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http断点续传简单实现(java)

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/* VQ5nq'{v  
**SiteFileFetch.java Cv ejb+  
*/ me6OPc;:!  
package NetFox; )}vNOE?X~  
import java.io.*; ps .]N   
import java.net.*; 'J&f%kx"  
\#-W <  
:0)3K7Q   
public class SiteFileFetch extends Thread { {j5e9pg1L|  
cKb)VG^  
]ul$*  
SiteInfoBean siteInfoBean = null; //文件信息Bean x_Jwd^`t!  
long[] nStartPos; //开始位置 R" )bDy?  
long[] nEndPos; //结束位置 %CUGm$nH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'I;!pUfVp  
long nFileLength; //文件长度 ;w|b0V6  
boolean bFirst = true; //是否第一次取文件 ]lw|pvtd  
boolean bStop = false; //停止标志 AcI,N~~  
File tmpFile; //文件下载的临时信息 ;$Y4xM`=m  
DataOutputStream output; //输出到文件的输出流 ")O`mXg-  
^<e@uNGg  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Y)N-V ]5L  
public SiteFileFetch(SiteInfoBean bean) throws IOException fFj grK8  
{ ZCKka0*  
siteInfoBean = bean; \<}&&SuH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); f7h*Vu`>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ydw)mT44K  
if(tmpFile.exists ()) X U/QA [K  
{ M?b6'd9f  
bFirst = false; aL J(?8M@  
read_nPos(); )ZrS{vY  
} )o-Q!<*1  
else t#%R q  
{ )X9W y!w0  
nStartPos = new long[bean.getNSplitter()]; MX4]Vpv  
nEndPos = new long[bean.getNSplitter()]; b@3_L4~  
} `qd+f{Q  
b=~i)`  
D +_oVob\  
~4P%%b0,o  
} R4ht6Vm3g)  
n,$IfC"  
[=B$5%A  
public void run() lWBb4 !l  
{ pV4Whq$  
//获得文件长度 mUS_(0q  
//分割文件 fDG0BNLY  
//实例FileSplitterFetch lds- T  
//启动FileSplitterFetch线程 8-y{a.,u.  
//等待子线程返回 &Tl 0Pf  
try{ ^rvx!?zO  
if(bFirst) >.dWjb6t  
{ vSi_t K4  
nFileLength = getFileSize(); '* \|; l#1  
if(nFileLength == -1) zC _<(4$-"  
{ TuW%zF/  
System.err.println("File Length is not known!"); rx (2yf  
} ~QvqG{bFB  
else if(nFileLength == -2) "\0v,!@  
{ p-1 3H0Kt  
System.err.println("File is not access!"); /mp*>sNr6  
} 8,0YD#x  
else oB74y  
{ DjSbyXvrg  
for(int i=0;i<nStartPos.length;i++) Gmf B  
{ )_/5*Ly@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u%~igt@x  
} GnP|x}YM  
for(int i=0;i<nEndPos.length-1;i++) @+atBmt  
{ J|&JD?  
nEndPos = nStartPos[i+1]; rvr-XGK36\  
} vN3Zr34  
nEndPos[nEndPos.length-1] = nFileLength; Oft4- 4$E  
} -V:"l  
} t3dlS`O  
TLoz)&@  
$Y5)(  
//启动子线程 Gs3LB/8?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :n /@z4#  
for(int i=0;i<nStartPos.length;i++) |&Ym@Jyj  
{ 6252N]*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f4L`.~b'hb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TEDAb >  
nStartPos,nEndPos,i); rj6#1kt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O(+phRwJ  
fileSplitterFetch.start(); }:Z#}8  
} H,N)4;F<c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =m5SK5vLKT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?_I[,N?@41  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NJNJjdD>  
nEndPos = " + nFileLength); J!:SPQ  
// fileSplitterFetch[nPos.length-1].start(); eds26(  
4wrk2x[  
XoA+MuDzpo  
//等待子线程结束 sg+uBCGB  
//int count = 0; }1>[  
//是否结束while循环 u%.$BD Hg  
boolean breakWhile = false; 0{#8',*}m?  
@:KJYm[  
26xXl|I  
while(!bStop) yRo- EP  
{ :O(^w}sle  
write_nPos(); jg?x&'u\)  
Utility.sleep(500); {J^lX/D  
breakWhile = true; byv[yGa`  
!"eIV@7  
WJ_IuX51'  
for(int i=0;i<nStartPos.length;i++) ( H6c{'&  
{ vap,y $C  
if(!fileSplitterFetch.bDownOver) sP ls zC[  
{ +|tC'gCnV  
breakWhile = false; 1x[)/@.'f  
break; }[M`uZ  
} Yot?=T};3{  
} D$T%\ P  
if(breakWhile) 6P';DB  
break; U^Xm)lL  
tO0!5#-VR  
,Jd ',>3  
//count++; W^s ;Bi+Nw  
//if(count>4) #lkM=lY'  
// siteStop(); (&!NC[n,  
} QcgfBsv96  
?:w1je7  
E8-P"`Qba  
System.err.println("文件下载结束!"); K# Jk _"W  
} F{UP;"8'  
catch(Exception e){e.printStackTrace ();} e @IA20  
} 5< ja3  
/ z}~zO  
Q:5KZm[[  
//获得文件长度 Ox@sI:CT  
public long getFileSize() 1bH;!J  
{ JJ%ePgWT  
int nFileLength = -1; mW:!M!kk  
try{ !H ~<  
URL url = new URL(siteInfoBean.getSSiteURL()); %*\es7m}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S%Us5`sd  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z ,EvQ8i  
)HvnoUO0  
d'Zqaaf k%  
int responseCode=httpConnection.getResponseCode(); ;INW`b~  
if(responseCode>=400) AZmb!}m+d  
{ O9r>E3-q  
processErrorCode(responseCode); SCz(5[MZJ  
return -2; //-2 represent access is error 2Y7)WPn  
} D&S26jrZ  
# 0Lf<NZ  
;s52{>&F]  
String sHeader; _%GGl$kH  
/IsS;0K%L  
.j-IX1Sa  
for(int i=1;;i++) {6}eN|4~#  
{ . Z%{'CC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #es9d3 ~\  
//Utility.log(in.readLine()); AGbhJ=tB  
sHeader=httpConnection.getHeaderFieldKey(i); >$ e9igwe  
if(sHeader!=null) C?2' +K  
{ 'z$Q rFW  
if(sHeader.equals("Content-Length")) mVR P~:+  
{ El@(mOu|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0)m(;>'70  
break; /FIE:Io  
} *<J*S#]  
} phgm0D7  
else l~ M_S<4n  
break; 2"B_At  
} yfm^?G|sW  
} ObiT-D?)g  
catch(IOException e){e.printStackTrace ();} -UD\;D?$  
catch(Exception e){e.printStackTrace ();} [B|MlrZ  
3:C oZ  
}6@pJ G  
Utility.log(nFileLength); B:+6~&,-  
Q*b]_0Rb  
w.0qp)}  
return nFileLength; D)d~3`=#  
} >>5NX"{  
WAS U0  
HTyLJe  
//保存下载信息(文件指针位置) B~_d^`  
private void write_nPos() +mp@b942*  
{ <-u8~N@43W  
try{ ^Y iJV7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %b"\bHH  
output.writeInt(nStartPos.length); Mv6 -|O  
for(int i=0;i<nStartPos.length;i++) dS<C@(  
{ L*~J%7  
// output.writeLong(nPos); 19j+lCSvH  
output.writeLong(fileSplitterFetch.nStartPos); 1Tm^  
output.writeLong(fileSplitterFetch.nEndPos); T16{_  
} $]/Zxd  
output.close(); l'TWkQ-  
} ruazOmnn~  
catch(IOException e){e.printStackTrace ();} 4A2?Uhp y  
catch(Exception e){e.printStackTrace ();} l@ap]R  
} oD$J0{K6  
.3MIcj=p  
/\W Qx e  
//读取保存的下载信息(文件指针位置) <0PT"ij  
private void read_nPos() ,.qMEMm  
{ 6CMub0   
try{ FGh] S-A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H `(exa:w  
int nCount = input.readInt();  $O dCL  
nStartPos = new long[nCount]; E,f>1meN=  
nEndPos = new long[nCount]; p^'3Odd|O  
for(int i=0;i<nStartPos.length;i++) L_K=g_]  
{ }sOwp}FV8X  
nStartPos = input.readLong(); pe{; ~-|6  
nEndPos = input.readLong(); y})70w@ +_  
} T9879[ZU\  
input.close(); :bC40@  
} hc'-Dh  
catch(IOException e){e.printStackTrace ();} Ed ,D8ND  
catch(Exception e){e.printStackTrace ();} 4M^G`WA}t9  
} D7S'*;F  
b/Xbs0q  
ME=/|.}D<  
private void processErrorCode(int nErrorCode) Vl2XDkhq  
{ Rh>}rGvCUN  
System.err.println("Error Code : " + nErrorCode); Ey4z.s'-l  
} qvv2O1c"A  
r{rQu-|.  
?2g`8[">  
//停止文件下载 HO' '&hz  
public void siteStop() tT79 p.z B  
{ rrCNo^W1  
bStop = true; P';?YV0  
for(int i=0;i<nStartPos.length;i++) @, Wvvh  
fileSplitterFetch.splitterStop(); %3$*K\Ai  
H8'Z#"h  
DHY@akhrK  
} Iy6$7~  
} 6}KZp~s  
//负责部分文件的抓取 '`Wwt.A  
**FileSplitterFetch.java E{n:J3_X^d  
*/ bk\yCt06y;  
package NetFox; @S 7sr-  
NMi45y(Y  
bcZf>:gVf  
import java.io.*; jr`Ess  
import java.net.*; -c}, :G"  
+(+Itmx2&  
7H|$4;X^  
public class FileSplitterFetch extends Thread { d`(@_czdF  
=lu/9 i6  
@_LN3zP  
String sURL; //File URL g=e71DXG2  
long nStartPos; //File Snippet Start Position <Engi!  
long nEndPos; //File Snippet End Position tu5*Qp\  
int nThreadID; //Thread's ID H~E(JLcU  
boolean bDownOver = false; //Downing is over 1Zi,b  
boolean bStop = false; //Stop identical z1Ov|Q`  
FileAccessI fileAccessI = null; //File Access interface |eWjYGwJa  
mSo_} je(  
SC- $B  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException UDL RCS8i  
{ !S_^94b@  
this.sURL = sURL; Q8_ d)t|  
this.nStartPos = nStart; wGZR31  
this.nEndPos = nEnd; \{EpduwZ  
nThreadID = id; "hy.GWF|*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0pSmj2/,.  
} STJJU]H  
5j-]EJb  
HdLH2+|P;D  
public void run() <2nZ&M4/s{  
{ 2 6>ZW4Z  
while(nStartPos < nEndPos && !bStop) -<_Ww\%8M  
{ ?SC[G-b  
#-GJ&m8  
XduV+$ 03  
try{ T t>8?  
URL url = new URL(sURL); +z$pg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Rd>B0;4  
httpConnection.setRequestProperty("User-Agent","NetFox"); a:_I  
String sProperty = "bytes="+nStartPos+"-"; M5trNSL&u  
httpConnection.setRequestProperty("RANGE",sProperty); A'%1ZQ33O  
Utility.log(sProperty); ~M(5Ho  
_fwb!T}$  
0Ld@H)  
InputStream input = httpConnection.getInputStream(); e*.b3 z  
//logResponseHead(httpConnection); VnT>K9&3  
SnYLdwgl  
H&yD*@  
byte[] b = new byte[1024]; G5FaYL.7  
int nRead; ZKdeB3D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1U,1)<z~u  
{ QL$S4 J"  
nStartPos += fileAccessI.write(b,0,nRead); /QEiMrz@6  
//if(nThreadID == 1) 1* ]Ev  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :F?x)"WoQ+  
} .uEPnzi  
8j4z{+'TQ  
bTSL<"(]N  
Utility.log("Thread " + nThreadID + " is over!"); c1xrn4f@a  
bDownOver = true; *;XWLd#  
//nPos = fileAccessI.write (b,0,nRead); x{&w?ng  
} w2xG_q  
catch(Exception e){e.printStackTrace ();} u@3y&b  
} A?*o0I  
} o5n^!gi4  
v-! u\  
c   c  
//打印回应的头信息 =-o'gL  
public void logResponseHead(HttpURLConnection con) W<<9y  
{ ~RD+.A  
for(int i=1;;i++) aSP4a+\*  
{ uZi.HG{<)  
String header=con.getHeaderFieldKey(i); &,.Y9; b  
if(header!=null) <s@-:;9~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O,.!2wVrN  
Utility.log(header+" : "+con.getHeaderField(header)); I_q~*/<h  
else >\!4Mk8  
break; Bu]t*$  
} LA[g(i 7  
} jp+_@S>  
Pe2wsR"_U  
dr<<!q /  
public void splitterStop() i7LJ&g/)  
{ cUO<.  
bStop = true; {ccIxL /~  
} 7_# 1Ec|;  
4c+$%pq5  
tW;:-  
} }Up.){.%  
DKm Z  
mw^7oO#  
/* Y[SU&LM  
**FileAccess.java |/ }\6L]  
*//文件访问(定位,写) y3<Y?M4  
package NetFox; 1h7+@#<:a  
import java.io.*; ]/cd;u  
n$(p-po  
|7@O( $b  
public class FileAccessI implements Serializable{ _u}4j9T  
Yif*"oO  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :h,`8 Di  
RandomAccessFile oSavedFile; ^JR;epVJ  
long nPos; A%\tiZe  
J`*iZvW#Bx  
Q# ?wXX47  
public FileAccessI() throws IOException M=]5WZO~A  
{ X _$a,"'~)  
this("",0); ; "3+YTtp  
} ~ np,_yI  
nNmsr=y5  
=IKEb#R/  
public FileAccessI(String sName,long nPos) throws IOException  oK 9'  
{ yGp z,X4x  
oSavedFile = new RandomAccessFile(sName,"rw"); y]e>E  
this.nPos = nPos; =xianQ<lK  
oSavedFile.seek(nPos); M|i o4+sy  
} l =IeJh  
y}08~L?2  
0D~ C 5}/4  
public synchronized int write(byte[] b,int nStart,int nLen) tD$lNh^  
{ 2-0$FQ@/  
int n = -1; +1 eCvt:,  
try{ Ejq#~Zhr!  
oSavedFile.write(b,nStart,nLen); kVS?RHR  
n = nLen; Ov82ibp_1  
} #2xSyOrmf  
catch(IOException e) ;o<m}bGaT  
{ Tx%VU8\?n  
e.printStackTrace (); b @;.F!x  
} pe&UQ C^  
]=F8p2w?  
fMf&?`V  
return n; kJ)gP2E  
} o0z67(N&g  
W2wpcc  
4O{Avt7C  
} nkeI60  
La[K!u\B  
UF__O.l__  
/* ]|:uU  
**SiteInfoBean.java vs&8wbS)  
*/ _U)%kY8  
package NetFox; i z]rFNR  
9j|gdfb%ml  
%zo= K}u  
public class SiteInfoBean { l+y-Fo@  
34|a:5c  
4-v6=gz.  
private String sSiteURL; //Site's URL 5 ZfP  
private String sFilePath; //Saved File's Path Me:{{-V4  
private String sFileName; //Saved File's Name ?PPZp6A3L=  
private int nSplitter; //Count of Splited Downloading File v@EQ^C2.&  
T,JA#Rk|1N  
UmKX*T9  
public SiteInfoBean() ?HR%bn gK  
{//nSplitter的缺省值为5 X21dX`eMN  
//default value of nSplitter is 5 $1*3!}_0  
this("","","",5); gH:ArfC  
} Wf>^bFb"$  
t0m*PJcF  
x|~zHFm6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $GF]/;\m  
{ 5@u~3jPd  
sSiteURL= sURL; ^O%9yEo  
sFilePath = sPath; $;D* n'8Fx  
sFileName = sName; ;8B.;%qkL  
this.nSplitter = nSpiltter; X,v4d~>]  
msk/p>{O  
$->d!  
} Q1tpCT  
6/mF2&&g  
%(LvE}[RJ  
public String getSSiteURL() Ygkv7>?,  
{ ^abD !8  
return sSiteURL; );}t&}  
} mrZ`Lm#>pS  
 ,-rB=|w  
]HvZ$  
public void setSSiteURL(String value) [6g O  
{ h{]#ag5`  
sSiteURL = value; w+f=RHX"{  
} QD<eQsvV  
jQtSwVDr  
:%tuNJjj  
public String getSFilePath() y @apJ;_R-  
{ v:d9o.h  
return sFilePath; Q~ 0Dfo w?  
} 68 x}w Ae  
MTmO>V&O  
q a!RH]B3  
public void setSFilePath(String value) ^9ng)  
{ 2@MN]Low  
sFilePath = value; Jgi Iq  
} (@ ]tG?I=  
H=. K  
+8^_D?*\n  
public String getSFileName() ^g!B.ll`  
{ vg^Myn   
return sFileName; :)P<jX-G  
} ,$Tk$  
Vm!i  
eoJ]4-WFq  
public void setSFileName(String value) \p6 }  
{ v["3  
sFileName = value;  wOHEv^,  
} .s};F/(diD  
Bxv8RB  
H~m]nV,r  
public int getNSplitter() #AncOo  
{ u7muaSy  
return nSplitter; `-D$Fsl  
} VG#Q;Xd}  
V.,bwPb{9  
_pSIJ3O  
public void setNSplitter(int nCount) FDq{M?6i  
{ (2%>jg0M  
nSplitter = nCount; 5\G)Q<A]*L  
} ~t9Mh^gij  
}  ? ICDIn  
/J;]u3e|  
k!13=Gh  
/* fq Y1ggL  
**Utility.java p\+6"28{_~  
*/ pF='jj51  
package NetFox; pbdF]>\  
#`j][F@N  
t F/nah  
public class Utility { (9z|a ,  
 ^Fp=y,D  
,o)4p\nV  
public Utility() VR v02m5  
{ AM?Ec1S #a  
lJj&kVHb  
MOLO3?H(  
} ji##$xC  
!Mil?^  
//线程睡眠 _m7c o :  
public static void sleep(int nSecond) {]M>Y%j48  
{ )G4rJ~#@  
try{ ;KS`,<^-  
Thread.sleep(nSecond); ;fx1!:;.  
} ]Wy.R6  
catch(Exception e) (j=DD6fC  
{ hfh.eL  
e.printStackTrace (); x3;jWg~'  
} xPvRQ  
} x@ 6\Ob  
Jy`G]]?  
//日志 DvJB59:_}  
public static void log(String sMsg) eE,;K1  
{ J=P;W2L  
System.err.println(sMsg); pe#*I/)b  
} Yhk6Uog{4  
2+&R" #I  
tnL."^%A2I  
public static void log(int sMsg) 1g81S_T .  
{ gA"<MI'y  
System.err.println(sMsg); +{Gw9h"5g*  
} N&N 82OG  
} <O bHf`Q  
M1gP R  
qSR? ,G  
/* =N;$0 Y(g  
**TestMethod.java fOJj(0=y  
*/ NlMQHma  
package NetFox; ,W8au"  
:@WLGK*u.  
Fu mn9  
public class TestMethod { @92gb$xT  
uc\.oG;~q  
Hp*gv/0  
public TestMethod() Es~DHX  
{ ///xx/weblogic60b2_win.exe >&[3  
try{ Q~h6J*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QglYU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); hOl=W |)v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `:R-[>5P8  
fileFetch.start(); F\Y,JUn[G  
} bWUS9WT  
catch(Exception e){e.printStackTrace ();} fX""xT NPi  
{ $X X  
Jtpa@!M  
} \ bC}&Iz6  
Kj=;>u  
RAdvIIQp:  
public static void main(String[] args) T[m ~6  
{ Q{8qm<0g  
new TestMethod(); SUo^c1)G  
} +=Yk-nJ  
} G tG&yeB  
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