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http断点续传简单实现(java)

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/* ;"ESN)*|i  
**SiteFileFetch.java  +Mhk<A[s  
*/ F u^j- Io  
package NetFox; f [.'V1  
import java.io.*; rlawH}1b  
import java.net.*; ~Hv>^u Mh  
hW/Ve'x[  
(i1x<  
public class SiteFileFetch extends Thread { WHOX<YJs  
"frioi`a2  
-^(KGu&L&u  
SiteInfoBean siteInfoBean = null; //文件信息Bean ='=4tj=z  
long[] nStartPos; //开始位置 {&^PDa|nD  
long[] nEndPos; //结束位置 >3ZhPvE-p'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9Li&0E  
long nFileLength; //文件长度 ;+|Z5+7!6  
boolean bFirst = true; //是否第一次取文件 GA/afc,V  
boolean bStop = false; //停止标志 'Ha> >2M  
File tmpFile; //文件下载的临时信息 vdQ#C G$/  
DataOutputStream output; //输出到文件的输出流 dKC*QHU  
tLN^k;w  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3 =c#LUA`  
public SiteFileFetch(SiteInfoBean bean) throws IOException I1l^0@J   
{ (=fLWK{8  
siteInfoBean = bean; Lj#xZ!mQS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qO8:|q1%;\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); V/#J>-os}W  
if(tmpFile.exists ()) afna7TlS  
{ 5 r_Z3/%  
bFirst = false; x4g/ok  
read_nPos(); Ovj^ 7r:<s  
} Eu "8IM!%-  
else S w%6-  
{ Jc}6kFgO6  
nStartPos = new long[bean.getNSplitter()]; FE^/us7r  
nEndPos = new long[bean.getNSplitter()]; GG<0k\RN  
} U{bv|vF  
&7>]# *  
*| W*Mu  
G!=(^G@J;  
} s3yGL  
 qsXkm4  
<_Z.fdUA  
public void run() ={ -kQq  
{ -sZ'<(3  
//获得文件长度 Fw{#4  
//分割文件 p~=z)7% e'  
//实例FileSplitterFetch ov H'_'  
//启动FileSplitterFetch线程 7CSz  
//等待子线程返回 :@"o.8p   
try{ }$L1A   
if(bFirst) Q _!tn*  
{ Y<(7u`F  
nFileLength = getFileSize(); }7b{ZbDI  
if(nFileLength == -1) C4`&_yoP4-  
{ IDD`N{EA  
System.err.println("File Length is not known!"); TQNdBq5I6  
} m ie~. "  
else if(nFileLength == -2) XTk :lzFH  
{ %t!r pyD  
System.err.println("File is not access!"); (Fuu V{x|  
} TOKt{`2}  
else _e ;b B?S  
{ *{j;LA.BR#  
for(int i=0;i<nStartPos.length;i++) 67&Q<`V1*q  
{ (|o @  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \lQI;b;$  
} do.>Y}d  
for(int i=0;i<nEndPos.length-1;i++) y7CO%SA  
{ \}u/0UF97  
nEndPos = nStartPos[i+1]; (Cq 38~mR  
} p{W Amly  
nEndPos[nEndPos.length-1] = nFileLength; yufw}Lo-  
} D|m0Vj b  
} qC"`i}7  
#I.~+M  
}vx,i99W?  
//启动子线程 kdlmj[=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fp\mBei  
for(int i=0;i<nStartPos.length;i++) P]y{3y:XxM  
{ <YEKbnw$o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O-)[!8r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =_iYT044p  
nStartPos,nEndPos,i); QRKP;aYt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *{k{  
fileSplitterFetch.start(); IDw`k[k  
} z"\w9 @W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &{glwVKV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qbjm,>H/^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qLb~^'<iD  
nEndPos = " + nFileLength); \b"|p%CL8  
// fileSplitterFetch[nPos.length-1].start(); hEZo{0:b"  
IA Ma  
2Q]W  
//等待子线程结束 '%ZKvZ-  
//int count = 0; _Li.}g@Bd  
//是否结束while循环 He4HI Z  
boolean breakWhile = false; qzA_ ~=g  
$ kHXt]fU  
+zk5du^gZ  
while(!bStop) wme#8/eUk  
{ 517wduj  
write_nPos(); r#1W$~?>  
Utility.sleep(500); ^z{Xd|{"  
breakWhile = true; l59 N0G  
w6h83m 3  
qN' 3{jiPL  
for(int i=0;i<nStartPos.length;i++) H Q[  
{ <oT1&C{  
if(!fileSplitterFetch.bDownOver) v@SHR0  
{ .bP8Z =  
breakWhile = false; e&:%Rr]x  
break; L'`Au/%S}  
} p^q/u  
} _unoDoB  
if(breakWhile) vL[IVBG^  
break; R2{]R&wtn0  
[_3&  
Zos.WS#  
//count++; 0QPY+6  
//if(count>4) `+vQ5l$;L  
// siteStop(); *,:2O&P  
} RFFbS{U*  
g@s`PBF7`  
,YBO}l  
System.err.println("文件下载结束!"); ,ZrR*W?iF  
} 8EdaqF  
catch(Exception e){e.printStackTrace ();} [bX ^_ Y  
} dyf>T}Iy  
FW;}S9u3  
-:'%YHxX  
//获得文件长度 SB('Nqih  
public long getFileSize() 6)ZaK  
{ 0F_hXy@K  
int nFileLength = -1; sKKc_H3YSH  
try{ 3WwCo.q;m  
URL url = new URL(siteInfoBean.getSSiteURL()); us1$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c /^:vTF  
httpConnection.setRequestProperty("User-Agent","NetFox"); F;_o `h  
Qx|HvT2P  
g{sp<w0  
int responseCode=httpConnection.getResponseCode(); 4Hb"yp$  
if(responseCode>=400) cmU0=js.  
{ BQ[R)o  
processErrorCode(responseCode); T95FoA  
return -2; //-2 represent access is error _7';1 D  
} !ii( 2U  
B=^M& {  
n{~&^Nby*I  
String sHeader; g@M5_I(W  
<3N\OV2  
eNi#% ?=WB  
for(int i=1;;i++) Q<MxbHk9  
{ "M2WK6?O5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *\}$,/m['  
//Utility.log(in.readLine()); 6|n3Q$p  
sHeader=httpConnection.getHeaderFieldKey(i); k'&1,78[l  
if(sHeader!=null) mC\<fo-u  
{ ?6ssSjR}  
if(sHeader.equals("Content-Length")) (6mw@gzr  
{ VSCKWYy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mAW(j@5sp  
break; lf KV%  
} _dAn/rj   
} L8'4d'N+ >  
else -6s]7#IC  
break; qRcg|']R  
} 4Wa$>vz  
} l:u1P  
catch(IOException e){e.printStackTrace ();} IDqUiN  
catch(Exception e){e.printStackTrace ();} vR5X  
dQ_'8 )  
N M),2%<  
Utility.log(nFileLength); .=G3wox3  
s[UV(::E  
5%V(eR  
return nFileLength; qM 1ZCt  
} aL;zN%Tw  
jpR]V86G  
x30|0EHYl[  
//保存下载信息(文件指针位置) A0;{$/  
private void write_nPos() d!Y%7LmSE@  
{ yV L >Ie/  
try{ .`J*l=u$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5\}Y=Pa  
output.writeInt(nStartPos.length); l& sEdEA  
for(int i=0;i<nStartPos.length;i++) %z[=T@  
{ -AVT+RE9z  
// output.writeLong(nPos); )>Z@')Uk:  
output.writeLong(fileSplitterFetch.nStartPos); O tQ]\:p7  
output.writeLong(fileSplitterFetch.nEndPos); l<S3<'&  
} $I#~<bW,  
output.close(); SJLs3iz_)  
} "W4|}plnu  
catch(IOException e){e.printStackTrace ();} >,k2|m  
catch(Exception e){e.printStackTrace ();} u6Ux nqNc  
} 2Q%M2Ua  
pBBKfv  
'|v<^EH  
//读取保存的下载信息(文件指针位置) zT/woiyB`  
private void read_nPos() $/JXI?K  
{ P@5-3]m=  
try{ /RhM6N  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jY/(kA]}  
int nCount = input.readInt(); +:70vZc:V@  
nStartPos = new long[nCount]; A>S7Ap4z>  
nEndPos = new long[nCount]; 'zMmJl}\vd  
for(int i=0;i<nStartPos.length;i++) C9k"QPE  
{ \7xc*v [  
nStartPos = input.readLong(); yEJ3O^(F  
nEndPos = input.readLong(); NL-PQ%lUA  
} "la0@/n  
input.close(); XknNb{. r  
} @{3_7  
catch(IOException e){e.printStackTrace ();} GvA4.s,  
catch(Exception e){e.printStackTrace ();} +@8, uL  
} I3x+pa^]2  
HJ"sK5Q  
D(TfW   
private void processErrorCode(int nErrorCode) <bhJ>  
{ >nK (  
System.err.println("Error Code : " + nErrorCode); RASk=B  
} TBF{@{.d  
,1<6=vL  
"OkZ [E)  
//停止文件下载 ix?Z:pIS0  
public void siteStop() ff fWvf  
{ 9M|#X1r{%{  
bStop = true; o2]Np~`g,  
for(int i=0;i<nStartPos.length;i++) 94*MRn1E  
fileSplitterFetch.splitterStop(); ) 54cG  
6 9uDc  
/Q#eP m  
} aGE} EK}  
} vt(n: Xk  
//负责部分文件的抓取 l#>A.-R*`  
**FileSplitterFetch.java Sw[*1C8  
*/ +Bt%W%_X  
package NetFox; Sv>CVp*  
PIQd=%?'  
qla=LS\-A+  
import java.io.*; `r\/5|M  
import java.net.*; [fkt3fS  
|-GbHfz  
0BjP|API  
public class FileSplitterFetch extends Thread { QT1oUP#*  
Q4N0j' QA  
MfFmJ7>Bg  
String sURL; //File URL 1O)m(0tb[  
long nStartPos; //File Snippet Start Position 7(LB}  
long nEndPos; //File Snippet End Position OH 88d:  
int nThreadID; //Thread's ID y=SpIbn{  
boolean bDownOver = false; //Downing is over Y~lOkH[z  
boolean bStop = false; //Stop identical UK@hnQU8`  
FileAccessI fileAccessI = null; //File Access interface EW]8k@&g  
"Nq5FcS9  
n4+ ^f~Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException />PH{ l  
{ 8N#.@\'kz.  
this.sURL = sURL; Q5Mn=  
this.nStartPos = nStart; Di$++T8"  
this.nEndPos = nEnd; [$\VvRu%  
nThreadID = id; ._'.F'd  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~"R;p}5 "  
} [,z>msEB.  
l]IQjjJ`  
{;JFoe+  
public void run() *tDxwD7  
{ &&96kg3  
while(nStartPos < nEndPos && !bStop) '0qKb*  
{ Q b5vyV `  
$KGRpI  
v?DA>  
try{ "(\]-%:7  
URL url = new URL(sURL); x.(Sv]+[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  /zir$  
httpConnection.setRequestProperty("User-Agent","NetFox"); ( M3-S5   
String sProperty = "bytes="+nStartPos+"-"; 5* ~E dT  
httpConnection.setRequestProperty("RANGE",sProperty); ^7$Q"  
Utility.log(sProperty); GN|xd+O_  
2>Kn'p  
q\fai^_  
InputStream input = httpConnection.getInputStream(); P2U[PO  
//logResponseHead(httpConnection); ?V)M!  
I[LHJ4  
TP=#U^g*  
byte[] b = new byte[1024]; 5 ^tetDz}  
int nRead; H|;BT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9\6ZdnEKu,  
{ ITU6Eq  
nStartPos += fileAccessI.write(b,0,nRead); anUH'mcK*  
//if(nThreadID == 1) <a D}Ko(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0INlo   
} >~G _'~_f  
%i.;~>  
\e?w8R.6w^  
Utility.log("Thread " + nThreadID + " is over!"); G`u";w_  
bDownOver = true; $n<X'7@0  
//nPos = fileAccessI.write (b,0,nRead); z'Fu} ho  
} `ItPTSOi  
catch(Exception e){e.printStackTrace ();} }/%^;@q;  
} U {s T %G  
} =l}XKl->  
DDU)G51>d  
)TkXdA?.  
//打印回应的头信息 82=>I*0Q  
public void logResponseHead(HttpURLConnection con) mH4Jl1S&  
{ yd`f<Hr<m  
for(int i=1;;i++) 'c/Z W  
{ {,o =K4CD  
String header=con.getHeaderFieldKey(i); QPz3IK%   
if(header!=null) t^<ki?*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q\Nz^~dQ:Y  
Utility.log(header+" : "+con.getHeaderField(header)); >xm:?WR  
else Eg]tDPN1  
break; #)<WQZ)  
} :c&F\Q=  
} pQBhheiM  
9%bqY9NFd  
W}>wRy  
public void splitterStop() { Em fw9L  
{ 4jz2x #T  
bStop = true; X>s'_F?  
} ! d" i  
:*E#w"$,j  
koOp:7r  
} kQ $.g<  
1}I%yOi)  
?\T):o;/  
/* ?h|w7/9  
**FileAccess.java gn4 Sz")  
*//文件访问(定位,写) N51RBA  
package NetFox; 3 *[YM7y  
import java.io.*; 7D)i]68E  
mMtX:  
Zd[6-/-:  
public class FileAccessI implements Serializable{ )?,X\/5  
Hd0?}w\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 A>Oi9%OY:  
RandomAccessFile oSavedFile; N:7;c}~  
long nPos; mM;p 7 sJ  
B)(ZRH  
m<e-XT  
public FileAccessI() throws IOException ^-pHhh|g  
{ "_36WX  
this("",0); Uz; pNWMk  
} SXm Hn.?  
kX:d?*{KB  
ugMf pT)  
public FileAccessI(String sName,long nPos) throws IOException G' a{;3  
{ tGh!5EZ6`  
oSavedFile = new RandomAccessFile(sName,"rw"); HCVMqG!  
this.nPos = nPos; BJI"DrF  
oSavedFile.seek(nPos); lG!We'?  
} `F TA{ba  
q.g0Oz@ z  
aYPD4yX"/  
public synchronized int write(byte[] b,int nStart,int nLen) H+2m  
{ t"L-9kCM  
int n = -1; e8ZMB$byP  
try{ J+20]jI  
oSavedFile.write(b,nStart,nLen); #[aHKq:?b  
n = nLen; I^yInrRh5  
} uf&Ke k,  
catch(IOException e) K trR+ :  
{ 0 P-eC|0  
e.printStackTrace ();  C%\.  
} p$OkWSi~  
f<aJiVP  
^SH8*7l7  
return n; Dwp-*QK^G  
} O!#bM< *  
BD (  
@ wJ|vW_.  
} j_2yTz"G-  
zd+<1R;  
| ?])]F  
/* CHX- 4-84{  
**SiteInfoBean.java 982n G-"  
*/ R#i{eE*WF  
package NetFox; \z>L,U  
,"Nfo`7  
('7qJkV  
public class SiteInfoBean { 1'>wrGr  
 b"C1  
?#rejA:  
private String sSiteURL; //Site's URL mU3 @|a/@0  
private String sFilePath; //Saved File's Path XrD@q  
private String sFileName; //Saved File's Name AUvUk<a  
private int nSplitter; //Count of Splited Downloading File 8@Kvh|  
\9GJa"xA`  
*D$[@-7  
public SiteInfoBean() mUW4d3tE  
{//nSplitter的缺省值为5 nd)bRB  
//default value of nSplitter is 5 nVVQ^i}`G  
this("","","",5); r.T!R6v}  
} hs  m%o\  
C:WXI;*cr  
+)eI8o0#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P,/=c(5\}  
{ ) FnJLd  
sSiteURL= sURL; Y^~Dr|5%  
sFilePath = sPath; )k}UjU`!  
sFileName = sName; >SR! *3$5  
this.nSplitter = nSpiltter; chr^>%Q_  
D[ -Gzqh  
{x#I&ra  
} G uLU7a  
`78:TU~5S  
L]C|&K P  
public String getSSiteURL() |wFfVDp  
{ WG0Ne;Ho  
return sSiteURL; ev_4!+ko  
} /T_@rm  
?onTW2cG;  
{!`0i  
public void setSSiteURL(String value) vdLBf+Zi  
{ o2C{V1nB  
sSiteURL = value; sAG#M\A6  
} )Kw Gb&l&  
LyB &u( )  
AQH\ ;L  
public String getSFilePath() 97%S{_2m/  
{ L6-zQztn  
return sFilePath; ogrh"  
}  *Fe  
E0Y>2HOuL  
O*8 .kqlgt  
public void setSFilePath(String value) `Z 3p( G  
{ ~T_4M  
sFilePath = value; <FfdOK_  
} I#m0n%-[  
cn~M: LW23  
)_\ZUem  
public String getSFileName() 6ofi8( n[  
{ @FBlF$vG  
return sFileName; 0+]ol:i  
} K~ 6[zJ4  
<lBY  
-t:~d:  
public void setSFileName(String value) %xq/eC7  
{ ;MH<T6b  
sFileName = value; 6/Pw'4H9$  
} hrRkam !y  
+l " z  
t69C48}15  
public int getNSplitter() G{ 9p.Q  
{ ?IWLH-fkP  
return nSplitter; xKl!{A9$w  
} YF]W<ZpY  
k_^| %xJ  
7vRFF@eq}  
public void setNSplitter(int nCount) t3dvHU&Z:  
{ ve [*t`  
nSplitter = nCount; GRt1]%l#$  
} U;l!.mze  
} j~IX  
/R2K3E#  
EO<{Bj=2  
/* NZ}DbA+g;|  
**Utility.java = %O@%v  
*/ hd@ >p.  
package NetFox; ^` 96L  
8N8N)#A[  
n%M-L[n  
public class Utility { {Gd<+tQg  
_qZ?|;o^  
_wC4n }J  
public Utility() X~`<ik{q  
{ lBbUA)z6  
PW[NW-S`c  
`H_.<``>  
} P2q'P&  
\ nIz5J}3  
//线程睡眠 LZ97nvK  
public static void sleep(int nSecond) km)5?  
{ &rcC7v K9  
try{ /ynvQ1#uA  
Thread.sleep(nSecond); >8pmClVvmR  
} "o=*f/M  
catch(Exception e) A1mxM5N  
{ )@X `B d  
e.printStackTrace (); X/5\L.g2  
} Z`?Z1SBt  
} ) N8 [@  
5iG+O4n%  
//日志 Hq[vh7Lux  
public static void log(String sMsg) 'g4t !__  
{ 1qR[& =/  
System.err.println(sMsg); dFu<h   
} M:!Twz$  
~F</ s.  
'pJ46"D@m  
public static void log(int sMsg) qMk"i@"  
{ `qNhB\  
System.err.println(sMsg); Ux<2!vh  
} tAPr4n!  
} (&=<UGY(w  
_;;'/rs j  
?f\;z<e|  
/* DPU%4te  
**TestMethod.java i|@lUXBp  
*/ +x7b9sHJ  
package NetFox; -R~!N#y  
`30og]F0YJ  
Yt 9{:+[RK  
public class TestMethod { @+gr>a1K#  
RS$!TTeQ  
9^;)~ G  
public TestMethod() ^[7ZBmS  
{ ///xx/weblogic60b2_win.exe ^x! N]  
try{ jkPye{j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); muAI$IRR   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'w'P rM,:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AI$r^t1  
fileFetch.start(); ]6`]+&  
} w3,1ImrXp  
catch(Exception e){e.printStackTrace ();} lw.4O^  
FD}hw9VyF@  
d!V;\w  
} [r_YQ*+ej  
A]z~Dw3  
H%!ED1zpA  
public static void main(String[] args) Px!M^ T!Pi  
{ D!K){ E  
new TestMethod(); h)W?8XdM  
} Fp)+>o T  
} igoXMsifT+  
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