http断点续传简单实现（java)

/* Gg'!(]v  
**SiteFileFetch.java 72OqXa*  
*/ rwLKY.J]  
package NetFox; v}j5G, [-  
import java.io.*; mufGv%U2  
import java.net.*; o{,IO!q  
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public class SiteFileFetch extends Thread { ]{6/6jl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean RQQ'Wg  
long[] nStartPos; //开始位置 D#&9zR86F  
long[] nEndPos; //结束位置 &>Ve4!i q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Hh^ "c}  
long nFileLength; //文件长度 =\%
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boolean bFirst = true; //是否第一次取文件 W:RjWn@<  
boolean bStop = false; //停止标志 uAA2G\3  
File tmpFile; //文件下载的临时信息 Z|n|gxe  
DataOutputStream output; //输出到文件的输出流 x*vD^1"'P  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'r]6 GC8Z$  
public SiteFileFetch(SiteInfoBean bean) throws IOException [n[dr@J7v  
{ R BHDfm'~7  
siteInfoBean = bean; P!+Gwm{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MT~^wI0a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]!{S2x&"  
if(tmpFile.exists ()) ]M*`Y[5"  
{ D5c 8sB  
bFirst = false; u @Ze@N%  
read_nPos(); =l43RawAmu  
} W9%v#;2  
else A,_O=hA2I  
{ 9-T<gYl  
nStartPos = new long[bean.getNSplitter()]; >XgJo7u  
nEndPos = new long[bean.getNSplitter()]; e n~m)r3&  
} x;7l>uR  
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} 66pjWS {X  
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public void run() [y9a.*]u/@  
{ IADHe\.  
//获得文件长度 x9Z89Gwi  
//分割文件 XZKlE F?  
//实例FileSplitterFetch {nwoJ'-V  
//启动FileSplitterFetch线程 P'qBqx[  
//等待子线程返回 L6_%SGY_iE  
try{ xZ`z+
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if(bFirst) (-WRZLOQ  
{ t\ oud{Cv  
nFileLength = getFileSize(); |)!f".`  
if(nFileLength == -1) .3C::~:  
{ cZBXH*-M!  
System.err.println("File Length is not known!"); ,kJ7c;:i  
} >O\+9T@  
else if(nFileLength == -2) +u Iq]tqe  
{ _dm0*T ?  
System.err.println("File is not access!"); &qS%~h%2  
} u$R5Q{H_  
else BjfVNF;hk:  
{ I/njyV)H  
for(int i=0;i<nStartPos.length;i++) u"q
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{ /8e}c`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cRf F!EV  
} X~jdOaq{F:  
for(int i=0;i<nEndPos.length-1;i++) S#M8}+ZD,  
{ ,)[9RgsE  
nEndPos = nStartPos[i+1]; b$DiDm  
} U&#` <R_0  
nEndPos[nEndPos.length-1] = nFileLength; VP A+/5TW  
} 9\.0v{&v  
} F NPu  
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//启动子线程 (O+d6oT=Z2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E'aOHSAg  
for(int i=0;i<nStartPos.length;i++) X\Bl? F   
{ .hmeP MK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^Q`5+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), aPelt`  
nStartPos,nEndPos,i); gw"cX
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L-w3A:jk  
fileSplitterFetch.start(); !s-A`} s+  
} tG$O[f@U6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  ,RR{Y-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A6=Z2i0w>X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |,,#DSe  
nEndPos = " + nFileLength); Z2M(euzfi3  
// fileSplitterFetch[nPos.length-1].start(); +JtKVF  
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//等待子线程结束 MOQ6&C`7q  
//int count = 0; P6GTgQ<'BA  
//是否结束while循环 ooJxE\L
  
boolean breakWhile = false; `'s_5Ek  
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while(!bStop)  ~frsgHW  
{ U*a#{C7"  
write_nPos(); Nl YFS?5  
Utility.sleep(500); "y
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breakWhile = true;  <)TIj6  
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for(int i=0;i<nStartPos.length;i++) eWDXV-xD
 
{ uNn1qV  
if(!fileSplitterFetch.bDownOver) :o^ioX.J  
{ X&zGgP/  
breakWhile = false; W5Z-s.o  
break; :<P4=P P  
} SEI0G_wk$  
} fsjLD|?|:  
if(breakWhile) myA;Y  
break; 9wR D=a  
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//count++; S} UYkns*  
//if(count>4) R7Qj<,  
// siteStop(); ~}b0zL  
} n3$=&  
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System.err.println("文件下载结束！"); >;Hx<FKxP  
} (X@\2M4@T#  
catch(Exception e){e.printStackTrace ();} legWY)4D;  
} b~&cYk'  
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//获得文件长度 Nmx\qJUR(  
public long getFileSize() R_G2C@y*  
{ 1K3XNHF  
int nFileLength = -1; ,mm97I  
try{ -E\G3/*51  
URL url = new URL(siteInfoBean.getSSiteURL()); /rZk^/'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /4Wf\ Zu  
httpConnection.setRequestProperty("User-Agent","NetFox"); $EY[CA E  
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int responseCode=httpConnection.getResponseCode(); &C MBTY#u  
if(responseCode>=400) qWW\d', .  
{ PWS8Dpb  
processErrorCode(responseCode); H'3 pHb  
return -2; //-2 represent access is error S=P}Jpq?Y;  
}  _:\rB  
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String sHeader; dsw^$R}  
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for(int i=1;;i++) 4Vi*Qa_,y  
{ =b$g_+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2j420
2  
//Utility.log(in.readLine()); &PPnI(s^K  
sHeader=httpConnection.getHeaderFieldKey(i); EC$F|T0f  
if(sHeader!=null) B)7:*Kj  
{ 8WDL.IO  
if(sHeader.equals("Content-Length")) e*'bY;8lo  
{ }BS EK<W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vfqXHc unj  
break; X$==J St  
} {P?G
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} VJ-t#q"  
else hvTc( 0;mB  
break; <9>L^GgXA  
} 1.p?1"4\u  
} "oxUKT  
catch(IOException e){e.printStackTrace ();} m>Wt'Cc  
catch(Exception e){e.printStackTrace ();} ij]~n  
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Utility.log(nFileLength); HAE$Np|>a  
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return nFileLength; / P@P1l|I  
} Uot(3p!S6  
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//保存下载信息（文件指针位置） DOtz  
private void write_nPos() H$?MPA-c  
{
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try{ ~L&z?
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output = new DataOutputStream(new FileOutputStream(tmpFile)); G?F!Z"S  
output.writeInt(nStartPos.length); Ke^/aGi}O  
for(int i=0;i<nStartPos.length;i++) IrRy1][Qr  
{ "T /$K  
// output.writeLong(nPos); y+BiaD!U  
output.writeLong(fileSplitterFetch.nStartPos); |b@`ykD  
output.writeLong(fileSplitterFetch.nEndPos); tPiC?=4R  
} #pRbRT9  
output.close(); ~Fvz&dO  
} 3U?gw!M>  
catch(IOException e){e.printStackTrace ();} )%Xp?H_  
catch(Exception e){e.printStackTrace ();} TQt[he$O  
} d^?e*USh  
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//读取保存的下载信息（文件指针位置） 7h/Mkim$5  
private void read_nPos() |LIcq0Z  
{ umPN=0u6  
try{ nUq@`G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ii`,cJl  
int nCount = input.readInt(); 'O~_g5kC  
nStartPos = new long[nCount]; -;Mh|!yg  
nEndPos = new long[nCount]; D_F1<q  
for(int i=0;i<nStartPos.length;i++) # .&t'"u  
{ 9_*3xu<7i  
nStartPos = input.readLong(); s;<]gaonB_  
nEndPos = input.readLong(); Q%'4jn?H  
} ;YokPiBy  
input.close(); f~?5;f:E  
} Yc[vH=gV}  
catch(IOException e){e.printStackTrace ();}  wD  
catch(Exception e){e.printStackTrace ();} %j0c|u  
} agoMsxI9  
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private void processErrorCode(int nErrorCode) 'U@Ep  
{ l;z+E_sQ  
System.err.println("Error Code : " + nErrorCode); )@B!  
} W:f)#'  
!x-9A  
@(/$;I,  
//停止文件下载 \HoVS  
public void siteStop() N}z]OvnZH  
{ `aMnTF5:  
bStop = true; 9@h-q(-  
for(int i=0;i<nStartPos.length;i++) /$qB&OWJn  
fileSplitterFetch.splitterStop(); 0^P9)<k'  
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} t P'._0n0  
} 0n{+_   
//负责部分文件的抓取 H5FWk  
**FileSplitterFetch.java '&AeOn  
*/ V-%jSe<  
package NetFox; o9D#d\G  
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import java.io.*; 
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import java.net.*; SX?hu|g_r  
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public class FileSplitterFetch extends Thread { U&+lw=  
)1 0aDTlr  
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String sURL; //File URL `+(JwQC4  
long nStartPos; //File Snippet Start Position p|>/Hz1v  
long nEndPos; //File Snippet End Position }z-)!8vF  
int nThreadID; //Thread's ID (:#4{C  
boolean bDownOver = false; //Downing is over W}^>lM\8  
boolean bStop = false; //Stop identical sBN4:8  
FileAccessI fileAccessI = null; //File Access interface B`%%,SLJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5zJ#d}%}S"  
{ gepYV}  
this.sURL = sURL; Xs4G#QsAJ  
this.nStartPos = nStart; 2c9]Ja3:6  
this.nEndPos = nEnd; L
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nThreadID = id; Gnqun%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]waCYrG<sY  
} <ot%>\C  
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public void run() g3w-Le&T  
{ s\ ]Rgi>w  
while(nStartPos < nEndPos && !bStop) SP|Dz,o  
{ V+y:!t`  
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try{ 4y9n,~Qgw  
URL url = new URL(sURL); l0wvWv*k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q0_|?]v  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;cZ]^kof  
String sProperty = "bytes="+nStartPos+"-"; bJ.68643  
httpConnection.setRequestProperty("RANGE",sProperty); 4d]T`  
Utility.log(sProperty); ])T_&%  
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InputStream input = httpConnection.getInputStream();  0c:jwtf  
//logResponseHead(httpConnection); 1'J|yq  
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byte[] b = new byte[1024]; jDM^e4U.l  
int nRead; 6EX8,4c\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |)R{(AK-  
{ DO=zxdTI!  
nStartPos += fileAccessI.write(b,0,nRead); Gm
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//if(nThreadID == 1) WXE{uGc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DvXbbhp  
} Zh.9j7 >p  
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Utility.log("Thread " + nThreadID + " is over!"); @y\M8C8  
bDownOver = true; J3=^+/g  
//nPos = fileAccessI.write (b,0,nRead); .zyi'Kj  
} y>m=A41:g  
catch(Exception e){e.printStackTrace ();} XS"lR |  
} yu62$d  
} 9k!#5_ M  
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//打印回应的头信息 O!\\m0\e  
public void logResponseHead(HttpURLConnection con) V,Br|r$l(  
{ 4qEe
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for(int i=1;;i++) GCPSe A~cx  
{ HveOG$pT  
String header=con.getHeaderFieldKey(i); DJhCe==$v  
if(header!=null) IE9A _u*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xk5
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Utility.log(header+" : "+con.getHeaderField(header)); /7<l`RSr  
else KrT+Svm  
break;  H@,(  
} (f|3(u'e?  
} pVm'XP
 
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public void splitterStop() sny
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{ vSy#[9}  
bStop = true; B?J#NFUb  
} U_c.Z{lC4  
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} K%A:W  
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/* ]\<^rEU  
**FileAccess.java ?-0>Wbg  
*//文件访问(定位，写) @dCoh-Q3  
package NetFox; @'EU\Y\l  
import java.io.*; cvvba 60  
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public class FileAccessI implements Serializable{ @t6B\ ?4'T  
RE(R5n28,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u%vq<|~-  
RandomAccessFile oSavedFile; LCRZ<?O[|  
long nPos; {?' DZR s  
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public FileAccessI() throws IOException F+!K9(`|  
{ ,9W|$2=F  
this("",0); G-]ndrTn  
} =FXZcP>h  
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public FileAccessI(String sName,long nPos) throws IOException 'e;]\< 0z  
{ q}#4bB9  
oSavedFile = new RandomAccessFile(sName,"rw"); _fu?,  
this.nPos = nPos; U1t7XZ3e  
oSavedFile.seek(nPos); g9`z]qGWS:  
} 4~3 N;]X  
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public synchronized int write(byte[] b,int nStart,int nLen) /MB3w m  
{ O!(M:.  
int n = -1; Ph'P<h:V  
try{ kw>W5tNpf:  
oSavedFile.write(b,nStart,nLen); ~4\J}Kn  
n = nLen; |T
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} Oozt&* F  
catch(IOException e) YULI y-W  
{ CD'.bFO^+T  
e.printStackTrace (); *eAsA(;  
} #%xzy@`  
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return n; B6&;nU>;  
} Pvq74?an`  
5 #)5Z8`X  
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} Pwn3/+"%K  
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/* |#);^z_  
**SiteInfoBean.java mX9amS&B$  
*/ dMw0Aw,2]8  
package NetFox; ]kQ*t{\  
+,&8U&~`  
ykv,>nSXLL  
public class SiteInfoBean { k[0Gz  
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private String sSiteURL; //Site's URL 9gFema{U  
private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name K]{Y >w  
private int nSplitter; //Count of Splited Downloading File yF-EHNNf  
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public SiteInfoBean() :nZVP_d+  
{//nSplitter的缺省值为5 )_eEM1  
//default value of nSplitter is 5 @7Oqp-  
this("","","",5); 7cTDbc!E-  
} !=7(3<?  
]_6w(>A@3#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J3OxM--8"  
{ ' XJ>;",[  
sSiteURL= sURL; SW!lSIk  
sFilePath = sPath; ToWiXH)4
 
sFileName = sName; @kCFc
}  
this.nSplitter = nSpiltter; 5hN`}Ve  
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+>b~nK>M
 
} DlHt#Ob7  
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public String getSSiteURL() F<K;tt  
{ cI~uI'  
return sSiteURL; z']TRjDbT  
} 3mI(5~4A]?  
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public void setSSiteURL(String value) >/@wht4- j  
{ Ah5`
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sSiteURL = value; -][~_Hd{  
} I!FIV^}Z(  
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~  
public String getSFilePath() N~rA/B]T  
{ 0!<qfT a  
return sFilePath; TR;"&
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} N`3q54_$  
}HB>Zb5  
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public void setSFilePath(String value) *$K_Tii  
{ h$p]M^Z7  
sFilePath = value; 87; E#2  
} T?vM\o%i3  
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public String getSFileName() GRM:o)4;#  
{ k!?sHUAj  
return sFileName; d}@b 3  
} K/xn4N_UX  
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public void setSFileName(String value) [{iPosQWj  
{ w ]8+ OP  
sFileName = value; oT76)O  
} <v&L90+s\;  
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public int getNSplitter() BK$cN>J  
{
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return nSplitter; Qt-7jmZw1  
} 5&59IA%S  
4eFqD;  
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public void setNSplitter(int nCount) Y~E 8z
 
{ `_YXU  
nSplitter = nCount; srzlr-J  
} ltQo_k  
} i}u,_ }  
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b+=@;0p*6B  
/* 7:[u.cd  
**Utility.java s#Os?Q?  
*/ s2Z'_rT  
package NetFox; #:B14E  
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public class Utility { o >wty3l:  
{lam
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:.
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public Utility() >m:;.vVY  
{ Nxm^jPM0  
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} `T'[H/  
t=l@(%O 0_  
//线程睡眠 ^LI\W'K  
public static void sleep(int nSecond) o#Gf7.E8  
{ ttP|}|O  
try{ ! 3 ;;6  
Thread.sleep(nSecond); Vs1H)T%  
} 1k)31GEQw  
catch(Exception e) 83(-/y  
{ 'c7'iDM  
e.printStackTrace (); <z.Y#{p?k  
} As{Q9o5j/  
} e w%rc.;  
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//日志 4h*c{do  
public static void log(String sMsg) %LM2CgH V  
{ |*fi!nvk@  
System.err.println(sMsg); H*.v*ro9_  
} K#%@4]jO3  
C.|.0^5  
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public static void log(int sMsg) ,kQCCn]  
{ ]D.} /g  
System.err.println(sMsg);
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} q!10G  
} /wi*OZ7R  

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/* tf3R  
**TestMethod.java ?]%ZJd  
*/ i,h)VCc  
package NetFox; T^ )\  
m$.7) 24  
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public class TestMethod { d53Eu`QW?  
w#d7  
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public TestMethod() sC'PtFK8z  
{ ///xx/weblogic60b2_win.exe ).32Im!;#R  
try{ >6KwZr BB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aCRiW;+'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Gh5 3Pne  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]."t  
fileFetch.start(); x'v-]C(@  
} r9Vt}]$aG  
catch(Exception e){e.printStackTrace ();} [-0=ZKH?  
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} |jI|},I  
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public static void main(String[] args) t`- [  
{ 'WNq/z"X  
new TestMethod(); tjLG$M1z`  
} !ra,HkU
'  
} z8dBfA<z  
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