http断点续传简单实现（java)

/* @4D$Xl  
**SiteFileFetch.java M38QA  
*/ qqSf17sW  
package NetFox; ~%QVjzMC  
import java.io.*; RAQi&?Ko  
import java.net.*; i
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public class SiteFileFetch extends Thread { [ENm(e$sI  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pN"d~Z8  
long[] nStartPos; //开始位置 Lh6G"f(n  
long[] nEndPos; //结束位置 ;_GS<[A3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^xO
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long nFileLength; //文件长度 K_4}N%P/))  
boolean bFirst = true; //是否第一次取文件 uFIr.U$V  
boolean bStop = false; //停止标志 ^E8XPK]-~  
File tmpFile; //文件下载的临时信息 x-km)2x=W  
DataOutputStream output; //输出到文件的输出流 ;aip1Df  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） '@h
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public SiteFileFetch(SiteInfoBean bean) throws IOException Bg*Oj)NM  
{ }^;Tt-*k  
siteInfoBean = bean; bBBW7',[a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #]'#\d#i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3PLv;@!#j}  
if(tmpFile.exists ()) (8u.Xbdh  
{ HgP9evz,0  
bFirst = false; oq4*m[  
read_nPos(); aCe<*;b@  
} O<Rm9tZ8  
else W|oLS  
{ (7G5y7wI"  
nStartPos = new long[bean.getNSplitter()]; y1!c:&  
nEndPos = new long[bean.getNSplitter()]; C&b^TLe  
} ika/ GG  
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} Lf|5miO  
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public void run() b/='M`D}#G  
{ n0:Y*Op  
//获得文件长度 JB~79Lsdz  
//分割文件 NWuS/Ur`9  
//实例FileSplitterFetch qr[H0f]  
//启动FileSplitterFetch线程 pt&(c[  
//等待子线程返回 y|1,h}H^n  
try{ (-tF=wR,W  
if(bFirst) Gk0f#;  
{ #8G(r9  
nFileLength = getFileSize(); .olDmFQD  
if(nFileLength == -1) TOp|Qtn  
{ Q<.847 )  
System.err.println("File Length is not known!"); b/:&iG;
 
} x,a(O@  
else if(nFileLength == -2) h\ema|  
{ 5"=qVmT)  
System.err.println("File is not access!"); |-l)$i@  
} %Ji@\|Zkf  
else 8|uFW7Q  
{ /l-lkG5  
for(int i=0;i<nStartPos.length;i++) vq|o}6Et  
{ ?'_E$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =^m,|j|d>4  
} &o>ctf.x  
for(int i=0;i<nEndPos.length-1;i++) B>}=x4-8  
{ :gMcl"t--  
nEndPos = nStartPos[i+1]; fGDR<t3yiQ  
} sf\p>gb  
nEndPos[nEndPos.length-1] = nFileLength; 47b=>D8  
} h0ufl.N_%  
} *6oQW  
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//启动子线程 C=&7V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )# le|Rf  
for(int i=0;i<nStartPos.length;i++) pZ?7'+u$L  
{ N6Mo|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :uE:mY%R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #;59THdtPk  
nStartPos,nEndPos,i); <QoSq'g#,=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #gzY _)E  
fileSplitterFetch.start(); [;3` Aw  
} / E~)xgPM<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =c 3;@CO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ww&~ZZZ {  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8.4
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nEndPos = " + nFileLength); !PX`sIkT  
// fileSplitterFetch[nPos.length-1].start(); bM[!E8dF  
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//等待子线程结束 ^a&-GhX;  
//int count = 0; 2JNO@  
//是否结束while循环 &eYnO~$!  
boolean breakWhile = false; @C]]VE  
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while(!bStop) jU\vg;nr  
{ x_&=IyU0j  
write_nPos(); +cS%b}O`$  
Utility.sleep(500); -F.A1{l[.  
breakWhile = true; UV}\#86!  
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for(int i=0;i<nStartPos.length;i++) wg<UCmfu!  
{ %$K2$dq5  
if(!fileSplitterFetch.bDownOver) V7}5Zw1  
{ 3T)GUzt`  
breakWhile = false; +L(0R&C  
break; =\;yxl
 
} Q@B--Omfh  
} 9aYDi)  
if(breakWhile) :<$B o  
break; y{CyjYpz^  
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: tKa1vL  
//count++; ~^#F5w"  
//if(count>4) #jdo54-  
// siteStop(); tmM8YN|  
} 6E~T$^Q}  
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System.err.println("文件下载结束！"); ^MJTlRUb  
} 1<Fh aK  
catch(Exception e){e.printStackTrace ();} hs'J'~a  
} rO8Q||@>A  
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//获得文件长度 ?'F>DN  
public long getFileSize() .I%p0ds1r  
{ sU>!sxW  
int nFileLength = -1; HZ$q`e  
try{ gG;d+s1  
URL url = new URL(siteInfoBean.getSSiteURL()); `uRf*-   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V\k?$}  
httpConnection.setRequestProperty("User-Agent","NetFox"); L`E^BuP/  
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int responseCode=httpConnection.getResponseCode(); pAwmQ
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if(responseCode>=400) C1 qyjlR  
{ o(iv=(o  
processErrorCode(responseCode); XEd|<+P1  
return -2; //-2 represent access is error %si5cc?  
} JN;92|x  
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String sHeader; 1o5DQ'~n  
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for(int i=1;;i++) 4h:R+o ^H^  
{ Yv0;UKd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qkX}pQkG)h  
//Utility.log(in.readLine()); s':fv[%  
sHeader=httpConnection.getHeaderFieldKey(i); H`!%"  
if(sHeader!=null) yl63VX8w}  
{ XAN{uD^3\%  
if(sHeader.equals("Content-Length")) 7/*a
 
{ n7UZ&ab  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Qg]8~^Q<  
break; nsChNwPX  
} xgl~4  
} eM)E3~K:2  
else ,>-Q#  
break; Zkn$D:
 
} ]
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} mG,%f"b0  
catch(IOException e){e.printStackTrace ();} -!]Ie4"  
catch(Exception e){e.printStackTrace ();} QW~-+BD  
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Utility.log(nFileLength); 8 j
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return nFileLength; }hT1@I   
} z!09vDB^  
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//保存下载信息（文件指针位置） B Z:H$v  
private void write_nPos() rVLUT  
{ .f'iod-  
try{ 5gpqN)|)[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /$OX'L&b  
output.writeInt(nStartPos.length); Kgi| 7w  
for(int i=0;i<nStartPos.length;i++) u*R9x3&/5  
{ pa0'\  
// output.writeLong(nPos); ;d17xu?ks  
output.writeLong(fileSplitterFetch.nStartPos); 6MC*2}W  
output.writeLong(fileSplitterFetch.nEndPos); ag6hhkjA  
} xJ"CAg|
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output.close(); {.7ve<K  
} Ln;jB&t  
catch(IOException e){e.printStackTrace ();} =m@5$  
catch(Exception e){e.printStackTrace ();} f3h&K}x  
} \R&4Nu2F  
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//读取保存的下载信息（文件指针位置） s^_E'j$  
private void read_nPos() YM9oVF-  
{ A[juzOn\  
try{ Ed/@&52z0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Gmcx#?|Tx  
int nCount = input.readInt(); Is6<3eQ\x  
nStartPos = new long[nCount]; &lYKi3}x  
nEndPos = new long[nCount]; Zp|LCE"  
for(int i=0;i<nStartPos.length;i++) "i$uV
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{ }vOUf#^k  
nStartPos = input.readLong(); /*GRE#7S  
nEndPos = input.readLong(); cK.T=7T  
} SfE^'G\  
input.close(); W-Cf#o  
} >/
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catch(IOException e){e.printStackTrace ();} Meh?FW||5  
catch(Exception e){e.printStackTrace ();} A%u@xL,_  
} v |/IN  
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private void processErrorCode(int nErrorCode) \~xOdqF/  
{ {aq\sf;i{  
System.err.println("Error Code : " + nErrorCode); 4%WV)lt  
} G+=6]0HT  
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//停止文件下载 .rj FhSr$  
public void siteStop() 2tvMa%1^  
{ ?MhRdY  
bStop = true; sY,!Ir`/`  
for(int i=0;i<nStartPos.length;i++) ;_0)f
 
fileSplitterFetch.splitterStop(); . FT*K[+ih  
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} N}\Da:_  
} !l'Az3'J|  
//负责部分文件的抓取 iL1.R+  
**FileSplitterFetch.java /2oTqEqaV  
*/ =K2Dxu_:  
package NetFox; uPe4Rr  
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import java.io.*; z)5n&w S  
import java.net.*; =y7]9SOq  
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public class FileSplitterFetch extends Thread { jG{}b6  
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String sURL; //File URL  $JmL)r  
long nStartPos; //File Snippet Start Position
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long nEndPos; //File Snippet End Position #;juZ*I  
int nThreadID; //Thread's ID =!xeki]|9  
boolean bDownOver = false; //Downing is over ~nb%w?vv  
boolean bStop = false; //Stop identical (7 Mn%Jp  
FileAccessI fileAccessI = null; //File Access interface t Zj6=#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,$3  
{ h`%K\C  
this.sURL = sURL; 14\%2nE  
this.nStartPos = nStart; .]ZM2  
this.nEndPos = nEnd; {mL/)\  
nThreadID = id; ORa!84L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &F\J%#{  
} 9G_=)8sOV  
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public void run() FStE/2?  
{ ?OKm~ Ek  
while(nStartPos < nEndPos && !bStop) *6*#"#D  
{ cFUYT$8>  
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try{ CV4V_G  
URL url = new URL(sURL); U^Z[6u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3HbHl?-UNU  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xkl^!,  
String sProperty = "bytes="+nStartPos+"-"; 4PiNQ'*  
httpConnection.setRequestProperty("RANGE",sProperty); XoSjYG(>,  
Utility.log(sProperty); p"H8;fPA0  
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InputStream input = httpConnection.getInputStream(); ~B(]0:  
//logResponseHead(httpConnection); d5A!kU _.  
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byte[] b = new byte[1024]; |!%A1 wp#  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QVn0!R{  
{
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nStartPos += fileAccessI.write(b,0,nRead); -xXNzC
 
//if(nThreadID == 1) d(wqKiGwe  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'n:Ft  
} %~p_bKd~  
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Utility.log("Thread " + nThreadID + " is over!"); lha)'
 
bDownOver = true; E
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//nPos = fileAccessI.write (b,0,nRead); '0 (Bb  
} _$ixE~w-!  
catch(Exception e){e.printStackTrace ();} T|.Q81.NE  
} !u6~#.7  
} ?RpT_
u  

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//打印回应的头信息 c;U\nC<Y  
public void logResponseHead(HttpURLConnection con) *~!xeL  
{ <Dm6CH  
for(int i=1;;i++) +{hxEDz  
{ y^@%Xrs  
String header=con.getHeaderFieldKey(i); 5.?O PK6  
if(header!=null) +crAkb}i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `zzX2R Je  
Utility.log(header+" : "+con.getHeaderField(header)); K+v 250J$-  
else #0`"gR#+  
break; Qmn5umd=?\  
} WP]<\_r2  
} HAO/r`7*  
"rX=G=  
]3={o3[:  
public void splitterStop() i"rMP#7  
{ (la<X<w  
bStop = true; sx]?^KR:  
} uTl:u  
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} MT6kJDyLu  
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/* G4x.''r&Sl  
**FileAccess.java Z;>~<#!4  
*//文件访问(定位，写) =rBFMTllM  
package NetFox; 7Ck;LF}>0  
import java.io.*; =\XAD+
 
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public class FileAccessI implements Serializable{ awkVjyqX  
izC>-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LpmspIPvf  
RandomAccessFile oSavedFile; B8_l+dXO  
long nPos; ;~1r{kXxA"  
mKsj7  
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public FileAccessI() throws IOException q#p)E=$  
{ 5z]dA~;*2  
this("",0); ("lcL2Bq  
} rqF PUp  
'
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/ruf1?\,R  
public FileAccessI(String sName,long nPos) throws IOException 6~!YEuA  
{ 4X\*kF%  
oSavedFile = new RandomAccessFile(sName,"rw"); 
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this.nPos = nPos; i*^K)SI8  
oSavedFile.seek(nPos); RChY+3,L)  
} LqUvEq  
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gx6&'${=#  
public synchronized int write(byte[] b,int nStart,int nLen) `+f\Q2]Z  
{ .|aSGvE  
int n = -1; aDOH3Ri0K!  
try{ 1|nB\xgu  
oSavedFile.write(b,nStart,nLen); E{fnh50^Q.  
n = nLen; )I>rC%2P  
} )/U1; O  
catch(IOException e) IL\mFjZ'  
{ i&HV8&KygN  
e.printStackTrace (); :_aY:`  
} U3V<ITZI8t  
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8 6+>|  
return n; DA wzXsx  
} }2r08,m  
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} vJCL m/}*  
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5r
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/* )m'_>-`^:  
**SiteInfoBean.java )/ZSb1!  
*/ ZF t^q/pw  
package NetFox; ..T(9]h  
|X.z|wKT6  
q#a21~S<  
public class SiteInfoBean { ,9pi9\S  
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private String sSiteURL; //Site's URL 5&kR1Bp#-  
private String sFilePath; //Saved File's Path # R&[+1=9j  
private String sFileName; //Saved File's Name Yq Fzbm{\  
private int nSplitter; //Count of Splited Downloading File d5=xOEv; :  
6wd]X-G++  
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public SiteInfoBean() :$tW9*\KY  
{//nSplitter的缺省值为5 h0eo:Ahi  
//default value of nSplitter is 5 q kKABow  
this("","","",5); Sy'>JHx  
} dJ!o/y6  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e||_j  
{ %OtW\T=u  
sSiteURL= sURL; <^\r9Qxl  
sFilePath = sPath; \nHlI=!P  
sFileName = sName; :A'!u r=\  
this.nSplitter = nSpiltter; <S}qcj
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} B1M/5cr.  
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public String getSSiteURL() mq
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{ xS}H483h6W  
return sSiteURL; nKO&ffb'<  
} } 8P}L@q  
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public void setSSiteURL(String value) <e^/hR4O  
{ DPwSg\*)  
sSiteURL = value; #'8PFw\zw  
} SIlg  
9CNHjs+-}s  
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public String getSFilePath() IebS~N E  
{ 5);#\&B  
return sFilePath; JqUVGEg  
} e%U*~{m+  
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public void setSFilePath(String value) 6.|~~/  
{ h9I)<_}R  
sFilePath = value; wuzz%9;@B  
} XNUqZ-M:  
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hwzUCh 5!  
public String getSFileName() g#4gGhI  
{ +V@=G &Ou0  
return sFileName; ~Z]vr6?$h  
} VTWE-:r  
{h"\JI!  
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public void setSFileName(String value) Nd_@J&  
{ F[EblJ  
sFileName = value; m GhJn  
} &-fx=gq=  
Jg:-TK/  
mx9/K+:  
public int getNSplitter() 7LwS =yP  
{ XijLS7Aw|  
return nSplitter; V]]qu:Mh8  
} |T_Pz&-  
@vYmkF`  
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public void setNSplitter(int nCount) +q/h:q.TV  
{ Qu,k  
nSplitter = nCount; t^,Qy.L0  
} 358/t/4{p  
} Pm^N0L9?q  
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/* ;a&:r7]=  
**Utility.java oKi1=d+T  
*/ el?V2v[  
package NetFox; }+4Bf+u:  
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public class Utility { 9.zQ<k2  
B)]{]z0+`  
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public Utility() Mlw9#H6  
{ oqba:y;AR  
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} I#X2UQzP  
J,G9m4Z7  
//线程睡眠 SrtVoe[  
public static void sleep(int nSecond) =>0M3 Qh{  
{ 1?RCJ]e5  
try{ RLz`aBT  
Thread.sleep(nSecond); 'UVv(-  
} :6$4K"^1  
catch(Exception e) U|7Qw|I7  
{ BZ+ mO  
e.printStackTrace (); P5}[*k%DQw  
} Rca Os  
} oPu|Q^I=  
R96o8#7Uv  
//日志 C^" Hj  
public static void log(String sMsg) %DRy&k/T  
{ !""!sFx)R  
System.err.println(sMsg); !)/iRw9re  
} Q^Z<RA(C  
gZ"{{#:}  
@=0r3  
public static void log(int sMsg) @`;Y/',  
{ mu6xL QdA  
System.err.println(sMsg); 3.<6;?  
} Cre0e$ a  
} \8*,&ak%  
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an=+6lIl  
/* 22/?JWL>  
**TestMethod.java BY4  R@)  
*/ +:"6`um|  
package NetFox; IN|i)?rh  
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public class TestMethod { Kcw1uLb  
2rj/wakd  
Wl !!5\  
public TestMethod() N^Hn9n  
{ ///xx/weblogic60b2_win.exe B)DC,+@$  
try{ 38U5^`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qsft*&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I^M#[xA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); urrO1  
fileFetch.start(); mF
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} g^z5fFLg/8  
catch(Exception e){e.printStackTrace ();} !k:zLjtp  
W.J:.|kt  
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} [/AdeR  
v#:+n+y\z  
*CH!<VB/  
public static void main(String[] args) i9&K  
{ #Z|%0r_~  
new TestMethod(); aT?p>  
} bIb6yVnHi  
}
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