http断点续传简单实现（java)

/* JOq<lb=  
**SiteFileFetch.java H >{K]7D/y  
*/ !r <|F  
package NetFox; Qq`\C0RZ  
import java.io.*; /)|y+<E]}  
import java.net.*; ,]"u!,yHb  
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public class SiteFileFetch extends Thread { =*U24B*U93  
@>j \~<%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean dVfDS-v!  
long[] nStartPos; //开始位置 DyZ90]N  
long[] nEndPos; //结束位置 %Q~Lk]B?t  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ::`wx@  
long nFileLength; //文件长度 0E[Se|!  
boolean bFirst = true; //是否第一次取文件 \ChcJth@o<  
boolean bStop = false; //停止标志 Y'
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File tmpFile; //文件下载的临时信息 0/]vmDr  
DataOutputStream output; //输出到文件的输出流 ?O?~|nI  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QD~`UJe>  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'b,D;'v  
{ c y$$}  
siteInfoBean = bean; x"80c(i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |i8dI)b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \&90$>h  
if(tmpFile.exists ()) %"2B1^o>
 
{ lhTbgM  
bFirst = false; _F EF+
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read_nPos(); /B7 GH5  
} dp+Y?ufr  
else x6tY _lzJ  
{ !W7ekPnK  
nStartPos = new long[bean.getNSplitter()]; ?J?!%Mw  
nEndPos = new long[bean.getNSplitter()]; e>)5j1  
} [_-K  
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} 7d5x4^EYE  
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public void run() 0]~n8mB>  
{ .Ps;O  
//获得文件长度 XN;eehB?aE  
//分割文件 H!u:P?j@\  
//实例FileSplitterFetch 8=9sIK2  
//启动FileSplitterFetch线程 9g"H9)EZ^  
//等待子线程返回 c`QsKwa  
try{ U\{Z{F%8  
if(bFirst) ENzeVtw0  
{ =qvU9p2o  
nFileLength = getFileSize(); z
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if(nFileLength == -1) Z}wAh|N-  
{ H5{J2M,f  
System.err.println("File Length is not known!"); wSMgBRV#^  
} CHB{P\WF  
else if(nFileLength == -2) "/"k50%  
{ 
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System.err.println("File is not access!"); Z5=!R$4  
} |T%/d#b~  
else |
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{ {cA )jW\'  
for(int i=0;i<nStartPos.length;i++) L8J/GVmj  
{ }2@$2YR[  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
:O%O``xT  
} 8Bvjj|~ (@  
for(int i=0;i<nEndPos.length-1;i++) 10&A3C(E  
{ m.*+0NG  
nEndPos = nStartPos[i+1]; Q~kwUZ  
} u4'Lm+&O  
nEndPos[nEndPos.length-1] = nFileLength; uJ$,e5q  
} >Z%^|S9  
} :xV&%Qa1  
4 #N#[;M  
/a_|oCeC}  
//启动子线程 eC-TZH@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P+SCX#{y  
for(int i=0;i<nStartPos.length;i++) T

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{ GFidriC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ES>3Cf
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OjI*HC  
nStartPos,nEndPos,i); C&T3vM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ElAG~u?  
fileSplitterFetch.start(); e|LXH/H  
} DxBt83e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &}uO ]0bR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pK`rm"6G  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cPXvTVvs  
nEndPos = " + nFileLength); iR-O6*PTC  
// fileSplitterFetch[nPos.length-1].start(); s"/8h#!zv  
9maw+c!~  
gyK"#-/_d  
//等待子线程结束 K*<n<;W  
//int count = 0; 9=SZL~#CE  
//是否结束while循环 [xC (t]S-  
boolean breakWhile = false; L{-w9(S`i  
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while(!bStop) lV?SvXe
 
{ lFcCWy  
write_nPos(); KlPH.R3MPO  
Utility.sleep(500); jc<3\
7  
breakWhile = true; weOMYJO;8  
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for(int i=0;i<nStartPos.length;i++) -h_v(s2  
{ #E1*1E  
if(!fileSplitterFetch.bDownOver) 5c#L6 dA)  
{ b} *cw2  
breakWhile = false; +CkK4<dF  
break; q)[gVL  
} 9&tV
#=s  
} J}x5Ko@  
if(breakWhile)
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break;  -<sXv
n  
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//count++; JeA}d  
//if(count>4)  }oG&zw  
// siteStop(); :\[F=  
} + y^s 6j}  
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System.err.println("文件下载结束！"); TCEbz8ql  
} P7o6B,9  
catch(Exception e){e.printStackTrace ();} F ;D_zo?  
} %>.v[d1c  
bQ)r8[o!  
"@n$(-.  
//获得文件长度 Dt?Fs  
public long getFileSize() 4c% :?H@2  
{ Di6:r3sEO  
int nFileLength = -1; iY2bRXA  
try{ DXUI/C f  
URL url = new URL(siteInfoBean.getSSiteURL()); c2C8}XJ|O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g#AA.@/Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~AO0(Lp  
|] YT6-?.  
(xTHin$  
int responseCode=httpConnection.getResponseCode(); $Z j.  
if(responseCode>=400) EPI*~=Z.U  
{ A1C@'9R*  
processErrorCode(responseCode); LF0~H}S;6B  
return -2; //-2 represent access is error vV|egmw01  
} n)0{mDf%  
5HU>o|.  
2{&" 3dq  
String sHeader; J4gIkZD  
>3bpa<M_  
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for(int i=1;;i++) Np<Aak  
{ ^Z!W3q Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); I/tz
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//Utility.log(in.readLine()); jsR1jou6  
sHeader=httpConnection.getHeaderFieldKey(i); FD*y[A ?  
if(sHeader!=null) =k_u5@.Z  
{ K!9=e7|P  
if(sHeader.equals("Content-Length")) m$^7sFD$  
{ mVkn~LD:0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =4I361oMf  
break; b{oNV-<&{  
} Y/+ D4^L  
} p.%$  
else D>mLSh  
break; ;f><;X~KX  
} *0U(nCT&m  
} U +]ab  
catch(IOException e){e.printStackTrace ();} 2
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catch(Exception e){e.printStackTrace ();} i ]_fhC  
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Utility.log(nFileLength); t@Jo ?0s  
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return nFileLength; !y),| #7P  
} %:y-"m1\u$  
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+)Ty^;+[1  
//保存下载信息（文件指针位置） YT_kMy>  
private void write_nPos() &F:7U!  
{ f`cz@  
try{ XBc+_=)$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NlDM
/  
output.writeInt(nStartPos.length); HGKm?'['  
for(int i=0;i<nStartPos.length;i++) ;gc2vDMv  
{ "P|G^*"~2  
// output.writeLong(nPos); d0xV<{
,-  
output.writeLong(fileSplitterFetch.nStartPos);  }QI*Ns  
output.writeLong(fileSplitterFetch.nEndPos);
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} giTlXz3D9  
output.close(); ABSeX  
} A=])pYE1  
catch(IOException e){e.printStackTrace ();} RBb@@k[v  
catch(Exception e){e.printStackTrace ();} saZ;ixV  
} A@#dv2JzP  
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//读取保存的下载信息（文件指针位置） wD<G+Y}  
private void read_nPos() o ).pF">jh  
{ *rbayH  
try{ N\0Sq-.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OS,$}I[`8  
int nCount = input.readInt(); k >MgrtJI  
nStartPos = new long[nCount]; H!A^ MI  
nEndPos = new long[nCount]; V>%%2"
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for(int i=0;i<nStartPos.length;i++) "Vh(%N`6  
{ X6;aF;"5  
nStartPos = input.readLong(); Y~CS2%j  
nEndPos = input.readLong(); :Cuae?O,  
} t_N `e(V  
input.close(); YK-R|z6K  
} &sRyM'XI  
catch(IOException e){e.printStackTrace ();} N>z8\y  
catch(Exception e){e.printStackTrace ();} / [19ITZ  
} 1Tl("XV3
 
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private void processErrorCode(int nErrorCode) }[Y):Yy  
{ C{Zv.
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System.err.println("Error Code : " + nErrorCode);  2O  
} uZ^i8;i  
I2 Kb.`'!  
nMnc&8r  
//停止文件下载 K%g\\uo   
public void siteStop() OlK2<<  
{ lojn8uL  
bStop = true;
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for(int i=0;i<nStartPos.length;i++) (-#{qkA  
fileSplitterFetch.splitterStop(); 0TNzVsu7  
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} k"U4E J{  
} 3ZVfZf  
//负责部分文件的抓取 nGf@zJDb  
**FileSplitterFetch.java E|TzrH  
*/ g %Am[fb  
package NetFox; M}vPWWcl  
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A gPg0(G  
import java.io.*; wVvU]UT  
import java.net.*; HqgH\  
r
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public class FileSplitterFetch extends Thread { %Xi%LUk{  
( r O j,D  
#-W5$1  
String sURL; //File URL %{{#Q]]&  
long nStartPos; //File Snippet Start Position ALv\"uUNu+  
long nEndPos; //File Snippet End Position -1o1k-8d  
int nThreadID; //Thread's ID 4{

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boolean bDownOver = false; //Downing is over H0HYb\TX?  
boolean bStop = false; //Stop identical `3OGCy  
FileAccessI fileAccessI = null; //File Access interface -K!-a'J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G pd:k  
{ ;CW$/^QNr5  
this.sURL = sURL; 3)ip@29F  
this.nStartPos = nStart; -bE|FFU  
this.nEndPos = nEnd; >"[u.1J_'I  
nThreadID = id; n>Ei1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fP|\1Y?CS  
} 8ah]D  
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public void run() a$GKrc,z  
{ cwroG#jGT  
while(nStartPos < nEndPos && !bStop) %Xl@o  
{ 71%u|k8|  
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try{ wnX6XyUH  
URL url = new URL(sURL); _e'mG'P(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nm~#$orI|  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9Dl \SF[  
String sProperty = "bytes="+nStartPos+"-"; w&{J9'~  
httpConnection.setRequestProperty("RANGE",sProperty); _=]
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Utility.log(sProperty); . ~<+  
5"Yw$DB9  
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InputStream input = httpConnection.getInputStream(); l.BNe)1!22  
//logResponseHead(httpConnection); X]!@xlwF\  
8vo} .JIl  
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byte[] b = new byte[1024]; m";gD[m  
int nRead; D6t]E)FH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RBXoU'.  
{ q~3&f  
nStartPos += fileAccessI.write(b,0,nRead); lySaJd  
//if(nThreadID == 1) QZlUUj\   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6D0,ME#  
} 4!jHZ<2Z  
($s{em4L  
8`2K=`]ES+  
Utility.log("Thread " + nThreadID + " is over!"); ;W].j%]Le  
bDownOver = true; CmTJa5:  
//nPos = fileAccessI.write (b,0,nRead); =N c`hP  
} ;vitg"Zh>  
catch(Exception e){e.printStackTrace ();} d1
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} Ba6xkEd  
} UU/|s>F  
2?j1~]DvZ  
,3j7Y5v  
//打印回应的头信息 BP6Shc|C  
public void logResponseHead(HttpURLConnection con) f/yK|[g~  
{ >UMnItq(l  
for(int i=1;;i++) }#J}8.  
{ =m:W  
String header=con.getHeaderFieldKey(i); 7r>W r#  
if(header!=null) DFonK{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NSq=_8  
Utility.log(header+" : "+con.getHeaderField(header)); U~m.I  
else zMKL: Um"  
break; (a?Ip)`I  
} St`m52V(5X  
} E`|qFG<  
r.^&%D  
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public void splitterStop() yH^*Fp8V  
{ R 6Em^A/>  
bStop = true; fm0(  
} Xhi?b|  
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)  
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} $b} +5  
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/* %a `dOEO  
**FileAccess.java k:Q<Uanc[  
*//文件访问(定位，写) 3:Wr)>l}#  
package NetFox; gwJu&HA/  
import java.io.*; K}BX6dA  
w C"%b#(}  
-cgukl4Va  
public class FileAccessI implements Serializable{ 1tdCzbEn+  
27:x5g?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CvJEY  
RandomAccessFile oSavedFile; $ *A3p  
long nPos; Z.pw!mu"  
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public FileAccessI() throws IOException ^q\zC%.  
{ L:-lqag!  
this("",0); s`RJl V  
} '9@R=#nd  
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public FileAccessI(String sName,long nPos) throws IOException T"U t).  
{ 8BDL{?Mu  
oSavedFile = new RandomAccessFile(sName,"rw"); Umg81!  
this.nPos = nPos; WKsx|a]U  
oSavedFile.seek(nPos); Phu| hx<  
} n b
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public synchronized int write(byte[] b,int nStart,int nLen) |m- `, we  
{ g/p }r.  
int n = -1; 4a!7|}W  
try{ (+dRD]|T  
oSavedFile.write(b,nStart,nLen); vq1&8=  
n = nLen; uszSFe]E  
} ^<0NIu}  
catch(IOException e) Bw.&3efd  
{ IviQ)hp  
e.printStackTrace (); 6a?p?I K^  
} o[hP&9>q  
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return n; B}+9U  
} uFZB8+  
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} 0z7mre^Q  
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/* yuEOQ\!(u  
**SiteInfoBean.java p]Zabky
 
*/ tY'QQN||  
package NetFox; 4&hqeY3  
/ LM  
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public class SiteInfoBean { yX3H&F
6  
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private String sSiteURL; //Site's URL Eu.qA9,@U  
private String sFilePath; //Saved File's Path &>.1%x
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private String sFileName; //Saved File's Name @;D}=
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private int nSplitter; //Count of Splited Downloading File :b*`hWnQ  
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fMPq  
public SiteInfoBean() Q0Qm0B5eY  
{//nSplitter的缺省值为5 k<zGrq=8J  
//default value of nSplitter is 5 Ks2%F&\cE  
this("","","",5); %C0O?q  
} pm@Z[g  
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E(kpK5h{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SoU'r]k1x  
{ Pl&`&N;  
sSiteURL= sURL; =v$s+`cP  
sFilePath = sPath; KGmc*Jwy  
sFileName = sName; wn|@D<  
this.nSplitter = nSpiltter; ^
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} cN}A rv  
jI`To%^Y  
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public String getSSiteURL() 0nq}SH  
{ p6Dv;@)Yn
 
return sSiteURL; wx%nTf/Oa  
} ^@lg5d3F  
m:fouMS  
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public void setSSiteURL(String value) ivz9R'  
{ {-N9
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sSiteURL = value; pkfOM"5'  
} A2:){`Mw  
*a,.E6C*  
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public String getSFilePath() =#2qX>?  
{ ^}/ E~Sg7\  
return sFilePath; W$Q)aA7  
} ,9tbu!Pvq  
%_R|@cyD  
eOPCYyN  
public void setSFilePath(String value) k.xv+^b9Q  
{ @*O{*2  
sFilePath = value; R5&$h$[/  
} ->2wrOH|H  
%^?3s5PXD  
uj9tr`Zh  
public String getSFileName() P,;b'-5C  
{ %>9+1lUhV  
return sFileName; +bc#GzVF  
} !QR?\9`  
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3^R][;  
public void setSFileName(String value) tZu*Asx7  
{ `Ivw`}L  
sFileName = value; Z++Z@J"  
} 5*wApu{2A  
?WQd  
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public int getNSplitter() r;on0wm&B  
{ .1}rzh}8  
return nSplitter; ]AZ\5C-J  
} M`+e'vdw  
!P60[*>  
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public void setNSplitter(int nCount) Hdbnb[e  
{ UK~B[=b9  
nSplitter = nCount; .W@4vrp
@  
} ' MS!ss=r  
} 3Da,]w<  
%V<F<  
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/* @>#{WI:"~  
**Utility.java e8ULf~I  
*/ L>~@9a\jO  
package NetFox; 4&oXy,8LC  
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vJj:9KcP>h  
public class Utility { by|?g8  
9 yW~79n  
p17|ld`  
public Utility() tf7v5iGe  
{ <5ft6a2fQ  
%eJ\d?nw  
tFvgvx\:  
} }}``~  
I`"-$99|t1  
//线程睡眠 "ji$@b_\?  
public static void sleep(int nSecond) jW1YTQ  
{ wj#J>C2]  
try{ ]D?# \|  
Thread.sleep(nSecond); fzRyG-cEpj  
} @!":(@3[  
catch(Exception e) iFnOl*TC  
{ YV1a3  
e.printStackTrace (); gY>;|),  
} 4C,kA+P  
} QxL@'n#5   
J)$&z*!  
//日志 z{`6#  
public static void log(String sMsg) <;z[+6T  
{ $#G6m`V  
System.err.println(sMsg);
'Vm5Cs$  
} O$"bd~X  
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public static void log(int sMsg) Hb A3*2  
{ Z{a{HX[Jx  
System.err.println(sMsg); ![a/kj  
} Wkg*J3O  
} 462!;/y  
192.W+H<  
L,b|Iq  
/* Ws^+7u  
**TestMethod.java Evr2|4|O~  
*/ %\X P:  
package NetFox; !cN?SGafZI  
;Na8_}  
k1f3?l vlU  
public class TestMethod { S_T{L  
&Rt+LN0qB0  
FE8+E\ U?  
public TestMethod() QmH/yy3.%  
{ ///xx/weblogic60b2_win.exe qE#&)  
try{ qPXANx<^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zdLVxL>87  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I;kf #nvao  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UM4@H1  
fileFetch.start(); #$rf-E5g-K  
} IwTr'}XIw  
catch(Exception e){e.printStackTrace ();} gro7*<  
rPiiC/T.`  
YW8K $W  
} '?{0z!!  
 /,1SE(  
\#\`!L[1  
public static void main(String[] args) DL'd&;6  
{ |`_ <@b  
new TestMethod(); i(M(OR/4  
} H_%d3 RI  
} [<D+pqh  
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