http断点续传简单实现（java)

/* WOX}Sw"  
**SiteFileFetch.java j1*f]va  
*/ Pbn!KX~F~  
package NetFox; W:`#% :C  
import java.io.*; @gY\;[#.  
import java.net.*; tY+$$GSQj  
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public class SiteFileFetch extends Thread { 'yY>as  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !GwL,)0@^  
long[] nStartPos; //开始位置 -Z0+oU(?YE  
long[] nEndPos; //结束位置 T2FE+A]n9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6C [E  
long nFileLength; //文件长度 sOBu7!G%  
boolean bFirst = true; //是否第一次取文件 f>polxB%N  
boolean bStop = false; //停止标志 pOT7;-#n  
File tmpFile; //文件下载的临时信息 'cBBt  
DataOutputStream output; //输出到文件的输出流 $s-Y%gc  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z=?aEU$7  
public SiteFileFetch(SiteInfoBean bean) throws IOException S`!-Cal`n  
{ -!e7L>w  
siteInfoBean = bean; s?rBE.g@}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); mr:CuqJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y_p.Gzy(^}  
if(tmpFile.exists ()) IiJZ5'{  
{ lg$zGa?  
bFirst = false; d0'HDVd  
read_nPos(); <S?#@F\"S  
} [?k8}B)mHB  
else o-C#|t3hH  
{ @7oL#-  
nStartPos = new long[bean.getNSplitter()]; 0bS|fMgc  
nEndPos = new long[bean.getNSplitter()];  :A1:  
} 
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} c>:R3^\lwx  
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public void run() ;30nd=  
{ XH}'w9VynR  
//获得文件长度 PG~$D];  
//分割文件 CW&.NT  
//实例FileSplitterFetch 2`GOJ,$  
//启动FileSplitterFetch线程 47K1$3P  
//等待子线程返回 tDg}Ys=4K>  
try{ )2IH 5  
if(bFirst) [ic87
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{ *Hz^K0:8(  
nFileLength = getFileSize(); f+_h !j  
if(nFileLength == -1) Z?5V4F:f  
{ aj^wRzJ}zA  
System.err.println("File Length is not known!"); P!G858V(  
} 0Hxmm@X2  
else if(nFileLength == -2) ?a(L.3E  
{ s$D ^>0  
System.err.println("File is not access!"); 7*5Z  
} [* ?Awf`  
else Z;/$niY  
{ "pP^*9FrA  
for(int i=0;i<nStartPos.length;i++) \%]I{  
{ hrGM|_BE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~\LCvcY"X  
} ).^}AFta  
for(int i=0;i<nEndPos.length-1;i++) xG&)1sT#-\  
{ Gs+3
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nEndPos = nStartPos[i+1]; Eow_&#WW;P  
} l vMlL5t  
nEndPos[nEndPos.length-1] = nFileLength; C?Bl{4-P}*  
} i.D
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} aI^/X{d  
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9RN-suE[  
//启动子线程 eIRLNxt+v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ia\eLzj  
for(int i=0;i<nStartPos.length;i++) E;JsBH  
{ +LM#n#T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bef_rH@`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OyU  
nStartPos,nEndPos,i); ~T&<CTh  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l&iq5}[n&  
fileSplitterFetch.start(); s7Ub@  
} 6f')6X'x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "#[!/\=?:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MjlP+; !  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $YN6<5R)  
nEndPos = " + nFileLength); ),G=s Oo  
// fileSplitterFetch[nPos.length-1].start();  #wL  
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h$4Hw+Yxs]  
//等待子线程结束 h%}/Cmx[  
//int count = 0;  A);  
//是否结束while循环 mEw ~yOW]M  
boolean breakWhile = false; R" ;xvo*  
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while(!bStop) ~0beuK&p  
{ kY*rb_2j  
write_nPos(); }VS5gxI1.  
Utility.sleep(500); yW$0\E6<r  
breakWhile = true; N"nd*?  
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for(int i=0;i<nStartPos.length;i++) |B?27PD  
{ Re P|UH  
if(!fileSplitterFetch.bDownOver) X!e[GJ  
{ $5Xh,DOg  
breakWhile = false; #Q2Y&2`yGT  
break; yzqVz_Fi*W  
} H&:jcgV*P  
} U2bjFLd"  
if(breakWhile) cWoPB _  
break; \v'p/G)g  
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//count++; /YZr~|65  
//if(count>4) xuqv6b.  
// siteStop(); a)wJT`xu  
} ,%uo6%  
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System.err.println("文件下载结束！"); rg^'S1x|  
}  -i0~]*  
catch(Exception e){e.printStackTrace ();} bD/~eIcWL  
} 3AU;>D^5  
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9WyAb3d'  
//获得文件长度 mIK7p6  
public long getFileSize() _f$^%?^  
{ a!=D[Gz*5  
int nFileLength = -1; d3D] k,  
try{ \ExMk<y_&  
URL url = new URL(siteInfoBean.getSSiteURL()); r"P|dlV-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eAE`#t  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7S}_F^  
R}O_[  
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int responseCode=httpConnection.getResponseCode(); tfj:@Z5&$C  
if(responseCode>=400) P-?0zF/T$  
{ &J+
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processErrorCode(responseCode); wne,e's}   
return -2; //-2 represent access is error LDPUD'  
} kqFP)!37  
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String sHeader; `@`CG[-9  
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for(int i=1;;i++) e)d`pQ6  
{ <J)]mh dm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '@_d(N1jTw  
//Utility.log(in.readLine()); |olA9mp|]  
sHeader=httpConnection.getHeaderFieldKey(i); nAv#?1cjz  
if(sHeader!=null) aDU<wxnSvO  
{ k$blEa4  
if(sHeader.equals("Content-Length")) Ff)8Q.m  
{ i<#QW'R(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .%xn&
3  
break; A1O'|7X  
} MN\HDKN  
} >T^;MS  
else ~E17L]ete  
break; -XB/lnG  
} A^USBv+9`  
} EV]1ml k$  
catch(IOException e){e.printStackTrace ();} 4h|c<-`>t  
catch(Exception e){e.printStackTrace ();} k>;`FFQU>  
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Utility.log(nFileLength); 6^]+[q}3  
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return nFileLength; F3On?x)  
} Te"ioU?.  
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//保存下载信息（文件指针位置） Hj^1or3R]  
private void write_nPos() ]Sf]J4eQ  
{ -t!~%_WCv  
try{ (A9Fhun  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0X6YdW_2X  
output.writeInt(nStartPos.length); J')o|5S1N  
for(int i=0;i<nStartPos.length;i++) geru=7  
{ Z^3rLCa  
// output.writeLong(nPos); m*&]!mM"0G  
output.writeLong(fileSplitterFetch.nStartPos); o#3ly-ht  
output.writeLong(fileSplitterFetch.nEndPos);
; ZA~p  
} d,k!qjf=r  
output.close(); T
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} E(>=rD/+  
catch(IOException e){e.printStackTrace ();} P3x8UR=fS  
catch(Exception e){e.printStackTrace ();} NG+GEqx  
} "L IF.)  
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//读取保存的下载信息（文件指针位置） 11Q1AN  
private void read_nPos() 0CnOL!3.I  
{ @0Ic3C[rH6  
try{ "g5^_UP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <? q?Mn  
int nCount = input.readInt(); YvaK0p0Z  
nStartPos = new long[nCount]; "H'B*vc-  
nEndPos = new long[nCount]; J!dm-L  
for(int i=0;i<nStartPos.length;i++) D+lAhEN  
{ .s?L^Z^  
nStartPos = input.readLong(); #NEE7'&S  
nEndPos = input.readLong(); L>jY.d2w=K  
} ` Fa~  
input.close(); kMIcK4.MH  
} ,0M_Bk"  
catch(IOException e){e.printStackTrace ();} V(H1q`ao9  
catch(Exception e){e.printStackTrace ();} )}Hpi<5N  
} B-*+r`@
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private void processErrorCode(int nErrorCode) B6MB48#0gs  
{ T6\[iJI|  
System.err.println("Error Code : " + nErrorCode); (
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} p$S*dr  
;AG8C#_  
.]8ZwAs=&  
//停止文件下载 l{*@v=b(  
public void siteStop() c[0}AGJ  
{ wON!MhA;  
bStop = true; /C
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for(int i=0;i<nStartPos.length;i++) uy>q7C  
fileSplitterFetch.splitterStop(); p*XANGA  
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} D}-/c"':}  
} Ogqj?]2QC  
//负责部分文件的抓取 j`{?OYD  
**FileSplitterFetch.java 8SMxw~9$  
*/ {5Q!Y&N.%  
package NetFox; owVX*&b{  
8?xE6  
/:cd\A}  
import java.io.*; ju8>:y8  
import java.net.*; 1KU! tL  
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#|uCgdi  
public class FileSplitterFetch extends Thread { )HEa<P^kJl  
Ki;*u_4{  
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String sURL; //File URL 3(>B Ke  
long nStartPos; //File Snippet Start Position )*u8/U  
long nEndPos; //File Snippet End Position `}p0VmD{NE  
int nThreadID; //Thread's ID /p/]t,-j2  
boolean bDownOver = false; //Downing is over |Tv#4st  
boolean bStop = false; //Stop identical `aOFs+<)  
FileAccessI fileAccessI = null; //File Access interface * `JYC  
z0d.J1VW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #$.;'#u'so  
{ ]_)yIi"  
this.sURL = sURL; CXH&U@57{  
this.nStartPos = nStart; p/ ,=OaVU  
this.nEndPos = nEnd; ?e%ZOI  
nThreadID = id; lt/1f{v[:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p'Y^X  
} [F+}V,  
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public void run() 8=!D$t\3  
{ 0-B5`=yU  
while(nStartPos < nEndPos && !bStop) -
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{ A[B<~  
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try{ 2IK}vDsis  
URL url = new URL(sURL); P?%s #I:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,>:U2%  
httpConnection.setRequestProperty("User-Agent","NetFox"); kpuz]a7pK  
String sProperty = "bytes="+nStartPos+"-"; _?nL+\'V  
httpConnection.setRequestProperty("RANGE",sProperty); )7hqJa-V  
Utility.log(sProperty); kBS9tKBWg  
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InputStream input = httpConnection.getInputStream(); G0Iw-vf  
//logResponseHead(httpConnection); s9mx  
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byte[] b = new byte[1024]; VG5i{1 0  
int nRead; #`^}PuQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;[ZEDF5H  
{ @@f"%2ZR[  
nStartPos += fileAccessI.write(b,0,nRead); e1yt9@k,  
//if(nThreadID == 1) *tA1az-jO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [+Iz@0q  
} R*,MfV  
@NR>{Eg  
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Utility.log("Thread " + nThreadID + " is over!"); sJKI!  
bDownOver = true; =nHUs1rKn  
//nPos = fileAccessI.write (b,0,nRead); Lj({[H7D!  
} PI {bmZ  
catch(Exception e){e.printStackTrace ();} }{Pp]*I<A  
} soxc0OlN  
} Ov@gh kr  
}CSDV9).S  
 1~gnc|?  
//打印回应的头信息 hE{K=Tz$  
public void logResponseHead(HttpURLConnection con)  m!!/Za  
{ X0HZH?V+  
for(int i=1;;i++) g&L!1<, p  
{ 70?\ugxA  
String header=con.getHeaderFieldKey(i); Z-%\ <zT  
if(header!=null) ic:zsuEm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G[PtkPSJ  
Utility.log(header+" : "+con.getHeaderField(header)); ScOK)nL"  
else 38B2|x  
break; 4
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} =jN.1}  
} b=C*W,Q_#  
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public void splitterStop() WCZjXDiwJ  
{ :U|1xgB  
bStop = true; )rU  
} e+7"/icK  
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} /8'NG6"H`  
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/* XS
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**FileAccess.java %6 zBSje  
*//文件访问(定位，写) ~7w"nIs<c  
package NetFox; ,_ H:J.ik  
import java.io.*; mthA4sz  
n&4N[Qlv,  
 tU5zF.%  
public class FileAccessI implements Serializable{ #lo6c;*m5  
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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 Y1\}5k{>  
RandomAccessFile oSavedFile; &&8x%Pml  
long nPos; !qQl@jO  
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|*xA8&/  
public FileAccessI() throws IOException L<cx:Vz  
{ k9R4Y\8P  
this("",0); yWc$>ne[L  
} tKuwpT1Qc  
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public FileAccessI(String sName,long nPos) throws IOException oSKXt}sh  
{ 2RX;Ob_  
oSavedFile = new RandomAccessFile(sName,"rw"); }-{H  Y  
this.nPos = nPos; 8NJqV+jn)t  
oSavedFile.seek(nPos); oCv.Ln1;Z  
} t>RY7C;PuS  
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public synchronized int write(byte[] b,int nStart,int nLen)
&m7]v,&  
{ 3ZPWze6  
int n = -1; jRlYU`?  
try{ BwEN~2u6  
oSavedFile.write(b,nStart,nLen); u~:y\/Y6  
n = nLen; ^Z+?h&%%  
} 1-uxC^u?|#  
catch(IOException e) ;8&3 dm]  
{ eKgBy8tNS0  
e.printStackTrace (); ,-LwtePJ0  
} {z5--TogJ  
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return n;
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} |A~jsz6pI  
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^/>(6>S^M  
} x+:UN'
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/* n,(sBOQ  
**SiteInfoBean.java =ho}oL,ZO  
*/ wssRA?9<  
package NetFox; 4he GnMD  
ek\ xx  
rU:
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public class SiteInfoBean { /t57!&  
R?|.pq/Ln  
/SR*W5#s  
private String sSiteURL; //Site's URL _Ey9G  
private String sFilePath; //Saved File's Path Fnv;^}\z  
private String sFileName; //Saved File's Name }eU*( }<^  
private int nSplitter; //Count of Splited Downloading File ~ 'cmSiz-  
xh,qNnGGi  
\ a<h/4#|  
public SiteInfoBean() k,6f &#x  
{//nSplitter的缺省值为5 jD]~ AwRJ  
//default value of nSplitter is 5 N^G Mp,8  
this("","","",5); IqHV)A  
} x"=f+Mr  
wk D^r(hiH  
r'r%w#=`t  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jXx<`I+]  
{ Yui3+}Ms  
sSiteURL= sURL; F#Ryu~,"  
sFilePath = sPath; 3{64 @s  
sFileName = sName; #4%]o%.  
this.nSplitter = nSpiltter; O, wJR  
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_ QI\  
} z+wA rPxc  
!u[9a;Sa#  
}5[qo`M  
public String getSSiteURL() ".V$~
n(  
{ '~<m~UXvD#  
return sSiteURL; K`WywH3-  
} Wx}8T[A}  
%#:{UR)
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yCR?UH;  
public void setSSiteURL(String value) WIT>!|w_  
{ @Zu5VpJ  
sSiteURL = value; gQg"j)  
} J.b9F:&}  
)h4f\0  
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public String getSFilePath() 0
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{ Su7?;Oh/yI  
return sFilePath; ;>yxNGV`  
}
&*,#5.  
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 .-c4wm}  
public void setSFilePath(String value) =E4LRKn  
{ u#$]?($}d  
sFilePath = value; Y|f[bw  
} H>IMf/%5N-  
ay ;S4c/_  
u@UMP@"#  
public String getSFileName() =,=A,kI[;  
{ /GN<\_o=q  
return sFileName;
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} )e+>w=t  
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public void setSFileName(String value) ci.+pF  
{ HGs $*  
sFileName = value; 2B[X,rL.pX  
} jyUjlYAAv`  
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public int getNSplitter() _Xc8Yg }`  
{ :Zbg9`d*  
return nSplitter; 1>_8d"<Gd  
} 2d #1=+V  
KNvZm;Q6  
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public void setNSplitter(int nCount) ^A$Zw+P  
{ 5|j<`()H :  
nSplitter = nCount; >}8j+t&T  
} %KhI>O<  
} 36Zf^cFJ  
9@(PWz=`?  
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/* H9`)BbR  
**Utility.java %KlrSo  
*/ x.!V^HQSN  
package NetFox; ZF9z~9  
]?kZni8j_  
2\MT;;ZTZ  
public class Utility { 4K#>f4(U`g  
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public Utility() $aDVG})  
{ Q:G4Z9Kt  
(ylTp]~mR-  
{9&;Q|D z  
} !Y0Vid  
9k'7832u  
//线程睡眠 30#s aGV  
public static void sleep(int nSecond) /tx]5`#@7]  
{ TOB-aAO  
try{ y|i,|  
Thread.sleep(nSecond); ?r "{}%  
} |^"1{7)  
catch(Exception e) )Xz,j9GzJS  
{ rxvx  
e.printStackTrace (); s 8jV(P(O  
} 7hD>As7`/  
} _ @NL;w:!  
kzQ+j8.,U  
//日志 X; \+<LE  
public static void log(String sMsg) pHXm>gTd,J  
{ jUYWrYJ  
System.err.println(sMsg); 45@ I*`  
} SuJ aL-;  
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public static void log(int sMsg) }_M~2L?i  
{ ~?Qe?hB  
System.err.println(sMsg); 9iIhte.  
} Z*]9E^  
} Cx@);4arj  
n`?aC|P2s  
1y@i}<9F  
/* 8sWJcmVo  
**TestMethod.java %A9NB!  
*/ ]3],r?-tJ  
package NetFox; 0y'H~(  
:1.L}4"gg  
shy-Gu&  
public class TestMethod { .LnGL]/  
Eak$u>Fd8c  
hB]Np1('  
public TestMethod() D(@S+r_ota  
{ ///xx/weblogic60b2_win.exe hc(#{]].  
try{ KEo,m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T"}5}6rSG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XSwl Tg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7?!d^$B  
fileFetch.start(); ed{ -/l~j  
} (&Kk7<#`  
catch(Exception e){e.printStackTrace ();} 5FPM`hLT  
;C9_?u~#  
4<w.8rR:A  
} JQ_sUYh~3  
#>("CAB02T  
~|DUt  
public static void main(String[] args) )5Q~I,dP  
{ YlJ@
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new TestMethod();
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} e{'BAj  
} Fc)@,/R"v  
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