http断点续传简单实现（java)

/* <c{RY.1[  
**SiteFileFetch.java 7oDr`=q1]r  
*/ e}e\*BL  
package NetFox; HzT"{N9  
import java.io.*; !58-3F%P  
import java.net.*; w7"Z@$fs  
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public class SiteFileFetch extends Thread { .Tdl'y:..  
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SiteInfoBean siteInfoBean = null; //文件信息Bean @qH<4`y.^  
long[] nStartPos; //开始位置 W&6P%0G/  
long[] nEndPos; //结束位置 B" wk:\zC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UGPD5wX?  
long nFileLength; //文件长度 Tp`by 1s  
boolean bFirst = true; //是否第一次取文件 ('xu2 ;<  
boolean bStop = false; //停止标志 'wX'}3_/g  
File tmpFile; //文件下载的临时信息 h2u>CXD  
DataOutputStream output; //输出到文件的输出流 ~OEP)c\k  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G)?O!(_  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0QDm3V0n  
{ "@E1^
  
siteInfoBean = bean; W]n%$a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H>`?S{J  
if(tmpFile.exists ()) }{S W~yW  
{ Mx-,:a9}  
bFirst = false; Vcl"qz@Fj  
read_nPos(); Fp06a!7<  
} >b |l6#%  
else ){")RrD(  
{ y8wOJZ<K
 
nStartPos = new long[bean.getNSplitter()]; ^Yn{Vi2.  
nEndPos = new long[bean.getNSplitter()]; z1F[okLA  
} &S<tX]v
 
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} Tfgx>2  
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public void run() ?4_^}B9  
{ |jaUVE_2[  
//获得文件长度 l<{]%=Qg  
//分割文件 U\ y?P:yy  
//实例FileSplitterFetch L$@^EENS  
//启动FileSplitterFetch线程 6$b"tdP  
//等待子线程返回 p(~>u'c  
try{ +8Zt<snG  
if(bFirst) q=}Lm;r  
{ j46fQ  
nFileLength = getFileSize(); c:51In|~{C  
if(nFileLength == -1) ZQnJTS+Rd  
{ 2anx]QV4  
System.err.println("File Length is not known!"); V4 Pf?g  
} xK0VWi  
else if(nFileLength == -2) OHqLMBW!!  
{ FcsEv {#U  
System.err.println("File is not access!"); Ab-S*|B  
} * "ER8\  
else ?'$=G4y&?  
{ P~i^V;g  
for(int i=0;i<nStartPos.length;i++) >RBq&'f  
{ OcMd'fwO  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +:~&"U^z&  
} b2H!{a"  
for(int i=0;i<nEndPos.length-1;i++) jfS?#;T)  
{ i,FG?\x@  
nEndPos = nStartPos[i+1]; _ts0@Z_:  
} netKt_  
nEndPos[nEndPos.length-1] = nFileLength; HPCgv?E3  
} i?'HVx  
} }!& w<wR  
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//启动子线程 CjOaw$s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B8|=P&L7N  
for(int i=0;i<nStartPos.length;i++) &.+[~2  
{ M`KrB5a+6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ()(@Qcc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C1|e1  
nStartPos,nEndPos,i); _1dG!!L_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yiu)0\ o  
fileSplitterFetch.start(); Q9 kKk  
} A`=ESz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 27E6S)zv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +fAAkO*GP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", . %tc7`k8  
nEndPos = " + nFileLength); ).N}x^  
// fileSplitterFetch[nPos.length-1].start(); TpZ) wC  
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//等待子线程结束 @*q\$Eg}2  
//int count = 0; }o=R7n%  
//是否结束while循环 Gc4N)oq)}b  
boolean breakWhile = false; =@binTC4  
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while(!bStop) 1F/`*z
 
{ gUL`)t\}*  
write_nPos(); ePIBg(  
Utility.sleep(500); =a?l@dI]  
breakWhile = true; !o:RIwS3  
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for(int i=0;i<nStartPos.length;i++) K,|Gtaa~  
{ s3_i5,y  
if(!fileSplitterFetch.bDownOver) Z=R>7~H  
{ (~}yt.7K  
breakWhile = false; =d7lrx+z  
break; zBB4lC{q  
} "KW\:uc /  
} QCa$<~c  
if(breakWhile) >efYpd#^  
break; //Hn[wEOh  
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//count++; f&8&UL>e`  
//if(count>4) 5p94b*l  
// siteStop(); ilayU  
} _9#4  
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System.err.println("文件下载结束！"); 3UD_2[aqN(  
} I@+dE V`Lf  
catch(Exception e){e.printStackTrace ();} /Kw
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} S=krF yFw  
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//获得文件长度 @5acTYQ  
public long getFileSize() 9!_`HE+(XJ  
{ sA3 4`ZAa  
int nFileLength = -1; '"~|L>F%G  
try{ hP`3Ao  
URL url = new URL(siteInfoBean.getSSiteURL());  7I^(vQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G5"UhnOD'  
httpConnection.setRequestProperty("User-Agent","NetFox"); e]uk}#4  
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int responseCode=httpConnection.getResponseCode(); yew9bn0a=  
if(responseCode>=400) B\KvKT|\  
{ , YTuZS  
processErrorCode(responseCode); `Kpn@Xg
 
return -2; //-2 represent access is error Sw%=/g  
} SL pd~ZC?  
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String sHeader; <3O>  
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for(int i=1;;i++) %$`pD I)  
{ IZi1N  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xv]O1fcI  
//Utility.log(in.readLine()); fk#SD "iJ  
sHeader=httpConnection.getHeaderFieldKey(i); 2o6KVQ  
if(sHeader!=null) ^Ml)g=Fq  
{ ;5PXPpJ  
if(sHeader.equals("Content-Length")) ::9U5E;!  
{ +QtK "5M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ojT TYR{  
break; ~U~
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} _?Rprmjx}  
} Y71io^td~j  
else *]W{83rXQ  
break; w/~,mzM"  
} #If}P$!  
} dF5EIPl;J  
catch(IOException e){e.printStackTrace ();} TW{.qed8^  
catch(Exception e){e.printStackTrace ();} HB||
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Utility.log(nFileLength); c,!Ijn\;(  
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return nFileLength; +]Po!bN@@  
} ht!o_0{~  
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//保存下载信息（文件指针位置） ^UEI`_HO0  
private void write_nPos() t}c ymX
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{ BCJo/m  
try{ fp.,MIS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rNO'0Ck=
 
output.writeInt(nStartPos.length); V~+Oil6sa  
for(int i=0;i<nStartPos.length;i++) Q\<C9%a  
{ ,gUSW  
// output.writeLong(nPos); &UEr4RK;I  
output.writeLong(fileSplitterFetch.nStartPos); c]
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output.writeLong(fileSplitterFetch.nEndPos); }XX)U_x  
} CDK0 $W n  
output.close(); ?y>P  
} vYKKv%LE  
catch(IOException e){e.printStackTrace ();} Urm&4&y  
catch(Exception e){e.printStackTrace ();} [v^T]L  
} CJz2.yd  
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//读取保存的下载信息（文件指针位置） Cf91#%:cN  
private void read_nPos() AT<K>&)  
{ M`q>i B  
try{ z4HIDb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); eY-W
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int nCount = input.readInt(); Xjw>Qws  
nStartPos = new long[nCount]; d/v{I  
nEndPos = new long[nCount]; WUvrC  
for(int i=0;i<nStartPos.length;i++) Mi%i_T^i  
{ COH0aNp;  
nStartPos = input.readLong(); IX$dDwY|O>  
nEndPos = input.readLong(); -Ds}kdxw  
} ='`z  
input.close(); Y4_/G4C  
} F@1~aeX-  
catch(IOException e){e.printStackTrace ();} zq>pK_WG  
catch(Exception e){e.printStackTrace ();} lG I1LUo  
} Aq yR+  
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private void processErrorCode(int nErrorCode) (+`pEDD{X  
{ %YkJA:  
System.err.println("Error Code : " + nErrorCode); {pH{SRM)B  
} mKugb_d?  
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umaF}}-Q{  
//停止文件下载 Dq/_^a/1  
public void siteStop() )a AKO`  
{ -*~= 4m<  
bStop = true; |]1-ck!  
for(int i=0;i<nStartPos.length;i++) ]P;uQ!  
fileSplitterFetch.splitterStop(); |_
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} EiQX*v  
} 9utiev~
3  
//负责部分文件的抓取 ![h+R@_(  
**FileSplitterFetch.java {;4Y5kj  
*/ )e(Rf!P{  
package NetFox; UbNA|`H  
jfP2n5X83  
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import java.io.*; m\o<a|  
import java.net.*; %X7R_>.   
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public class FileSplitterFetch extends Thread { #?\$*@O  
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String sURL; //File URL >L\$
  
long nStartPos; //File Snippet Start Position ,V1/(|[h  
long nEndPos; //File Snippet End Position a8ya5EO  
int nThreadID; //Thread's ID 0zQ"5e?qy  
boolean bDownOver = false; //Downing is over U_i%@{  
boolean bStop = false; //Stop identical K&Ner(/X`6  
FileAccessI fileAccessI = null; //File Access interface Rah"La  
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d` %8qLIW  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1/X@~  
{ r<VZEbm)  
this.sURL = sURL; Oxo?\ :T  
this.nStartPos = nStart; fFDI qX  
this.nEndPos = nEnd; O'm><a>8  
nThreadID = id; O<7Q>m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t"x 8]Gy  
} p4mi\~Q  
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public void run() vU
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{ 'D`O4TsP>  
while(nStartPos < nEndPos && !bStop)
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{ ).U\,@[A{  
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try{ g_X-.3=2K  
URL url = new URL(sURL); [.J&@96,b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wpgO09  
httpConnection.setRequestProperty("User-Agent","NetFox"); _gU:!:}  
String sProperty = "bytes="+nStartPos+"-"; 8Na.H::cZ  
httpConnection.setRequestProperty("RANGE",sProperty); <;Q1u,Mc  
Utility.log(sProperty); @Wgd(Ezd  
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InputStream input = httpConnection.getInputStream(); [v47_ 5O  
//logResponseHead(httpConnection); q^!_jMN5  
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byte[] b = new byte[1024]; NSe Huk  
int nRead; mj{B_3b5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mJ+M|#Ox  
{ pH&*
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nStartPos += fileAccessI.write(b,0,nRead); d*qb^C{'"  
//if(nThreadID == 1) 7~b=G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <P
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} #IJm*_J<  
4
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Utility.log("Thread " + nThreadID + " is over!"); /{1sU}k-  
bDownOver = true; yyPQ^{zD  
//nPos = fileAccessI.write (b,0,nRead); *JnY0xP  
} J?6.yL;  
catch(Exception e){e.printStackTrace ();} 7Qdf#DG  
} U ?iw  
} #jrtsv]  
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//打印回应的头信息 v C23  
public void logResponseHead(HttpURLConnection con) HQp\0NC]  
{ F}
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for(int i=1;;i++) 7bV(eV  
{ @jL](Mq|]  
String header=con.getHeaderFieldKey(i); ;x<5F+b  
if(header!=null) mJxr"cwHl  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (vX) <Z !  
Utility.log(header+" : "+con.getHeaderField(header)); Zv]'9,cbk  
else /esdtH$=  
break; 6=cfr; BH2  
} k8KRVXgx  
} )Ehi8  
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public void splitterStop() Q};n%&n&  
{ fe!eZiE  
bStop = true; '/OcJVSR  
} @h&:xA56  
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} 1Kjqs)p^  
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/* ^C=dq(i=[  
**FileAccess.java Vc[aNpE  
*//文件访问(定位，写) r'
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package NetFox; O]4v\~@-j  
import java.io.*; SFu]*II;
{  
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}SfS\b{|~  
public class FileAccessI implements Serializable{ noNJ+0S  
M)F_$ ICE-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c,2OICj  
RandomAccessFile oSavedFile; tJG+k)EE  
long nPos; bO i-QD  
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! k[JP+;  
public FileAccessI() throws IOException *{_N*p\{  
{ (ZPl~ZO  
this("",0); <ni_7
8  
} c;?J  
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Ucx"\/"  
public FileAccessI(String sName,long nPos) throws IOException 0BwxPD#6bv  
{ p4F%FS:`  
oSavedFile = new RandomAccessFile(sName,"rw"); xH\!j  
this.nPos = nPos; eJ*u]GH U  
oSavedFile.seek(nPos); ZveNe~D7C  
} `q9n`h1  
8J#U=q
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public synchronized int write(byte[] b,int nStart,int nLen) Za
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{ qzj.N$9]  
int n = -1; yhkKakg,)  
try{ o;9 G{Xj3@  
oSavedFile.write(b,nStart,nLen); _/czH<   
n = nLen; Y{Ff I+  
} 9u6VN]divB  
catch(IOException e) f, '*f:(  
{ cR{F|0X  
e.printStackTrace (); qyBC1an5,  
} 'fs tfk  
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return n; csd9[=HW/Q  
} eZoAy[  
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} LOgFi%!6:  
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/* }S$
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**SiteInfoBean.java 7KHQ0  
*/ \@Gcx}Y8h  
package NetFox; ~,_@|,)  
BbM/Rd1tAm  
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public class SiteInfoBean { 2,Aw6h;  
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private String sSiteURL; //Site's URL cyLl,OA  
private String sFilePath; //Saved File's Path EJP]E)  
private String sFileName; //Saved File's Name K5rra%a-7  
private int nSplitter; //Count of Splited Downloading File cij8'("+!  
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*;(^)Sj4Q  
public SiteInfoBean() G!`PP  
{//nSplitter的缺省值为5 FWB *=.A9  
//default value of nSplitter is 5 C;5`G *e  
this("","","",5); _s+G02/q1  
} {{Qbu}/@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hH9~.4+*`g  
{ eZ$M#I=o  
sSiteURL= sURL; Sgr. V)  
sFilePath = sPath; ^D]J68)#a  
sFileName = sName; t 9t '9  
this.nSplitter = nSpiltter; #1C]ZV] B  
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} @U4hq7xzV2  
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public String getSSiteURL() d&+0JI<  
{ UdVf/PGx  
return sSiteURL; [!>9K}z,=  
} f~*7hv\  
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public void setSSiteURL(String value) 8{]nS8i  
{ @ze2'56F}  
sSiteURL = value; Q lA?dXQ  
} 5HsF#  
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public String getSFilePath() Fc80HK5R  
{ dF09_nw  
return sFilePath; J2 /19'QE  
} :\I*_00!  
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public void setSFilePath(String value) <[D>[  
{ |AacV  
sFilePath = value; RJUIB  
} .heU Ir,  
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public String getSFileName() g1?9ge1  
{ SB08-G2  
return sFileName; o<iU;15  
}
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public void setSFileName(String value) )[cuYH>  
{ &PH:J*?C}  
sFileName = value; DRR)mQBb  
} =E>P,"D  
zfE8=d8U  
M|
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public int getNSplitter() k0O5c[j  
{ %LzARTX
 
return nSplitter; _yUYEq<`  
} S6_:\Q  
a$h^<D ^  
mhX66R  
public void setNSplitter(int nCount) QxA( *1  
{ 83I 5n&)  
nSplitter = nCount; %k32:qe  
} #AB5}rPEI  
} oPF]]Imu  
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/* P$0c{B4I  
**Utility.java iF MfBg  
*/ n
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package NetFox; W7b m}JHn  
p}h.2)PO  
:\qapFV  
public class Utility { \o/eF&  
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public Utility() Dw7Xy}I/  
{ \>pm (gF  
QK#wsw  
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} A7%/sMv  
'Etq;^H  
//线程睡眠 :{ZwzJ  
public static void sleep(int nSecond) Q!qD3<?5  
{ *Cf!p\7!  
try{ T@i* F M  
Thread.sleep(nSecond); NN=^4Xpc:  
} 23i2y
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catch(Exception e) G`kz 0Vk  
{ U|Gy9"  
e.printStackTrace (); PU,$YPrZ  
} hmd3W`8D  
} (AtyM?*  
M-@X&bm,S  
//日志
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public static void log(String sMsg) 7L6L{~8 W  
{ A"&<$5Q  
System.err.println(sMsg); CxjB9#  
} MjQju@  
\.O&-oi  
Wh| T3&  
public static void log(int sMsg) &Q;sbI}  
{ dd<l;4(  
System.err.println(sMsg); z)U7  
} fV5$[CL1  
} qD?`Yd  
@-L]mLY  
ltDohm?  
/* <7F-WR/2n  
**TestMethod.java |k90
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*/ -5 PVWL\  
package NetFox; w6cl3J&  
^7gKs2M  
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public class TestMethod { vVw@^7U  
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public TestMethod() oo2d,  
{ ///xx/weblogic60b2_win.exe K&`1{,  
try{ 4Ex&AR8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
[. 9[?8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?..BA&zRk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2O[sRm)  
fileFetch.start(); =hFY-~U  
} 'xj5R=V  
catch(Exception e){e.printStackTrace ();} l7qW)<r  
w/ rQOHV{  
F[Mwd &P@  
} (~zu4^9w  
2<I=xWwFA  
f%@~|:G:  
public static void main(String[] args) o>,r<
  
{ GIxs>E'X  
new TestMethod(); 0LH6G[  
} wCNn/%C  
} I ]ZZN6"  
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