http断点续传简单实现（java)

/* z%}"=  
**SiteFileFetch.java Ar%*NxX  
*/ qnP4wRpr  
package NetFox; $QiMA,  
import java.io.*; p{E(RsA  
import java.net.*; U6JD^G=qR,  
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public class SiteFileFetch extends Thread { U&3!=|j  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'iMzp]V;  
long[] nStartPos; //开始位置 9/"&6,  
long[] nEndPos; //结束位置 c!@|yE,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x8lBpr  
long nFileLength; //文件长度 ~&:-c v  
boolean bFirst = true; //是否第一次取文件 \3vQXt\dM$  
boolean bStop = false; //停止标志 A!Tl  
File tmpFile; //文件下载的临时信息 v&:[?<6-  
DataOutputStream output; //输出到文件的输出流 'DW|a  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） bK "I9T #  
public SiteFileFetch(SiteInfoBean bean) throws IOException zlLZ8b+  
{ 3Ei^WDJ  
siteInfoBean = bean; sI\NX$M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C6ql,hR^h`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Gs#9'3_U5  
if(tmpFile.exists ()) \J:+Wl.9A  
{ k4#j l<R  
bFirst = false; gj;gl ="3  
read_nPos(); f@sC~A. 9\  
} -~z@W3\  
else V@0T&#  
{ .XgY&5Qk  
nStartPos = new long[bean.getNSplitter()]; ^E%R5JN  
nEndPos = new long[bean.getNSplitter()]; Y
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} $mxG-'x%K  
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} #>yOp
*  
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public void run() EG4~[5[YgI  
{ `n,RC2yo  
//获得文件长度 5k
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//分割文件 G5hRx@vfrL  
//实例FileSplitterFetch `K VSYC  
//启动FileSplitterFetch线程 QXj#Brp  
//等待子线程返回 n\9IRuYO  
try{ l&\y]ZV={  
if(bFirst) .XpuD,^;@  
{ 6O?zi|J[:  
nFileLength = getFileSize(); x`?>j$  
if(nFileLength == -1) sssw(F  
{ &NF$_*\E  
System.err.println("File Length is not known!"); z*HM_u  
} )4fQ~)  
else if(nFileLength == -2) %nJo:/  
{ dr#%~I  
System.err.println("File is not access!"); *~U*:>hS  
} y ;mk]  
else uznqq}  
{ }#g]qK  
for(int i=0;i<nStartPos.length;i++) OGEe8Z9Jt  
{ <uU<qO;6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @nqM
#  
} O<fy^[r:`  
for(int i=0;i<nEndPos.length-1;i++) ]9_t
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{ bD)"Jy  
nEndPos = nStartPos[i+1]; 0x*1I1(c  
} q1HJ_y  
nEndPos[nEndPos.length-1] = nFileLength; E$_zBD%  
} 'Rnzu0<lF  
} idHI)6!  
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//启动子线程 xd `MEOY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0fj C>AS  
for(int i=0;i<nStartPos.length;i++) o w(9dB&E  
{ wMgF*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RKrNmD*rk*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zWPX  
nStartPos,nEndPos,i); ~%lUzabMa  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fAkfNH6  
fileSplitterFetch.start(); %1 RWF6  
} [PXq<ST  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #P!<u Lc%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OL_#Uu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h[Sd3Z*  
nEndPos = " + nFileLength); iWWt
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// fileSplitterFetch[nPos.length-1].start(); ^EN )}:%Z  
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//等待子线程结束 ElTB{C>u  
//int count = 0; {tYY _BI<  
//是否结束while循环 )cL(()N  
boolean breakWhile = false; lA4-ZQ2Zp[  
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while(!bStop) nN.Gn+Cl  
{ l(x0d  
write_nPos(); Bi9Q8#lh  
Utility.sleep(500); g/l:q&Q<  
breakWhile = true; XXm7rn  
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*Dq ++  
for(int i=0;i<nStartPos.length;i++) |) cJ  
{ )Vy0V=  
if(!fileSplitterFetch.bDownOver) dHAT($QG  
{ a:GM|X  
breakWhile = false; Q
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break; Uufig)6  
} zrSYLG  
} L[:AUe  
if(breakWhile) 22ySMtxn  
break; PI$i_3N  
9%21Q>Y?b  
g :B4zlKG  
//count++; )^P54_2  
//if(count>4) 2oc18#iG(  
// siteStop(); jLn#%Ia}  
} AMB{Fssz  
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System.err.println("文件下载结束！"); i@D4bd9lR  
} #?\(l%  
catch(Exception e){e.printStackTrace ();} 7MZH'nO  
} ,j{tGj_  
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//获得文件长度 E,ilJl\  
public long getFileSize() 5|jY  
{ t%e<]2-8  
int nFileLength = -1; ]Hl{(v\HO  
try{ f tl$P[T  
URL url = new URL(siteInfoBean.getSSiteURL()); K@:omT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IP{$lC  
httpConnection.setRequestProperty("User-Agent","NetFox"); >h:'Z*9  
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int responseCode=httpConnection.getResponseCode(); IDf\!QGx  
if(responseCode>=400) teb(gUy}L6  
{ 6DU(KYN  
processErrorCode(responseCode); 569p/?  
return -2; //-2 represent access is error }&L%c>  
} ~}{_/8'5  
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String sHeader; 4 7mT  
}8YY8|]LI  
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for(int i=1;;i++) H)S!%(x4  
{ B#IUSHC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hP'4PLK  
//Utility.log(in.readLine()); Tc"J(GWG  
sHeader=httpConnection.getHeaderFieldKey(i); DC/Cz
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if(sHeader!=null) {U>N*&_`  
{ qe(gKKA%q  
if(sHeader.equals("Content-Length")) x%k@&d;z  
{ PRUl-v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I0H]s/*C%9  
break; qAd=i0{N  
} n8)&1 q?V  
} $nW9VMa  
else \p.yR.  
break; >l%8d'=Jl  
} F_-xp1|  
} 8oI|Z=  
catch(IOException e){e.printStackTrace ();} $aU.M3  
catch(Exception e){e.printStackTrace ();} JvvN>bg  
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Utility.log(nFileLength); dR_6j}  
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return nFileLength;
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} Sx J0Y8#z  
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//保存下载信息（文件指针位置） ^
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private void write_nPos() ia_@fQ  
{ \\13n4fAv  
try{ DrioBb@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sG_/E-%5'  
output.writeInt(nStartPos.length); EN[T3 Y  
for(int i=0;i<nStartPos.length;i++) Ua:@,};  
{ Q
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// output.writeLong(nPos); R@pY+d9qp  
output.writeLong(fileSplitterFetch.nStartPos); 9M($_2,44  
output.writeLong(fileSplitterFetch.nEndPos); :2M&C+f[  
} P%Vq#5  
output.close(); a:l-cZ/!  
} uJH[C>  
catch(IOException e){e.printStackTrace ();} \X\f~CB  
catch(Exception e){e.printStackTrace ();} | ?vm.zp  
} K,! V _  
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//读取保存的下载信息（文件指针位置） Pf,@U'f|  
private void read_nPos() JN9>nC!Zy_  
{ ^vT!24sK  
try{ #|,cy,v4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H I_uR$m  
int nCount = input.readInt(); vC@^B)
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nStartPos = new long[nCount]; -L]-u6kC[  
nEndPos = new long[nCount]; 1|"BpX~D  
for(int i=0;i<nStartPos.length;i++) x$o^;2Z  
{ x>##qYT  
nStartPos = input.readLong(); _ {wP:dI "  
nEndPos = input.readLong(); )kI**mI}  
} 3TCRCz  
input.close(); Ic_NQ<8  
} >l AtfN='  
catch(IOException e){e.printStackTrace ();} WG6 0  
catch(Exception e){e.printStackTrace ();} 4P1}XYD-2  
} KgkRs?'z  
2
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private void processErrorCode(int nErrorCode) M+VWAh#uD  
{ [yk-<}#B  
System.err.println("Error Code : " + nErrorCode); F{a;=h#@Q  
} v ;}s`P\"  
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pk.\IKlG]  
//停止文件下载 7`A]X,:  
public void siteStop() RQo a  
{ O8bxd6xb  
bStop = true; KfBT'6t  
for(int i=0;i<nStartPos.length;i++) =HsE:@  
fileSplitterFetch.splitterStop(); Q*%}w_D6f  
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2 HQ3G~U  
} LYRpd  
} HBOyiIm Q  
//负责部分文件的抓取 D%yY&q;  
**FileSplitterFetch.java h,m 90Hd+  
*/ r <5}& B`  
package NetFox;
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import java.io.*; $+7uB-KsU  
import java.net.*; '-RacNY  
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public class FileSplitterFetch extends Thread { nDC0^&  
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String sURL; //File URL 9|}Pf_5]%[  
long nStartPos; //File Snippet Start Position thJ~* 0^  
long nEndPos; //File Snippet End Position 6u+aP  
int nThreadID; //Thread's ID %;dj6):@  
boolean bDownOver = false; //Downing is over m]AT-]*f  
boolean bStop = false; //Stop identical edq,:  
FileAccessI fileAccessI = null; //File Access interface eyyME c!  
'{jr9Vh  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W~ET/h  
{ (n*:LS=0  
this.sURL = sURL; p8!T) ?|  
this.nStartPos = nStart; C{zp8 A(Dh  
this.nEndPos = nEnd; [rT.k5_  
nThreadID = id; [|KvlOvP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?PT>V,&  
} @ps(3~?7  
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public void run() :HO5 T  
{ z2uL[deN'"  
while(nStartPos < nEndPos && !bStop) Fa )QDBz)  
{ *$<W"@%^J  
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try{ dg24h7|]  
URL url = new URL(sURL); %A$&9c%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O9sEaVX  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q# B0JT1  
String sProperty = "bytes="+nStartPos+"-"; \c:$eF  
httpConnection.setRequestProperty("RANGE",sProperty); '*b]$5*p  
Utility.log(sProperty); m|aK_  
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InputStream input = httpConnection.getInputStream(); Z]]Ur  
//logResponseHead(httpConnection);
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byte[] b = new byte[1024]; cgMF?;V  
int nRead; (h3L=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m$W>~  
{ ;XurH%Mg  
nStartPos += fileAccessI.write(b,0,nRead); 4a-JC"  
//if(nThreadID == 1) hF,|()E[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nMyl(kF[  
} #0P_\X`E   
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}  
Utility.log("Thread " + nThreadID + " is over!"); 3=YpZ\l}  
bDownOver = true; __g k:a>oQ  
//nPos = fileAccessI.write (b,0,nRead); -r={P_E6  
} 4#B'pJMw9  
catch(Exception e){e.printStackTrace ();} Y &Cb  
} >[fu&r1  
} ef7{D P  
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//打印回应的头信息 SMX]JZmH  
public void logResponseHead(HttpURLConnection con) G](4!G&  
{ hO=L|BJ?I  
for(int i=1;;i++) .5(YL8d  
{  K& #il  
String header=con.getHeaderFieldKey(i); I,{YxY[$7  
if(header!=null) SO$Af!S:bB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !bE-&c  
Utility.log(header+" : "+con.getHeaderField(header)); 6Wu*zY_+  
else .:$(o&  
break; 8W\yM;'  
} _}R[mr/  
} 4dX{an]Cz  
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public void splitterStop() ).SJ*Re*^I  
{ k QuEG5n.-  
bStop = true; R~\R>\  
} Jb QK$[z"  
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} (~GQncqa  
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/* 1M]=Nv  
**FileAccess.java ubcB<=xb  
*//文件访问(定位，写) g+ c*VmY  
package NetFox; ^65I,Z"  
import java.io.*; O3} JOv_  
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public class FileAccessI implements Serializable{ 1<YoGm&  
)+G"57p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vMTf^V  
RandomAccessFile oSavedFile; Q(bOar5  
long nPos; {R}F4k  
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public FileAccessI() throws IOException 4q}+8F`0F  
{ @J[@Pu O  
this("",0); X1Yw=t~a  
} ldA_mj{  

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public FileAccessI(String sName,long nPos) throws IOException V8^la'_j  
{ ~:ASv>m  
oSavedFile = new RandomAccessFile(sName,"rw"); >JpBX+]5m  
this.nPos = nPos; im<bo Mv  
oSavedFile.seek(nPos); v:t;Uk^Y  
} M3tl4%j  
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public synchronized int write(byte[] b,int nStart,int nLen) )?F&`+  
{ DrJ?bG;[  
int n = -1; d:%b  
try{ K./qu^+k  
oSavedFile.write(b,nStart,nLen); ;TAj;Tf]H  
n = nLen; |N)Ik8  
} *~#I5s\s!  
catch(IOException e) my (@~'  
{ R#T-o,m  
e.printStackTrace (); =zkN63S  
} cQ8[XNa  
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return n; lLD
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} Gv-VDRS  
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} )DgXsT  
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/* 0AQazhm  
**SiteInfoBean.java 6G8No-#y  
*/ Rb6BY-/J  
package NetFox; Pb5yz-?  
l6  G6H$  
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public class SiteInfoBean { F>fCp  
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private String sSiteURL; //Site's URL AO-5>r  
private String sFilePath; //Saved File's Path 4MgN
  
private String sFileName; //Saved File's Name 5vx 4F f  
private int nSplitter; //Count of Splited Downloading File msl.{  
W A/dt2D|  
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public SiteInfoBean() hA7=:LG  
{//nSplitter的缺省值为5 ;ku
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//default value of nSplitter is 5 5YY5t^T  
this("","","",5); :""HyjY!  
} 'RjEdLrI  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'OY4Q'Z  
{ E
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sSiteURL= sURL; )U&9d   
sFilePath = sPath; 67j kU!  
sFileName = sName; ^ja]e%w#  
this.nSplitter = nSpiltter; yXNr[7  
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:?M_U;;z2+  
} H$`U] =s|  
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public String getSSiteURL() x3+ -wv  
{ M':-f3aT%  
return sSiteURL; V:\:[KcL^  
} csP4Oq\g[  
v;,W ^#`  
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public void setSSiteURL(String value) "n%j2"TYJj  
{ )N.3Q1g-  
sSiteURL = value; 0L}`fYf  
} TU|#Pz7n-Z  
2F4<3k!&  
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public String getSFilePath() #
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{ &~:EmLgv  
return sFilePath; de:@/-|  
} +7.|1x;C  
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public void setSFilePath(String value) \BHZRytQF  
{ ,rB(WKU  
sFilePath = value; /YJo"\7  
} OyO<A3  
/~,*DH$)  
Ao K9=F}  
public String getSFileName() $kUB%\`  
{ [jgVN w""D  
return sFileName; hK?GIbRZ  
} "r^RfZ;  
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public void setSFileName(String value) gj^)T_E_  
{ F_@B ` ,  
sFileName = value; e{x>u(  
} b|i4me@  
=xk>yw!O)  
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public int getNSplitter() |4+'YgO  
{ m` 1dB%;?  
return nSplitter; z^9oaoTl  
} [N
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public void setNSplitter(int nCount) ]]|#+$ ~  
{ SdnnXEB7  
nSplitter = nCount; 6wp1jN  
} ]L3U2H`7  
} .gO|=E"  
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&eMd^l}:#  
/* tl dK@!E3  
**Utility.java ,!Wo6{'  
*/ m* 3ipI{h  
package NetFox; ?dJd7+A  
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[{Wo:c9Qq1  
public class Utility { 6FDj:~  
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)>~jjR  
public Utility() 3EYEd39E  
{ z</C)ObL  
?NA$<0  
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} b%
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!Q\*a-C  
//线程睡眠 (BY 0b%^  
public static void sleep(int nSecond) !/G}vu  
{ V7WL Gy.,  
try{ M6wH$!zRa  
Thread.sleep(nSecond); 4q.;\n  
} 6%V:Z  
catch(Exception e) +2MF#{ tS  
{ EMnz;/dMt  
e.printStackTrace (); l~$)>?ZD  
} ;bwBd:Y  
} nc1~5eo  
<VZ43I  
//日志 %ddH4Q/p  
public static void log(String sMsg) n[>hJ6  
{ zU1D@  
System.err.println(sMsg); > %KEMlKZ  
} GP+=b:C{E  
b'pwRKpx  
_#\Nw0{  
public static void log(int sMsg) lL zR5445)  
{ @
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System.err.println(sMsg); D2VYw<tEA  
} |ru!C(  
} r(Sh  
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/* Tu-lc)  
**TestMethod.java g7323m1=  
*/ 0j8fU7~6S  
package NetFox; GyL9}  
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public class TestMethod { kb 74:  
7=G6ao7  
0V6, &rTF  
public TestMethod() q25p3  
{ ///xx/weblogic60b2_win.exe 2|7:`e~h  
try{ {ccc[G?>.Q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8b0j rt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Mq~E'g4#  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  IZrcn  
fileFetch.start(); y9mV6.r  
} <k[_AlCmsg  
catch(Exception e){e.printStackTrace ();} yl?LXc[)  
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> 3x^jh  
} $cn8]*Z=  
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public static void main(String[] args) !Gnm<|.  
{ ^/Hf$tYI!`  
new TestMethod(); hpQ #`rhn  
} 1q;R+65  
}  6 wd  
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