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http断点续传简单实现(java)

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/* iX~V(~v  
**SiteFileFetch.java n- p|7N  
*/ ^f>+5G  
package NetFox; 514;!Q4K  
import java.io.*; p=eSHs{>A  
import java.net.*; M,6m*  
(/c9v8Pr(7  
3q<\ \8Y*  
public class SiteFileFetch extends Thread { aWW|.#L  
ca-|G'q  
1J^{h5?lU  
SiteInfoBean siteInfoBean = null; //文件信息Bean -p9|l%W  
long[] nStartPos; //开始位置 RzNv|   
long[] nEndPos; //结束位置 {V8 v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~GMlnA]6  
long nFileLength; //文件长度 ~`T3 i  
boolean bFirst = true; //是否第一次取文件 \U,.!'+  
boolean bStop = false; //停止标志 GYCc)Guc  
File tmpFile; //文件下载的临时信息 ^cd+W?  
DataOutputStream output; //输出到文件的输出流 5^[V%4y>  
d&t |Y:,8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) AOhsat;O`  
public SiteFileFetch(SiteInfoBean bean) throws IOException p.&FK'&[0  
{ _v<EFal  
siteInfoBean = bean; )mJl-u[0+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `2 Vc*R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }7k+tJ<   
if(tmpFile.exists ()) Fn$EP:>  
{ +.5 /4?  
bFirst = false; |no '^  
read_nPos(); G[)QGZ}8b  
} HLa|yc B%  
else Id|38   
{ 1+v)#Wj  
nStartPos = new long[bean.getNSplitter()]; ;L++H5Kz6  
nEndPos = new long[bean.getNSplitter()]; -bduB@#2d  
} W|; .G9  
vY:A7yGW  
 !3}vl Y1  
O0c#-K.f  
} 3\G&fb|?}R  
V#=o<  
&.;tdT7  
public void run() r@^h,  
{ 5q}680s9+  
//获得文件长度  g&#.zJ[-  
//分割文件 I[G<aI!  
//实例FileSplitterFetch D8qZh1w%A|  
//启动FileSplitterFetch线程 5&\Q0SX(~  
//等待子线程返回 vEOoG>'Zq  
try{ :J5xO%WA(  
if(bFirst) G)M9to  
{ MW6d-  
nFileLength = getFileSize(); S2h?Q $e3  
if(nFileLength == -1) aB+Ux< -  
{ PJsiT4<  
System.err.println("File Length is not known!"); },e f(  
} D~G24k6b3  
else if(nFileLength == -2) ?,O{,2}  
{ D*I%=);B_  
System.err.println("File is not access!"); ?(n|ykXwc  
} la[xbv   
else 3u3(BY{"\F  
{ 0sLR5A  
for(int i=0;i<nStartPos.length;i++) =4 36/O`K  
{ sTU`@}}  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  =6Ihk  
} 7ae8nZ3&  
for(int i=0;i<nEndPos.length-1;i++) t[Xx LG*  
{ ;gu_/[P  
nEndPos = nStartPos[i+1]; U8PSJ0ny  
} ZC@sUj"  
nEndPos[nEndPos.length-1] = nFileLength; $RfM}!7?  
} XL1v&'HLV  
} swntz  
5\A[ra  
_t_X`  
//启动子线程 mvyqCOp 0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VZ 5EV'D8!  
for(int i=0;i<nStartPos.length;i++) j ~:Dr   
{ CfNHv-jDL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rfpeX   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Gcna:w>6d  
nStartPos,nEndPos,i); qe8dpI;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OEnJ".&V  
fileSplitterFetch.start(); : 2Ho  
} TW8E^k7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %XM wjBM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |<t"O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s `B"qw  
nEndPos = " + nFileLength); lED-Jo2  
// fileSplitterFetch[nPos.length-1].start(); h/j+ b.|  
R_e{H^pY^  
PMebn$(  
//等待子线程结束 Q-k{Lqa-  
//int count = 0; mFC0f?nr  
//是否结束while循环 mzLDZ# =b  
boolean breakWhile = false; I9-vV>:z  
Y9F!HM-`  
 |W];8  
while(!bStop) n [H3b}  
{ t9685s  
write_nPos(); ,A T!:&<X  
Utility.sleep(500); NguJ[  
breakWhile = true; `9}\kn-</8  
- &Aw] +  
wws)**]J8  
for(int i=0;i<nStartPos.length;i++) &`[y]E'  
{ </ 3 Shq  
if(!fileSplitterFetch.bDownOver) ]([:"j  
{ d h#4/Wa,  
breakWhile = false; rLw3\>y  
break; n7>CK?25  
} 0!!b(X(  
} S\RjP*H*  
if(breakWhile) RsIR}.*  
break; <2Lcy&w_M  
Bvj-LT=)  
{%.FIw k  
//count++; O:cta/M  
//if(count>4) c%9wI*l  
// siteStop(); TO7%TW{L  
} !*_5 B'  
v<c~ '?YzO  
!r]elX  
System.err.println("文件下载结束!"); }>Gnp c  
} P~$FgAV  
catch(Exception e){e.printStackTrace ();} :oh(M|;/2  
} u4*7 n-(  
BQq,,i8H  
bU9B2'%E  
//获得文件长度 t2d _XQOK  
public long getFileSize() /^v?Q9=Y  
{ #-?pY"N,  
int nFileLength = -1; o_>id^$>B  
try{ a<9cj@h  
URL url = new URL(siteInfoBean.getSSiteURL()); WD c2Qt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5|&8MGW-$  
httpConnection.setRequestProperty("User-Agent","NetFox"); b37P[Q3  
P[6@1  
6UOV,`:m+  
int responseCode=httpConnection.getResponseCode(); *$mDu,'8  
if(responseCode>=400) *)+1BYMo  
{ lX$6U| !  
processErrorCode(responseCode); G66A]FIg  
return -2; //-2 represent access is error 8@S7_x  
} EkS7j>:  
q|,cMPS3  
!m)P*Lw  
String sHeader; >Q':+|K}  
SZW+<X  
M il ![A1  
for(int i=1;;i++) +Gv{Apd"  
{ 2gLa4B-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &(a#I]`9M  
//Utility.log(in.readLine()); a'=C/ s+  
sHeader=httpConnection.getHeaderFieldKey(i); ^{\gD23  
if(sHeader!=null) 7DaMuh~<  
{ c#X9d8>  
if(sHeader.equals("Content-Length")) +rse,b&U(  
{ _X5@%/Vz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9fp@d  
break; 2]W"sT[  
} qd\5S*Z1  
} Cj^:8 ?%  
else )vVt{g  
break; Ln/6]CMl  
} l`D^)~o8  
} ." 9t<<!  
catch(IOException e){e.printStackTrace ();} ;O` \rP5w  
catch(Exception e){e.printStackTrace ();} s *$Re)}S  
^M36=~j  
'ap<]mf2  
Utility.log(nFileLength); rF C6"_  
S0?4}7`A  
J-C3k`%O  
return nFileLength; ,Y 1&[  
} ` QC  
pUtd_8  
*PQu9>1w  
//保存下载信息(文件指针位置) v,z s dr"d  
private void write_nPos() 0IU>KGJ-0s  
{ PAG.],"D  
try{ M JJ]8:%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GQ<]Sd}[  
output.writeInt(nStartPos.length); h&Thq52R  
for(int i=0;i<nStartPos.length;i++) ?Ne@OMc  
{ =\CJsS.  
// output.writeLong(nPos); 9+<%74|,  
output.writeLong(fileSplitterFetch.nStartPos); $B6CLWB  
output.writeLong(fileSplitterFetch.nEndPos); @pq#?  
} .Y B}w  
output.close(); HsrIw  
} O%RkU?ME  
catch(IOException e){e.printStackTrace ();} jSa9UD  
catch(Exception e){e.printStackTrace ();} Q|40 8EM  
} X"QIH|qx-  
fh~"A`d  
R  Fgy  
//读取保存的下载信息(文件指针位置) EX^}#|e*h  
private void read_nPos() ];BGJ5^j  
{ z"/Mva3|  
try{ 4u} "ng   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #sl_ BC9  
int nCount = input.readInt(); 2uonT,W  
nStartPos = new long[nCount]; {ctEjgiE  
nEndPos = new long[nCount]; cBICG",TA  
for(int i=0;i<nStartPos.length;i++) H:9Z.|{Gv  
{ "-aak )7w  
nStartPos = input.readLong(); JNhHQvi\  
nEndPos = input.readLong(); w`Q"mx*  
} 0Y rdu,c  
input.close(); c)H (w  
} 4dy2m!  
catch(IOException e){e.printStackTrace ();} -dX{ R_*  
catch(Exception e){e.printStackTrace ();} |Z%I3-z_DS  
} Xk#"rM< Y  
7P3PQ%:  
b=:$~N@Y  
private void processErrorCode(int nErrorCode) _isqk~ ul  
{ TMt,\gTd  
System.err.println("Error Code : " + nErrorCode); =gI;%M\'  
} 4o,%}bo&  
>:W7f2%8`  
>7@kwj-f)  
//停止文件下载 =+um:*a.  
public void siteStop() a*4"j2j v  
{ Lg[v-b=?I  
bStop = true; QF^_4Yn  
for(int i=0;i<nStartPos.length;i++) YTBZklM  
fileSplitterFetch.splitterStop(); 'qD5  
Cj).  
cd8ZZ 8L  
} [hy:BV6H+  
} gH87e  
//负责部分文件的抓取 x!\FB.h4!(  
**FileSplitterFetch.java |~'D8 g:Ak  
*/ J?/.|Y]e  
package NetFox; } sTo,F$  
u<8 f ;C_  
s|3@\9\  
import java.io.*; ]8,:E ]`O  
import java.net.*; k+k&}8e  
$'$#Xn,hU  
f.f5f%lO~  
public class FileSplitterFetch extends Thread {  U)oH@/q  
?O1:-vpZ  
f"XFf@!  
String sURL; //File URL g8+w?Zn}  
long nStartPos; //File Snippet Start Position p #vZYwe=L  
long nEndPos; //File Snippet End Position 0,)Ao8  
int nThreadID; //Thread's ID _ED,DM  
boolean bDownOver = false; //Downing is over J &,N1B  
boolean bStop = false; //Stop identical }@IRReQ  
FileAccessI fileAccessI = null; //File Access interface e|wH5(V  
z4l O  
T';<;6J**  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %(4G[R[  
{ ~$g$31/  
this.sURL = sURL; tPO\e]  
this.nStartPos = nStart; .E !p  
this.nEndPos = nEnd; }5n((7@X  
nThreadID = id; <0[{Tn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <:#O*Y{  
} n^QOGT.s6`  
bDdJh}Vz  
@\gTi;u/x  
public void run() /EY ^ui  
{ f'/@h Na3  
while(nStartPos < nEndPos && !bStop) s>sIji  
{ 2N]u!S;d  
W":is"  
COS(pfC  
try{ mT N6-V  
URL url = new URL(sURL); g*UI~rp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oo\0X  
httpConnection.setRequestProperty("User-Agent","NetFox"); YJgw%UVJ5m  
String sProperty = "bytes="+nStartPos+"-"; Ks&~VU  
httpConnection.setRequestProperty("RANGE",sProperty); f.Y9gkt3d  
Utility.log(sProperty); ?sl 7C gl  
3Rid 1;L0U  
OHnHSb'?\  
InputStream input = httpConnection.getInputStream(); AYHfe#!  
//logResponseHead(httpConnection); s PNX)  
DbSl}N;  
4-q7o]%5<  
byte[] b = new byte[1024]; Uo{h. .7?  
int nRead; _]E ~ci}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) # k+Gg w  
{ rl)(4ad=  
nStartPos += fileAccessI.write(b,0,nRead); 9GnNL I{  
//if(nThreadID == 1) riI0k{   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +Ux)m4}j  
} NLDmZra  
A.9,p  
W>b(hVBE  
Utility.log("Thread " + nThreadID + " is over!"); &]~z-0`$!  
bDownOver = true; `Rj<qz^7  
//nPos = fileAccessI.write (b,0,nRead); STgl{#  
} 6y)xMX  
catch(Exception e){e.printStackTrace ();} %h U8ycI*h  
} jY-i`rJN  
} %8H*}@n  
0pYz8OB  
b2 ~~ !C  
//打印回应的头信息 y(|6`  
public void logResponseHead(HttpURLConnection con) 76[aOC2Ad  
{ U{D ?1tF  
for(int i=1;;i++) F#_7mC   
{ JJ56d)37.  
String header=con.getHeaderFieldKey(i); XF2u<sDe  
if(header!=null) &0TOJ:RP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rWbuoG+8  
Utility.log(header+" : "+con.getHeaderField(header)); !lE (!d3M  
else Oa~t&s  
break; k%QhF]  
} zQ xZR}'  
} tklU zv  
IoNZ'g?d  
T3['6%  
public void splitterStop() GFvZdP`s4  
{ , j ,[4^  
bStop = true; >H@ dgb  
} }M f}gCEW  
9A\J*OU  
VS^%PM#:/  
} 3a#637%  
%Zx/XMs}e  
IDzP<u8v  
/* yuswWc '  
**FileAccess.java TEB%y9  
*//文件访问(定位,写) ?7G?uk]3,@  
package NetFox; xXZ$#z\ Z,  
import java.io.*; N##T1 Qm)  
=KNg "|  
e~J% NU'&  
public class FileAccessI implements Serializable{ q=bJ9iJsq  
<(d ^2-0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1*?IDYB  
RandomAccessFile oSavedFile; XPzwT2_E  
long nPos; `a:@[0r0U  
Y,WcHE  
iUA2/ A  
public FileAccessI() throws IOException >;o^qi_$  
{ ZcX%:ebKS  
this("",0); FH M^x2  
} $ sEe0  
*%ZfE,bu8<  
Gyy:.]>&  
public FileAccessI(String sName,long nPos) throws IOException 8NeP7.U<w  
{ -O~WHi5}  
oSavedFile = new RandomAccessFile(sName,"rw"); |IH-a"  
this.nPos = nPos; 0"u*Kn  
oSavedFile.seek(nPos); j3`:;'L  
}  ^]wm Y  
+Qu~UK\   
-N5r[*>  
public synchronized int write(byte[] b,int nStart,int nLen) /.05rTpp  
{ QfU 0*W?r  
int n = -1; GfQMdLy\Z  
try{ ;eG%#=>  
oSavedFile.write(b,nStart,nLen); bm%2K@ /U  
n = nLen;  2b1LC!'U  
} ..<(HH2  
catch(IOException e) l/LRr.x  
{ ezwcOYMXK  
e.printStackTrace (); :@_CQc*yB  
} E(8!VY ^  
FO3!tJ\L  
lhQ*;dMj%"  
return n; Ca+d ?IS  
} bLu6|YB  
Podm 3b  
XPUH\I=  
} #k)G1Y[c  
sPkT>q  
,2H5CFX/  
/* OD>-^W t;%  
**SiteInfoBean.java ; {I{X}b  
*/ rVQ:7\=Z  
package NetFox; u9mMkzgSkP  
/CKkT.Le  
"TtK!>!.  
public class SiteInfoBean { a+\ Gz  
~<v`&Gm?"  
M%&`&{  
private String sSiteURL; //Site's URL }kL% l  
private String sFilePath; //Saved File's Path q7 Uu 8JXF  
private String sFileName; //Saved File's Name ?Dd2k%o  
private int nSplitter; //Count of Splited Downloading File hpWAQ#%oHm  
]N1$ioC#  
+t.T+` EG  
public SiteInfoBean() A!iH g__/t  
{//nSplitter的缺省值为5 gADt%K2 #Z  
//default value of nSplitter is 5 $6fHY\i#R  
this("","","",5); \jq1F9,  
} * I'O_D  
.vQ2w  
n0Ze9W+<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e"^1- U\  
{ MB^ b)\X  
sSiteURL= sURL; $Ae/NwIlc  
sFilePath = sPath; Kh<v2  
sFileName = sName; ;1{S"UY  
this.nSplitter = nSpiltter; vU{ZB^+&6o  
2Y  6/,W  
a^Zn }R r  
} 4pA<s-  
#J2856bzS  
?/dz!{JC  
public String getSSiteURL() ` mCcD  
{ >Cd%tIie*  
return sSiteURL; q;kM eE*  
} u#J5M&#  
.^JID~<?#  
> )#*}JI  
public void setSSiteURL(String value) ynP^|Ou  
{ 9Eg'=YJ  
sSiteURL = value; Wt8;S$!=R  
} LfgR[!  
dhm ;  
A FfgGO  
public String getSFilePath() xu+wi>Y^  
{ N SHlo*)}  
return sFilePath; iy$]9Wf6=@  
} ) 3Y E$,  
P.;B V",  
[&FMVM`  
public void setSFilePath(String value) mhlJzGr*q  
{ +hXph  
sFilePath = value; zT_{M qY  
} -pqShDar|  
D"A`b{z  
OkzfQ hC}  
public String getSFileName() cE]tvL:g  
{ #exE ~@fy-  
return sFileName; {_(;&\5  
} MIt\[EB  
,dh*GJ{5  
00b )Bg  
public void setSFileName(String value) A|y&\~<A  
{ sF|<m)Kt{W  
sFileName = value; zhN'@Wj'_  
} Iupk+x>  
yRvq3>mU  
bd)A6a\h  
public int getNSplitter() s BRw#xyS  
{ ,HMB`vF  
return nSplitter; 4qyL' \d[  
} @9vz%1B<l  
e j!C^  
1Ete;r%5=  
public void setNSplitter(int nCount) Pi+,y  
{ U4LOe}Ny  
nSplitter = nCount; jr!x)yd  
} vaK$j!%FE  
} +(|T\%$DT  
nH T2M{R  
vkBngsS  
/* dAAE2}e  
**Utility.java W"wP%  
*/ Keof{>V=CA  
package NetFox; v5<Ext rV  
vhhsOga  
uOW9FAW  
public class Utility { umls=iz  
_/MKU!\l  
`7N[rs9|S  
public Utility() C@Wm+E~;8  
{ Q>Q$BCD5  
oPWvZI(\&  
.[O*bk  
} T+2?u.{I  
*5|\if\  
//线程睡眠 #Va@4<4r  
public static void sleep(int nSecond) mH}AVje{ `  
{ WVwNjQ2PM  
try{ 0c:CA>F  
Thread.sleep(nSecond); -?e~S\JH  
} roRZE[ya  
catch(Exception e) o'D6lkf0  
{ q)!{oi{x(  
e.printStackTrace (); Iqo4INGIi  
} <ygkK5#q  
} k ( R  
-M[5K/[  
//日志 QiwZk<rb  
public static void log(String sMsg) eKLxNw5  
{ PU-;Q@< E  
System.err.println(sMsg); U15Hq*8Z  
} yY,.GzIjCj  
YjG0: 9  
l<qxr.X  
public static void log(int sMsg) ]p#Zdm1EL  
{ /wvA]ooT  
System.err.println(sMsg); nTYqZlI,  
} }-8K*A3  
} XPX{c|]>.  
IlS{>6  
|4-Ey! P  
/* ] >`Q"g~0  
**TestMethod.java qtgj"4,:`  
*/ LW,!B.`@  
package NetFox; $wX5`d 1  
l}<s~ip  
N 4,w  
public class TestMethod { &|9?B!,`  
1` 9/[2z  
rVf`wJ6b  
public TestMethod() $1UN?(r  
{ ///xx/weblogic60b2_win.exe w1s#8:  
try{ QR^pu.k@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GU"MuW`u2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tpCEWdn5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u,'c:RMV  
fileFetch.start(); flmcY7ZV  
} TYLf..i<  
catch(Exception e){e.printStackTrace ();} orL7y&w(v:  
kW/ksz0)  
 ExnszFX*  
} vmmu[v  
Wje7fv  
l sUQ7%f  
public static void main(String[] args) 1bvL  
{ 9`vse>,-hg  
new TestMethod(); 2@A7i<p  
} ;N4mR6  
} s!UC{)g,  
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