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http断点续传简单实现(java)

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/* ehe;<A  
**SiteFileFetch.java V\4zK$]  
*/ ` 0}z ;&:  
package NetFox; ;kv/(veQ1<  
import java.io.*; [ _N w5_  
import java.net.*; gdKn!; ,w#  
} 63Qh}_Y  
Q`* v|Lp  
public class SiteFileFetch extends Thread { =FfxHo1k  
*W&}}iL  
{!G  
SiteInfoBean siteInfoBean = null; //文件信息Bean pZUXXX  
long[] nStartPos; //开始位置 AIK99  
long[] nEndPos; //结束位置 "z/)> ?Wn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .{}=!>U2  
long nFileLength; //文件长度 h:qt?$]J  
boolean bFirst = true; //是否第一次取文件 hI Q 2s  
boolean bStop = false; //停止标志 ytkV"^1^  
File tmpFile; //文件下载的临时信息 ~E J+<[/  
DataOutputStream output; //输出到文件的输出流 We51s^(  
$wq[W,'#L  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Yfotq9.=+  
public SiteFileFetch(SiteInfoBean bean) throws IOException gZ b +m  
{ -<MA\iSP  
siteInfoBean = bean; $MPh\T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KbP( ;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @_ Q  
if(tmpFile.exists ()) yR|Beno  
{ EJ&aT etQ  
bFirst = false; nz%{hMNYH  
read_nPos(); E]<Ce;Vj  
} BZr$x8%ki  
else ecg>_%.>  
{ k.MAX8  
nStartPos = new long[bean.getNSplitter()]; P_{jZ}y(  
nEndPos = new long[bean.getNSplitter()]; B<}0r 4T}  
} ~8#Ku,vEy  
_/(7:  
VP\'p1a  
pA|Z%aL  
} m.|__L  
45+w)Vf!  
,-[e{=Cz  
public void run() dH8^\s .F  
{ /j|Rz5@ =  
//获得文件长度 F[HMX4  
//分割文件 rQ+2 -|#  
//实例FileSplitterFetch 8;vpa*  
//启动FileSplitterFetch线程 }/cMG/%  
//等待子线程返回 k_$9cVA  
try{ Rfuq(DwD6  
if(bFirst) Kx[u9MD  
{ 93+p~?  
nFileLength = getFileSize(); HXY,e$c#y  
if(nFileLength == -1) =:~%$5[[  
{ FR%u1fi  
System.err.println("File Length is not known!"); PRo;NE  
} A"$UU6Z4  
else if(nFileLength == -2) Q;EQ8pL?"  
{ <XAW-m9SC  
System.err.println("File is not access!"); W{6%Hh p  
} <R%]9#re  
else /-_<RQ  
{ f:)%+)U<Xm  
for(int i=0;i<nStartPos.length;i++) t^Hte^#S  
{ |}YeQl  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); q)Uh_l.Cj  
} [`'[)B  
for(int i=0;i<nEndPos.length-1;i++) $&>z`bAS>  
{ p=-:Z?EW1  
nEndPos = nStartPos[i+1]; K@DK4{  
} gr%!<2w  
nEndPos[nEndPos.length-1] = nFileLength; 0 jszZ_  
} O5;$cP:  
} ,cg%t9  
CG -^}xE:  
dDeImSeV  
//启动子线程 ejID5NqG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nWd]P\a'V  
for(int i=0;i<nStartPos.length;i++) a*fUMhIi  
{ TGe)%jZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OB&lq.r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \4B2%H  
nStartPos,nEndPos,i); JC[G5$E  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sp VE'"^  
fileSplitterFetch.start(); fQtV-\Bc  
} _r6aLm2n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8&0+Az"{O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $cUTe  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X=Th  
nEndPos = " + nFileLength); 'Itsu~fza  
// fileSplitterFetch[nPos.length-1].start(); 6,D)o/_  
:vqfWK6mv  
q_sQC5:s  
//等待子线程结束 pO~lVM  
//int count = 0; HS% P  
//是否结束while循环 k8~/lE.Wy  
boolean breakWhile = false; [kjmEMF9i  
SW^/\cJ^  
.@(+.G  
while(!bStop) @\_l%/z{  
{ :mpR}.^hv  
write_nPos(); .^Z^L F  
Utility.sleep(500); !x, ;&  
breakWhile = true; /<\B8^yQ  
tCw.wDq3=  
6N^sUc0s  
for(int i=0;i<nStartPos.length;i++) Gxj3/&]^Y  
{ 13X0LN  
if(!fileSplitterFetch.bDownOver) 3Xun>ZQ-  
{ s?j` _ B  
breakWhile = false; C6-71 `C0  
break; .%iJin"  
} ~qk5Mk4$  
} ~gjREl,+D#  
if(breakWhile) H /kSFf{  
break; T==(Pw7R7  
5,pKv  
Ai 9UB=[R  
//count++; 6jGPmOM/  
//if(count>4) %kcyE<c  
// siteStop(); D)u 9Y  
} >*5+{~k~4  
RH+'"f  
r-ldqj  
System.err.println("文件下载结束!"); H,F/u&O  
} 0%9Nf!j  
catch(Exception e){e.printStackTrace ();} mM&*_#( 6  
} _B5t)7I  
x9c/;Q &m  
: Y{aa1  
//获得文件长度 $h({x~Oj9  
public long getFileSize() N0D)d  
{ :-I~-Yj  
int nFileLength = -1; vWM3JH~a6  
try{ FzDZ<dJ  
URL url = new URL(siteInfoBean.getSSiteURL()); *i}Nb* Z3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8, >YB+Hb  
httpConnection.setRequestProperty("User-Agent","NetFox"); z&"-%l.b@}  
(Nky?*  
+:s]>R eDa  
int responseCode=httpConnection.getResponseCode(); q $Hg\ {c  
if(responseCode>=400) XuQ7nlbnq  
{ |+^-b}0  
processErrorCode(responseCode); fCA/   
return -2; //-2 represent access is error xKKR'v:o\  
} T%%+v#+  
:OF:(,J  
qrFC4\q}  
String sHeader; g' xR$6t  
V ifQ@  
/<HEcB  
for(int i=1;;i++) 2hjR'6h"Y  
{ 1D,$Az~.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^Ms)T3dM  
//Utility.log(in.readLine()); :uAW  
sHeader=httpConnection.getHeaderFieldKey(i); NW.<v /?=,  
if(sHeader!=null) p8>.Q/4  
{ ?D].Za^km  
if(sHeader.equals("Content-Length")) Pgy&/-u  
{ MZ(TST"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q+MV@8w  
break; g[rxK n\Z  
} 'wo[iNy[  
} a:PS}_.  
else kp4*|$]  
break; X[frL)k]  
} uc% &g  
} f PoC yl  
catch(IOException e){e.printStackTrace ();} 0/8rYBV  
catch(Exception e){e.printStackTrace ();} kKFSCl/g  
b6IYo!3  
]7QRelMiz+  
Utility.log(nFileLength); B%v2)+?@  
X(-e-:B4;  
.b4_O CGg  
return nFileLength; 9.KOrg5}L  
} [e2sUO0~r  
cT8`l!RD<  
qsB,yckml  
//保存下载信息(文件指针位置) -%&_LE9ZtS  
private void write_nPos() 2V}tDN7c  
{ q;T3bxp+  
try{ ?fog 34g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); idwiM|.iU  
output.writeInt(nStartPos.length); Xd_86q8o  
for(int i=0;i<nStartPos.length;i++) @j%r6N  
{ \dyJ=tg  
// output.writeLong(nPos); oKIry 8'^N  
output.writeLong(fileSplitterFetch.nStartPos); _}X_^taTZS  
output.writeLong(fileSplitterFetch.nEndPos); n7 RswX  
} `?P k~7  
output.close(); ;79X# hI  
} Wgl7)Xk.)  
catch(IOException e){e.printStackTrace ();} SR 9 Cl  
catch(Exception e){e.printStackTrace ();} i$) `U]  
} KzRw)P  
[sC]<2 r  
5!ll #/ {`  
//读取保存的下载信息(文件指针位置) /B$"fxFf  
private void read_nPos() D6iHkDTg  
{ ti:qOSIDTA  
try{ Hno:"k?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :X>%6Xj?RV  
int nCount = input.readInt(); (+<SR5,/3  
nStartPos = new long[nCount]; |Ire#0Nwx  
nEndPos = new long[nCount]; Do7&OBI~  
for(int i=0;i<nStartPos.length;i++) p @@TOS  
{ G: FP9  
nStartPos = input.readLong(); %nJ^0X_]  
nEndPos = input.readLong(); t[B\'f!  
} aU]A#g   
input.close(); pYo]lO  
} l`L}*Q- 5  
catch(IOException e){e.printStackTrace ();} ]8(_{@ /  
catch(Exception e){e.printStackTrace ();} :)v4:&do  
} V#?GDe}[  
6!} @vp![  
OO@ (lt  
private void processErrorCode(int nErrorCode) =,0E]M Z  
{ QN_Zd@K*A  
System.err.println("Error Code : " + nErrorCode); Zx(VwB2   
} Egv (n@1  
8LP L4l  
hKw4[wB]  
//停止文件下载 ;BV1E|j  
public void siteStop() 4P@Ak7iL(V  
{ a3i4eGT-  
bStop = true; M,Q(7z?#5  
for(int i=0;i<nStartPos.length;i++) .__X- +^  
fileSplitterFetch.splitterStop(); OWsK>egD  
?5e:w?&g@  
2f1WT g)  
} $m`?x5rL8  
} ql5NSQ>{  
//负责部分文件的抓取 "d'D:>z]%  
**FileSplitterFetch.java sQrP,:=r#  
*/ 'rJkxU{  
package NetFox; A4.Q \0  
dxkq*  
j nvi_Rodm  
import java.io.*; vn@9Sqk  
import java.net.*; cq`v8  
B&&:A4  
w66iLQ\@  
public class FileSplitterFetch extends Thread { @b\/\\{  
$:V'+s4o  
[z$th  
String sURL; //File URL 4 2aYM!  
long nStartPos; //File Snippet Start Position 9L;fT5Tp7  
long nEndPos; //File Snippet End Position y^:!]-+  
int nThreadID; //Thread's ID WpE\N0Yg  
boolean bDownOver = false; //Downing is over (J8 (_MF  
boolean bStop = false; //Stop identical 7A|n*'[T>  
FileAccessI fileAccessI = null; //File Access interface PSz|I8 c  
/t`s.!k  
dieGLA<5_X  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lz.ta!6  
{ M XsSF|-  
this.sURL = sURL; 0R&$P 6  
this.nStartPos = nStart; b f.__3{  
this.nEndPos = nEnd; 5LU8QHj3  
nThreadID = id; d^sS{m\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~aKxwH  
} ?sV0T)uk  
)IQa]A  
)%lPa|7s  
public void run() [V_Z9-f*  
{ 4(>|f_$  
while(nStartPos < nEndPos && !bStop) K^j7T[pR  
{ %EA|2O.D  
s(W]>Ib  
A L|F Bd  
try{ ?4Z`^uy  
URL url = new URL(sURL); Su99A.w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); coq7La[  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?yop#tjCbY  
String sProperty = "bytes="+nStartPos+"-"; !, Y1FC  
httpConnection.setRequestProperty("RANGE",sProperty); fB+4mEG@  
Utility.log(sProperty); $8gj}0}eH  
<&:OSd:%  
v0)I rO  
InputStream input = httpConnection.getInputStream(); };"-6e/9  
//logResponseHead(httpConnection); -J8&!S8X  
!t/I j~o  
f QSP]?  
byte[] b = new byte[1024]; R{"Kh2q_  
int nRead; 33dHTV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BH"f\oc  
{ wlk{V  
nStartPos += fileAccessI.write(b,0,nRead); mm(Ff>O  
//if(nThreadID == 1) ^6R?UG;6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?-w<H!Y7  
} UfcQFT{()  
F}p)Q$0  
M:6Yy@#T.  
Utility.log("Thread " + nThreadID + " is over!"); tQ=P.14>:  
bDownOver = true; P%M Yr"<$E  
//nPos = fileAccessI.write (b,0,nRead); JGl0 (i*|  
} ^ Q]I)U  
catch(Exception e){e.printStackTrace ();} W8{g<. /  
} z\wY3pIr2  
} EM9K^l`  
wp7<0PP  
)Y.H*ca  
//打印回应的头信息 [w&B>z=g$  
public void logResponseHead(HttpURLConnection con) .} al s  
{ +?r,Nn  
for(int i=1;;i++) PhTMXv<cE  
{ #[$^M:X.  
String header=con.getHeaderFieldKey(i); 5Fa.X|R~  
if(header!=null) Fq\vFt|m<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); S"+X+Oxp7?  
Utility.log(header+" : "+con.getHeaderField(header)); Yxik .S+G  
else 2wR?ON=Q  
break; 5=Cea  
} )5n*4A  
} V0 70oZ  
BN??3F8C  
s6=jHrdvv  
public void splitterStop() GH ] c  
{ [t #xX59  
bStop = true; G`1!SEae  
} 66ULR&D8  
PM ]|S`  
fCC^hB]'  
} RLl*@SEi"  
Eod'Esye5  
JmlMfMpXMs  
/* b ]A9$-  
**FileAccess.java pjG/`  
*//文件访问(定位,写) .8[*`%K>  
package NetFox; p1}umDb%  
import java.io.*; FFC"rG  
{\:"OcP #  
Q`= ,&;T>  
public class FileAccessI implements Serializable{ _#;UXAi  
ZQ@ Ul  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ::<v; `l  
RandomAccessFile oSavedFile; 3 UXaA;  
long nPos; b { M'aV  
M%{,?a0V  
.|?UqZ(,  
public FileAccessI() throws IOException Cpg>5N~;L  
{ <rQ+ErDA  
this("",0); =[_=y=G  
} o57r ,`N  
/+ yIcE(&3  
8%\0v?a5  
public FileAccessI(String sName,long nPos) throws IOException Sm5 T/&z  
{ vyS8yJUY  
oSavedFile = new RandomAccessFile(sName,"rw"); .#Vup{.  
this.nPos = nPos; Al}D~6MD  
oSavedFile.seek(nPos); Sv#S_jh  
} b=$(`y  
lEXER^6  
Mp-hNO}.Z  
public synchronized int write(byte[] b,int nStart,int nLen) Q0j4 c  
{ Crg@05Z  
int n = -1; vRI0fDu  
try{ !pJd^|4A]  
oSavedFile.write(b,nStart,nLen); ?"@`SEdnU2  
n = nLen; ]=Tle&yM+T  
} aGz$A15#  
catch(IOException e) tS[@3h  
{ |#i|BVnoE  
e.printStackTrace (); <>71;%e;'  
} +eUWf{(_  
Bx" eX>A8  
(qyT,K8  
return n; u%24% Q  
} DnP "7}v  
HSG7jC'_  
wdMVy=SS  
} ehTRw8"R  
goje4;  
gt \O  
/* wg}rMJoG|  
**SiteInfoBean.java 4 Q<c I2|  
*/ wAA9M4  
package NetFox; is6M{K3  
JqTR4[`Z\  
Dkyw3*LCn%  
public class SiteInfoBean { :k/Z|  
-Cc2|~n  
:ceT8-PBRx  
private String sSiteURL; //Site's URL Va-.  
private String sFilePath; //Saved File's Path 1e)5D& njS  
private String sFileName; //Saved File's Name `:*O8h~i^8  
private int nSplitter; //Count of Splited Downloading File ?#0m[k&`  
3uy^o  
W*WSjuFr2  
public SiteInfoBean() J#) %{k_  
{//nSplitter的缺省值为5 h8 !(WO!  
//default value of nSplitter is 5 ^3O`8o  
this("","","",5); i5; _  
} $ISx0l~  
_t-e.2a v  
N2.(0 G  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) spG3"Eodi  
{ [kKg?I$D@B  
sSiteURL= sURL; H[[#h=r0f  
sFilePath = sPath; I7]qTS[vg  
sFileName = sName; 2qDyb]9  
this.nSplitter = nSpiltter; bH`r=@.:cu  
Q&`if O  
Vg^,Ky,  
} 1zGhX]z  
m#|h22^H  
/VHQ!Wi  
public String getSSiteURL() OhiY <  
{ S]g`Ds<  
return sSiteURL; 9Ac4'L  
} bFB.hkTP  
g$T% C?  
e\95X{_'  
public void setSSiteURL(String value) zW:r7 P.  
{ \H {UJ  
sSiteURL = value; $Ma*qEB  
} KYM%U" jD  
A|<i7QVY  
/#Lm)-%G  
public String getSFilePath() Sej(jJX1  
{ ^X| Bzz)  
return sFilePath; &'"dYZj{  
} ZRn!z`.0  
PL*1-t?#  
i:n1Di1~E  
public void setSFilePath(String value) jpt-5@5O  
{ u!TMt8+c  
sFilePath = value; ;.I,R NM  
} lnWs cb3t  
=y]F cxF  
a"!r]=r  
public String getSFileName() +L-(Lz[p  
{ !)HB+yr  
return sFileName; W.7XShwd*2  
} il~A(`+YO  
Jl-:@[;  
,r,$x4*  
public void setSFileName(String value) LB/1To  
{ 8],tGMu  
sFileName = value; q{2 +Inf#:  
} -`ss7j&b3  
Co^GsUJ  
0I7 r{T  
public int getNSplitter() -:|t^RM;FT  
{ I`uOsZBO/  
return nSplitter; _5H0<%\  
} UE 1tm  
!~-@p?kW/  
4%>2 >5  
public void setNSplitter(int nCount) DgGG*OXY  
{ EeDK ^W8N  
nSplitter = nCount; gT#hF]c:  
} ; G4g;YHy|  
} f19'IH$n{  
x.ucsb  
w'&QNm>  
/* Q+zy\T  
**Utility.java VskdC?yIp  
*/ ~!#2s'  
package NetFox; Lem:zXj  
?vg|;Q  
gh<2i\})'  
public class Utility { d#u*NwY}  
]^v*2!_(  
t$(<9  
public Utility() QRz5eGpW  
{ w3 K>IDWI7  
+OfHa\Nz  
#OVS]Asn}  
} YjzGF=g#  
[KNA5(Y0  
//线程睡眠 SxW.dT8{  
public static void sleep(int nSecond) VL/KC-6  
{ Xr]<v%,C  
try{ p{w:^l(  
Thread.sleep(nSecond); E#(dri*#t  
} U@"f(YL+"  
catch(Exception e) ANlzF& K  
{ !d{Ijs'T  
e.printStackTrace (); VPUm4%?p$  
} FV5~sy  
} RFT`r  
N&]_U%#Q  
//日志 ]Nb~-)t%B  
public static void log(String sMsg) 2A(IsUtqO:  
{ DNGj81'c  
System.err.println(sMsg); x?n13C  
} +W^$my)<  
+.IncY8C$  
@9\L|O'~?  
public static void log(int sMsg) f6JC>Np  
{ k'PNfx\K  
System.err.println(sMsg); `c/mmS  
} ?.6fVSa  
} o>@9[F,h+  
U%l<48@8  
gbjql+Mx+  
/* {:ZsUnzm  
**TestMethod.java /<)kI(gf  
*/ aJSBG|IC  
package NetFox; 9 M!U@>  
K%3{a=1  
<iN xtD0  
public class TestMethod { \) vI-  
/tu\q  
{]3Rk  
public TestMethod() ~s -"u *>  
{ ///xx/weblogic60b2_win.exe IpKpj"eoLy  
try{ Oi,:q&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lvk r2Meu<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fe+2U|y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7R=A]@  
fileFetch.start(); ?f4jqF~Fh  
} G\/7V L  
catch(Exception e){e.printStackTrace ();} MRa |<yK  
*Fm#Qek  
YHfk; FI  
} 3mH(@ -OA  
U_ *K%h\m  
_aK4[*jnqh  
public static void main(String[] args) >;Vy{bL8  
{ y({EF~w  
new TestMethod(); |>jlmaV  
} k8O%gO  
} C252E  
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