http断点续传简单实现（java)

/* LE}V{%)xD  
**SiteFileFetch.java Lm3~< vP1e  
*/ vdIert?p  
package NetFox; ? FlQ\q  
import java.io.*; |}><)}  
import java.net.*; Zk] /m  
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public class SiteFileFetch extends Thread { \k 6'[ln  
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SiteInfoBean siteInfoBean = null; //文件信息Bean e|}B;<  
long[] nStartPos; //开始位置  35%\"Y?  
long[] nEndPos; //结束位置 )_olJCdaP^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 BIh^b?:zU  
long nFileLength; //文件长度 Mz6PH)e;  
boolean bFirst = true; //是否第一次取文件 `Kbf]"4q  
boolean bStop = false; //停止标志 8+@j %l j  
File tmpFile; //文件下载的临时信息 hQ ?zc_3  
DataOutputStream output; //输出到文件的输出流 fSF_O}kLp  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） s[bQO1g;*  
public SiteFileFetch(SiteInfoBean bean) throws IOException \IaUsx"#o{  
{ ZM16 ~k  
siteInfoBean = bean; $1 t IC_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Vbv)C3ezD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !nU
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if(tmpFile.exists ()) 4;*
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{ H
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bFirst = false; N 9W,p2  
read_nPos(); rS8}(lf  
} ykYef  
else m+Kl   
{ (YM2Cv{4  
nStartPos = new long[bean.getNSplitter()]; 6Ts[NXa  
nEndPos = new long[bean.getNSplitter()]; }jg1..)"<  
} N*+L'bO  
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} k+BY3a  
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public void run() K7X*N  
{ )FN\jo!!.  
//获得文件长度 eLIZ<zzW0}  
//分割文件 #/> a`Ur_  
//实例FileSplitterFetch wk#cJ`wG;  
//启动FileSplitterFetch线程 lVCnu>8  
//等待子线程返回 :%_h'9Qq  
try{ Vi`P &uPF  
if(bFirst) KM"BHaSkF  
{ jO-T1P']Y  
nFileLength = getFileSize(); @ZRg9M:N  
if(nFileLength == -1) DwGRv:&HH  
{ vmg[/#  
System.err.println("File Length is not known!"); nC(Lr,(  
} 2@W`OW Njm  
else if(nFileLength == -2) 2wu\.{6Zp  
{ dVg'v7G&V(  
System.err.println("File is not access!"); Ma4eu8  
} vi.INe  
else R^B8** N  
{ NxSSRv^rx  
for(int i=0;i<nStartPos.length;i++) *zQhTYY  
{ Id1de>:;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); orOq5?3  
} EU Z7?4o  
for(int i=0;i<nEndPos.length-1;i++) z\"9T?zoo  
{ k
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nEndPos = nStartPos[i+1];  //0Y#"  
} n-g#nEc:  
nEndPos[nEndPos.length-1] = nFileLength; g/(BV7V  
} *eGG6$I  
} Zv2]X-  
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_0BQnzC=  
//启动子线程 2}XxRJ0   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #"8'y  
for(int i=0;i<nStartPos.length;i++) \H&;.??W  
{ fR?'HsQg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %}JSR y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O0;mXH  
nStartPos,nEndPos,i); +@c$n`>)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u{7->[=  
fileSplitterFetch.start(); -oTdi0P  
} * =*\w\ te  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L1WvX6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *pDS%,$xe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p()LQT!  
nEndPos = " + nFileLength); !L( )3=  
// fileSplitterFetch[nPos.length-1].start(); k{O bm g  
1_TniR3z1  
hYh~%^0dt  
//等待子线程结束 S=W^iA6>  
//int count = 0; wwv+s~(0  
//是否结束while循环 &*bpEdkZ  
boolean breakWhile = false; v_WF.sb~  
8H1&=)M=  
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while(!bStop) );h  
{ XD" 4t4~>  
write_nPos(); -p%cw0*Y]C  
Utility.sleep(500); ZuZCIqN  
breakWhile = true; D^a(|L3;  
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for(int i=0;i<nStartPos.length;i++) i9V,  
{ c$lZ\r"  
if(!fileSplitterFetch.bDownOver) mN>(n+ly  
{ Q+/P>5O/  
breakWhile = false; x0%yz+i{:  
break; $d,/(*Y#-  
} pFV~1W:  
} uH(M@7"6_!  
if(breakWhile) _T7XCXEk   
break; #2lvRJB  
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//count++; HGDiwA  
//if(count>4) G*,7pc  
// siteStop(); XL
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}
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System.err.println("文件下载结束！"); cnRg
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} bvHQ#:}H  
catch(Exception e){e.printStackTrace ();} bR1Q77<G\  
} 7F_N{avr  
kZ]pV=\Y*  
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//获得文件长度 (Q&O'ng1  
public long getFileSize() @6%7X7m  
{ }$sTnea  
int nFileLength = -1; Ck>]+rl  
try{ #3{{[i(;i  
URL url = new URL(siteInfoBean.getSSiteURL()); vT @25  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W`P>vK@=  
httpConnection.setRequestProperty("User-Agent","NetFox"); :."6g)T  
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int responseCode=httpConnection.getResponseCode(); yhI;FNSf  
if(responseCode>=400) "c?31$6  
{ xn@oNKD0  
processErrorCode(responseCode); g>#}(u!PH  
return -2; //-2 represent access is error | +uc;[`  
} th<>%e}5c  
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String sHeader; +JM@kdE5b  
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for(int i=1;;i++) Crl:v8  
{ `Q/\w1-Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7Ka4?@bQ  
//Utility.log(in.readLine()); 6#.9T;&  
sHeader=httpConnection.getHeaderFieldKey(i); FQE(qltf,
 
if(sHeader!=null) cct/mX2&~  
{ .6I'V3:Kg  
if(sHeader.equals("Content-Length")) :h/v"2uDN  
{ eAqpP>9n  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hy@b/Y![M  
break; =fdW H4  
} ?GtI.flV  
} NB86+2stu  
else Y"^.6  
break; ZR"qrCSw`  
} _meW9)B  
} :7JP(j2  
catch(IOException e){e.printStackTrace ();} Z c#Jb  
catch(Exception e){e.printStackTrace ();} M _lLP8W}  
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Utility.log(nFileLength); Y7 K2@257  
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return nFileLength; ${}9/(x/^  
} 2- (}=N  
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:#{0yno)H  
//保存下载信息（文件指针位置） Iz;^D!  
private void write_nPos() *J >6i2M,u  
{ yF_/.mI  
try{ _34%St!lg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @v!#_%J  
output.writeInt(nStartPos.length); <^'IC9D]  
for(int i=0;i<nStartPos.length;i++) }_mMQg2>=  
{ o>T+fBHE  
// output.writeLong(nPos); y\[* mgl:  
output.writeLong(fileSplitterFetch.nStartPos); fF=tT C  
output.writeLong(fileSplitterFetch.nEndPos); ]{#Xcqx  
} ?YDMl  
output.close(); 'A\0^EvVv  
} P"t Dq&  
catch(IOException e){e.printStackTrace ();} k,8^RI07@  
catch(Exception e){e.printStackTrace ();} t]iKU@3  
} %K7;ePu  
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//读取保存的下载信息（文件指针位置） ,^<39ng  
private void read_nPos() ^gNbcWc7CU  
{ +Jn\`4/J:  
try{ 0ia-D`^me  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v6E5#pse8  
int nCount = input.readInt(); g:U -kK!i  
nStartPos = new long[nCount]; yS[HYq  
nEndPos = new long[nCount]; IjXxH]2  
for(int i=0;i<nStartPos.length;i++) ,_D@ggL-  
{ B<$6Dj%L  
nStartPos = input.readLong(); /11CC \  
nEndPos = input.readLong(); q|IU+r:! 3  
} St> E\tXp  
input.close(); Goy[P2m  
} +^J;ic  
catch(IOException e){e.printStackTrace ();} '"ze Im~  
catch(Exception e){e.printStackTrace ();} 5B8fz;l= B  
} jqTK7b  
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private void processErrorCode(int nErrorCode) aSJD'u4w.a  
{ kho0@o+'^  
System.err.println("Error Code : " + nErrorCode); /^I!)|At  
} qg<Y^y  
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HqV4!o9'  
//停止文件下载 olXfR-2>1  
public void siteStop() |  >yc|W  
{ 9}42s+  
bStop = true; ljz=u;O)  
for(int i=0;i<nStartPos.length;i++) EU'rdG*t/R  
fileSplitterFetch.splitterStop(); k)y<iHR_o  
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} hewc5vrL  
} P=9UK`n  
//负责部分文件的抓取 &zVXd  
**FileSplitterFetch.java knb0_nA  
*/ 9(_n8br1  
package NetFox; 9#~jlq(  
Y`6<:8[?  
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import java.io.*; g?Rq .py]!  
import java.net.*; MU:v& sk  
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public class FileSplitterFetch extends Thread { 'dv
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String sURL; //File URL
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long nStartPos; //File Snippet Start Position CWB<I  
long nEndPos; //File Snippet End Position n* .<L  
int nThreadID; //Thread's ID /5 OQ0{8p  
boolean bDownOver = false; //Downing is over YdB/s1|G  
boolean bStop = false; //Stop identical YG*}F|1  
FileAccessI fileAccessI = null; //File Access interface |S]fs9  
73{<;z}i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Eq=JmO'gHs  
{ Bi"cWO  
this.sURL = sURL; e ^`La*n  
this.nStartPos = nStart; 8vfC  
this.nEndPos = nEnd; <$#^)]Ts  
nThreadID = id; TQ[J,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _.EM])b  
} pE0@m-p  
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e ]2GAJLI  
public void run() Z7?\ >4V  
{ %j{*`}
 
while(nStartPos < nEndPos && !bStop) rTJ;s  
{ oL!C(\ER
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try{ B2WPbox  
URL url = new URL(sURL); 5a2;@}%V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gl2l%]=\'  
httpConnection.setRequestProperty("User-Agent","NetFox"); }wJH@'0+  
String sProperty = "bytes="+nStartPos+"-"; 0wF)bQv1  
httpConnection.setRequestProperty("RANGE",sProperty); GW7+#  
Utility.log(sProperty); X
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InputStream input = httpConnection.getInputStream(); }We-sZ/w7r  
//logResponseHead(httpConnection); U><$p{)  
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byte[] b = new byte[1024]; >{Xyl):  
int nRead; d*@K5?O.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F+W{R+6  
{ CE| *&G  
nStartPos += fileAccessI.write(b,0,nRead); O>" |5wj  
//if(nThreadID == 1) Q]dKyMSSA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )<e,-XujY  
} ws U@hqS  
nS Vr,wU  
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Utility.log("Thread " + nThreadID + " is over!"); 64^3ve3/a=  
bDownOver = true; 5F]2.<i  
//nPos = fileAccessI.write (b,0,nRead); i@%a!].I  
} 6!=q+sw/X  
catch(Exception e){e.printStackTrace ();} Zl.,pcL  
} eF4f7>5Cv  
} ,WAJ& '^  
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//打印回应的头信息 `?d` #)Ck  
public void logResponseHead(HttpURLConnection con) ?-<>he  
{ SF"r</c[  
for(int i=1;;i++) R#rfnP >  
{ 5E}]
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String header=con.getHeaderFieldKey(i); bJynUZ  
if(header!=null) DD[<J:6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I-Am9\  
Utility.log(header+" : "+con.getHeaderField(header)); uOh
  
else LF+E5{=:R  
break; `84,R
!  
} V%`\x\Xat  
} $j4/ohwTDY  
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public void splitterStop() 1>umf~%Wa  
{ [LV>z  
bStop = true; Su+[Q6oC@  
} L_M(Lj  
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} .B!  Z0  
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/* pTH5-l_f]  
**FileAccess.java AMK(-=  
*//文件访问(定位，写) D23 c/8K  
package NetFox; g?@fHFct  
import java.io.*; KvO5-g  
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public class FileAccessI implements Serializable{ oS<*\!&D  
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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 Bt(nm>Ng  
RandomAccessFile oSavedFile; Sb}=j;F  
long nPos; Kv ajk~  
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public FileAccessI() throws IOException RQ8;_)%  
{ Lx|0G $  
this("",0); .F/s(  
} %kP=VUXj  
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public FileAccessI(String sName,long nPos) throws IOException h1$75E?,  
{ h"f_T [  
oSavedFile = new RandomAccessFile(sName,"rw"); 7s Gf_`Z  
this.nPos = nPos; P]2V~I/X  
oSavedFile.seek(nPos); &#!1 Y[e^  
} N%)q.'M  
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public synchronized int write(byte[] b,int nStart,int nLen) '*<I<? z;  
{ _s}`ohKvD  
int n = -1; nW oh(a  
try{ O-3aU!L  
oSavedFile.write(b,nStart,nLen); @]Ac >&  
n = nLen; 3KtJT&RuL  
} oFsV0 {x%)  
catch(IOException e) ju1B._48  
{ |w5,%#AeO$  
e.printStackTrace (); y<c7RK]  
} 3`Xzp  
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return n; K{ntl-D&y  
} /.>%IcK  
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} gJ^taUE  
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x~](d8*=  
/* Vd'=Fe;eB  
**SiteInfoBean.java Xv+,Z<>iQ  
*/ D2RvFlAXu  
package NetFox; h05<1>?|  
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e`Co ='  
public class SiteInfoBean { Of}C.N8  
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private String sSiteURL; //Site's URL $oPc,zS-gL  
private String sFilePath; //Saved File's Path ,wngS=  
private String sFileName; //Saved File's Name hoLA*v2<  
private int nSplitter; //Count of Splited Downloading File t/l<X]o  
yI^7sf7k  
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public SiteInfoBean() .Ad9(s  
{//nSplitter的缺省值为5 -lR7 @S  
//default value of nSplitter is 5 {BgJ=0g?  
this("","","",5); yJ;Qe_up  
} $#(j2sL1  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p6ryUJc6  
{ 45OAJ?N  
sSiteURL= sURL; nYe:$t3F=  
sFilePath = sPath; 9Q'[>P=1  
sFileName = sName; p1W6s0L  
this.nSplitter = nSpiltter; )KGz -!1c  
1MmEP  
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} wJ"]H!r0  
4um^7Ns)7  
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public String getSSiteURL() UD9JE S,  
{ @Gy.p5J8  
return sSiteURL; hD4>mpk  
} 0 ZSn r+  
rinTB|
5  
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public void setSSiteURL(String value) \[]?9Z=n  
{ G,<l}(tEG  
sSiteURL = value; Z*-a=u%gl'  
} S)/548=`  
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public String getSFilePath() (H\ `/%Bp  
{ hDQk z
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return sFilePath; i1'G_bo4F7  
} 5>ktr)]  
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public void setSFilePath(String value) Vhr6bu]  
{ 6YV"H  
sFilePath = value; N(2M  w:}  
} ]&dPY[~,/i  
;>S|?M4GZ  
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public String getSFileName() ?7J::}R  
{ ap2g^lQXq  
return sFileName; s+z5"3'n  
} \jmZt*c  
eN\+  

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public void setSFileName(String value) MSRk|0Mcr  
{ i0zrXaKV  
sFileName = value; $PAAmaigi  
} !Ce!D0Tx  
.2s^8gO  
*2rc
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public int getNSplitter() tGzp=PyA  
{ ayQeT  
return nSplitter; drk BW}_  
} Od:-fw  
^P*-bV4  
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public void setNSplitter(int nCount) 6As%<g=  
{ Dwr 9}Z-]  
nSplitter = nCount; Bf6i{`!G  
} Z
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} Tu5p`p3-j  
ael] {'h]  
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/* UEhFId  
**Utility.java M{)&SNI*C  
*/ j%Xa8$  
package NetFox; /Ov1eQBNG  
!l Egta[Ql  
F^aD#  
public class Utility { vU]n0)<KB  
@LSh=o+  
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public Utility() T7Y}v,+-  
{ ]>Gi_20*
.  
;NrPMz  
&flRrJ  
} EU04U  
#TC}paIpj  
//线程睡眠 y)a)VvU":  
public static void sleep(int nSecond) &U7h9o H  
{ MvnQUZ  
try{ = ^Vp \  
Thread.sleep(nSecond); 6(uZn=  
} wG9aX*(n  
catch(Exception e) 9qgs*]J
 
{ `@v;QLD"d<  
e.printStackTrace (); 4>a(!ht  
} "tK|/R+  
} %>6ilGQ+  
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//日志 .\&k]}0qA?  
public static void log(String sMsg) 3HW&\:q5'M  
{ DHv86TvJt  
System.err.println(sMsg); 9+xO2n  
} <RZq
s  
r| )45@  
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public static void log(int sMsg) ~P"Agpx3u  
{ RA;/ ?l  
System.err.println(sMsg); -sZb+2tDa  
} Li"+`  
} W&&|T;P<J  
8lGM>(:o  

,<)D3K<  
/* L
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**TestMethod.java TA2ETvz^  
*/ ZS;V?]\(  
package NetFox; q-ko)]  
he:z9EG}  
W$()W)   
public class TestMethod { `wQs$!a
  
&1?6Q_p6c  
s=F[.X9lp  
public TestMethod() i3Bpim.  
{ ///xx/weblogic60b2_win.exe a]xGzv5  
try{ NQX?&9L`r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); LME&qKe5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u[Si=)`VPk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `JpFqZ'58  
fileFetch.start(); 6vR6=@(`>  
} }qhYHC  
catch(Exception e){e.printStackTrace ();} -aS@y.z  
QB!_z4UJ_;  
3\ ,t_6}  
} x[Hx.G}5+  
peT9
1b  
_DT,iF*6  
public static void main(String[] args) dJQK|/  
{ W5= j&
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new TestMethod(); EhM=wfGKw  
} bgKC^Q/F  
} FI.F6d)E$  
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