http断点续传简单实现（java)

/* im|( 4f  
**SiteFileFetch.java T_|%nF-+  
*/ MWl?pG!Y  
package NetFox; ]/hF!eO  
import java.io.*; G?CaCleG  
import java.net.*; Y 
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public class SiteFileFetch extends Thread { D*BZp0x  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `&2~\o/  
long[] nStartPos; //开始位置 GOuBNaU{  
long[] nEndPos; //结束位置 8+K=3=05#U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S7]\tw_L)  
long nFileLength; //文件长度 B,@geJ  
boolean bFirst = true; //是否第一次取文件 8}z]B^?Fy  
boolean bStop = false; //停止标志 'RK.w^  
File tmpFile; //文件下载的临时信息 XG FjqZr`  
DataOutputStream output; //输出到文件的输出流 ~XGBE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t&}Z~Zp  
public SiteFileFetch(SiteInfoBean bean) throws IOException |^9+c2  
{ BK`NPC$a  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [mwJ*GJ-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ilK8V4k<T)  
if(tmpFile.exists ()) !W:QLOe6F  
{ 6\86E$f=h  
bFirst = false; 'OGOT0(  
read_nPos(); I#l9  
} %9mCgHQ9  
else Kw'Dzz%kN  
{ "!)8bTW  
nStartPos = new long[bean.getNSplitter()]; ,|I\{J #C  
nEndPos = new long[bean.getNSplitter()]; We#*.nr{3Z  
} v%3)wD  
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} 1jmhh!,  
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public void run() zJ9ZqC]  
{ z!Kadqns  
//获得文件长度 hl~(&D1^  
//分割文件 ;$i9gP[|m  
//实例FileSplitterFetch @ x*#7Y  
//启动FileSplitterFetch线程 v )7d  
//等待子线程返回 (I.uQP~H  
try{ Cu;X{F'H  
if(bFirst) q1dYiG.-Z  
{ 5, Yk5?l<'  
nFileLength = getFileSize(); v,>F0ofJ  
if(nFileLength == -1) tzpGKhrk6  
{ jo<sN  
System.err.println("File Length is not known!"); &P3B  
} B_5q}Bp<  
else if(nFileLength == -2) Wr)%C  
{ >mF
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System.err.println("File is not access!"); 8KWTd
 
} `?JrC3  
else #<'/sqL  
{ N83RsL "}_  
for(int i=0;i<nStartPos.length;i++) :o}7C%Q8  
{ x6DH0*[.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =hl-c  
} $Z28nPd/  
for(int i=0;i<nEndPos.length-1;i++) }Tc)M_  
{ `"ie57-  
nEndPos = nStartPos[i+1]; A94VSUDA:  
} .h+<m7  
nEndPos[nEndPos.length-1] = nFileLength; q/OraPAB  
} tDN-I5q  
} Zl,K#  
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//启动子线程 Zt!l3(*tt  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dN*<dz+4r  
for(int i=0;i<nStartPos.length;i++) Z<,gSut'Y  
{ T)C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }Xc|Z.6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CKBi-q FH  
nStartPos,nEndPos,i);  Mxr#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {iQ<`,)Y  
fileSplitterFetch.start(); /asyj="N7  
} &H4UVI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u|:VQzPd-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [2\`Wh:%P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5Rec}H  
nEndPos = " + nFileLength); V)(pe #P  
// fileSplitterFetch[nPos.length-1].start(); ]`4QJ;#  
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+$ -#V
  
//等待子线程结束 9hguC yr@h  
//int count = 0; Ck^=H  
//是否结束while循环 g<lX Xj2  
boolean breakWhile = false; d?{2A84S  
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while(!bStop) gRqz8UI  
{ {W4t]Ff  
write_nPos(); {(MG: B  
Utility.sleep(500); 1b!l+ 8!  
breakWhile = true; cEQa 6  
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for(int i=0;i<nStartPos.length;i++) mE7Jv)@  
{ aEM#V  
if(!fileSplitterFetch.bDownOver) &GZR-/  
{ O~Fk0}-  
breakWhile = false; :YI>AaYWDO  
break; 9(PFd%  
} k m|wB4  
} $7bmUQ|  
if(breakWhile) CKR9APkv  
break; P<(mH=K  
QA9vH'  
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//count++; =N0cz%  
//if(count>4) =~S   
// siteStop(); o{Ep/O`  
} uJ y@  
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d!X?R}  
System.err.println("文件下载结束！"); ]s SoIT  
} 2M1mdkP3  
catch(Exception e){e.printStackTrace ();} ky%%H;  
} (1HN, iJy  
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//获得文件长度 ;Dgp !*v=  
public long getFileSize() #P@r[VZ{6  
{ {p\KB!Y-  
int nFileLength = -1; 24T
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try{ 18HHEW{  
URL url = new URL(siteInfoBean.getSSiteURL()); u'b_zlW@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +~v(*s C  
httpConnection.setRequestProperty("User-Agent","NetFox"); %jf gncW  
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int responseCode=httpConnection.getResponseCode(); O:x%!-w  
if(responseCode>=400) PWU#`>4  
{ =w8 YZs8w  
processErrorCode(responseCode); Lgfr"{C  
return -2; //-2 represent access is error srkOad  
} <KA@A}  
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String sHeader;  zVa+5\Q  
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for(int i=1;;i++) lq5E?B  
{ <coCu0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J)-> 7h=  
//Utility.log(in.readLine()); A~>=l=  
sHeader=httpConnection.getHeaderFieldKey(i); y_&XF>k91  
if(sHeader!=null) X9j+$X\j  
{ =R"tnjR  
if(sHeader.equals("Content-Length")) N-|Jj?c  
{ bW|y -GM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); O5?Eb  
break; yB1>83!q  
} u2Obb`p S  
} ?rDwYG(u]@  
else a40BisrD~6  
break; >KFJ1}b|3  
} "
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} dp70sA!JF  
catch(IOException e){e.printStackTrace ();} }+J@;:  
catch(Exception e){e.printStackTrace ();} g <o;\\  
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Utility.log(nFileLength); 7A6sSfPUy  
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return nFileLength; BxU1Q&  
} K=)R!e8  
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b!?  
//保存下载信息（文件指针位置） A'8K^,<  
private void write_nPos() dFFqs&cQ  
{ QR'g*Bro  
try{ kDh(~nfj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +GS=zNw#  
output.writeInt(nStartPos.length); ;gnr\C*G  
for(int i=0;i<nStartPos.length;i++) W!X]t)Ow  
{ c,wU?8Nc|$  
// output.writeLong(nPos); /f<(K-o]  
output.writeLong(fileSplitterFetch.nStartPos); i#=X#_ +El  
output.writeLong(fileSplitterFetch.nEndPos); @k,(i=**  
} 7p$*/5fk  
output.close(); #O+]ydvT  
} #^ #i]{g  
catch(IOException e){e.printStackTrace ();} ZtoE=7K  
catch(Exception e){e.printStackTrace ();} E=NY{|>  
} {SJ7Yfs  
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//读取保存的下载信息（文件指针位置） :nUsC+oBS  
private void read_nPos() bicL%I2h  
{ Fw m:c[G  
try{ I "2FTGA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5.#9}]  
int nCount = input.readInt(); >}*jsqaVU  
nStartPos = new long[nCount]; l)s+"C#  
nEndPos = new long[nCount]; X~3P?O]kFv  
for(int i=0;i<nStartPos.length;i++) "n,ZP@M;  
{ }8: -I Nj4  
nStartPos = input.readLong(); :,,y63-f4  
nEndPos = input.readLong(); % cdP*  
} VH6|(=8  
input.close(); <1BK5%?  
} o7XRa]O  
catch(IOException e){e.printStackTrace ();} #UD  
catch(Exception e){e.printStackTrace ();} DG?\6Zh  
} TWEqv<c  
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private void processErrorCode(int nErrorCode) J9.p8A^^2  
{ E(_I3mftm  
System.err.println("Error Code : " + nErrorCode); nk 9 K\I  
} reJ?38(  
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pw yl,A  
//停止文件下载 3yB6]U  
public void siteStop() #%"
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{ L.[uMuUa  
bStop = true; F|`B2Gr  
for(int i=0;i<nStartPos.length;i++) 2{I
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fileSplitterFetch.splitterStop(); G5J ZB7C  
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} mm<iT59  
} G%jJ>T4  
//负责部分文件的抓取 Yj/nzTVJ[  
**FileSplitterFetch.java E*CQG;^=N  
*/ 3#9r4;&  
package NetFox; l]y%cJ~$'D  
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import java.io.*; gD+t'qg$  
import java.net.*; T)tHN#6I  
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public class FileSplitterFetch extends Thread { :wmf{c  
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String sURL; //File URL SH$cn,3F8  
long nStartPos; //File Snippet Start Position ":^ NLBm>5  
long nEndPos; //File Snippet End Position 0QH3,Ps1C  
int nThreadID; //Thread's ID wK`ieHmp  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical C|;Mhe'r=  
FileAccessI fileAccessI = null; //File Access interface 7oLf5V1~  
8Pr7aT:,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9.OwH(Ax7  
{ ~nc([%!=  
this.sURL = sURL; v:Z4z6M-  
this.nStartPos = nStart; 6 %k+
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this.nEndPos = nEnd; +ls*//R  
nThreadID = id; !"x7re  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C 3XZD4.2  
} {!eANm'  
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public void run() =>ztBw\  
{ Y0fO.k#C^  
while(nStartPos < nEndPos && !bStop) tvH\iS#V  
{ ,\9mAt1O  
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try{ jM1%6  
URL url = new URL(sURL); xgT~b9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L8]{B  
httpConnection.setRequestProperty("User-Agent","NetFox"); fw|+7 O  
String sProperty = "bytes="+nStartPos+"-"; V>jhGf  
httpConnection.setRequestProperty("RANGE",sProperty); K7xWE,y  
Utility.log(sProperty); kAB+28A  
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InputStream input = httpConnection.getInputStream(); ,WB_C\.#XN  
//logResponseHead(httpConnection); "`i:)Et  
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byte[] b = new byte[1024]; ^L-w(r62<  
int nRead; sLAuR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6%\Q*r*N  
{ *fH_lG%  
nStartPos += fileAccessI.write(b,0,nRead); c@ZS|U*(  
//if(nThreadID == 1) Gkv~e?Kc~^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); << ;HY}s  
} 3 IWLBc  
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Utility.log("Thread " + nThreadID + " is over!"); G=Hf&l  
bDownOver = true; t`Y!"l  
//nPos = fileAccessI.write (b,0,nRead); 8@%mnyQ  
} '{0[&i*  
catch(Exception e){e.printStackTrace ();}  &(1H!  
} 5K ,#4EOV  
} IObx^N_K  
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//打印回应的头信息 Zgg'9E  
public void logResponseHead(HttpURLConnection con)  gmRT1T  
{ Jh43)#G-  
for(int i=1;;i++) )XP#W|;  
{ -.{oqs
$  
String header=con.getHeaderFieldKey(i); 4N~+G `  
if(header!=null) UK6xkra?#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {eEC:[  
Utility.log(header+" : "+con.getHeaderField(header)); 8wII{FHX  
else +:>JZ$  
break; +%Lt".o  
} `s`C{|wv  
} V\6(d  
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public void splitterStop() OQ(D5GR:4  
{ @n7t?9Bx  
bStop = true; wy{\/?~c  
} )d +hZ'  
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} `
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/* 0%s3
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**FileAccess.java L`UG=7r q  
*//文件访问(定位，写) Q PFeBl  
package NetFox; <t{?7_ 8  
import java.io.*; X"[dQ_o  
k7^R,.c@  
~{kM5:-iw  
public class FileAccessI implements Serializable{ >[ug zJ  
v@8S5KJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'aD6>8/Hj  
RandomAccessFile oSavedFile; nW4Vct  
long nPos; z,{e]MB)M  
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*  
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public FileAccessI() throws IOException %won=TG8  
{ 8p (!]^z  
this("",0); fokwW}>B[f  
} fyI_  
E'5Ajtw;  
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public FileAccessI(String sName,long nPos) throws IOException 1GtOA3,~;-  
{ NJZXs_%>$  
oSavedFile = new RandomAccessFile(sName,"rw"); n6b3E*  
this.nPos = nPos; 6*ZU}xT  
oSavedFile.seek(nPos); [}>#YPZ  
} 2B7h9P.NB  
&*B>P>x  
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public synchronized int write(byte[] b,int nStart,int nLen) Dp*:Q){>E  
{ 8q?;2w\l  
int n = -1; Kb}MF9?:e  
try{ K~c^*;F  
oSavedFile.write(b,nStart,nLen); 6Wj@r!u  
n = nLen; AD^X(rW  
} coD
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catch(IOException e) 4d!S#zx  
{ Nd`HB=ShJ  
e.printStackTrace (); cV-i*L4X  
} P7z:3o.  
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return n; BBcj=]"_
 
} '/k^C9~m r  
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} 0pD W _  
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/* |K%}}g[<e;  
**SiteInfoBean.java J"-_{)0lD  
*/ R1}IeeZO?&  
package NetFox; sltk@  
Nz~(+pVWg5  
OR]T`meO  
public class SiteInfoBean { A8J8u,u9  
$,TGP+vH  
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private String sSiteURL; //Site's URL {VR`;  
private String sFilePath; //Saved File's Path Vt'L1Wr0v  
private String sFileName; //Saved File's Name jZRhKT  
private int nSplitter; //Count of Splited Downloading File lr WLN  
34SA
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public SiteInfoBean() sxo;/~.p  
{//nSplitter的缺省值为5 8x9Rm  
//default value of nSplitter is 5 4IZlUJ?j+c  
this("","","",5); /|?F)%v\  
} |H8^  
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~ FGe~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) D}w<84qX  
{ > @+#  
sSiteURL= sURL; X(]Zr  
sFilePath = sPath; [B,'=,Hbs  
sFileName = sName; %swR:
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this.nSplitter = nSpiltter; <s_=-" il  
2
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:
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} (3VGaUlx  
),=@q+{E{  
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public String getSSiteURL() b$Ln}<  
{ fD{II+T  
return sSiteURL; tjj^O%SV<  
} ]
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public void setSSiteURL(String value) a
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{ )Vg2Jix,]  
sSiteURL = value; gz;&
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} MLV:U  
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j$vK<SF  
public String getSFilePath() Ra[>P _  
{ dx@QWTNE  
return sFilePath; cD2+hp|9  
} &Yf",KcL*I  
n_P3\Y|  
qaG#;  
public void setSFilePath(String value) 'z5h3J  
{ \vCGU>UY  
sFilePath = value; DI,K(_@G  
} 0I5&a  
v0#*X5C1'  
{oUAP1V^  
public String getSFileName() JO=1ivZl  
{ h%TLD[[/jr  
return sFileName; RPH1''*!  
} B76 v}O:  
vX;HC'%n  
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public void setSFileName(String value)
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{ wzh]97b  
sFileName = value; J R$r!hX  
} rk|a5-i  
fxgU~'  
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public int getNSplitter() iY~rne"l  
{ g$FEEDF  
return nSplitter; 5wT>N46UX  
} }mZVL~|V  
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public void setNSplitter(int nCount) BAV>o|-K  
{ C!&y  
nSplitter = nCount; .VM3D0aV  
} ghAi{@s$)  
} UXH"si:  
=P`~t<ajB  
zN~6HZ_:^  
/* vfwA$7N  
**Utility.java r&%.z*q  
*/ I :)W*SK  
package NetFox; k1='c7s  
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hat>kXm2K  
public class Utility { `uo,__y  
;AIc?Cg  
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public Utility() B4ZIURciGz  
{ T6M+|"92  
{G3i0r  
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} E4i0i!<z  
u6Je@e_!  
//线程睡眠 --fFpM3EvS  
public static void sleep(int nSecond) 1J}8sG2`  
{ y(a!YicA?  
try{ eV7u*d?  
Thread.sleep(nSecond); `/n
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} Y<f_`h^r  
catch(Exception e) iqwkARG"  
{ gSt`
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e.printStackTrace (); uD9|.P}  
} *7
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} zt=0o|k  
P0Z!?`e=M  
//日志 j1-,Sqi  
public static void log(String sMsg) j_cs;G: "  
{ p fT60W[m  
System.err.println(sMsg); ycAKK?O*  
} IQH[Q9%  
',I0ih#Ls  
o)Z=m:t,lK  
public static void log(int sMsg) Kw5Lhc1V  
{ a%vrt)Gx  
System.err.println(sMsg); A,gEM4  
} mQ~:Y
  
} !CUoHTmB  
9QC.TG@  
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/* i38[hQR9a  
**TestMethod.java [KJ q  
*/ M@Q3M(z  
package NetFox; Vz=auM1xZ  
h8e757z  
FFKGd/:!  
public class TestMethod { \ I`p|&vG  
wzCUZ1N9q  
sTRJ:fR  
public TestMethod() O) atNE  
{ ///xx/weblogic60b2_win.exe ;]sYf  
try{ ``U^COD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?.=}pAub  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lB91An  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E:`v+S_h  
fileFetch.start(); WjSc/3Qy  
} _aWl]I){5  
catch(Exception e){e.printStackTrace ();} eLD|A=X?  
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} 81LNkE,  
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. #lsic8]  
public static void main(String[] args) a|7a_s4(  
{ M=qb^~ l
 
new TestMethod(); 7JJ/D4uT  
} =3ioQZ^Vz  
} KnhoaBB  
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