http断点续传简单实现（java)

/* j/
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**SiteFileFetch.java ]E/~PV  
*/ /y<nAGtD&  
package NetFox; K@UQ O  
import java.io.*; &lp5W)D  
import java.net.*; E")g1xGaK  
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public class SiteFileFetch extends Thread { nD8CP[bRo  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3.^Tm+ C  
long[] nStartPos; //开始位置 ~-.^eT kP  
long[] nEndPos; //结束位置 +~~&FO2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D)*OQLHW  
long nFileLength; //文件长度 ]J%p&y+6  
boolean bFirst = true; //是否第一次取文件 @&G< Np
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boolean bStop = false; //停止标志 ZC\&n4~7  
File tmpFile; //文件下载的临时信息 k-uwK-B}v+  
DataOutputStream output; //输出到文件的输出流 rIg5Wcd  
o :tz_5  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Xob,jo}a  
public SiteFileFetch(SiteInfoBean bean) throws IOException KNw{\Pz~w  
{ Q5:8$ C}+  
siteInfoBean = bean; :J{| /"==  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SpB\kC"K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); '8|y^\  
if(tmpFile.exists ()) [`eqma  
{ |d B`URP  
bFirst = false; ;F:~HrxT}  
read_nPos(); #kt3l59Ty  
} M_Qv{   
else :~1sF_  
{ ,GH;jw)P  
nStartPos = new long[bean.getNSplitter()]; >){"x(4`  
nEndPos = new long[bean.getNSplitter()]; :GaK.W q  
} iO,_0Y4  
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|  
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} 1sT%g}w@|  
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public void run() JXBTd=r_oM  
{ v_$'!i$  
//获得文件长度 Gc'CS_L  
//分割文件 > (.V(]{3y  
//实例FileSplitterFetch _FJ,, /~  
//启动FileSplitterFetch线程 Zss `##  
//等待子线程返回 w>q:&Q  
try{ qf7oG0  
if(bFirst) d
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{ "&,Gn#'FG  
nFileLength = getFileSize(); N4wv'OrL]  
if(nFileLength == -1) \ tK{!v+  
{ V*bX>D/  
System.err.println("File Length is not known!"); lOc!KZHUp  
} Y8^pgv  
else if(nFileLength == -2) OZ/!=;  
{ EM.7,;|N  
System.err.println("File is not access!"); X}/{90UD  
} !)}3[h0  
else Y<vsMf_U  
{ YR{%pZp  
for(int i=0;i<nStartPos.length;i++) jv C.T]<B  
{ .=nx5yz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m\}8N u  
} x'.OLXx>  
for(int i=0;i<nEndPos.length-1;i++) J9kmIMq-C  
{ FHu -';  
nEndPos = nStartPos[i+1]; ;0R>Dg  
} krw_1Mm  
nEndPos[nEndPos.length-1] = nFileLength; R>ak 3Y  
} !2R<T/9~  
} n8!qz:z/  
aa'u5<<W  
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//启动子线程 huu v`$~y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *7ggw[~  
for(int i=0;i<nStartPos.length;i++) Oh\+cvbG  
{ :a 5#yh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G9/5KW}-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x1$:u6YD22  
nStartPos,nEndPos,i); PyS~2)=B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4r&S&^  
fileSplitterFetch.start(); /lC&'hT  
} _msV3JBr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oj6b33z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _m  *8f\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >~g(acH%`x  
nEndPos = " + nFileLength); ?3{R'Buv]  
// fileSplitterFetch[nPos.length-1].start(); &!y7PWHJ  
:< )"G&  
q]-CTx$  
//等待子线程结束 9'qU4I  
//int count = 0; YSvZ7G(m>  
//是否结束while循环 '%u7XuU-]  
boolean breakWhile = false; .)7r /1o  
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while(!bStop) {EoRY/]  
{ #q06K2  
write_nPos(); ;Jn"^zT  
Utility.sleep(500); 7# /c7
 
breakWhile = true; C/J
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for(int i=0;i<nStartPos.length;i++) ha;Xali ]  
{ fI/?2ZH  
if(!fileSplitterFetch.bDownOver) Y\.ds%G  
{ DA/l`Pn  
breakWhile = false; sg.8Sd"]7  
break; QW5S=7  
} t3#My2=  
} Z$0+jpG_s  
if(breakWhile) woHB![Q,  
break; uN:|4/;{&  
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//count++; D^?jLfW8  
//if(count>4) fkp
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// siteStop(); 4@K9%  
} 6I$laHx?  
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System.err.println("文件下载结束！"); \(nb >K  
} h6*&1r  
catch(Exception e){e.printStackTrace ();} `A]CdgA  
} %uuh+@/&yz  
)JO#Z(  
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//获得文件长度 Kk}|[\fW  
public long getFileSize() m3apeIEi[  
{ }~?B
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int nFileLength = -1; u,zA^%  
try{ x>>#<hOz[  
URL url = new URL(siteInfoBean.getSSiteURL()); 'IorjR@40  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FS3MR9  
httpConnection.setRequestProperty("User-Agent","NetFox"); W\'njN  
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int responseCode=httpConnection.getResponseCode(); c+6/@y  
if(responseCode>=400) WjyuaAWY  
{ E%eTjvvxus  
processErrorCode(responseCode); dQ6n[$Q@N  
return -2; //-2 represent access is error -_m>C2$6x  
} 6.o8vC/PZ  
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String sHeader; jV(\]g"/=  
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for(int i=1;;i++) z (N3oBW  
{ QT1(= wK3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); 1v)X]nW  
sHeader=httpConnection.getHeaderFieldKey(i); !]%M  
if(sHeader!=null) tSST.o3  
{ C~do*rnM^  
if(sHeader.equals("Content-Length")) p!+7F\  
{ S?X2MX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dQoZhE  
break; Uoskfm  
} Wq bfZx  
} g/)$-Z)Nu  
else }PZz(Ms  
break; R&w2y$  
} c0J=gZiP  
} |G2hm8 Y  
catch(IOException e){e.printStackTrace ();} xwjim7#_:  
catch(Exception e){e.printStackTrace ();} 1E(~x;*)  
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Utility.log(nFileLength); 'Zq$W]i  
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return nFileLength; _eB?G  
} f@ &?K<  
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//保存下载信息（文件指针位置） /UJ@e  
private void write_nPos() Wvhg:vup  
{ }uI(D&?+h  
try{ A),nkw0X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); so* lV  
output.writeInt(nStartPos.length); GZL{~7n  
for(int i=0;i<nStartPos.length;i++) J`6X6YZ  
{ 5e!YYt>  
// output.writeLong(nPos); o8 A]vaa  
output.writeLong(fileSplitterFetch.nStartPos); <Tq&Va_w  
output.writeLong(fileSplitterFetch.nEndPos); jzuOs,:R  
} /PP\L]
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output.close(); 2gn*B$a  
} n-h2SQl!  
catch(IOException e){e.printStackTrace ();} Nhh2P4gH  
catch(Exception e){e.printStackTrace ();} 5zebH  
} V}1D1.@  
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//读取保存的下载信息（文件指针位置） ^
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private void read_nPos() S.;>:Dd[K  
{ \]y4e^FZZ  
try{ Evz;eobW/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JHY0J &4s  
int nCount = input.readInt(); E$z)$`"1  
nStartPos = new long[nCount]; 0> pOP  
nEndPos = new long[nCount]; B,sv! p+q5  
for(int i=0;i<nStartPos.length;i++) 5xZ*U  
{ ^ <Z^3c>/  
nStartPos = input.readLong(); ,`7;S,f  
nEndPos = input.readLong(); `aFy2x`3  
} A>"v1W
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input.close(); 4(aDi;x"w  
} 7m;2M]BRi  
catch(IOException e){e.printStackTrace ();} 4X2XSK4  
catch(Exception e){e.printStackTrace ();} c#qOK  
} |aiP7C  
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private void processErrorCode(int nErrorCode) qyP|`Pm4  
{ zy(i]6  
System.err.println("Error Code : " + nErrorCode); 1'5I]D ec  
} 0y$aGAUm  
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9`J!]WQ1[  
//停止文件下载 8ALvP}H  
public void siteStop() _VU/j9<+  
{ gf]biE"k  
bStop = true; ({3hX"C@Q  
for(int i=0;i<nStartPos.length;i++) "7R"(.~>  
fileSplitterFetch.splitterStop(); =RR225  
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} _C9*M6IU  
} KlgPDV9mg  
//负责部分文件的抓取 $or?7 w>  
**FileSplitterFetch.java { 7y.0_Y
  
*/ P5;LM9W  
package NetFox; t<O5_}R%d  
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import java.io.*; aa<9%j  
import java.net.*; ~Mv@Bl  
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public class FileSplitterFetch extends Thread { r3o_mO?X  
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; Xy\7tx  
String sURL; //File URL uLYz!E+E  
long nStartPos; //File Snippet Start Position Q)\7(n  
long nEndPos; //File Snippet End Position EG5'kYw2  
int nThreadID; //Thread's ID EAQg4N:D7L  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical 4!Ez#\  
FileAccessI fileAccessI = null; //File Access interface wiWpzJz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uX{n#i,~L  
{ = GirUW D  
this.sURL = sURL; I__|+%oC  
this.nStartPos = nStart; `"v5bk  
this.nEndPos = nEnd; .BGM1ph}~  
nThreadID = id; "|CzQ&e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^(I4Do~}  
} mrDIt4$D  
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public void run() l-"c-2-!  
{ aH)$#6${Ap  
while(nStartPos < nEndPos && !bStop) nAn/Vu  
{ @Md%gEh;&  
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try{ *loPwV8  
URL url = new URL(sURL); G#/}
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -ea>}S  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8P r H"pI  
String sProperty = "bytes="+nStartPos+"-"; @NGK2J  
httpConnection.setRequestProperty("RANGE",sProperty); 0uzm@'^  
Utility.log(sProperty); Ec| Gom?  
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InputStream input = httpConnection.getInputStream(); THirh6  
//logResponseHead(httpConnection); wZVY h  
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byte[] b = new byte[1024]; <va3Ly)c&  
int nRead; I0 a,mO;m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ((A]FOIbO  
{ 8YC\Bw  
nStartPos += fileAccessI.write(b,0,nRead); uR{HCZ-  
//if(nThreadID == 1) u2 a U0k:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (OT /o&cQ  
} 3*$A;%q  
@'U9*:}U  
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Utility.log("Thread " + nThreadID + " is over!");  ~dfc  
bDownOver = true; t>|Y-i3cb  
//nPos = fileAccessI.write (b,0,nRead); pN/)$6=  
} M}NmA  
catch(Exception e){e.printStackTrace ();} 0!F"s>(H  
} !%x8!;za  
} )W)m?%  
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{]plT~{e  
//打印回应的头信息 b:/;  
public void logResponseHead(HttpURLConnection con) {J q[N}  
{ T;jp2 #  
for(int i=1;;i++) kM5N#|!  
{ \o9-[V#Gm  
String header=con.getHeaderFieldKey(i); hK"hMyH^  
if(header!=null) 1g6AzUXg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9;s:Bo  
Utility.log(header+" : "+con.getHeaderField(header)); v5l)T}Nb  
else ^'i(@{{o\  
break; jq#_*&Eg]  
} B"TZ8(<  
}
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public void splitterStop() LAeJz_9U  
{ g1VdP[Y#  
bStop = true; LY2oBX@fC  
} r H;@N  
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} 0ZPwE
P  
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/* 9@ [R>C  
**FileAccess.java 9K~2!<  
*//文件访问(定位，写) SV16]V
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package NetFox; j*>+^g\Q6  
import java.io.*; Kdk0#+xtP  
1eQ9(hzF  
*"` dO9Yf_  
public class FileAccessI implements Serializable{ *T j(IN  
OiX
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^pZ1uN!b  
RandomAccessFile oSavedFile; D'Tb=  
long nPos; >k,|N4(  
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public FileAccessI() throws IOException !"/]<OQ   
{ 3^ ~M7=k  
this("",0); By{zX,6'  
} A<l8CWv[  
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public FileAccessI(String sName,long nPos) throws IOException N&7= hni  
{ bqp6cg\p  
oSavedFile = new RandomAccessFile(sName,"rw"); XJy~uks,  
this.nPos = nPos; CI"7* z_  
oSavedFile.seek(nPos); "OF4#a17  
} !spp*Q)#\  
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public synchronized int write(byte[] b,int nStart,int nLen) T%~w~stW  
{ I&~kwOP  
int n = -1; \Zz"%i  
try{ 0 3fCn"  
oSavedFile.write(b,nStart,nLen); exw~SvT3  
n = nLen; ,gGIkl&  
} t-Rfy`I3  
catch(IOException e) D7|[:``  
{ MTo<COp($  
e.printStackTrace (); nmZz`P
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} <<`*o[^L  
:;W[@DeO[  
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return n; xF: O6KL  
} E^w2IIw  
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}  H"czF  
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/* 's>  
**SiteInfoBean.java a5=8zO#%g  
*/ W_l/Jpv!W  
package NetFox; wBZ=IMDu\  
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public class SiteInfoBean { bA}9He1  
4-;"w;  
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private String sSiteURL; //Site's URL 
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private String sFilePath; //Saved File's Path sC >_ulkoa  
private String sFileName; //Saved File's Name [ZC]O2'  
private int nSplitter; //Count of Splited Downloading File ir/m.~?  
-F
=?M+9[  
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public SiteInfoBean() MuXp*s3[  
{//nSplitter的缺省值为5 O O?e8OU  
//default value of nSplitter is 5 TI4#A E  
this("","","",5); ,5oe8\uz  
} "1O!Ck_n  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MB.\G.bV  
{ &_Kb;UVRj  
sSiteURL= sURL; ]-[M&i=+&  
sFilePath = sPath; :5Vk+s]8  
sFileName = sName; !v/5G_pr  
this.nSplitter = nSpiltter; F5UvD[i  
 8:=&=9%  
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} +UbSqp1BS  
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public String getSSiteURL() _M'WTe  
{ I\e?v`e  
return sSiteURL; n@5Sp2p  
} 8K+(CS>xvO  
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public void setSSiteURL(String value) gc(Gc vdB\  
{ ;pe1tp  
sSiteURL = value; H$'|hUwds%  
} U\aP  
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public String getSFilePath() ,fWQSc\}  
{ ;W%nB
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return sFilePath; (NfP2E|B  
} aAM!;3j]B`  
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:5)Dn87  
public void setSFilePath(String value) vHR-mQUs  
{ CTawXHM  
sFilePath = value; Q{%2Npvq  
} dRwOt  
:"m~tU3&  
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public String getSFileName() y8} fj=  
{ 7$3R}=Z`\q  
return sFileName; S1jI8 #z}_  
} u.v 5!G  
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*R9s0;&:  
public void setSFileName(String value) G!]%xFwYa  
{ L8OW@)|  
sFileName = value; 6Gt~tlt:L  
} 9%fd\o@X  
VnlgX\$}  
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public int getNSplitter() L1J \C  
{ 1.S7MSpTV  
return nSplitter; 6 3TeTGp$  
} Xjb 4dip  
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'ec G:B`S  
public void setNSplitter(int nCount) (!b_o A8V  
{ UI:YzR  
nSplitter = nCount; w+A:]SU  
} S
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} 5L ]TV\\  
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/* 05
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**Utility.java Z_b^K^4  
*/ 1XfH,6\8i  
package NetFox; {u!Q=D$3  
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public class Utility { F; upb5  
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public Utility() !LGnh  
{ ku2gFO  
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} }iGpuoXT`  
$qz(9M(m#  
//线程睡眠 -dRnozs6W  
public static void sleep(int nSecond) "n<rP 3y  
{ Om%HrT  
try{ c}XuzgSY  
Thread.sleep(nSecond); \R"}=7  
} 'K|Jg.2  
catch(Exception e) k8>(-W"A  
{ }s*H|z  
e.printStackTrace (); VSm[80iR0  
} 01N]|F:  
} a#i85su  
^pI&f{q  
//日志 v?AQ&'Fk  
public static void log(String sMsg) CMQlxX?  
{ !WTZ=|  
System.err.println(sMsg); ~Te9Lq|  
} =J@M,mbHg  
_:RQ9x'  
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public static void log(int sMsg) FI.Ae/(U  
{ Z>897>  
System.err.println(sMsg); OO7sj@  
} 7!-3jU@m  
} kzky{0yKk=  
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/* G,jv Mb`+  
**TestMethod.java [{s 1=c  
*/ BIu%A]e"  
package NetFox; @ve4rc/LI  
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public class TestMethod { B/:
+(|  
%_kXC~hH_  
j|6@>T1  
public TestMethod() ]1 V,_^D  
{ ///xx/weblogic60b2_win.exe ;q=0NtCS=4  
try{ q+j.
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $q"/q*ys  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m7dpr$J  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |3Fo4K%+  
fileFetch.start(); Mz?xvP?z  
} fG *1A\t]  
catch(Exception e){e.printStackTrace ();} P4\{be>e  
"PFczoRZ  
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} 0r4,27w  
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public static void main(String[] args) S_Tv Ix/7&  
{ X
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new TestMethod(); mYU7b8x_  
} v?BVUH>#
9  
} J 8!D."'Q0  
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