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http断点续传简单实现(java)

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/* D0 /DI  
**SiteFileFetch.java X(k{-|9]  
*/ KdT[*-  
package NetFox; DH:GI1Yu>I  
import java.io.*; GIm " )}W  
import java.net.*; 46bl>yk9<  
\.H9$C$  
g@~!kh,TH  
public class SiteFileFetch extends Thread { (#!] fF"!x  
|5xYT 'V  
e Om< !H  
SiteInfoBean siteInfoBean = null; //文件信息Bean %9C`  
long[] nStartPos; //开始位置 9 Uha2o  
long[] nEndPos; //结束位置 N] 14  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #bT8QbJ(  
long nFileLength; //文件长度 M{?.hq  
boolean bFirst = true; //是否第一次取文件 w 66 v\x~  
boolean bStop = false; //停止标志 j8GY`f#  
File tmpFile; //文件下载的临时信息 E6Q]A~  
DataOutputStream output; //输出到文件的输出流 -<qxO  
:dP~.ZY7  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) SY-ez 91  
public SiteFileFetch(SiteInfoBean bean) throws IOException l{Jt sI  
{ $Y6I_U  
siteInfoBean = bean; 8Q2]*%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ia629gi5s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q!6|lZB3  
if(tmpFile.exists ()) &]P"48NT  
{ nPcS3!7B#  
bFirst = false; 'LVn^TB_f&  
read_nPos(); 6M ^IwE  
} TQP+>nS,  
else X ZS5B~E '  
{ 8|O=/m^]  
nStartPos = new long[bean.getNSplitter()]; N&T:Lt_N  
nEndPos = new long[bean.getNSplitter()]; 43zUN  
} +TC1nkX  
*>jjMyn  
LA-_3UJx  
#HeM,;Xp  
} q-3]jHChh  
ddsUz1%l  
v:KX9A.  
public void run() b'i'GJBQ+$  
{ ,c>N}*6h=W  
//获得文件长度 `Da+75 f6v  
//分割文件 FigR1/3o'6  
//实例FileSplitterFetch gQ37>  
//启动FileSplitterFetch线程 0rD#s{?   
//等待子线程返回 57~Uqt  
try{ nV}8M  
if(bFirst) (}Sr08m  
{ No) m/17y  
nFileLength = getFileSize(); Sp:l;SGd  
if(nFileLength == -1) gv#4#]  
{ Ia2(Km  
System.err.println("File Length is not known!"); C.~ j'5N  
} ?GdsOg^  
else if(nFileLength == -2) _\.{6""  
{ !X|k"km"  
System.err.println("File is not access!"); $X*mdji  
} #~^btL'dHF  
else #,L~w  
{ 7^$)VBQ/  
for(int i=0;i<nStartPos.length;i++) XS?gn.o\  
{ "PMQyzl  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o0ZIsrr  
} ?aBj#  
for(int i=0;i<nEndPos.length-1;i++) ak;6z]f8[  
{ n@!wp/J,  
nEndPos = nStartPos[i+1]; +\0T\;-Xe  
} Vtb1[cnna  
nEndPos[nEndPos.length-1] = nFileLength; n`(~O O  
} {Oj7  
} |uI?ySF  
jin db#)bz  
#;[Bl=3(  
//启动子线程 @%1IkvJV  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G?`-]FMO  
for(int i=0;i<nStartPos.length;i++) ;+ azeW ^  
{ 0VN7/=n|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zB*euHIqZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L@RIZu>ZW+  
nStartPos,nEndPos,i); hN   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); - v]Qhf&>  
fileSplitterFetch.start(); )%mg(O8uL  
} s)zJT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }`xdWY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _;hf<|c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OfTfNhpK  
nEndPos = " + nFileLength); 5RF4]$zT  
// fileSplitterFetch[nPos.length-1].start(); 0,_b)  
ESTM$k }X  
gZO&r#   
//等待子线程结束 VO=!8Yx[  
//int count = 0; A`[@ 8  
//是否结束while循环 7(bQ}mHl\  
boolean breakWhile = false; j8++R&1f]  
f'X9HU{Cz  
.oqIZ\iik  
while(!bStop) hmpr%(c`  
{ wpXgPVZT  
write_nPos(); ,:)`+v<  
Utility.sleep(500); 1!1!PA9u  
breakWhile = true; {EA1vo"  
1@>$ Gcc  
|mhKIis U  
for(int i=0;i<nStartPos.length;i++) eQUe >*  
{ d(-EcY>?  
if(!fileSplitterFetch.bDownOver) \OQkZ.cU;  
{ R_ ZK0ar  
breakWhile = false; $TG =w  
break; c6&Q^p|CF  
} "?3`  
} !E2W\chi  
if(breakWhile) %Jp|z? [/  
break; 8|@9{  
e(?]SU|  
=2Cj,[$  
//count++; wM~H(=s`D  
//if(count>4) wi_'iv  
// siteStop(); 7b[wu~'( n  
} 5'KA'>@  
),(V6@Z?  
/(hUfYm0  
System.err.println("文件下载结束!"); Kcy@$uF{2  
} [;A[.&6  
catch(Exception e){e.printStackTrace ();} IgIYguQ   
} /mA,F;   
PL X>-7@  
=-"c*^$]  
//获得文件长度 nhT-Ido  
public long getFileSize() v+G=E2Lhv  
{ y7/F _{  
int nFileLength = -1; j$Ab>}g]  
try{ L\%orLEmK  
URL url = new URL(siteInfoBean.getSSiteURL()); 0.Ta Xbi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v6GPS1:a  
httpConnection.setRequestProperty("User-Agent","NetFox"); i#/]KsSp  
W3H+.E  
HCWNo  
int responseCode=httpConnection.getResponseCode(); +s++7<C  
if(responseCode>=400) S >yLqPp  
{ [sF(#Y:I  
processErrorCode(responseCode); H[ m <RaG8  
return -2; //-2 represent access is error M|,mr~rRG  
} `=UWqb(K_  
@-HG`c ct  
]bZ(HC?KZr  
String sHeader; rHjq1-t  
l12{fpm  
rV6/Tdy  
for(int i=1;;i++) x3 >  
{ /w(e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |~!U4D\  
//Utility.log(in.readLine()); t]aea*B  
sHeader=httpConnection.getHeaderFieldKey(i); -=`#fDvBn  
if(sHeader!=null) 0@I S  
{ "ZwKk G  
if(sHeader.equals("Content-Length")) ,<-G<${  
{ #|[ M?3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6eFp8bANN#  
break; ^r6!l.  
} [F!Y%Zp  
} w[tmCn+  
else U8.7>ENnP&  
break; _>+8og/%@  
} R :X0'zeRr  
} T*g:# ^4  
catch(IOException e){e.printStackTrace ();} i|`dWOVb  
catch(Exception e){e.printStackTrace ();} ]:>,A@7  
aJ Z"D8C  
Gg Jf7ie4  
Utility.log(nFileLength); -m *Sq  
Lk\P7w{  
u .f= te  
return nFileLength; 21hv%CF\9  
} zk-.u}RBFG  
kF(n!2"W  
7lV.[&aKW  
//保存下载信息(文件指针位置) i4Lc$20?d  
private void write_nPos() #7ohQrP  
{ [e[<p\]  
try{ I9h ?;(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H0m|1 7  
output.writeInt(nStartPos.length); LUB${0BrA  
for(int i=0;i<nStartPos.length;i++) y!tC20Q   
{ KlRr8 G!Z  
// output.writeLong(nPos); h/?l4iR*  
output.writeLong(fileSplitterFetch.nStartPos); ;X*cCb`h   
output.writeLong(fileSplitterFetch.nEndPos); ) e5 @  
} wLK07e(  
output.close(); *na?n2Yzt  
} A,sr[Pa@  
catch(IOException e){e.printStackTrace ();} '5&s=M_  
catch(Exception e){e.printStackTrace ();} .<@8gNm3  
} [ ol9|sdu  
kuyjnSo9i  
hxQqa 0B  
//读取保存的下载信息(文件指针位置) y@0E[/O  
private void read_nPos() ]vwW]O7  
{ Pj}6 6.  
try{ VD_$$Gn*q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Zm6{n '  
int nCount = input.readInt(); zR2B- &]H  
nStartPos = new long[nCount]; `tP7ncky  
nEndPos = new long[nCount]; _S>JKz  
for(int i=0;i<nStartPos.length;i++) lXcx@#~  
{ % qV 6  
nStartPos = input.readLong(); |{CfWSB7~@  
nEndPos = input.readLong(); 8Z(Mvq]f&  
} *98$dQR$  
input.close(); 6I@h9uIsze  
} "[y-+)WTG  
catch(IOException e){e.printStackTrace ();} g+J-Zg6  
catch(Exception e){e.printStackTrace ();} (sh)TBb5  
} ?@E!u|]K  
 }Y;K~J  
gNt(,_]ZR  
private void processErrorCode(int nErrorCode) z`:lcF{V  
{ (J z1vEEV  
System.err.println("Error Code : " + nErrorCode); |JQQU! x  
} 293M\5:  
H1} RWaJ  
#O+),,WS  
//停止文件下载 Q%xC}||1s"  
public void siteStop() C=eF.FB;'  
{ h*-Pr8  
bStop = true; z CvKDlL  
for(int i=0;i<nStartPos.length;i++) zux{S; :?  
fileSplitterFetch.splitterStop(); iyg*Xbmi~.  
%}%Qc6.H  
Z]B~{!W1  
} @nux9MX<9  
} ]*AR,0N&  
//负责部分文件的抓取 {WYX~Mvvj  
**FileSplitterFetch.java ZpnxecJUJ  
*/ Za 1QC;7  
package NetFox; %44leINx  
UEguF &  
e J6$-r  
import java.io.*; =>_\fNy  
import java.net.*; 'Iw NTM  
<ZNzVnVA  
RS8Hf~0G  
public class FileSplitterFetch extends Thread { \SB c;  
>k (C  
b45-:mi!&#  
String sURL; //File URL ~{jcH  
long nStartPos; //File Snippet Start Position "hsb8-  
long nEndPos; //File Snippet End Position <i&_ooX  
int nThreadID; //Thread's ID ~vyf4TF<#  
boolean bDownOver = false; //Downing is over sVOyT*GY  
boolean bStop = false; //Stop identical |a Vn&qK  
FileAccessI fileAccessI = null; //File Access interface t+!$[K0/  
hpD!2 K3>  
'h,VR=e<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `Tv[DIVW  
{ "$YJX1u3  
this.sURL = sURL; |>dI/_'  
this.nStartPos = nStart; =w{Z@S(ukz  
this.nEndPos = nEnd; vkri+:S3  
nThreadID = id; lE4HM$p   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _sTROd)Vh  
} =`H@%  
'F9jq  
OG>}M$ Ora  
public void run() ,,q10iF  
{ toBHkiuD  
while(nStartPos < nEndPos && !bStop) 4bYK}o S  
{ 8ap%?  
z?R|Ok  
!WQ-=0cm  
try{ oYm[V<nIl  
URL url = new URL(sURL); nH[yJGZYSA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wa{`VS  
httpConnection.setRequestProperty("User-Agent","NetFox"); @eKec1<  
String sProperty = "bytes="+nStartPos+"-"; )QU  
httpConnection.setRequestProperty("RANGE",sProperty); ! t?iXZ  
Utility.log(sProperty); :% ,:"  
Ezd_`_@R  
J;8IY=  
InputStream input = httpConnection.getInputStream(); wNpTM8rfU#  
//logResponseHead(httpConnection); Y,^@P  
CDK 5  
!xo{-@@wS  
byte[] b = new byte[1024]; CTq&-l:f  
int nRead; Nh_Mz;ITuu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B#Vz#y  
{ r{L> F]Tw  
nStartPos += fileAccessI.write(b,0,nRead); >I-RGW'A  
//if(nThreadID == 1) *Doa* wQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jtW!"TOY  
} S.-TOE  
'!!CeDy  
! |<Fo'U  
Utility.log("Thread " + nThreadID + " is over!"); kuszb~`zPY  
bDownOver = true; BBwy,\o#  
//nPos = fileAccessI.write (b,0,nRead); \Je0CD=e`  
} 3q\,$*D.  
catch(Exception e){e.printStackTrace ();} KBx6NU?;PO  
} ^:^9l1]  
} eg;~zv  
Z`ID+  
5B3G @KR  
//打印回应的头信息 \fz<.l]  
public void logResponseHead(HttpURLConnection con) A$Hfr8w1u  
{ R{<kW9!  
for(int i=1;;i++) Q ayPo]O  
{ jaII r06  
String header=con.getHeaderFieldKey(i); v3~?;f,l  
if(header!=null) }ppN k:B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <Tzrj1"Q3  
Utility.log(header+" : "+con.getHeaderField(header)); D9^h; 8  
else n|Q@UPb/=  
break;  *x@Onj  
} .WA-&b_  
} CQF:Rnb  
8lvV4yb  
g+vva"  
public void splitterStop() RO+GK`J  
{ Lo{ E:5q  
bStop = true; G|!Tj X7s  
} vlmB`T  
qouhuH_WtJ  
%Nlt H/I  
} M?Y;a5{  
n' n/Tu   
;K:zmH  
/* bzBEX mC  
**FileAccess.java x<tb  
*//文件访问(定位,写) i [7\[  
package NetFox; ^}/PGG\~r  
import java.io.*; le|~BG hL  
<\r T%f}3^  
o=1Uh,S3R  
public class FileAccessI implements Serializable{ B+P(M!m3  
4gI/!,J(b  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 jS]ru-5.  
RandomAccessFile oSavedFile; +%yfcyZ.  
long nPos; x kx^%3dV  
ey7 f9  
+h|`/ &,  
public FileAccessI() throws IOException %(3|R@G.  
{ +"\sc;6m.  
this("",0); P+@/O  
} t<.)Z-Ii  
n{n52][J]  
dk[!V1x4\  
public FileAccessI(String sName,long nPos) throws IOException yj 3cyLXw  
{ CGW.I$u  
oSavedFile = new RandomAccessFile(sName,"rw"); T*Y~\~Jhu  
this.nPos = nPos; [kVS O  
oSavedFile.seek(nPos); a!6{:8Zi0  
} >)fi^  
q/4J.j L  
9UdM`v)(  
public synchronized int write(byte[] b,int nStart,int nLen) rK'L6o  
{ =upeRY@u5  
int n = -1; u^@f&BIG]:  
try{ }eCw6  
oSavedFile.write(b,nStart,nLen); H%qsjB^  
n = nLen; 1gL2ia  
} "jeb%k  
catch(IOException e) j/323Za+  
{ `uv2H$  
e.printStackTrace (); ?8npG]L)  
} tU}h~&M  
132{# tG]  
}|0^EWL  
return n; 2J7:\pR^  
} %aG5F}S2~  
9vuyv*-}e  
g/ T   
} %". HaI]  
[L3=x;U  
hci6P>h<ia  
/* ? &o2st  
**SiteInfoBean.java pA'4|ffwe  
*/ fx41,0;gZq  
package NetFox; b z`+k,*  
B nFwlw  
1{)5<!9!l  
public class SiteInfoBean { K[I=6  
N]>=p.#j  
5kc/Y/4o  
private String sSiteURL; //Site's URL z`.<U{5  
private String sFilePath; //Saved File's Path Sj%u)#Ub  
private String sFileName; //Saved File's Name C)um9}  
private int nSplitter; //Count of Splited Downloading File faE t6  
Go5J%&E9  
TH%Qhv\]  
public SiteInfoBean() 0IsPIi"7  
{//nSplitter的缺省值为5 .?8;qA  
//default value of nSplitter is 5 wcrCEX=I>{  
this("","","",5); Q:2>}QgX}  
} /C:Y94B-z  
u 1>2v  
wT6"U$cV  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) pj\u9 L_  
{ du<tGsy  
sSiteURL= sURL; [g7L&`f9  
sFilePath = sPath; g;H=6JeG/  
sFileName = sName; ^h(ew1:  
this.nSplitter = nSpiltter; t|w_i-&b,  
Km qMFB62  
m( r,Acy6  
} =:xW>@bh|  
+%+tr*04O  
[`ebM,W  
public String getSSiteURL() l.q&D< _  
{ vLv@&lMW  
return sSiteURL; kjTduZ/3 "  
} u0JB\)(-/h  
UFXaEl}R   
B{QBzx1L9c  
public void setSSiteURL(String value) %6|nb:Oa  
{ 5MroNr  
sSiteURL = value; H9'$C/w  
} 8H%;WU9-  
iN bIp"W  
}5ret  
public String getSFilePath() +5w))9@  
{ D>`xzt'.6  
return sFilePath; /j #n  
} .M qP_Z',  
@CpfP;*{w`  
JB%',J  
public void setSFilePath(String value) "|x^|n8i  
{ %v=*Wb\3|  
sFilePath = value; =ElO?9&  
} Y4J3-wK5  
|)IlMG  
dH;8mb|#'  
public String getSFileName() ~uj#4>3T  
{ ,1y@Z 5wy  
return sFileName; {kA0z2Fe  
} Yk'XGr)  
y`L>wq,KU  
Lm iOhx  
public void setSFileName(String value) 0CZ :Bo[3  
{ g{7.r-uu  
sFileName = value; AuvkecuIh  
} MU($|hwiL  
_('=b/  
.eS<Dbku<  
public int getNSplitter() Z_LFIz*c  
{ ^P[e1?SZG  
return nSplitter; g?c xp +  
} NN%*b yK  
4.k0<  
?k+xSV  
public void setNSplitter(int nCount) [u =+3b  
{ ;0Q4<F  
nSplitter = nCount; DHy q^pJ  
} qSM|hHDo)  
} cutuDZ  
Q$a{\*[:+  
 U'k*_g  
/* 6]&OrS[  
**Utility.java .6ylZ  
*/ TtJH7  
package NetFox; 9)h"-H;5:  
)cX*I gO  
Ab~3{Q]#  
public class Utility { 9"N~yKa`"K  
B~'vCuE  
&pP;Neh;  
public Utility() 7!$Q;A  
{ |T<_5Ik  
c/:b.>W  
~Zun&b)S  
} /74QMx?  
;nI] !g:  
//线程睡眠 F3y9@dA]  
public static void sleep(int nSecond) S50k>_a;  
{ zUt' QH7E.  
try{ EB0TTJR?#  
Thread.sleep(nSecond); g1;:KzVv  
} ^+*N%yr  
catch(Exception e) 5 )A1\  
{ ,L|%"K]yM  
e.printStackTrace (); t*=CZE-  
} @#l `iK  
} w_aknt T  
 03L]  
//日志 DRSr%d  
public static void log(String sMsg) RaO-H  
{ MOQ6 :  
System.err.println(sMsg); |-b#9JQ[A  
} 4`lLf  
[xbSYu,&  
`:ArT}F  
public static void log(int sMsg) $r^GE  
{ O n8v//=&  
System.err.println(sMsg); "x#-sZ=  
} +UCG0D  
} T tfo^ksw  
eJrQ\>z]V&  
oro$wFxJO  
/* ~Sdb_EZ  
**TestMethod.java loEPr5 bL  
*/ 5A,K6f@:g  
package NetFox; ,j#XOy`mzy  
R]JT&p|w.1  
,A9]CQ  
public class TestMethod { hE &xE;  
>d(~# Z`  
EW}Bzh>b  
public TestMethod() ##q2mm:a9P  
{ ///xx/weblogic60b2_win.exe zU,9T  
try{ 3Lfqdqj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); SDC4L <!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R1s`z|?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AKY1o.>z  
fileFetch.start(); Mhm@R@  
} w{{gu1#]G  
catch(Exception e){e.printStackTrace ();} .nO\kgoK  
d}Xr}  
fIM,lt  
} )n1_(;  
/~DI 6g  
FX;QG94!  
public static void main(String[] args) O 5!7'RZ  
{ _;W.q7 b]  
new TestMethod(); {k(g]#pP  
} @g|v;B|{  
} u/UrAqw  
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