB-R  
nEndPos = " + nFileLength); /XA*:8~!  
// fileSplitterFetch[nPos.length-1].start(); fh66Gn,  
4#t=%}  
AFeFH.G6Jr  
//等待子线程结束 o.Bbb=*rZ  
//int count = 0; D(&Zq7]n  
//是否结束while循环 t8;nP[`  
boolean breakWhile = false; 6-\' *5r  
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while(!bStop) 4/_!F'j  
{ 6JeAXj1g+  
write_nPos(); @HE?G  
Utility.sleep(500); BlM(
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breakWhile = true; U]B-B+
-  
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for(int i=0;i<nStartPos.length;i++) X)=m4\R  
{ pcQkJF  
if(!fileSplitterFetch.bDownOver) jwuSne  
{ {9) 
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breakWhile = false; {%RwZ'  
break; ooCfr?E  
} ~ 588md :  
} * bhb=~  
if(breakWhile) [
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break; ]GsI|se  
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//count++; <u1`o`|-  
//if(count>4) ]3Ibl^J  
// siteStop(); t0?tXe.B  
} E70o nR!i  
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System.err.println("文件下载结束！"); -s7!:MB%g  
} 
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catch(Exception e){e.printStackTrace ();} #;+SAoN  
} 91nB?8ZE6,  
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*y` (^kyS  
//获得文件长度 kw7E<aF!  
public long getFileSize() U'~]^F%eyu  
{ m( %PZ*s  
int nFileLength = -1; (/9erfuJ  
try{ J/,m'wH  
URL url = new URL(siteInfoBean.getSSiteURL()); I>6zX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I47sqz7  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5^CWF|  
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int responseCode=httpConnection.getResponseCode(); k!x`cp  
if(responseCode>=400) aWP9i&  
{ M"msLz  
processErrorCode(responseCode); @3U=kO(^+\  
return -2; //-2 represent access is error 'F:Tv[qx  
} gNkBHwv  
w4&\-S#  
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String sHeader; Z Y5Pf 1  
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for(int i=1;;i++) )jjaY1E  
{ JL<<EPC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A!uiM*"W  
//Utility.log(in.readLine()); zyt >(A1  
sHeader=httpConnection.getHeaderFieldKey(i); jfam/LL{V  
if(sHeader!=null) E}#&2n8Y  
{ hvA|d=R(  
if(sHeader.equals("Content-Length")) YM.  
{ HV]u9nrt#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Kw:%B|B<T  
break; 7xO~v23oe  
} 3;!!`R>e  
} a1QW0d  
else F[)tg#}@G  
break; *_HF%JYMZ  
} q]s_hWWv  
} -3m!970  
catch(IOException e){e.printStackTrace ();} +Z=y/wY  
catch(Exception e){e.printStackTrace ();} ,Vof<,x0  
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Utility.log(nFileLength); 41Ab,  
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return nFileLength; ZG~d<kM&8s  
} 3BF3$_u)o  
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H
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//保存下载信息（文件指针位置） SO<9?uk.  
private void write_nPos() F%O+w;J4  
{ Q|U [|U  
try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ~]n=TEJ>  
output.writeInt(nStartPos.length); H!l9a  
for(int i=0;i<nStartPos.length;i++) wLvM<p7OX  
{ IABF_GwF  
// output.writeLong(nPos); CT'#~~QB  
output.writeLong(fileSplitterFetch.nStartPos); XPnHi@x  
output.writeLong(fileSplitterFetch.nEndPos); !!cN4X  
} [h8macx  
output.close(); eax"AmO  
} HXkXDX9&'.  
catch(IOException e){e.printStackTrace ();} ,rNud]NM8  
catch(Exception e){e.printStackTrace ();} hf7[<I,jov  
} +%K~HYN  
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//读取保存的下载信息（文件指针位置） 9w=[}<E  
private void read_nPos() k]2_vk^  
{ MN:LL <  
try{ E Q:6R|L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |=V~CQ]  
int nCount = input.readInt(); y'non0P.  
nStartPos = new long[nCount]; |.-Muv  
nEndPos = new long[nCount]; vskp1Wi(  
for(int i=0;i<nStartPos.length;i++) upZf&4 I8  
{ &VG  
nStartPos = input.readLong(); <|w(Sn  
nEndPos = input.readLong(); ^ohIJcI-  
} c: (nlYZ  
input.close(); #]Jg>  
} }d5~w[  
catch(IOException e){e.printStackTrace ();} O]Y
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catch(Exception e){e.printStackTrace ();} r@ !  
} H?V b
 
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private void processErrorCode(int nErrorCode) y! QYdf?  
{ ,R-aO= %  
System.err.println("Error Code : " + nErrorCode); s=556  
} Py?Q::  
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//停止文件下载 4U u`1gtz  
public void siteStop() 'ud[#@2  
{ wxT(ktE  
bStop = true; QV4FA&f&  
for(int i=0;i<nStartPos.length;i++) 4=N(@mS  
fileSplitterFetch.splitterStop(); Yb1Q6[!  
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}
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} rZE+B25T~  
//负责部分文件的抓取 [khXAf1{Q  
**FileSplitterFetch.java g}L>k}I?!W  
*/ (A "yE4rYK  
package NetFox; l kyK  
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import java.io.*; nlaW$b{=  
import java.net.*; P]armg%  
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public class FileSplitterFetch extends Thread { &:1q3gDm  
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String sURL; //File URL S0}=uL#dt  
long nStartPos; //File Snippet Start Position \1QY=}  
long nEndPos; //File Snippet End Position *kEzGgTzoS  
int nThreadID; //Thread's ID 8DM! ]L  
boolean bDownOver = false; //Downing is over ?nq%'<^^  
boolean bStop = false; //Stop identical <Y$( lszT  
FileAccessI fileAccessI = null; //File Access interface )V&hS5P=S  
Cl{Ar8d}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aPQxpK?  
{ qv'w 7T  
this.sURL = sURL; l[rK)PM  
this.nStartPos = nStart; I0!]J{  
this.nEndPos = nEnd; $g/h=w@  
nThreadID = id; ?nWzJ5w3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yrd1J$  
} vTTXeS-b  
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public void run() d`~~Ww1  
{ 5}c8v2R:B  
while(nStartPos < nEndPos && !bStop) bvZ:5M  
{  G8!|Lo  
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try{ =G"ney2  
URL url = new URL(sURL); K9y~ e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TPak,h(1  
httpConnection.setRequestProperty("User-Agent","NetFox"); oYt34@{?  
String sProperty = "bytes="+nStartPos+"-"; C\B4Uu6q  
httpConnection.setRequestProperty("RANGE",sProperty); j-.Y!$a%6  
Utility.log(sProperty); |qz%6w=  
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InputStream input = httpConnection.getInputStream(); GR4DxlX  
//logResponseHead(httpConnection); ZY@ntV?  
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byte[] b = new byte[1024]; !&NrbiuN  
int nRead; `uH7~ r^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) euVj,m  
{ -3guuT3x\  
nStartPos += fileAccessI.write(b,0,nRead); iq[IZdza  
//if(nThreadID == 1) xc\zRsY`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d325Cw?  
} F\L!.B  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; U4<c![Pp.  
//nPos = fileAccessI.write (b,0,nRead); 51y#AQ@  
} h72CGA|  
catch(Exception e){e.printStackTrace ();} " 0m4&K(3,  
} h9#)Eo  
} z^z`{B  
/,UnT(/k(  
P.
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//打印回应的头信息 ~QDM .5  
public void logResponseHead(HttpURLConnection con) C+[)^2M{  
{ aB?usVoS  
for(int i=1;;i++) aT(_c/t.  
{ Rn]xxa'  
String header=con.getHeaderFieldKey(i); S!+>{JyQ  
if(header!=null) y@It#!u0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o]<9wc:FZ  
Utility.log(header+" : "+con.getHeaderField(header)); a^pbBDi W  
else Jazgn5  
break; A.dbb'^  
} %.?V\l  
} XM
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public void splitterStop() [uLsM<C  
{ 4+s6cQ]S`  
bStop = true; !8|}-eFY  
} D79:L:  
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} 75lh07  
^gZ,A]  
d7 H*F  
/* /XEW]/4  
**FileAccess.java JXYZ5&[  
*//文件访问(定位，写) >
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package NetFox; GNe^~  
import java.io.*; Y)+q[MZ R  
+
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public class FileAccessI implements Serializable{ qc5[e  
#j=yQrJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G{E`5KIvm  
RandomAccessFile oSavedFile; Zd-6_,r  
long nPos; 2wHbhW[  
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public FileAccessI() throws IOException RZ xwr  
{ =R|XFZ,  
this("",0); Y`Io}h G$  
} vIbM@Y4 '?  
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public FileAccessI(String sName,long nPos) throws IOException 2R.LLE  
{ <7`zc7c]#  
oSavedFile = new RandomAccessFile(sName,"rw"); FutS  
this.nPos = nPos; Mjy:k|aY"  
oSavedFile.seek(nPos); a4=(z72xe  
} S!.&#sc  
I4{xQI  
Cul=,;pkB  
public synchronized int write(byte[] b,int nStart,int nLen) q*3keB;X  
{ Jt@lH  
int n = -1; 5$D"uAp<V  
try{ d#H9jg15e  
oSavedFile.write(b,nStart,nLen); PD-&(ka.  
n = nLen; b' y*\9Ru  
} q1( [mHZ  
catch(IOException e) n]ba1t8ZA  
{ '=n?^EPE3  
e.printStackTrace (); 4^F%bXJ)  
} Oo}h:3?  
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return n; "4)N]Nj  
} ,T<JNd'  
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} zqo0P~  
 p;w&}l{{  
+*:mKx@Nw  
/* d*0RBgn  
**SiteInfoBean.java VNHceH  
*/ :~vodh  
package NetFox; At4\D+J{Vs  
|JxVfX8^  
9Yv:6@.F  
public class SiteInfoBean { VP~2F E  
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private String sSiteURL; //Site's URL 'Oue 1[  
private String sFilePath; //Saved File's Path 3I
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private String sFileName; //Saved File's Name pg4W?N`  
private int nSplitter; //Count of Splited Downloading File % /VCjuV  
&uK(. @  
6*q1%rs:w  
public SiteInfoBean() Q=`yPK>{$N  
{//nSplitter的缺省值为5 ;7QXs39S  
//default value of nSplitter is 5 Mh.1KI[t  
this("","","",5); 10Ik_L='  
} 25$_tZPAI  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .d]/:T -0  
{ h|CZ~  
sSiteURL= sURL; oAQQ OtpZN  
sFilePath = sPath; @MES.g  
sFileName = sName; /\w4k  
this.nSplitter = nSpiltter; o utJ/~9;  
Y 3BJ@sqz  
&Q883A J  
} w\bwa!3Y  
)4L2&e`k)(  
^ `y7JXI:  
public String getSSiteURL() nF<K84  
{ uL`
#
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return sSiteURL; !C#oZU]P  
} f+
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public void setSSiteURL(String value) 'f\9'v  
{ g"m' C6;  
sSiteURL = value; K ze?@*  
} M:/NW-:  
{EoYU\x  
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public String getSFilePath() tOiz tYu  
{ .SD-6GVD  
return sFilePath; _O`p(6  
} h0tiWHw  
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public void setSFilePath(String value) Kjd3!%4mB  
{ Qr$'Q7  
sFilePath = value; :y-;
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} oMQ4q{&|  
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public String getSFileName() 1=R$ RI  
{ 4=L>  
return sFileName; L|CdTRgRCB  
} $ZM'dIk?  
#n>U7j9`O  
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public void setSFileName(String value) .l1
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{ NnLK!Q  
sFileName = value; [ohLG_9  
} $hhXsu=  
0cS$S Mn{  
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public int getNSplitter() z &EDW5I  
{ &=g3J4$z  
return nSplitter; * ,aF-  
} 0=$/  
~ WWhCRq  
wQ+pVu?6_  
public void setNSplitter(int nCount) rl|'.~mc  
{ yYP_TuNa  
nSplitter = nCount; D S U`(`  
} [bhKL5l  
} # e?B  
f24W*#IX  
9\Jc7[b  
/* ]-\68bN  
**Utility.java Z/q6Q#  
*/ yB UQ!4e  
package NetFox; YSP\+ZZ  
]Dq6
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n _K1%  
public class Utility { 1/M^7Vb.  
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/vSGmW-*  
public Utility()  d$$5&a  
{ q} e#L6cM  
{=GmXd%D  
!Cr3>tA  
} D6bYg `  
|+ F ~zIu'  
//线程睡眠 syl7i>P  
public static void sleep(int nSecond) W.j^L;  
{ w-K A~  
try{ eFiG:LS7  
Thread.sleep(nSecond); X:i?gRy"  
} 50_[hC&C)  
catch(Exception e) wH~A> 4*(  
{ I
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e.printStackTrace (); cGV%=N^BE<  
} Y_%:%J  
} xuXPVJdi  
v@\S$qU2  
//日志 `etw[#~N  
public static void log(String sMsg) Hu|Tj<S  
{ vb>F)X?b_  
System.err.println(sMsg); AU9C#;JD  
} JvAXLT  
oMbd1uus  
:s *  
public static void log(int sMsg) #/YS  
{ kLgkUck8]  
System.err.println(sMsg); apL$`{>US  
} :!aLa}`@  
}
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BM!ZdoKrKt  
/* Y<T0yl?  
**TestMethod.java </25J((  
*/ :E")Zw&sW3  
package NetFox; kkl'D!z2g  
&wQ;J)13  
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public class TestMethod { Ze0qRLuH!  
PNm@mC_fh  
"1a;);S=*)  
public TestMethod() |ke0G  
{ ///xx/weblogic60b2_win.exe gv67+Mf  
try{ `3\aX|4@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2K:A4)jZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); AS;Sz/YP  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N@|<3R!N*e  
fileFetch.start(); [<XYU,{R  
} r?DCR\Jq  
catch(Exception e){e.printStackTrace ();} 'l'3&.{Yfk  
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A+l(ew5Lw$  
} cSPQ NYU:  
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KYiJXE[Q-  
public static void main(String[] args) nD5wN
~[J  
{ @rGY9%E  
new TestMethod(); %IO*(5f  
} 7hk<{gnr  
} ^Laqq%PI  
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