http断点续传简单实现（java)

/* P+=m.  
**SiteFileFetch.java ,II3b(l  
*/ LrT EF j  
package NetFox; \P")Eh =d  
import java.io.*; V)l:fUm2  
import java.net.*; [`s0 L#  
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public class SiteFileFetch extends Thread { @0]WMI9B"B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w52py7  
long[] nStartPos; //开始位置 l#%7BGwzY  
long[] nEndPos; //结束位置 'O\
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 "qd|!:bE  
long nFileLength; //文件长度 gPb.%^p  
boolean bFirst = true; //是否第一次取文件 >3@3~F%xAX  
boolean bStop = false; //停止标志 jT}={[9b  
File tmpFile; //文件下载的临时信息 MtaGv#mJ  
DataOutputStream output; //输出到文件的输出流 8>Cf}TvErx  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9}m?E<6&  
public SiteFileFetch(SiteInfoBean bean) throws IOException GBT|1c'i  
{ !|UX4  
siteInfoBean = bean; X^K^az&L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {-8Nq`w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'Grii,  
if(tmpFile.exists ()) ge:a{L  
{ &)gc{(4$  
bFirst = false; Z\x
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read_nPos(); *OznZIn  
} BAY e:0  
else I`H&b& .`  
{ 8V 4e\q  
nStartPos = new long[bean.getNSplitter()]; )$bF*  
nEndPos = new long[bean.getNSplitter()]; BV:Ca34&  
} BQ)>}YHk  
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} B^r?N-Z A  
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public void run() {H)hoAenA  
{ {+=hYB|&  
//获得文件长度 Z,e|L4&  
//分割文件 R54ae:8  
//实例FileSplitterFetch I;%1xdPt  
//启动FileSplitterFetch线程 lnHY?y7{  
//等待子线程返回 peBHZJ``RX  
try{ >Zs!  
if(bFirst) ;Vs2e  
{ ,;Wm>V)o  
nFileLength = getFileSize(); `bfUP s  
if(nFileLength == -1) G<D8a2q  
{ hTzj{}w  
System.err.println("File Length is not known!"); R[j?\#  
} (${ #l  
else if(nFileLength == -2) &K[sb%  
{ *$BUow/>  
System.err.println("File is not access!"); _.Hj:nFHz  
} `;+x\0@<  
else kSzap+nB?  
{ GEF's#YWK  
for(int i=0;i<nStartPos.length;i++) G3io!XM)D  
{ /MY's&D(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $"W[e"Q  
} {$hWz(  
for(int i=0;i<nEndPos.length-1;i++) nPdkvs   
{ zGR,}v%%  
nEndPos = nStartPos[i+1]; -dA9x~o  
} ">CRFee0  
nEndPos[nEndPos.length-1] = nFileLength; eyJWFJh  
} gv>DOez/  
} jVd`J  
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//启动子线程 V 97ORI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Mf#@8"l  
for(int i=0;i<nStartPos.length;i++) 1F,U^O  
{ oo\^}jb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5=I({=/>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e'A_4;~@s  
nStartPos,nEndPos,i); BInSS*L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Lv['/!DJ|  
fileSplitterFetch.start(); [|oG}'Xz  
} 1C{0
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Si]?4:E7=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7*+CX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M$%ON>Kq  
nEndPos = " + nFileLength); [mu8V+8@d4  
// fileSplitterFetch[nPos.length-1].start(); #$xtUCqX  
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~6n|GxR.[  
//等待子线程结束 :38h)9>RK  
//int count = 0; 5?SE?VC=t  
//是否结束while循环 b4cTn 6  
boolean breakWhile = false; 7>y]uT@ar  
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while(!bStop) H`)eT6:|/  
{ ocWl]h].  
write_nPos(); a<q9~QS  
Utility.sleep(500); >IrQhSF  
breakWhile = true; 7;q0'_G  
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for(int i=0;i<nStartPos.length;i++) p-{ 4 $W  
{ F\xIVY  
if(!fileSplitterFetch.bDownOver) S1Y,5,}  
{ T$"~Vu  
breakWhile = false; fYy w2"  
break; Mb2a;s  
} z@3gNY&7.8  
} -d'FKOD  
if(breakWhile) !9PAfi?  
break; .8^mA1fmX  
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//count++; _lkVT']  
//if(count>4) 1a(\F7  
// siteStop(); 2~f*o^%l  
} KPO w  
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System.err.println("文件下载结束！"); N
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} ?wG  
catch(Exception e){e.printStackTrace ();} i /[{xRXiR  
} ,Ohhl`q(  
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//获得文件长度 @
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public long getFileSize() vc|tp_M67  
{ W vB]Rs  
int nFileLength = -1; 6 :3Id  
try{ }C_g;7*  
URL url = new URL(siteInfoBean.getSSiteURL()); f\cTd/?Ju  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1
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httpConnection.setRequestProperty("User-Agent","NetFox"); J' P:SC1  
k 6[   
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int responseCode=httpConnection.getResponseCode(); TxK v!-1  
if(responseCode>=400) ~3j+hN8<  
{ oCOv 6(  
processErrorCode(responseCode); 5l8F.LtO\  
return -2; //-2 represent access is error 
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} 6O{QmB0KK  
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String sHeader; D? %*L  
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for(int i=1;;i++) jRC{8^
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{ qpe9?`vVX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); oQ]FyV
 
//Utility.log(in.readLine()); )?SF
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sHeader=httpConnection.getHeaderFieldKey(i); q!0HsF  
if(sHeader!=null) &77J,\C$:  
{ w,j!%N  
if(sHeader.equals("Content-Length")) n^;-&  
{ {ObY1Y`ea  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }rmr0Bh  
break; O
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} S;Sy.Lp  
} lH_p
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else ;q9Y%*  
break; {= &&J@:  
} n Yx[9HN  
} `Z>=5:+G@2  
catch(IOException e){e.printStackTrace ();} F%y#)53g  
catch(Exception e){e.printStackTrace ();} 81|[Y'f  
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Utility.log(nFileLength); I/St
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return nFileLength; IxWi>8  
} *y<eK0  
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//保存下载信息（文件指针位置） .{t5_,P  
private void write_nPos() jNX6Ct?  
{ W7|nc,i0\  
try{ _X?_|!;J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [^a7l$fmi  
output.writeInt(nStartPos.length); 8u)>o* :  
for(int i=0;i<nStartPos.length;i++) k8n9zJ8  
{ sSKD"  
// output.writeLong(nPos); )UU`uzU;u  
output.writeLong(fileSplitterFetch.nStartPos); B=W#eu <1  
output.writeLong(fileSplitterFetch.nEndPos); 8hww({S2  
} 30I-E._F  
output.close(); u8?$W%eW  
} g; -3  
catch(IOException e){e.printStackTrace ();} 9 AD*  
catch(Exception e){e.printStackTrace ();} Da[#X`Kp$  
} Y]6dYq{k  
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//读取保存的下载信息（文件指针位置） L:&'z:,<  
private void read_nPos() e`LvHU_0  
{ %F150$(D  
try{ @Zhd/=2[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t;3).F  
int nCount = input.readInt(); +}udIi3:l  
nStartPos = new long[nCount]; T"H"m4{'  
nEndPos = new long[nCount]; N\]-/$z  
for(int i=0;i<nStartPos.length;i++) 3dZj<(.
 
{ p<D@l2vt  
nStartPos = input.readLong(); %=K[C  
nEndPos = input.readLong(); "+O/OKfR0  
} um/F:rp  
input.close(); [C-FJ>=S  
} GK6~~ga=  
catch(IOException e){e.printStackTrace ();} -8"
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catch(Exception e){e.printStackTrace ();} N@X6Z!EO  
} *=O3kUoL  
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private void processErrorCode(int nErrorCode) 4yTgH0(T  
{ R9-mq;u+  
System.err.println("Error Code : " + nErrorCode); Zonn  
} PL31(!`@d  
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//停止文件下载 MR4k#{:w  
public void siteStop() Y>c+j  
{ ~S~+'V,d  
bStop = true; 6,1oLvU  
for(int i=0;i<nStartPos.length;i++) w?*79 u  
fileSplitterFetch.splitterStop(); _XT;  
2Gj)fMK38  
4,YL15.  
} R$dNdd9m  
} *e:I*L  
//负责部分文件的抓取 Fku<|1}&y  
**FileSplitterFetch.java 7NOF^/nU  
*/ /i_FA]Go  
package NetFox; qM3NQ8Rm  
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import java.io.*; ?%ltoezf  
import java.net.*; -+2A@kmEJ  
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public class FileSplitterFetch extends Thread { inq {" 6  
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String sURL; //File URL U
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long nStartPos; //File Snippet Start Position }{PG^Fc<P  
long nEndPos; //File Snippet End Position ' qT\I8%  
int nThreadID; //Thread's ID 9zx9t  
boolean bDownOver = false; //Downing is over p74Nd4U$s  
boolean bStop = false; //Stop identical Hd-g|'^K  
FileAccessI fileAccessI = null; //File Access interface 805oV(-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Zf??/+[  
{ [ gR,nJH.  
this.sURL = sURL; eMn'z]M&]  
this.nStartPos = nStart; PN J&{4wY  
this.nEndPos = nEnd; 64"DT3:  
nThreadID = id; }=gD,]2x8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C(>g4.-p8  
} h'vBWtMa  
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public void run() ZcHIk{|  
{ t1yfSStp  
while(nStartPos < nEndPos && !bStop) >@a7Zzl0H  
{ 77+3CME{'  
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try{ \j.l1O  
URL url = new URL(sURL); T.%yeJiE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JXt_
  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ck m:;q  
String sProperty = "bytes="+nStartPos+"-"; aehB,l0  
httpConnection.setRequestProperty("RANGE",sProperty); "?iyvzo  
Utility.log(sProperty); K,PN:  
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InputStream input = httpConnection.getInputStream(); s`v$r,N0  
//logResponseHead(httpConnection); y La E]  
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byte[] b = new byte[1024]; r/)ZKO,  
int nRead; Azr|cKu]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d}|z+D  
{ rAqS;@]0  
nStartPos += fileAccessI.write(b,0,nRead); QaA?UzB  
//if(nThreadID == 1) u2fp~.'P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?V~vP%1  
} )3f\H  
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Utility.log("Thread " + nThreadID + " is over!"); #_IuB) qy  
bDownOver = true; {+Wknm%  
//nPos = fileAccessI.write (b,0,nRead); oxI?7dy5  
} 7GErh,  
catch(Exception e){e.printStackTrace ();} &U([Wd?E2  
} BbL]0i  
} GZuWAa  
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//打印回应的头信息 2r+nr  
public void logResponseHead(HttpURLConnection con)  %(K}1[  
{ '|Lv-7  
for(int i=1;;i++) f|/ ,eP$  
{ g"c7$  
String header=con.getHeaderFieldKey(i); 2BT+[  
if(header!=null) (_3'nFg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wQ9@ l  
Utility.log(header+" : "+con.getHeaderField(header)); P)Oe?z;G?  
else B"5xs  
break; QOPh3+.5  
} X1[zkb  
} p"H/N_b4  
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public void splitterStop() ~*^o[~x]\  
{ c@nh>G:y{&  
bStop = true; %uiCC>cC  
} ,R7j9#D  
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} F~OQ'59!Pf  
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/* -QBM^L  
**FileAccess.java ;K4uu<e\  
*//文件访问(定位，写) 6o(.zk`d  
package NetFox; +9yMtR  
import java.io.*; <F-IF7>a  
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public class FileAccessI implements Serializable{ j+gh*\:q  
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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 X%B$*y5  
RandomAccessFile oSavedFile; e5;YY  
long nPos; +br' 2Pn  
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public FileAccessI() throws IOException 1>2 /1>  
{ S&'s/jB  
this("",0); ^'+#BPo9@  
} %@q2  
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public FileAccessI(String sName,long nPos) throws IOException CC$rt2\e  
{ g]BA/Dw  
oSavedFile = new RandomAccessFile(sName,"rw"); ~xws5n}F  
this.nPos = nPos; 3.ShAL  
oSavedFile.seek(nPos); v5?ct?q  
} P"@^BQ4  
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public synchronized int write(byte[] b,int nStart,int nLen) hew"p(`  
{ adgd7JjI*  
int n = -1;  s%5XB
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try{ ,u-9e4  
oSavedFile.write(b,nStart,nLen); lKqFuLHwF  
n = nLen; iex]J@=e  
} {FILt3f;  
catch(IOException e) *{p:C  
{ i!(5y>I_  
e.printStackTrace (); x~D8XN{  
} 2<'ol65/c  
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return n; NMrf I0tbG  
} "st+2#{  
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} EF9
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/* g2u\gR5  
**SiteInfoBean.java i;IhsKO0R  
*/ Nm%#rZrN~Q  
package NetFox; Uw3wR!:  
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public class SiteInfoBean { 6 lEv<)cC  
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private String sSiteURL; //Site's URL Wu8zK=Ve(  
private String sFilePath; //Saved File's Path tk:G6Bkid  
private String sFileName; //Saved File's Name wqzpFPk(  
private int nSplitter; //Count of Splited Downloading File hx:^xW@r4P  
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public SiteInfoBean() Cj YI*  
{//nSplitter的缺省值为5 2)QZYgfh  
//default value of nSplitter is 5 )%8st'  
this("","","",5); .O&YdUo  
} uy<b5.!-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t/3qD7L  
{ 0&tr3!h\
 
sSiteURL= sURL; yDRi  
sFilePath = sPath; ^B7Ls{  
sFileName = sName; ,*m|Lt%;R  
this.nSplitter = nSpiltter; 'S&Zq:  
{*  w _*  
~HKzqGQy>  
} %8YUK/(|n  
8~Pdr]5  
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public String getSSiteURL() O+=}x]q*y  
{ z('t#J!b  
return sSiteURL; |~rKDc  
} IQ xi@7%&  
D)Jac@,0  
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public void setSSiteURL(String value) O+[s4]  
{ 4#ikdjB;  
sSiteURL = value; vCOtED*<  
} 2gEF$?+q?  
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public String getSFilePath() %<U0  
{ L2%D$!9  
return sFilePath; ]bstkf}~u  
} /`y^z"!  
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public void setSFilePath(String value) wk1/&  
{ W
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sFilePath = value; =gZA9@]W2  
} M<Dvhy[  
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public String getSFileName() Ip *8R]W  
{ Pw6%,?lQ  
return sFileName; 38:5g_  
} {7_C|z:'p&  
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public void setSFileName(String value) ^7=h%{>=  
{ >Dz8+y  
sFileName = value; =hI;5KF  
} gebL6oc%  
0E{DO<~  
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public int getNSplitter() \i<7Lk  
{ v(, tu/  
return nSplitter; Q6N?cQtOT  
} pA_e{P/  
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public void setNSplitter(int nCount) Oa M~rze  
{ O]61guxro  
nSplitter = nCount; '#Do( U'  
} J\J3'u  
} P=s3&NDD  
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/* ZQ-6n1O  
**Utility.java mSO7r F  
*/ ^}J,;Zhu5  
package NetFox; .;(a;f+{;  
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public class Utility { {j4&'=C:  
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public Utility() Deq@T {  
{ ^)aj,U[  
_'n]rQ'  
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} G6xNR  
b7gN|Hw5 H  
//线程睡眠 b.9[Vf_G  
public static void sleep(int nSecond) HJd{j,M  
{ S9
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try{ Mh{;1$j#  
Thread.sleep(nSecond); a^Q ?K\c4N  
} K1&t>2=%  
catch(Exception e) _3#_6>=M  
{ ",aEN=+|hV  
e.printStackTrace (); SQ'%a-Mct  
} U_Q;WPJ  
} cxx8I  
- Nt8'-  
//日志 B$S
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public static void log(String sMsg) ~~Rq
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{ abS3hf  
System.err.println(sMsg); !JVv`YN  
} BH}M]<5  
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public static void log(int sMsg) ][XCpJ)8  
{ }j!C+
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System.err.println(sMsg); /)?qD
 
} p1T0FBV L  
} %MCS_'N J  
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>\3N#S"PF  
/* R0|4KT-i  
**TestMethod.java ;hh.w??  
*/ -M4VC^_  
package NetFox; IIF <Zkpb  
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public class TestMethod { ]u:Ij|.'y0  
_94R8?\_V7  
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public TestMethod() o"kL,&  
{ ///xx/weblogic60b2_win.exe _lC0XDZ  
try{ 2Zg%4/u,Zp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g[\8s~g,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -"XHN=H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]LMtZUz  
fileFetch.start(); %zhSSB=BJ  
} 3T[zieX  
catch(Exception e){e.printStackTrace ();} ,vBB". LY'  
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} =)x+f/c]  
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public static void main(String[] args) =Q6JXp  
{ y I[kaH"J  
new TestMethod(); 9! yDZ<s  
} BL-7r=Z  
}
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