http断点续传简单实现（java)

/* 3AWNoXh  
**SiteFileFetch.java $w
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*/ xN\PQ,J  
package NetFox; iw|6w,-)C  
import java.io.*; oI9Jp`  
import java.net.*; 4C&L%A  
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^
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public class SiteFileFetch extends Thread { :('7ly!h  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %gB 0\C  
long[] nStartPos; //开始位置 Z']D8>d  
long[] nEndPos; //结束位置 YcS}ug7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }Y(yDg;"  
long nFileLength; //文件长度 3Q^@!hu  
boolean bFirst = true; //是否第一次取文件 ?^9TtxM  
boolean bStop = false; //停止标志 1!. CfQi  
File tmpFile; //文件下载的临时信息 8Ua;< h%  
DataOutputStream output; //输出到文件的输出流 Do}mCv  
%J\1W"I?  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^+:_S9qst  
public SiteFileFetch(SiteInfoBean bean) throws IOException <o5+*X  
{ q2}<n'o+  
siteInfoBean = bean; Lxm1
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n$ye:p>`-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z3=DM=V;v  
if(tmpFile.exists ()) _s./^B_w!  
{ j;fmmV@  
bFirst = false; &$fe%1#  
read_nPos(); F"9f6<ge  
} )J+vmY~&  
else SGMLs'D   
{ 5gWn{[[e)y  
nStartPos = new long[bean.getNSplitter()]; =:(8F*Q  
nEndPos = new long[bean.getNSplitter()]; 4NxtU/5-sU  
} @p jah(i`  
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} e[}R1/!L  
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public void run() >l
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{ 'sI=*c  
//获得文件长度 1cS{3  
//分割文件 z#b31;A@$  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 6C>x,kU  
//等待子线程返回 9="i'nYp  
try{ a3]'%kKp  
if(bFirst) :Vq gmn  
{ M:h~;+s  
nFileLength = getFileSize(); ]*-9zo0  
if(nFileLength == -1) -\yaP8V  
{ v`B7[B4K3  
System.err.println("File Length is not known!"); 6/9 A'!4C  
} +vfk+6  
else if(nFileLength == -2) NL))!Pi  
{ MId\dFu  
System.err.println("File is not access!"); u2'xM0nQ  
} >4=sEj  
else zEJ|;oL  
{ r'fNQJ >  
for(int i=0;i<nStartPos.length;i++) X\\WQxj  
{ ;<%~g8:XL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,WbO8#z+  
} mfLS</A  
for(int i=0;i<nEndPos.length-1;i++) .EGZv(rz&  
{ EKf"e*|(L  
nEndPos = nStartPos[i+1]; ^<xpp.eY  
} \}t(g}7T  
nEndPos[nEndPos.length-1] = nFileLength; GOHRBV  
} JI5?, )-St  
} .Vq-
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//启动子线程 $Y][-8{t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2#5SI  
for(int i=0;i<nStartPos.length;i++) ptGM'  
{ |/zE(ePc{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~^=QBwDW8N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4`)B@<  
nStartPos,nEndPos,i); XbYW,a@w2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v#:#w.]-Y  
fileSplitterFetch.start(); YSk,kU  
} <T:u&Ic  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %WHue  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f;#hcRSH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y!fV+S,  
nEndPos = " + nFileLength); F?e_$\M  
// fileSplitterFetch[nPos.length-1].start(); <LQwH23@  
:<Y,^V(  
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//等待子线程结束 !0ySS {/  
//int count = 0; o6K\z+.{  
//是否结束while循环 @rkNx@[~  
boolean breakWhile = false; LJYFz=p"  
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while(!bStop) +LV~%?W  
{ =dUeQ?>t=  
write_nPos(); Ix !O&_6s  
Utility.sleep(500); i;`rzsRb  
breakWhile = true; sCSrwsbhv  

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for(int i=0;i<nStartPos.length;i++) gO4`e(W  
{ Z1u{.^~^z  
if(!fileSplitterFetch.bDownOver) )Ve?1?s '8  
{ py9(z`}  
breakWhile = false; zCj]mH`es'  
break; nRN&
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} {,|*99V  
} %O>ehIerD  
if(breakWhile) #0"Fw$P
c  
break; Uaj8}7v  
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&(-+?*A`E  
//count++; WMZ&LlB%  
//if(count>4) (}vi"mCeW  
// siteStop(); bNp RGhlV  
} a_w#,^/P  
~\<Fq\.x  
{e0cc1Up}  
System.err.println("文件下载结束！"); 6;9SU+
/  
} Xa\{WM==;  
catch(Exception e){e.printStackTrace ();} IIUoB!
`  
} ]wWN~G)2lV  
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//获得文件长度 xRq|W4ay  
public long getFileSize() 8-UlbO6  
{ wlKfTJrn&  
int nFileLength = -1; G+[hE|L~y  
try{ p ElF,Y  
URL url = new URL(siteInfoBean.getSSiteURL()); DG}t!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DzYi> E:*  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5X4; (Qj  
/=A^@&:_#  
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int responseCode=httpConnection.getResponseCode(); p]:5S_$  
if(responseCode>=400) ihBlP\C  
{ L0Bcx|)"$`  
processErrorCode(responseCode); _5EM<Ux  
return -2; //-2 represent access is error W'eF | hu  
} j8WnXp_  
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String sHeader; Co&#mVY4,  
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for(int i=1;;i++) AK%`EsI^  
{ ?<b
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,IF3VE&r  
//Utility.log(in.readLine()); PsMoH/+"  
sHeader=httpConnection.getHeaderFieldKey(i); s"?Z jV)`  
if(sHeader!=null) vdAaqM6D  
{ }&Ngh4/  
if(sHeader.equals("Content-Length")) ;*5$xs&=_Z  
{ w,> ceu/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "C&l7K;bp  
break; _Je<_pl!D  
} W~2`o*\l  
} Vb az#I  
else /]=Ih  
break; v\PqhIy"  
} C|bnUN  
} n|sP0,$N1  
catch(IOException e){e.printStackTrace ();} <R582$( I  
catch(Exception e){e.printStackTrace ();} {Y6U%HG{{r  
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Utility.log(nFileLength); FY+0r67]  
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return nFileLength;
=v]\{.  
} Z5/^pyc  
<]xGd!x$  
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//保存下载信息（文件指针位置） '!^5GSP3&  
private void write_nPos() ~VYZu=p
 
{ q">lP(t  
try{ *UhYX)J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F9p'|-   
output.writeInt(nStartPos.length); )0UVT[7  
for(int i=0;i<nStartPos.length;i++) uP2e/a  
{ m1H_kJ  
// output.writeLong(nPos); 35;|r  
output.writeLong(fileSplitterFetch.nStartPos); }7&.FV"  
output.writeLong(fileSplitterFetch.nEndPos); W{:^P0l  
} 89o&KF]  
output.close(); L"{qF<@V7&  
} 2%P{fJbwd  
catch(IOException e){e.printStackTrace ();} 0=O(+ yi  
catch(Exception e){e.printStackTrace ();} wd*8w$\  
} +A%|.;  
-d5b,leC^  
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//读取保存的下载信息（文件指针位置） djJD'JL  
private void read_nPos() 4Bg
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{ sh;DCd  
try{ _W]R|kYl$'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E#}OIZ\S  
int nCount = input.readInt(); UtPFkase  
nStartPos = new long[nCount]; nX%b@cOXj  
nEndPos = new long[nCount]; uqy&PS  
for(int i=0;i<nStartPos.length;i++) 3kfrOf.4h  
{ 3+vbA;R  
nStartPos = input.readLong(); N$]B$vv  
nEndPos = input.readLong(); ,yc_r=_  
} " E+V>V+  
input.close(); Cge@A'2  
} GPV=(}z  
catch(IOException e){e.printStackTrace ();} AB(WK9o  
catch(Exception e){e.printStackTrace ();} 0x BO5[w,Y  
} -
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private void processErrorCode(int nErrorCode) `R[cM;c2  
{ 8LuM eGs  
System.err.println("Error Code : " + nErrorCode); >}<1  
} SFqY*:svOw  
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@cYb37)q=  
//停止文件下载 r+v?~m!  
public void siteStop()
{<ms;Oi'  
{ (Yi1U~{:  
bStop = true; DR]=\HQ  
for(int i=0;i<nStartPos.length;i++) }@6Tcn1  
fileSplitterFetch.splitterStop(); (~S=DFsP  
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} >_XC  
} vYl2_\,Y?  
//负责部分文件的抓取 by}C;eN  
**FileSplitterFetch.java ~]f6@n  
*/ ($QQuM=  
package NetFox; "06t"u<%  
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import java.io.*; U]Y</>xGI  
import java.net.*; WSEw:pln  
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public class FileSplitterFetch extends Thread { 7b8+"5~  
lo!^h]iE!  
+G:CR,Z>+  
String sURL; //File URL >lPWji'4;  
long nStartPos; //File Snippet Start Position M'gGoH}B+q  
long nEndPos; //File Snippet End Position T'6MAxEZUq  
int nThreadID; //Thread's ID zTBf.A;e7  
boolean bDownOver = false; //Downing is over +/+>:  
boolean bStop = false; //Stop identical `:b*#@  
FileAccessI fileAccessI = null; //File Access interface vJ,r}$H3  
8MQb5( !  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r=}v` R&  
{ sdp3geBYo  
this.sURL = sURL; =D~>$Y  
this.nStartPos = nStart; JjMa
 
this.nEndPos = nEnd; i}Q"'?  
nThreadID = id; G0%},Q/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r7ebFJEf  
} uH{oJSrK  
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public void run() iW%~>`tT  
{ xeNj@\jdC5  
while(nStartPos < nEndPos && !bStop) NHaY&\  
{ /SW*y@R2l  
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:  
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try{ G!T_X*^q2U  
URL url = new URL(sURL); =\`iC6xP}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %6.WGuO  
httpConnection.setRequestProperty("User-Agent","NetFox"); rdH3!
 
String sProperty = "bytes="+nStartPos+"-"; Z".Xroq~  
httpConnection.setRequestProperty("RANGE",sProperty); \>$3'i=mQ  
Utility.log(sProperty); ]?G|:Kx$y%  
r'(*#  
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InputStream input = httpConnection.getInputStream(); Gf=3h4  
//logResponseHead(httpConnection); b(_f{R7PY  
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byte[] b = new byte[1024]; "5HSCl$r%  
int nRead; W1Vy5V|M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :%-w/QwTR  
{ y{KYR)  
nStartPos += fileAccessI.write(b,0,nRead); F|a'^:Qs  
//if(nThreadID == 1) a[_IG-l|i4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ${)oi:K@:  
} uG$*DeZti  
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Utility.log("Thread " + nThreadID + " is over!"); riZ :#I  
bDownOver = true; N7u|< 0[  
//nPos = fileAccessI.write (b,0,nRead); Y&<]:)  
} l6*MiX]q  
catch(Exception e){e.printStackTrace ();} ]ZnASlc)  
} P$x9Z3d_  
} e9RH[:  
'NMO>[.  
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//打印回应的头信息 ,j6R/sg  
public void logResponseHead(HttpURLConnection con) GT7&>}FJ)  
{ yJ/YK  
for(int i=1;;i++) [l/!&6  
{  + \]-"  
String header=con.getHeaderFieldKey(i); sW-0G$,|  
if(header!=null) <Umr2Vw-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k Nvb>v  
Utility.log(header+" : "+con.getHeaderField(header)); +MZI\>  
else D;
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break; 9W0*|!tQ,+  
} dS8ydG2  
} 9 JhCSw-<)  
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public void splitterStop() _NB*+HVo  
{ "F =NDF  
bStop = true; q9
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} *c\XQy  
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} mlxtey6H3  
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/* +_L]d6  
**FileAccess.java OwT_W)$  
*//文件访问(定位，写) A=0{}B#  
package NetFox; Y7zs)W8xTT  
import java.io.*; Q6Hgh
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public class FileAccessI implements Serializable{ !?>QN'p.b  
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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 @ta:9wZ  
RandomAccessFile oSavedFile; -u(,*9]cJ*  
long nPos; Lk!m1J5  
eR,/}g\  
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public FileAccessI() throws IOException P-a8S*RRa  
{ Rc:}%a%e  
this("",0); _9]vlxgtG(  
} -wrVEH8  
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public FileAccessI(String sName,long nPos) throws IOException ol41%q*  
{ '}9 Nvr)+  
oSavedFile = new RandomAccessFile(sName,"rw"); 7H09\g&  
this.nPos = nPos; {?Nm"#  
oSavedFile.seek(nPos); PZQAlO,  
} ^.R!sQ  
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public synchronized int write(byte[] b,int nStart,int nLen) O_qwD6s-_  
{ t V( WhP  
int n = -1; I eJI-lo  
try{ 0@!huk  
oSavedFile.write(b,nStart,nLen); :._Igjj$=  
n = nLen; 8h0CG]  
} z"T+J?V/  
catch(IOException e) sfipAM  
{ hsQDRx%H}  
e.printStackTrace (); ht*(@MCr<  
} \i/HHP[%  
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return n; ?QmtZG.$  
} !qp$Xtf+  
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} g5y`XFY  
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5
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/* Ea&NJ]& g  
**SiteInfoBean.java {f\wIZ-K A  
*/ L{P'mG=4  
package NetFox; aPzn4}~/_  
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public class SiteInfoBean { "5L?RkFi\  
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{?`7D:]`^  
private String sSiteURL; //Site's URL 4~3 n =
T*  
private String sFilePath; //Saved File's Path *~g*J^R
}  
private String sFileName; //Saved File's Name 1&! i:F#  
private int nSplitter; //Count of Splited Downloading File (BPO*'  
~CT]&({  
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public SiteInfoBean() &:5*^1oP  
{//nSplitter的缺省值为5 L'r&'y[  
//default value of nSplitter is 5 z?<B@\~  
this("","","",5); lHtywZ@%3  
} rbnAC*y8'L  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t 86w&  
{ >vp4R`  
sSiteURL= sURL; BK%.wi  
sFilePath = sPath; )M
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sFileName = sName; x;)I%c  
this.nSplitter = nSpiltter; e,epKtL  
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} P4q5#r  
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public String getSSiteURL() !DzeJWM|  
{ #<< el;n  
return sSiteURL; L&DjNu`!9  
} Sc]K-]1(H  
w.w{L=p:<"  
x)*Lu">  
public void setSSiteURL(String value) 72d|Jbd  
{ ?/OF=C#  
sSiteURL = value; ~*7$aj  
} E+i*u   
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public String getSFilePath() Ny2 Z <TW  
{ LWv<mtuYf  
return sFilePath; b'\Q/;oz>  
} Q3tyK{JE  
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public void setSFilePath(String value) $uHQl#!;  
{ LAlwQ^v|  
sFilePath = value; {/]2~!  
} R|8vdZ%@  
6&os`!  
`jGeS[FhR  
public String getSFileName() ;Y\LsmZ;F  
{ "G [Nb:,CR  
return sFileName; wHbkF#[:i  
} wx*?@f>u^  
.qSDe+A  
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public void setSFileName(String value) u:f ]|Q
 
{ ^AH[]sE_  
sFileName = value; gLX<>|)*  
} 4HGTgS  
i8V\x>9  
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public int getNSplitter() L]H'$~xx*  
{ ;&&<zWq3h  
return nSplitter; KMwV;r  
} aO(PVS|P  
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public void setNSplitter(int nCount) QCW4gIp  
{ D_d>A+  
nSplitter = nCount; xRD+!3  
} ;[::&qf  
} ;|WUbc6&g  
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/* kw$7G1Q  
**Utility.java ~{I.qv)>M~  
*/ d <}'eBT'  
package NetFox; kM506U<g  
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public class Utility { nZbI}kcm  

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public Utility() Ei_~K';  
{ Qb^G1#r@C  
$Aw@xC^!  
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} [Kwj 7q`  
JJd qdX;  
//线程睡眠 RRt(%Wm*  
public static void sleep(int nSecond) &YXJ{<s  
{ "tCTkog3]  
try{ WiytHuUF  
Thread.sleep(nSecond); PT2;%=f
 
} L(TM& ps\-  
catch(Exception e) P~trxp=k  
{ @GN2v,WA?  
e.printStackTrace (); 0SL{J*S4[#  
} v8ap"9b  
} S[F06.(1  
-'$ob~*  
//日志 :/T\E\Qr  
public static void log(String sMsg) T'5{p  
{ |Mq+QDTTw~  
System.err.println(sMsg); G\gjCp?!  
} 5*$yY-A  
O=2|'L'h!  
I_<VGUk  
public static void log(int sMsg) 6j(/uF4!#  
{ n4kq=Z%
 
System.err.println(sMsg); ^!1!l-  
} ">bhxXeiN  
} ZIx-mC5  
zTg\\z;  
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/* '|IcL1c=I  
**TestMethod.java (!nkv^]  
*/ yNns6  
package NetFox; (t-hi8"  
5tlRrf  
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public class TestMethod { %
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:.x(( FU  
"|8oFf)l@B  
public TestMethod()  aO&U=!  
{ ///xx/weblogic60b2_win.exe 5%Qxx\q  
try{ L0g+RohW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BmX'%5ho  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a#j,0FKv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IIR+qJ__|  
fileFetch.start(); y&$n[j  
} 7_\sx7h{3  
catch(Exception e){e.printStackTrace ();} Yj
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7S{qo&j'  
L"bJ#0m  
} |owr?tC  
a4,V(Hlm  
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public static void main(String[] args) &ys>z<Z  
{ Q>{$Aqc,e  
new TestMethod(); L)JB^cxf  
} .t@|2  
} t$!zgUJ  
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