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http断点续传简单实现(java)

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/* V|q`KOF  
**SiteFileFetch.java @&F\M}  
*/ P-LdzVt(^  
package NetFox; G?e\w+}Pj@  
import java.io.*; O Bp&64  
import java.net.*; }~bx==SF6!  
8j^3_lD  
9C"d7--  
public class SiteFileFetch extends Thread { CY?19Ak-xd  
rv2 6vnJy"  
k0>]7t$L  
SiteInfoBean siteInfoBean = null; //文件信息Bean Z]\IQDC  
long[] nStartPos; //开始位置 ){M)0,:  
long[] nEndPos; //结束位置 Pf?zszvs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2`V[Nb  
long nFileLength; //文件长度 M!Wjfq ^~  
boolean bFirst = true; //是否第一次取文件 '"4S3Fysm  
boolean bStop = false; //停止标志 qCUn. mI  
File tmpFile; //文件下载的临时信息  cq,8^o&  
DataOutputStream output; //输出到文件的输出流 cpJ(77e  
v0 uA]6:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Uoqt  
public SiteFileFetch(SiteInfoBean bean) throws IOException r)/nx@x  
{ Yd>ej1<  
siteInfoBean = bean; iI@m e=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3A)Ec/;~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vN8Xq+  
if(tmpFile.exists ()) Ip&Q'"HYj  
{ F =Zc_  
bFirst = false; Y?b4* me  
read_nPos(); laX67Vjv  
} #>[5NQ;$'  
else \4FKZ>1+R  
{ k,M %"FLQ  
nStartPos = new long[bean.getNSplitter()]; MET"s.v  
nEndPos = new long[bean.getNSplitter()]; 0!(BbQnWI  
} zSM;N^X8?  
RLL2'8"A  
@, %IVKg\  
nApkK1?  
} |-! yKB  
*E1v  
/GDGE }  
public void run() -'wFaW0%I  
{ t w?\bB  
//获得文件长度 GJB= 5nE  
//分割文件 Ej7>ywlW  
//实例FileSplitterFetch ,^d!K(xb  
//启动FileSplitterFetch线程 w=K!U]  
//等待子线程返回 %@4/W  N  
try{ @!MhVNS_<  
if(bFirst) \8HLQly|@  
{ =3= $F%  
nFileLength = getFileSize(); r1o_i;rg  
if(nFileLength == -1) -0R;C`(!  
{ 1p]Z9$Y  
System.err.println("File Length is not known!"); LjOHlT'  
} N-9qNLSP  
else if(nFileLength == -2) YnLwBJ2i  
{ $4Ko  
System.err.println("File is not access!"); 3.vQ~Fvl  
} n"P29"  
else $,v[<T`  
{ cy+EJq I  
for(int i=0;i<nStartPos.length;i++) *k%3J9=-1  
{ 5lp};  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0*-nVC1  
} G"._]3 CPF  
for(int i=0;i<nEndPos.length-1;i++) I X]K "hT  
{ O"Ua|8  
nEndPos = nStartPos[i+1]; y5AJ1A6?E  
} w:~Y@ b~D  
nEndPos[nEndPos.length-1] = nFileLength; R:}u(N  
} Ml Bw=Nr  
} hExw}c  
i9FtS7  
C1 YG=!  
//启动子线程 Uq8=R)1<|d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OYC\+ =  
for(int i=0;i<nStartPos.length;i++) qp6*v&  
{ Bt\z0*t=s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zLa3Q\T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y3J;Kk#AH  
nStartPos,nEndPos,i); 5?()o}VjAO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _=\=oC  
fileSplitterFetch.start(); 3>I   
} %j*i=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q:#Kt@W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |0jmOcZF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D" 4*&  
nEndPos = " + nFileLength); 6uAo0+-k  
// fileSplitterFetch[nPos.length-1].start(); OSsxO(;g  
xn)eb#r  
53w@  
//等待子线程结束 U.[?1:v  
//int count = 0; ?(!<m'jEy  
//是否结束while循环 uDZ$'a  
boolean breakWhile = false; x`#|8  
nvdo|5  
z U~o"Jv  
while(!bStop) `S{Blv  
{ MGmUgc  
write_nPos(); u?>]C6$  
Utility.sleep(500); -q-/0d<l  
breakWhile = true; |4F 3Gu  
DG&[.dR+  
d5x>kO'[l  
for(int i=0;i<nStartPos.length;i++) 3N ]  
{ 8] BOq:  
if(!fileSplitterFetch.bDownOver) J}035  
{ L,XWX8  
breakWhile = false; 0K&\5xXM  
break; sZ,mRT  
} +cw;a]o^>  
} ( _{\tgSm  
if(breakWhile) ':v@Pr|  
break; 'Si 1r%'m#  
Z{|U!tn  
KvM}g2"  
//count++; O-M4NKl]6  
//if(count>4) f8DF>]WW  
// siteStop(); -cjwa-9 ~  
} JERWz~n}  
6L~tUe.G  
W|PKcZ ]Uc  
System.err.println("文件下载结束!"); LZCziW  
} `W8A *  
catch(Exception e){e.printStackTrace ();} l 1RpG"  
} =/k*w#j  
}a(x L'F  
;plzJ6>  
//获得文件长度 |$r|DX1[  
public long getFileSize() _%)v9}D  
{ 0nF>E@j^[  
int nFileLength = -1; dJhT}"x  
try{ 3zO'=gwJ  
URL url = new URL(siteInfoBean.getSSiteURL()); 4No!`O-!&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #K3A{ jb,  
httpConnection.setRequestProperty("User-Agent","NetFox"); QES[/i +  
y7 I')}SC  
JNzNK.E!m-  
int responseCode=httpConnection.getResponseCode(); kq[*q-:"x  
if(responseCode>=400) Z=sCYLm  
{ zS*X9|p  
processErrorCode(responseCode); {]\Q UXH  
return -2; //-2 represent access is error 3N?WpA768/  
} Z6}B}5@y  
M]?#]3XBNo  
x}G["ZU}v]  
String sHeader; =OIx G}*  
T4`.rnzyRb  
.[1"Med J  
for(int i=1;;i++) ~M 6^%  
{ 93|u. @lEy  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vj I>TIy  
//Utility.log(in.readLine()); %f.(^<G u  
sHeader=httpConnection.getHeaderFieldKey(i); R{~Yh.)~  
if(sHeader!=null) %3ecV$  
{ A f@IsCOJ  
if(sHeader.equals("Content-Length")) 3S-nsMs.  
{ Gw6*0& 3')  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .y{qsL^P  
break; Vcg$H8m  
} Be{7Rj v  
} -Cxk#-sb#  
else qlJP2Ig~  
break; ;T!mNKl  
} +*3\ C!  
} )TxAhaz+  
catch(IOException e){e.printStackTrace ();} 00'R1q4  
catch(Exception e){e.printStackTrace ();} M3j_sd'N  
m'$]lf;*  
H4 }^6><V  
Utility.log(nFileLength); RsS?ibozl  
3&kHAXzM  
9g#L"T=  
return nFileLength; 6R1){,8  
} ~Rx[~a  
X8Px  
| 1H"ya  
//保存下载信息(文件指针位置) v V:eU-a  
private void write_nPos() 08&DP^NS  
{ r5z_{g  
try{ *P&ZE   
output = new DataOutputStream(new FileOutputStream(tmpFile)); K oPTY^  
output.writeInt(nStartPos.length); 8Letpygm  
for(int i=0;i<nStartPos.length;i++) ;2 oR?COW  
{ +2=N#LM  
// output.writeLong(nPos); 0[g8  
output.writeLong(fileSplitterFetch.nStartPos); k/W$)b:Of`  
output.writeLong(fileSplitterFetch.nEndPos); |HXI4 MU"  
} /"+ n{*9  
output.close(); m98j`t  
} Q>u$tLX&  
catch(IOException e){e.printStackTrace ();} QT/TZ:  
catch(Exception e){e.printStackTrace ();} A,rgN;5fb  
} U@dztX@u  
ygr[5Tl  
RuDn1h#u{  
//读取保存的下载信息(文件指针位置) wE:hl  
private void read_nPos() Af5O;v\  
{ ,p/iN9+Z  
try{ 't \:@-tQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .w^M?}dx  
int nCount = input.readInt(); k.>*!l0  
nStartPos = new long[nCount]; ce&)djC7U  
nEndPos = new long[nCount]; j8?z@iG  
for(int i=0;i<nStartPos.length;i++) ^EE 3E'  
{ RG|]Kt8  
nStartPos = input.readLong(); $QmP' <  
nEndPos = input.readLong(); v bzeabm  
} *yOpMxE  
input.close(); ,/{mRw%  
} 2`/JT  
catch(IOException e){e.printStackTrace ();} P9v N5|"M  
catch(Exception e){e.printStackTrace ();} HJ]\VP9Zb  
} 7%L%dyN  
@47MJzC  
utKtxLX"  
private void processErrorCode(int nErrorCode) x F7C1g(  
{ ]kx)/n-K  
System.err.println("Error Code : " + nErrorCode); IF%^H K@  
} I{AteL  
:Eq=wbAw  
>up'`K,  
//停止文件下载 fQc2K|V  
public void siteStop() J:Uf}!D  
{ 48Y5ppcS  
bStop = true; NJSzOL_  
for(int i=0;i<nStartPos.length;i++) \ Xow#@[  
fileSplitterFetch.splitterStop(); pUki!TA  
c%c/mata?  
C#[YDcp4  
} |ZW%+AQ|  
} SC)4u l%  
//负责部分文件的抓取 l j*ELy  
**FileSplitterFetch.java Lzu;"#pw  
*/ EU.vw0}u8  
package NetFox; _;",7bT80  
$8h^R#  
T1m'+^?"  
import java.io.*; U.~, Bwb  
import java.net.*; $Z(fPKRN/  
gE%{#&*  
rXXIpQRi$S  
public class FileSplitterFetch extends Thread { 3UgusH3  
U;o[>{L   
YJ_`[LnL  
String sURL; //File URL XH&Fn+  
long nStartPos; //File Snippet Start Position [?VYxX@  
long nEndPos; //File Snippet End Position }q9;..oL  
int nThreadID; //Thread's ID !4d6wp"  
boolean bDownOver = false; //Downing is over d)`XG cx{=  
boolean bStop = false; //Stop identical  ::Y   
FileAccessI fileAccessI = null; //File Access interface vAi NOpz#  
wP3_RA]z  
 c'?4*O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException AEaT  
{ iaBy/!i  
this.sURL = sURL; e_s9E{(  
this.nStartPos = nStart; ]bCeJE.+)  
this.nEndPos = nEnd; 2T/C!^iJ)  
nThreadID = id; B~oSKM%8R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =ZM#_uW  
} Y, K): ~T  
&P{  
;K38I}  
public void run() |1J=wp)#  
{ xMJF1O?3  
while(nStartPos < nEndPos && !bStop) X||Z>w}v  
{ 5g  ,u\`  
Dt?O_Bdv[  
qp (ng 8%c  
try{ R)?b\VK2$  
URL url = new URL(sURL); U*F|Z4{W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xExy?5H7  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^ a%U *>P  
String sProperty = "bytes="+nStartPos+"-"; |eL&hwqzG  
httpConnection.setRequestProperty("RANGE",sProperty); B;t U+36nM  
Utility.log(sProperty); Rro|P_  
<y5V],-U  
RP'`\| |*  
InputStream input = httpConnection.getInputStream(); :/fG %e  
//logResponseHead(httpConnection); I$0JAy  
^c{}G<U^  
+4^XFPq~  
byte[] b = new byte[1024]; cC w,b]  
int nRead; ~d6 _  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'TpW-r:  
{ |`T3H5X>  
nStartPos += fileAccessI.write(b,0,nRead); K;;Q*NN-  
//if(nThreadID == 1) Im%|9g;P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VpSk.WY/ e  
} _ b}\h,Ky  
):?ype>  
Ls#pe  
Utility.log("Thread " + nThreadID + " is over!"); 8}h ^Frh  
bDownOver = true; 7r?O(0>  
//nPos = fileAccessI.write (b,0,nRead); lM Gz"cym  
} 6"Q/Y[y  
catch(Exception e){e.printStackTrace ();} R-]QU`c  
} ; iQ@wOL]  
} 6~GaFmW=  
], Wh]q  
d$)'?Sf]h  
//打印回应的头信息 g(<02t!OT=  
public void logResponseHead(HttpURLConnection con) AWC zu5ve  
{ Mh'QD)28c  
for(int i=1;;i++) \@nmM&7C!4  
{ B5Rmz&  
String header=con.getHeaderFieldKey(i); pVn 6>\xa  
if(header!=null) I=&5mg=m  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,R0@`t1 p  
Utility.log(header+" : "+con.getHeaderField(header)); Ou/@!Y1  
else Q_/{TE/sO5  
break; I^/Ugu  
} -_'M *-  
} *{tn/ro6a  
o1"U'y-9V  
h *)spwF-  
public void splitterStop() Vi`+2%4  
{ tp$NT.z  
bStop = true; &J^@TgqL^  
} R6dw#;6{I  
K2nq2Gbn  
z;1tJ  
} Tz58@VYV  
W5}.WFu  
xXH%7%W'f  
/* }aXc,;Ps  
**FileAccess.java ZA>hN3fE'  
*//文件访问(定位,写) ^mFuZ~g;?  
package NetFox; lE08UEk1i  
import java.io.*; `Q1T-H_  
Eag->mw/~  
2i', e  
public class FileAccessI implements Serializable{ N::_JH? ^=  
h3a HCr E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7~cN  
RandomAccessFile oSavedFile; IvetQ+  
long nPos; ;E:ra_l  
N<Rb<p%  
8^p/?R^bu  
public FileAccessI() throws IOException G hLgV  
{ 3nd02:GF  
this("",0); 82Nh;5T r  
} Ts:dnGR5  
Nol',^)  
4 u X<sJ*  
public FileAccessI(String sName,long nPos) throws IOException W>dS@;E  
{ u)&6;A4  
oSavedFile = new RandomAccessFile(sName,"rw"); =NAL*4c+  
this.nPos = nPos; W6&" .2  
oSavedFile.seek(nPos); ~t<BZu  
} !#3#}R.$Fl  
&AGV0{NMh]  
IyOujdKa  
public synchronized int write(byte[] b,int nStart,int nLen) y_qFXd  
{ #$K\:V+ 4  
int n = -1; ~yt+xWV  
try{ h_?D%b~5  
oSavedFile.write(b,nStart,nLen); q{ @>2AlK  
n = nLen; PQ@(p%   
}  tAP~  
catch(IOException e) W=mh*G3y  
{ [@#P3g\:>W  
e.printStackTrace (); r&0v,WSp&S  
} r4Pm i  
2aW&d=!ZV  
3 _:yHwkD  
return n; ff-9NvW4v  
} tLS5yT/  
HkJ$r<J2  
lj@c"Yrk  
} ff?:_q+.N  
8NPt[*  
l *yml  
/* +_06{7@h  
**SiteInfoBean.java Z)|*mJ  
*/ \W( C=e  
package NetFox; (Pin9^`ALc  
rh${pHl  
|6"zIHvtc  
public class SiteInfoBean { 7tUl$H;I/R  
A 99 .b  
^&h|HO-5  
private String sSiteURL; //Site's URL 4punJg~1  
private String sFilePath; //Saved File's Path r?\hZ*|M  
private String sFileName; //Saved File's Name dW,$yH_  
private int nSplitter; //Count of Splited Downloading File _Wk!d3bsx  
"npj%O<bd  
87>\wUJ  
public SiteInfoBean() lk%rE  
{//nSplitter的缺省值为5 Hl?\P6   
//default value of nSplitter is 5 $a(wM1S4  
this("","","",5); 1 ;4TA}'H  
} kJlRdt2  
f<!eJO:<'  
+ 3aAL&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (JL{X`gs#  
{ $0AN5 |`g\  
sSiteURL= sURL; *'QD!Tc  
sFilePath = sPath; |B;:Ald  
sFileName = sName; #Ji&.T^U/  
this.nSplitter = nSpiltter; |TkMrj0  
+smPR  
x!tCK47Yq  
} qI) Yzc/  
7$\;G82_  
R% l=NHB}  
public String getSSiteURL() cmZ39pjBJ  
{ A>bo Xcr  
return sSiteURL; ,+oQ 5c(f  
} bEMD2ABm  
|jU/R  
<I&X[Sqp  
public void setSSiteURL(String value) z$QYl*F1  
{ w=rh@S]  
sSiteURL = value; f}Mc2PQ-  
} A]WU*GL2H  
/Pxt f~$  
dK#:io[Nz  
public String getSFilePath() G9 ;X=c  
{ ) 'j7Ra  
return sFilePath; ^}a..@|%W  
} <KoiZ{V   
^GD"aerNr  
w +fsw@dK&  
public void setSFilePath(String value) [W ,Ej  
{ [GyW1-p33w  
sFilePath = value; *_}ft-*w  
} K pDKIi  
Q;*TnVbJ  
#e}Q|pF  
public String getSFileName() Ovxs+mQ  
{ J2f}{!b+I  
return sFileName; dzjp,c@  
} (oBvpFP33  
mp*&{[XoVC  
XT9]+b8(M  
public void setSFileName(String value) bX Q*d_]WT  
{ C*a>B,H  
sFileName = value; M2W4 RovfR  
} `aD~\O  
*P7 H=Yf&  
UMILAoR  
public int getNSplitter() &G\Vn,1v  
{ <U%4$83$  
return nSplitter; T`mG+"O  
} J$F 1sy  
v6uR[18  
mEeD[dMN  
public void setNSplitter(int nCount) s;Q0  
{ ` $*I%oT;  
nSplitter = nCount; R}_B\#Q  
} 9AF%Y:y  
} !w2J*E\  
io%WV%1_  
mhVdsa  
/* ,P ~jO  
**Utility.java 1Bp?HyCR  
*/ :%7y6V*  
package NetFox; c|m*< i  
`v?XFwnV`  
Of0(.-Q w  
public class Utility { VUnO&zV{  
iga.B  
G%ytp=N  
public Utility() o|(Ivt7jk  
{ ;O8'vp  
w_qX~d/  
o]/*YaB2>  
} AK$&'t+$}7  
Yw=7(}  
//线程睡眠 g?B4b7II  
public static void sleep(int nSecond) V3D`pt\[x  
{ [GQn1ZLc  
try{ lldNIL6B%  
Thread.sleep(nSecond); Gk:tT1  
} rf?%- X(V  
catch(Exception e) v}\4/u  
{ h'lqj0  
e.printStackTrace (); R*0]*\C z  
} 59Lc-JJ  
} 8=!uQQ  
\MqOHM.[  
//日志 >PuQ{T I  
public static void log(String sMsg) ^+p7\D/E(  
{ ;n,xu0/  
System.err.println(sMsg); :'`y}'  
} U}T{r%9  
r)S:-wP  
B/O0 ~y!n  
public static void log(int sMsg) L:j3  
{ FYs]I0}|  
System.err.println(sMsg); dJv2tVm&'  
} @*Tql:Qcd^  
} 9Js+*,t  
&R5zt]4d&  
"?%2`*\  
/* Ie4\d2tQ;  
**TestMethod.java :%_\!FvS  
*/ +Jm~Um!  
package NetFox; 1-V"uLy@gC  
HmiG%1+{A  
E/V_gci  
public class TestMethod { ?wP/l  
A^ofs*"Y  
z~"Q_gme  
public TestMethod() hCBre5  
{ ///xx/weblogic60b2_win.exe N TcojA{V$  
try{ gLm,;'h%u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ''dS {nQs  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GQ(*k)'a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {p.^E5&  
fileFetch.start(); w_h{6Kc<  
} 8eVy*h2:=  
catch(Exception e){e.printStackTrace ();} P!Brw72  
sZI"2[bk  
i 50E#+E8  
} kXV;J$1  
STl8h}C  
JC0#pU;  
public static void main(String[] args) b(oe^jeGz  
{ C$p012D1  
new TestMethod(); +e^ CL#Gs  
} 5vFM0  
} $PG(>1e  
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