http断点续传简单实现（java)

/* /$-Tg)o5i  
**SiteFileFetch.java N"k IQe*}1  
*/ I
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package NetFox; %pd-{KR  
import java.io.*; @a]O(S>Ub  
import java.net.*; }<=4A\LZ  
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public class SiteFileFetch extends Thread { <$+Cd=71\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {vf4l4J(  
long[] nStartPos; //开始位置 ^1 U<,<  
long[] nEndPos; //结束位置 OL0W'C9oA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *f ;">(`o*  
long nFileLength; //文件长度 L`6 R  
boolean bFirst = true; //是否第一次取文件  Oye:V  
boolean bStop = false; //停止标志 TQ`4dVaf  
File tmpFile; //文件下载的临时信息 ^hyY,X  
DataOutputStream output; //输出到文件的输出流 k.@OFkX.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,z@"pI b  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3U\| E  
{ z]d2 rzV(_  
siteInfoBean = bean; Nk ~"f5q7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MpCK/eiC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /&jh10}H  
if(tmpFile.exists ()) ~k[mowz0  
{ 40i]I@:JK  
bFirst = false; 0; PV gO;9  
read_nPos(); vCe]iB  
} [OU[i(,{  
else Z8xKg  
{ -:]-g:;/  
nStartPos = new long[bean.getNSplitter()]; =ICakh!TO  
nEndPos = new long[bean.getNSplitter()]; A@81wv  
} r2.f8U  
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} T=~D>2C  
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public void run() sngM4ikhs  
{ UZDXv=r|  
//获得文件长度 ]8~{C>ch$  
//分割文件 8x/]H(J  
//实例FileSplitterFetch "> ]{t[Ib  
//启动FileSplitterFetch线程 \.l8]LH  
//等待子线程返回 ?BA~$|lfxu  
try{ c7R<5f  
if(bFirst) ?P>3~3 B  
{ eY'< UO  
nFileLength = getFileSize(); YQ _]Jv k  
if(nFileLength == -1) -+)06BqF}  
{ "MX9h }
7  
System.err.println("File Length is not known!"); tA{B~>  
} [!'fE#"a  
else if(nFileLength == -2) 58>C,+  
{ 4apy{W  
System.err.println("File is not access!"); Yn+d!w<3:  
} /t
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else 5S/YVRXq  
{ q37d:Hp  
for(int i=0;i<nStartPos.length;i++) |%~Zo:Q<$>  
{ l'm\*=3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z^_-LX:%  
} \:Vm7Zg  
for(int i=0;i<nEndPos.length-1;i++) M4rK  
{ q1_iV.G<  
nEndPos = nStartPos[i+1]; U5!~@XjG>  
} P+2@,?9#  
nEndPos[nEndPos.length-1] = nFileLength; p?idl`?^3  
} ih\
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} P7D__hoE  
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,B8u?{O  
//启动子线程 s+a} _a:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8{)j"rghah  
for(int i=0;i<nStartPos.length;i++) l1#F1q`^t  
{ _i@4R<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X :wfm
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~[
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nStartPos,nEndPos,i); E9 6` aF{]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `SM37({c  
fileSplitterFetch.start(); *w,C5 f  
} =4_Er{AT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `~;`q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0CR~ vQf#r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C>~ms2c  
nEndPos = " + nFileLength); zNRR('B?  
// fileSplitterFetch[nPos.length-1].start(); H
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//等待子线程结束 [#mRlL0yk  
//int count = 0; (JI[y"2  
//是否结束while循环 <yg!D21Y  
boolean breakWhile = false; B$D7}=|kc  
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r  
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while(!bStop) ms/!8X$Mz  
{ al@H
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write_nPos(); +DwE~l  
Utility.sleep(500); OGWZq(c"6  
breakWhile = true; 6i7
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for(int i=0;i<nStartPos.length;i++) W<tw],M-#  
{ u?%FD~l:uU  
if(!fileSplitterFetch.bDownOver) /+JHnedK  
{ ,We'AR3X  
breakWhile = false; -.t/c}a#  
break; ^=@`U_(,G  
} \.K4tY+V  
} j[Z<|Da  
if(breakWhile) [$e\?c  
break; `:#IZ  
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//count++; H7?Sd(U  
//if(count>4) z;Yo76P  
// siteStop(); d]r?mnN W  
} 155
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System.err.println("文件下载结束！"); @|6#]&v`  
} $az9Fmta  
catch(Exception e){e.printStackTrace ();} G:4'
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} @wPyXl  
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//获得文件长度 3](At%ss  
public long getFileSize() aNDpCpy  
{ )l6(ss!J  
int nFileLength = -1; W'! I+nh  
try{ tYUg%2G  
URL url = new URL(siteInfoBean.getSSiteURL()); Q$58K9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mbZn[D_zi  
httpConnection.setRequestProperty("User-Agent","NetFox"); (U([T-H  
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int responseCode=httpConnection.getResponseCode(); Y{7)$'At  
if(responseCode>=400) mPJ@hr%3  
{ s0\}Q=s[  
processErrorCode(responseCode); !$pnE:K  
return -2; //-2 represent access is error 32z2c:G  
} *6/OLAkyF  
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String sHeader; JJ4w]Dd4  
7!PU}[:  
+. tcEbFL  
for(int i=1;;i++) 5a%i%+;N  
{ ]QSQr*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2ut)m\)/)  
//Utility.log(in.readLine()); r<OqI*7  
sHeader=httpConnection.getHeaderFieldKey(i); p>h}k_s  
if(sHeader!=null) W4&Itj  
{ I''X\/|  
if(sHeader.equals("Content-Length")) 7Sl"q=>  
{ {xu~Dx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o7kQ&w  
break; oCSJ<+[(C  
} &6&$vF65c  
}  N~vK8j@  
else PM^Xh*~  
break; Ti>2N  
} PX>>h}%  
} ~9Cw5rwH<;  
catch(IOException e){e.printStackTrace ();} -7u_\XFk  
catch(Exception e){e.printStackTrace ();} yW@YW_2;4  
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Utility.log(nFileLength); hka`STK{  
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return nFileLength; OLE@35"v]  
} ;T3}#Q*qC  
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//保存下载信息（文件指针位置） FV\$M6 _  
private void write_nPos() q'KXn0IY#  
{ lS |:4U.  
try{ @m+FAdA 0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0,1)Sg*  
output.writeInt(nStartPos.length); UL0n>Wa5  
for(int i=0;i<nStartPos.length;i++) iJSyi;l|  
{ >uR;^B5m  
// output.writeLong(nPos); eCwR }m?_  
output.writeLong(fileSplitterFetch.nStartPos); p+}eP|N  
output.writeLong(fileSplitterFetch.nEndPos); d6ckvD[  
} iJb-F*_y  
output.close(); >2ny/AK|  
} ZN}U^9m=  
catch(IOException e){e.printStackTrace ();} bo[[
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catch(Exception e){e.printStackTrace ();} `teaE7^Wm  
} %ZTI ?a  
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//读取保存的下载信息（文件指针位置） @<z#a9  
private void read_nPos() \4Z"s[8}  
{ EfqC_,J*3  
try{ 4\y>pXML-U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &uXu$)IZ  
int nCount = input.readInt(); N4w&g-  
nStartPos = new long[nCount]; UQO?hZ!y/.  
nEndPos = new long[nCount]; +?^lnoX  
for(int i=0;i<nStartPos.length;i++) 5!qLJmd=  
{ CO{AC~  
nStartPos = input.readLong(); bYwe/sR  
nEndPos = input.readLong(); _Kg"l5?B  
} no9=K4h`  
input.close(); qbKcI+)47  
} YJ{_%z|U  
catch(IOException e){e.printStackTrace ();} E
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catch(Exception e){e.printStackTrace ();} mhMRY9ahB  
} zv~b-Tp  
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@] 3`S  
private void processErrorCode(int nErrorCode) FB n . 4  
{ Am=O-; b'8  
System.err.println("Error Code : " + nErrorCode); eb7~\|9l1i  
} Hr/Q?7g  
e!P]$em|1E  
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//停止文件下载 /JmWiBQIn  
public void siteStop() 0RP{_1k  
{ =' &TqiIv"  
bStop = true;  EHda  
for(int i=0;i<nStartPos.length;i++) |3=tF"h  
fileSplitterFetch.splitterStop(); tx]!|x" F  
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} 9`G}GU]@}  
} !uN_<!  
//负责部分文件的抓取 T^H`$;\  
**FileSplitterFetch.java *wV`7\@  
*/ L87=*_!B;  
package NetFox; I ka V g L  
>:P-3#e*  
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import java.io.*; M3YC@(N% k  
import java.net.*; 8g6G},Y0  
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public class FileSplitterFetch extends Thread { J" U!j  
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String sURL; //File URL 2$1D+(5;  
long nStartPos; //File Snippet Start Position 0]2@T=*kTY  
long nEndPos; //File Snippet End Position l%v2O'h  
int nThreadID; //Thread's ID vR'rYDtU@  
boolean bDownOver = false; //Downing is over 0ae}!LO  
boolean bStop = false; //Stop identical ZCDcf   
FileAccessI fileAccessI = null; //File Access interface e`;U9Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Mf`@X[-;  
{ -_fh=}.n+"  
this.sURL = sURL; v}&J*}_XZ  
this.nStartPos = nStart; PZhpp"  
this.nEndPos = nEnd; bf
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nThreadID = id; <26Jif:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q[TW  
} ef]60OtP  
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public void run() v:u=.by99  
{ V,>uM >$  
while(nStartPos < nEndPos && !bStop) ,{g B$8z^  
{ )k&!&  
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try{ 7hl,dtn7  
URL url = new URL(sURL); ' O d_:]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); we2D!Ywr  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9pq-"?vHY0  
String sProperty = "bytes="+nStartPos+"-"; TbR!u:J  
httpConnection.setRequestProperty("RANGE",sProperty);  ui1h M  
Utility.log(sProperty); R%)7z)~  
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InputStream input = httpConnection.getInputStream(); |v= */
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//logResponseHead(httpConnection); |H4f&&Wd  

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byte[] b = new byte[1024]; Rx.dM_S  
int nRead; |gM@}!DL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P{o//M  
{ I]0 D*z  
nStartPos += fileAccessI.write(b,0,nRead); K5:>  
//if(nThreadID == 1) z#t;n  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IGcYPL\&  
} fz`\-"f]  
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Utility.log("Thread " + nThreadID + " is over!"); (
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bDownOver = true; 8B|B[,`  
//nPos = fileAccessI.write (b,0,nRead); [:bYd}J  
} mE3M$2}  
catch(Exception e){e.printStackTrace ();} ec"+Il  
} p|VgtQ/)%  
} 4'U #<8  
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//打印回应的头信息 R^tDL  
public void logResponseHead(HttpURLConnection con) VT5o#NR{R  
{ TW~9<c  
for(int i=1;;i++) D|X@aUp8}  
{ (xlAS  
String header=con.getHeaderFieldKey(i); F!~oJ  
if(header!=null) ljw>[wNv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); GB` G(a  
Utility.log(header+" : "+con.getHeaderField(header)); av4g/7=  
else ip2BvN&  
break; |-.r9;-b  
} E:S (v  
} kc}&\y  
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public void splitterStop() Yp8GW1@  
{ 0Nq6>^ %  
bStop = true; H<bB@(i  
} D?}K|z LQ  
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} G5'HrV  
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/* ~91) DNaE  
**FileAccess.java 6xAR:  
*//文件访问(定位，写) V~_aM@q1  
package NetFox; Tq`rc"&7u  
import java.io.*; !%Qm{R  
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public class FileAccessI implements Serializable{ g=_@j`  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Pq)C(Z  
RandomAccessFile oSavedFile; MPF;P&6  
long nPos; =r1@?x  
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public FileAccessI() throws IOException pG(%yIiAi  
{ Hv.nO-c  
this("",0); ecG,[1];  
} 3F|#nq  
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public FileAccessI(String sName,long nPos) throws IOException s'^"s_j  
{ Y76UhtYH  
oSavedFile = new RandomAccessFile(sName,"rw"); NY9\a[[^[8  
this.nPos = nPos; Gtpl5gQH  
oSavedFile.seek(nPos); xcA5  
} xix:= a  
]Y
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public synchronized int write(byte[] b,int nStart,int nLen) Ht!]%  
{ S1oP_A[|  
int n = -1; Qfd4")zhG  
try{ [ #1<W`95  
oSavedFile.write(b,nStart,nLen); uf<nVdC.  
n = nLen; N)b.$aC  
} yJGM"$  
catch(IOException e) l
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{ CAvyS  
e.printStackTrace (); BA t0YE`-,  
} 1#-=|:U  
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return n; Uel^rfE`  
} w5tcO%+k1  
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} qL?`l;+  
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/* eJ O+MurO  
**SiteInfoBean.java ^CWxYDG*  
*/ XlGDv*d:#d  
package NetFox; K:\db'``  
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public class SiteInfoBean { eQQ*ZNG  
!HPye@Ua  
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private String sSiteURL; //Site's URL a-<&(jV  
private String sFilePath; //Saved File's Path /6PL  
private String sFileName; //Saved File's Name :]g>8sWL  
private int nSplitter; //Count of Splited Downloading File Bp>Z?"hTe  
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bw& U[|A0%  
public SiteInfoBean() @K:TGo,%I  
{//nSplitter的缺省值为5 sj& j\<(  
//default value of nSplitter is 5 C`LHFqv  
this("","","",5); lZ![?t}2`  
} c.;}e:)s  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >^5UXQr  
{ r[}5<S Q  
sSiteURL= sURL; ,8^QV3  
sFilePath = sPath; ym~  
sFileName = sName; f7_EqS=(  
this.nSplitter = nSpiltter; <+\ w.!  
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} #2qDn^s  
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public String getSSiteURL() ?1kXV n$  
{ xYUC|c1Q9  
return sSiteURL; XzF-g*e  
} k9Xv@v  
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public void setSSiteURL(String value) _)U[c;^6  
{ U&}v1wdZ3  
sSiteURL = value; VQ,;~^Td  
} )J<VDO:_YA  
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public String getSFilePath() (o5^
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{ V0ig#?]  
return sFilePath; S7Tc9"oqV  
} @P@j9yR  
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public void setSFilePath(String value) >q!:*  
{ ZP}NFh%,u  
sFilePath = value; b|KlWt'  
} f0d*%  
}mx>3G{d  
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public String getSFileName() z +NwGVk3  
{ jf WZLb)  
return sFileName; ;[,r./XmH  
} f+xhS,i
DR  
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public void setSFileName(String value) kl0|
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{ 6myF!  H=  
sFileName = value; (n+FEE<  
} @3_[NI%  
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public int getNSplitter() @7j$$  
{ s=BJ7iU_68  
return nSplitter; Y:-O/X  
} Q%Fa1h:2&  
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public void setNSplitter(int nCount) [42Eq
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{ $YztLcn  
nSplitter = nCount; r-aCa/4y!  
} "k'P #v{f  
} lc8zF5  
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/*
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**Utility.java \zMx~-2oN  
*/ 5dXDL~/2p  
package NetFox; j :$Ruy  
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public class Utility { &o]ic(74c?  
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public Utility() pHKGK7 S-  
{ (S)jV0  
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} 6 #m:=  
^2}p%j>  
//线程睡眠 qvN`46c  
public static void sleep(int nSecond)  aWTvowA  
{ Hph$Z1{  
try{ k0^t$J W  
Thread.sleep(nSecond); )r|Pm-:A{  
} cf{rK`Ff^  
catch(Exception e) IQNvhl.{  
{ @||GMA+|  
e.printStackTrace (); UJ^MS4;I3  
} 8^2E77s4U  
} dZIruZ)x
 
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//日志 g3Z"ri~!G  
public static void log(String sMsg) eX3|<Bf  
{ 3@8Zy:[8<  
System.err.println(sMsg); kl[Jt)"4@  
} <#%kmYSL  
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public static void log(int sMsg) 5kdh!qy[$,  
{ qw35LyL  
System.err.println(sMsg); tuIQiWHbM  
} <#>{7" }  
} %Xjg/5G-  
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/* h'|J$  
**TestMethod.java ^w6~?'}  
*/ GEbm$\  
package NetFox; m&{%6  
A=bBI>GEYP  
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public class TestMethod { =Eb4Iyz  
&T&>4I!'M  
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public TestMethod() O&@pi-=o  
{ ///xx/weblogic60b2_win.exe ay`A Gr  
try{ .0b4"0~T6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ? e<D +  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rcU*6`IWA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ''3b[<  
fileFetch.start(); dk[MT'DV  
} /&!4oBna  
catch(Exception e){e.printStackTrace ();} "R %3v.Z  
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} Uf\,U8UB  
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public static void main(String[] args) HBiUp$(mB  
{ nz_1Fu>g|  
new TestMethod(); >(BAIjF E\  
} :/~TV   
} (!"&c* <  
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