http断点续传简单实现（java)

/* [ `7%sn]$  
**SiteFileFetch.java 8p&kLo&  
*/ ~g6"'Cya?k  
package NetFox; $.pTB(tO  
import java.io.*; o\Uu?.-<  
import java.net.*; #%:c0=  
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public class SiteFileFetch extends Thread { C5|db{=\.*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gxwo4.,  
long[] nStartPos; //开始位置 [$pmPr2  
long[] nEndPos; //结束位置 r`jWp\z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UUeB;'E+  
long nFileLength; //文件长度 Tzzq#z&F  
boolean bFirst = true; //是否第一次取文件 yhpz5[AuO  
boolean bStop = false; //停止标志 SRZL\m}  
File tmpFile; //文件下载的临时信息 P ZxFZvE  
DataOutputStream output; //输出到文件的输出流 >O#grDXb  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） X8i(~ B  
public SiteFileFetch(SiteInfoBean bean) throws IOException <_Eg?ePW#  
{ \ECu5L4  
siteInfoBean = bean; &fwS{n;U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }XR:2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "7,FXTa
er  
if(tmpFile.exists ()) d,0 }VaY=D  
{ d;7uFh|o  
bFirst = false; "0CjP+1k  
read_nPos(); `]=oo%(h  
} GaekFbW)  
else .&1C:>  
{ DWU`\9xA*  
nStartPos = new long[bean.getNSplitter()]; bc I']WgB-  
nEndPos = new long[bean.getNSplitter()]; #Yuvbb[  
} rY0u|8.5Q  
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} :7g=b%;  
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public void run() XL$* _c <)  
{ $w#r"= )  
//获得文件长度 -%CoWcGP  
//分割文件 ytz SAbj  
//实例FileSplitterFetch dRi5hC$  
//启动FileSplitterFetch线程 l;A,0,i  
//等待子线程返回 A"v
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try{ p(F" /  
if(bFirst) 1f'Hif*r_X  
{ *sw7niw  
nFileLength = getFileSize(); bFS>)
 
if(nFileLength == -1) o|BP$P8V  
{ %+)
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System.err.println("File Length is not known!"); bzN-*3YE=  
} S8d8%R~1=h  
else if(nFileLength == -2) (ll*OVL  
{ !y:%0{l  
System.err.println("File is not access!"); H*^
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} =&wmWy  
else epHJ@W@#  
{ ;< jbLhHwD  
for(int i=0;i<nStartPos.length;i++)  p?D2)(  
{ B+d<F[|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |'O[7uT  
} -|k)tvAm  
for(int i=0;i<nEndPos.length-1;i++) g
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{ ;22l"-F  
nEndPos = nStartPos[i+1]; j(:I7%3&(*  
} B(?Yw>Xd[  
nEndPos[nEndPos.length-1] = nFileLength; [H<bh%  
} w%AcG~`j!B  
} E/&Rb*3  
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//启动子线程 3A:q7#m  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bzDIhnw  
for(int i=0;i<nStartPos.length;i++) A1)wo^,  
{ j"^+oxH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T{qTj6I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $Nrm!/)*'}  
nStartPos,nEndPos,i); wbDM5%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 
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fileSplitterFetch.start();
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} CQ`=V2:"ON  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9Zry]$0~R
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NNhL*C[_7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UJ-?k&j,  
nEndPos = " + nFileLength); ~ ~uAc_  
// fileSplitterFetch[nPos.length-1].start(); )"zvwgaW  
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5D M"0  
//等待子线程结束 8
}H1_y-g[  
//int count = 0; l`kWz5[~  
//是否结束while循环 O}9KJU  
boolean breakWhile = false; Wg{k$T_>  
M8H5K  
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while(!bStop) y4h=Lki@
 
{ *Av"JAX  
write_nPos(); e%8|<g+n6  
Utility.sleep(500); p!]6ll^  
breakWhile = true; ?JL7=o X  
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for(int i=0;i<nStartPos.length;i++) dKl^jsd  
{ ]9}HEu;1M  
if(!fileSplitterFetch.bDownOver) $$:ZX  
{ ARcv;H 5  
breakWhile = false; n wI!O  
break; BBcV9CGU  
} .NtbL./=|  
} zP6.xp3  
if(breakWhile) XeBP`\>Ve  
break; -hC,
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+ [Hh,I7  
//count++; 5*[2yKsTi  
//if(count>4) WyP W*  
// siteStop(); -,K!  
} .9O$G2'oh  
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System.err.println("文件下载结束！"); p4p@^@<>X  
} K't]n{$  
catch(Exception e){e.printStackTrace ();} r>GZ58i  
} ?5kHa_^  
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//获得文件长度 L@JOGCYy  
public long getFileSize() fib}b?vk  
{ *,BzcZ  
int nFileLength = -1; Vf(6!iRP@  
try{ bI|2@HV2  
URL url = new URL(siteInfoBean.getSSiteURL()); Zw wqSyuGf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u.rY#cS,-R  
httpConnection.setRequestProperty("User-Agent","NetFox"); u^029sH6j  
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int responseCode=httpConnection.getResponseCode(); /  g 2b  
if(responseCode>=400) 'mV9{lj7E  
{ JI vo_7{  
processErrorCode(responseCode); %/updw#{B  
return -2; //-2 represent access is error [5Lz/ix=  
} 1#1 riM -  
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String sHeader; &HSq(te  
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for(int i=1;;i++) ^U]UqX`  
{ A/`%/0e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^wS5>lf7p  
//Utility.log(in.readLine()); H:"maS\I  
sHeader=httpConnection.getHeaderFieldKey(i); vB+ '  
if(sHeader!=null) 4V~?.  
{ wb~@7,D  
if(sHeader.equals("Content-Length")) }- Wa`t7U  
{ &5:tn=E  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K(q-?n`<  
break; H'HSD,>(  
} Uo2GK3nT  
} _SA5e3#   
else -1J[n0O.  
break; RVeEkv[qp  
} v%ioj
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} /@|/^vld  
catch(IOException e){e.printStackTrace ();} gJM`[x`T  
catch(Exception e){e.printStackTrace ();} (T2m"Yi:  
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Utility.log(nFileLength); FHV-BuH5  
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return nFileLength; KIWe@e  
} B7!3-1<k>  
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//保存下载信息（文件指针位置） 8Ac:_Zg  
private void write_nPos() tToTxf~  
{ #t+d iR  
try{ KGg3 !jY  
output = new DataOutputStream(new FileOutputStream(tmpFile));  z^<"x|:  
output.writeInt(nStartPos.length); !/wtYI-`  
for(int i=0;i<nStartPos.length;i++) 7a~X:#  
{ KY~-;0x  
// output.writeLong(nPos); yeMB0Z*r  
output.writeLong(fileSplitterFetch.nStartPos); 53[~bwD  
output.writeLong(fileSplitterFetch.nEndPos); Gy(=706  
} Q@HopiC  
output.close(); Er{>p|n=  
} \P6$mh\T  
catch(IOException e){e.printStackTrace ();} GN2Sn`;  
catch(Exception e){e.printStackTrace ();} y~\oTJb  
} .p(T^ m2A*  
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}1upi=+aE  
//读取保存的下载信息（文件指针位置） mrjswF27$o  
private void read_nPos() `V04\05  
{ X)% A6M  
try{ >=-(UA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BT"XT5@  
int nCount = input.readInt(); ruld B,n  
nStartPos = new long[nCount]; c.e2M/  
nEndPos = new long[nCount]; 55fC~J<  
for(int i=0;i<nStartPos.length;i++) HKUn`ng  
{ (P:<t6;+  
nStartPos = input.readLong(); 6g)GY"49  
nEndPos = input.readLong(); m*kl  
} FFEfI4&SfS  
input.close(); @P?~KW6<|  
} V6,H}k  
catch(IOException e){e.printStackTrace ();} gK'1ZLdZ2  
catch(Exception e){e.printStackTrace ();} /PSd9N*=y  
} TtTj28k7  
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private void processErrorCode(int nErrorCode) ,1
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{ M]2]\km  
System.err.println("Error Code : " + nErrorCode); ,tu
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} ia+oX~W!VR  
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//停止文件下载 4p,EBn9(  
public void siteStop() I$Op:P6.E  
{ oUQ,6
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bStop = true; #W.#Hjpp  
for(int i=0;i<nStartPos.length;i++) :Ra,Eu  
fileSplitterFetch.splitterStop(); /n{omx  
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} [`"ZjkR_J  
} a C\MJ9  
//负责部分文件的抓取 ,NyY>~+  
**FileSplitterFetch.java ijK"^4i  
*/ !C3MFm{B  
package NetFox; LcTt)rs f  
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import java.io.*; 7`zHX&-W  
import java.net.*; L(|N[#  
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public class FileSplitterFetch extends Thread { CR"|^{G  
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String sURL; //File URL }J:U=HJ  
long nStartPos; //File Snippet Start Position 8"2=U6*C  
long nEndPos; //File Snippet End Position g"p%C:NN  
int nThreadID; //Thread's ID BW}U%B^.  
boolean bDownOver = false; //Downing is over t4zkt!`B  
boolean bStop = false; //Stop identical Eg#K.5hJ  
FileAccessI fileAccessI = null; //File Access interface 4U+xb>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [65`$x
-  
{ (_mnB W  
this.sURL = sURL; tl,.fjZn  
this.nStartPos = nStart; ;g5m0l5  
this.nEndPos = nEnd; Ui_8)z _  
nThreadID = id; c'>/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cu7hBfj  
} =.f-w0V  
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public void run() I7|Pi[e  
{ |[<_GQl  
while(nStartPos < nEndPos && !bStop) mZtCL  
{ -3t7*  
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try{ 2&:f&"  
URL url = new URL(sURL); 0=@?ob7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C%$edEi  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]/[FR5>  
String sProperty = "bytes="+nStartPos+"-"; 8Wrh]egu1  
httpConnection.setRequestProperty("RANGE",sProperty); 1an^1!  
Utility.log(sProperty); cs,N <|  
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InputStream input = httpConnection.getInputStream(); [;4g  
//logResponseHead(httpConnection); \\PjKAsh  
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byte[] b = new byte[1024]; \8)U!9,$nn  
int nRead; / ;$#d}R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FOv=!'So  
{ C]O(T2l{l  
nStartPos += fileAccessI.write(b,0,nRead); /f:dv?!km  
//if(nThreadID == 1) c(3~0Yr  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f/ ?_  
} oRm L {UDZ  
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Utility.log("Thread " + nThreadID + " is over!"); 0[RL>;
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bDownOver = true; *rM^;4Zt  
//nPos = fileAccessI.write (b,0,nRead); 1Ce@*XBU  
} ^nT/i .#_  
catch(Exception e){e.printStackTrace ();} <":;+Ng+  
} oz,np@f)J  
} bx#>BK!  
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//打印回应的头信息 3AHlSX  
public void logResponseHead(HttpURLConnection con) :}Xll#.,m  
{ X@$f$=  
for(int i=1;;i++) (n*^4@"2
 
{ V@B__`y7  
String header=con.getHeaderFieldKey(i); q 0$,*[PH  
if(header!=null) NO~*T?&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4iqoR$3Fc  
Utility.log(header+" : "+con.getHeaderField(header)); 00G%gQXk,  
else 4~k\j  
break; ]p _L)  
} DwaBdN[!7  
} NE"@Bk cm  
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public void splitterStop() W}3.E "K  
{ fRrvNj0{V  
bStop = true; )2pbpbWX>  
} s:OFVlC%\  
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} = 6tHsN23  
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/* 4zASMu  
**FileAccess.java +vYoB$!  
*//文件访问(定位，写) |S_T^'<W  
package NetFox;  V_C-P[2~  
import java.io.*; m`IC6
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public class FileAccessI implements Serializable{ tkVbo.[8K  
{FO;Yg'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8MK>)P o)  
RandomAccessFile oSavedFile; kQ4dwF~  
long nPos; l/BLUl~z  
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public FileAccessI() throws IOException M^MdRu  
{ =CK4.   
this("",0); .clP#r{U  
} y#>,+a#5  
wQv'8A_}  
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public FileAccessI(String sName,long nPos) throws IOException #OBJzf*p  
{ .E
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oSavedFile = new RandomAccessFile(sName,"rw"); E>&n.%  
this.nPos = nPos; D Gr> 2  
oSavedFile.seek(nPos); yN~dU0.G6!  
} Uh.oErHQD  
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public synchronized int write(byte[] b,int nStart,int nLen) `%CtWJ(e  
{ "nZ*{uv  
int n = -1; Z= jr-)kK  
try{ =NOH:#iQ  
oSavedFile.write(b,nStart,nLen); i\1TOP|h  
n = nLen; I3 .x9  
} AP[|Ta  
catch(IOException e) {88)~  
{ kdCUORMK  
e.printStackTrace (); #6ri-n  
} P9=?zh6G.  
6;C3RU]  
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return n; }Mo=PWI1?  
} Xg<*@4RD8  
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} n,=VQOu  
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/* 4$qWiG~  
**SiteInfoBean.java Wi[~fI8^!  
*/ K3m
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package NetFox; .gG1kWA-  
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public class SiteInfoBean { NLS
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private String sSiteURL; //Site's URL /DQc&.jK  
private String sFilePath; //Saved File's Path ,S'p%g  
private String sFileName; //Saved File's Name 4Fp0ZVT  
private int nSplitter; //Count of Splited Downloading File ~vXa
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ZQ)>s>-  
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public SiteInfoBean() xZ|Y?R5m  
{//nSplitter的缺省值为5 jov:]Bic  
//default value of nSplitter is 5 b7
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this("","","",5); 6b%WHLUeT  
} T%6&PrQ7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  Np'2}6P  
{ o4*+T8[|5  
sSiteURL= sURL; Q-MQ9'  
sFilePath = sPath; ?*?RP)V  
sFileName = sName; COTp  
this.nSplitter = nSpiltter;  PZ{Dv'C  
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} i/~
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public String getSSiteURL() TJ:]SB  
{ .A-]_98Z  
return sSiteURL; ~_Lr=CD;4  
} ?;vgUO  
*uo'VJI7_,  
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public void setSSiteURL(String value) cx}Q2S  
{ s<9RKfm  
sSiteURL = value; C?i >.t  
} v^zu:Z*  
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public String getSFilePath() VQ0fS!5'  
{ hSFn8mpXT  
return sFilePath; ;5tazBy&:C  
} HsnLm67'  
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public void setSFilePath(String value) ynw5-aS3  
{ X=Ys<TM,  
sFilePath = value; HcedE3Rg  
} GrTulN?  
:=8t"rO=W  
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public String getSFileName() e|&6$A>4]  
{ `2`\]X_A{  
return sFileName; n+BJxu?  
} :.?gHF.?  
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public void setSFileName(String value) >0dv+8Mn  
{ o$[z],RO  
sFileName = value; u{FDdR9<  
} zCOgBT~p  
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public int getNSplitter() ~}!3G  
{ ,(.MmP`  
return nSplitter; 0vVV%,v  
} P ~#>H{  
v3GwD00  
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public void setNSplitter(int nCount) pSm $FBW h  
{ 0<8XI>.3D  
nSplitter = nCount; R-Z~V  
} mo1oyQg8  
} qim 'dp:  
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/* K9vIm4::d$  
**Utility.java d/}SAvtt  
*/ h'$QC )P  
package NetFox; ]uspx[UIc  
4QIE8f Y  
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public class Utility { =C
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4O:W#bx  
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public Utility() <" @zn  
{ $!5\E>y#  
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} l<Q>N|1#k%  
rC
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//线程睡眠 zE)~0v
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public static void sleep(int nSecond) lCF`*DM#  
{ \m=?xb8 f  
try{ `MEYd U1  
Thread.sleep(nSecond); &20P,8@  
} aF|d^  
catch(Exception e) c}[+h5  
{ M7>(hVEAW'  
e.printStackTrace (); _5MNMVLwW  
} )RYG%  
} '!P"xBVAu  
hUz[uyt  
//日志 cECi')  
public static void log(String sMsg) YF:2>w<  
{ :K?0e`  
System.err.println(sMsg); E42eOGp9i  
} B/Gd(S`@q  
"4H8A=  
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public static void log(int sMsg) -Q;#sJ?  
{ hF3&i=;.  
System.err.println(sMsg); (-NHxo  
} k>
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} F8e<}v&7R  
^MD;"A<  
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/* bXYA5wG  
**TestMethod.java $jI>[%  
*/ Gjz[1d  
package NetFox; BpO9As 1um  
j%<}jw[2  
# x>ga  
public class TestMethod { gM>=%/.  
8*g ^o\M  
-~)OF  
public TestMethod() rZbEvS  
{ ///xx/weblogic60b2_win.exe [ neXFp}S  
try{ |m,VTViv;i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r^HAaGpC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); w W$(r-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {+("C] b  
fileFetch.start(); C9Bh@v%90^  
} 'ul\Q`N3  
catch(Exception e){e.printStackTrace ();} Qq0l*)mX  
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7Tf]:4Y"  
} >s*DrfX6  
++[5q+b  
W(
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public static void main(String[] args) qH%")7>  
{ \tJFAc  
new TestMethod(); 9x~-*8aw  
} <o:@dS  
} N4^5rrkL  
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