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http断点续传简单实现(java)

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/* nC^?6il  
**SiteFileFetch.java 0PD]#.+  
*/ D+d\<":  
package NetFox; +Ck F#H ~  
import java.io.*; Qfr%BQV  
import java.net.*; rxjMCMF  
^Afq)26D  
|&WeXVH E  
public class SiteFileFetch extends Thread { $+)2CXQe5  
;|e{J$  
qYc]Y9fi  
SiteInfoBean siteInfoBean = null; //文件信息Bean 72@raA#y  
long[] nStartPos; //开始位置 \k_0wt2x1  
long[] nEndPos; //结束位置 :<4:h.gO8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FW(y#Fmqs  
long nFileLength; //文件长度 :Eq=wbAw  
boolean bFirst = true; //是否第一次取文件 T1c2J,+}R  
boolean bStop = false; //停止标志 mw";l$Aq}  
File tmpFile; //文件下载的临时信息 [_Y\TdR  
DataOutputStream output; //输出到文件的输出流 nJ |O,*`O  
T;X8T  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) X64OX9:YF  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]0.? 1se  
{ X*VHi  
siteInfoBean = bean; R:kNAtK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y15KaoK?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fw,ruROqD  
if(tmpFile.exists ()) M@fUZh  
{ Dp!3uR ']p  
bFirst = false; ?I&ha-."  
read_nPos(); |3W\^4>,  
} .j:[R.  
else fg"@qE-;  
{ !fr /WxJ  
nStartPos = new long[bean.getNSplitter()]; .g_B KeU  
nEndPos = new long[bean.getNSplitter()]; -Czq[n=0(  
} dHc38zp  
~,KAJ7O_  
EU.vw0}u8  
j7=I!<w V  
} =wHHR1e  
LivPk`[  
I <`9ANe  
public void run() -~ytk=  
{ Y%:FawR  
//获得文件长度 <T{2a\i 4f  
//分割文件 )nU%}Z  
//实例FileSplitterFetch Fv=7~6~  
//启动FileSplitterFetch线程 bs$x%CR  
//等待子线程返回 jC> l<d_  
try{ o B;EP  
if(bFirst) L {(\k$>'  
{ ^l;nBD#nJ  
nFileLength = getFileSize(); Z<6xQTx  
if(nFileLength == -1) Vd^_4uqnV  
{ mz@`*^7?  
System.err.println("File Length is not known!"); cMOvM0f  
} :#v8K;C  
else if(nFileLength == -2) .f 4a+w  
{ '{WYho!  
System.err.println("File is not access!"); 5"xZ'M~=  
} j>X;a39|  
else 4a]m=]Hm  
{ CPc<!CC  
for(int i=0;i<nStartPos.length;i++) }c(".v#  
{ zlzr;7m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N8|=K_;&  
} "f\2/4EIl  
for(int i=0;i<nEndPos.length-1;i++) zq -"jpZG  
{ {^gb S  
nEndPos = nStartPos[i+1]; AEaT  
} &WAO.*:y  
nEndPos[nEndPos.length-1] = nFileLength; n~N>c*p  
} e_s9E{(  
} *f|9A/*B3  
T">-%-t  
2T/C!^iJ)  
//启动子线程 +N1oOcPC>C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?F'gh4  
for(int i=0;i<nStartPos.length;i++) y]Q G;  
{ hWpn~q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CL%?K<um  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), MVHj?  
nStartPos,nEndPos,i); &RP!9{F<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <y1V2Np  
fileSplitterFetch.start(); LcCb[r  
} +cv7]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;Vc@]6Ck  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6J0HaL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u38FY@U$  
nEndPos = " + nFileLength); JmdXh/X  
// fileSplitterFetch[nPos.length-1].start(); rhY>aj  
.b>1u3  
R)?b\VK2$  
//等待子线程结束 <(W0N|1v  
//int count = 0; yyZH1A  
//是否结束while循环  ,!_  
boolean breakWhile = false; 2h0I1a,7  
49n.Gc  
V3baEy>=z  
while(!bStop) (.\GI D+i  
{ 6$[7t?u  
write_nPos(); Bmuf[-}QW  
Utility.sleep(500);  9],;i7c  
breakWhile = true; 3;=nQ{0b  
:gv`)  
0L10GJ"(  
for(int i=0;i<nStartPos.length;i++) [o8a(oC  
{ 1\1a;Q3W%,  
if(!fileSplitterFetch.bDownOver) X1G[&  
{ fU^B 3S6X  
breakWhile = false; ^c{}G<U^  
break; O-B~~$g  
} O @fX +W?U  
} ,GEMc a,`  
if(breakWhile) j-|YE?AA  
break; GXB4&Q!C  
RL/~E xYC  
BX$t |t;!m  
//count++; Y W_E,A>h  
//if(count>4) <$Q\vCR  
// siteStop(); 4S|! iOY  
} X&DuX %x0  
|8}f  
ie+&@u  
System.err.println("文件下载结束!"); *>%34m93  
} ):?ype>  
catch(Exception e){e.printStackTrace ();} TN3, \qgV  
} T.="a2iS2  
8}h ^Frh  
?^P#P0  
//获得文件长度 Yf Udpa0  
public long getFileSize() m! &bK5+*  
{ K v"e\ E  
int nFileLength = -1; awuUaE  
try{ Z y@35;r  
URL url = new URL(siteInfoBean.getSSiteURL()); %Q"zU9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ga~N7  
httpConnection.setRequestProperty("User-Agent","NetFox"); _i~n!v  
]YkF^Pf!v  
[9UKVnX.V  
int responseCode=httpConnection.getResponseCode(); g6 EdCG.V  
if(responseCode>=400) xG0IA 7  
{ w=\Lw+X  
processErrorCode(responseCode); YXXUYi~!f  
return -2; //-2 represent access is error Z:aDKAboU  
} 9x.vz  
OqUEj 0X  
wqBGJ   
String sHeader; LA$uD?YA  
1Lwi?~!LI  
0K7]<\)  
for(int i=1;;i++) pVn 6>\xa  
{ lqA U5K{wQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); USu/Y29  
//Utility.log(in.readLine()); (FZL>  
sHeader=httpConnection.getHeaderFieldKey(i); ==(9P`\  
if(sHeader!=null) 7|PpAvMF  
{ nS[0g^}  
if(sHeader.equals("Content-Length")) b_ Sh#d&  
{ 0TU~Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uoFH{.)  
break; wE3^6  
} ba|x?kz  
} )/2* <jr  
else jo=XxA  
break; y=YD4m2W  
} &Th/Qv}[  
} td4*+)'FY  
catch(IOException e){e.printStackTrace ();} 94I8~Jj4  
catch(Exception e){e.printStackTrace ();} @]tFRV  
F0:Fv;  
* b>W  
Utility.log(nFileLength); wRf_IBhCd  
 1JgnuBX"  
mB;W9[  
return nFileLength; <oV _EZ  
} i:OD)l  
G,>tC`!  
/a17B  
//保存下载信息(文件指针位置) z_!P0`  
private void write_nPos() 8<3J!X+  
{ _Pa(5-S'KR  
try{ D9e"E1f+"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e%x$Cb:znn  
output.writeInt(nStartPos.length); 0 sVCTJ@  
for(int i=0;i<nStartPos.length;i++) zm2&\8J  
{ #QZg{  
// output.writeLong(nPos); Eag->mw/~  
output.writeLong(fileSplitterFetch.nStartPos); KJ,{w?p~ )  
output.writeLong(fileSplitterFetch.nEndPos); <;#d*&]  
} $y\'j5nk3  
output.close(); t-dN:1  
} JXBW0|8b  
catch(IOException e){e.printStackTrace ();} /7|u2!#Ui  
catch(Exception e){e.printStackTrace ();} 7~cN  
} 9cFFQM|o  
|U1X~\""  
&GwBxJ  
//读取保存的下载信息(文件指针位置) R`G%eG)+  
private void read_nPos() N<Rb<p%  
{ /4 RKA!W  
try{ n5 @H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s \#kqw\x  
int nCount = input.readInt(); 2uS&A \   
nStartPos = new long[nCount]; ujB:G0'r  
nEndPos = new long[nCount]; -`]B4Nt6  
for(int i=0;i<nStartPos.length;i++) ]jG%<j9A  
{ W5$jIQ}Bw  
nStartPos = input.readLong(); Z4}Yw{=f  
nEndPos = input.readLong(); Y[$[0  
} FOB9CsMe  
input.close(); 1>b kVA  
} W>dS@;E  
catch(IOException e){e.printStackTrace ();} 4a>z]&s  
catch(Exception e){e.printStackTrace ();} !OPK?7   
} _.J{U0N  
^w^cYM,  
W6&" .2  
private void processErrorCode(int nErrorCode) [:a;|t  
{ @`k!7? Sq  
System.err.println("Error Code : " + nErrorCode); Ee9u7TFT  
} s?=f,I  
NeCTEe|V  
#g4X`AHB  
//停止文件下载 xex/L%!Rj  
public void siteStop() 6;dB   
{ dSsMa3X[n  
bStop = true; zi2hi9A  
for(int i=0;i<nStartPos.length;i++) #$K\:V+ 4  
fileSplitterFetch.splitterStop(); P`[6IS#\S  
#1z}~1-  
S#!PDg  
} j!&g:{ e  
} +;`Cm.Iu  
//负责部分文件的抓取 /QHvwaW[  
**FileSplitterFetch.java o&rejj#  
*/ }pPxN@X  
package NetFox; mY(~94{d  
PPDm*,T.  
.pu]21m=  
import java.io.*; `iv,aQ '  
import java.net.*; |w6:mtaS  
+H/^RvUjF  
!s\-i6S>  
public class FileSplitterFetch extends Thread { @`$8rck`  
D?qA aq&4  
dy, ,x  
String sURL; //File URL T*J]e|aF  
long nStartPos; //File Snippet Start Position $>OWGueq64  
long nEndPos; //File Snippet End Position Wxb/|?,  
int nThreadID; //Thread's ID hX$k8 o0  
boolean bDownOver = false; //Downing is over GpN tvo~  
boolean bStop = false; //Stop identical }UHuFff,  
FileAccessI fileAccessI = null; //File Access interface 76} N/C  
0mH>fs 4  
oO$a4|&,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #`); UAf  
{ 7O;v5k~iQ  
this.sURL = sURL; nW{ ). P  
this.nStartPos = nStart; h<6@&yzp  
this.nEndPos = nEnd; ?t'O\n)M  
nThreadID = id; PS`v3|d}}}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (Pin9^`ALc  
} "%<Oadz ap  
6~&4>2b0f  
)]n:y M  
public void run() h/V0}|b  
{ ~ ${. sD\  
while(nStartPos < nEndPos && !bStop) d#vq+wR  
{ P`Anf_  
a)Qx43mOS  
o9<jj>R;  
try{ r?\hZ*|M  
URL url = new URL(sURL); @/`b:sv&*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <{9E.6G`n  
httpConnection.setRequestProperty("User-Agent","NetFox"); t{Q9Kv  
String sProperty = "bytes="+nStartPos+"-"; #";(&|7  
httpConnection.setRequestProperty("RANGE",sProperty); FX+Ra@I!  
Utility.log(sProperty); C \H%4p1r  
fE|([ ` !  
fHb0pp\[.  
InputStream input = httpConnection.getInputStream(); Y=x]'3}^  
//logResponseHead(httpConnection); O>Xyl4U  
$a(wM1S4  
`+\ +  
byte[] b = new byte[1024]; +<"sC+2  
int nRead; 9-Qu b+0o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IpB0~`7YI  
{ |mc!v*O  
nStartPos += fileAccessI.write(b,0,nRead); x>!#8?-h  
//if(nThreadID == 1) Av _1cvR:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o\g",O4-  
} p(v+j_ak  
i 0L)hkV  
;I:jd")  
Utility.log("Thread " + nThreadID + " is over!"); ljlQ9wb[s  
bDownOver = true; nr! kx)j  
//nPos = fileAccessI.write (b,0,nRead); 55zimv&DV  
} 4Xe3PdE  
catch(Exception e){e.printStackTrace ();} 'X<R)E  
} J5mMx)t@  
} Nf}G "!  
]gQgNn?  
qI) Yzc/  
//打印回应的头信息 T,!?+#  
public void logResponseHead(HttpURLConnection con) JyjS#BWi  
{ [q?{e1  
for(int i=1;;i++) -SlLX\>p  
{ 0V}%'Ec<e  
String header=con.getHeaderFieldKey(i); L/F!Y%=;[  
if(header!=null) ql2>C.k3L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2Af1-z^^K  
Utility.log(header+" : "+con.getHeaderField(header)); -$QzbRF5R  
else wg<DV!GZ  
break; H`9E_[  
} W-<C%9O!  
} mKvk6OC  
-Z-|49I/mN  
a^@6hC>sr  
public void splitterStop() MkRRBvk  
{ f}Mc2PQ-  
bStop = true; {qp XzxV  
} 8)\ ?6C  
;xN 4L  
dK#:io[Nz  
} HKP<=<8/O  
TXv3@/>ZlG  
E"b+Q  
/* 0%<Fc9#  
**FileAccess.java {uM*.]  
*//文件访问(定位,写) jri=UGf  
package NetFox; ^Cst4=:W  
import java.io.*; \uc]+nV!o  
V) a<)  
x<>#G~-  
public class FileAccessI implements Serializable{ ]L"jt8E  
?R(fxx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yS0!#AG  
RandomAccessFile oSavedFile; X"z^4?Aj+  
long nPos; K pDKIi  
~5N0=)  
5*/~) wN\U  
public FileAccessI() throws IOException -v/1R1$e1  
{ Ovxs+mQ  
this("",0); [1F.   
} pi*cO  
 Eh^c4x  
`+CRUdr  
public FileAccessI(String sName,long nPos) throws IOException jL8.*pfv  
{ 2`9e20  
oSavedFile = new RandomAccessFile(sName,"rw"); ~Y7>P$G)  
this.nPos = nPos; ^":UkPFCx:  
oSavedFile.seek(nPos); D|9xD  
} )[C]1N=tK  
b(Zh$86  
fa//~$#"{L  
public synchronized int write(byte[] b,int nStart,int nLen) 6ey{+8  
{ b}HL uX  
int n = -1; )\s{\u \  
try{ C< 3` ]l  
oSavedFile.write(b,nStart,nLen); g`i?]6c}jt  
n = nLen; ;.Zgt8/.  
} "oz : & #+  
catch(IOException e) T`mG+"O  
{ +DmfqKKbd  
e.printStackTrace (); 6!sC  
} 5Tag-+  
0ft81RK  
]$oo1ssZ1  
return n; Ngi] I#V z  
} oJ734v[X  
Xia4I* *  
O`j1~o<{  
} Lp.dF)C\  
%CV@FdB  
-N $4\yp  
/* :[xFp}w{  
**SiteInfoBean.java <'N"GLJ  
*/ }$i Kz*nx|  
package NetFox; ? l/VCEZP  
lHerEv<ja  
O?L6Ues  
public class SiteInfoBean { He vZ}.  
a> qB k})  
[U'I3x,  
private String sSiteURL; //Site's URL c|m*< i  
private String sFilePath; //Saved File's Path NXo$rf:  
private String sFileName; //Saved File's Name 4zKmoYt  
private int nSplitter; //Count of Splited Downloading File v+Mi"ZAd  
hGh91c;4  
l7 Pn5c  
public SiteInfoBean() 2T 3tKX  
{//nSplitter的缺省值为5 pse$S=  
//default value of nSplitter is 5 0Lb:N]5m8  
this("","","",5); opsjei@  
} xl2;DFiYt  
%])U(  
w_qX~d/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V1di#i:  
{ xKl\:}Ytp  
sSiteURL= sURL; AK$&'t+$}7  
sFilePath = sPath; *ThP->&:(  
sFileName = sName; 41G}d+  
this.nSplitter = nSpiltter; @=r YOQj |  
NW_i<#  
0RFBun{  
} ;$,b w5  
n=Ze p{^  
JOwm|%>3a  
public String getSSiteURL() 42$ pvw<  
{ 8k +^jj  
return sSiteURL; |ht:_l 8  
} 7md,!|m  
gZq _BY_U  
h'lqj0  
public void setSSiteURL(String value) |2ImitN0  
{ ":@\kw  
sSiteURL = value; ~'1gX`o:  
} &A}hx\_T  
B']-4X{SGa  
fk&>2[^&  
public String getSFilePath() rj}O2~W~4  
{ >PuQ{T I  
return sFilePath; hZ_@U?^  
} VO JA}$  
cY mgJBG  
Th_PmkvC  
public void setSFilePath(String value) B@w/wH  
{ /_SQKpic  
sFilePath = value; ibH!bS{  
} hXnfZx%  
A(eB\qG  
PH.g+u=v  
public String getSFileName() %>'Zy6C<j  
{ _=Z?5{7S >  
return sFileName; S5o,\wT  
} ?}RPn f  
qP{Fwn  
3c%_RI.  
public void setSFileName(String value) gFpub_  
{ f+!k:}K  
sFileName = value;  T<oDLJA\  
} R_W6}  
=U7P\s w2  
1-V"uLy@gC  
public int getNSplitter() P{,A%t  
{ UpaF>,kM  
return nSplitter; ee/3=/H|;  
} v]Fw~Y7l!  
(/7b8)g  
'Zs3b4n8  
public void setNSplitter(int nCount) iC{(vL0P+  
{ U ,NGV0  
nSplitter = nCount; OUq%d8 W  
} GQ(*k)'a  
} {p.^E5&  
.Hnhd/ c  
ayI<-s-  
/* oN2#Jh%dH  
**Utility.java ,eGguNA9  
*/ GKc?  
package NetFox; 7KesfH?  
> ^=n|%  
~R&rQJJeJ  
public class Utility { qj9[mBkP"  
U&i#cF   
Z`_x|cU?J  
public Utility() Lk)I;;  
{ C$p012D1  
L;lu)|b"  
i?ZVVE=r  
} !2Gua1z!CJ  
 ZC]|s[  
//线程睡眠 NH;e|8  
public static void sleep(int nSecond) f&j\gYWq  
{ A9lw^.  
try{ eC"k-a8j+  
Thread.sleep(nSecond); up{0ehr  
} 4E2#krE%  
catch(Exception e) Sg$\H  
{ ?q7MbQw  
e.printStackTrace (); DKJ_g.]X  
} b@c(Nv  
} AyWdJ<OU  
E[WU  
//日志 #.rkvoB0N  
public static void log(String sMsg) wz1nV}  
{ -oUGmV_  
System.err.println(sMsg); N5{v;~Cm}V  
} 2Z(t/Zp>  
X-tw)  
 )ut$644R  
public static void log(int sMsg) -RJ~Sky[  
{ =igTY1|af  
System.err.println(sMsg); ^vxx]Hji  
} ,,H;2xYf  
} F!3p )?  
ep~+]7\  
ber&!9  
/* 0$ON`Vsu|  
**TestMethod.java &@,lF{KTL  
*/ ZJF"Yo  
package NetFox; %%F, G  
Ell14Iki  
'z^'+}iyv  
public class TestMethod { je@&|9h  
(a0(ZOKH  
Mk~U/oq  
public TestMethod() e]nP7TIU  
{ ///xx/weblogic60b2_win.exe oKYa ?  
try{ 8o[gzW:Q)U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >;XtJJS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X&HYWH'@,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); - . o,bg  
fileFetch.start(); Rz&`L8Bz  
} Zr1"'+-  
catch(Exception e){e.printStackTrace ();} (u ^8=#  
g4=C]\1  
IqV" 4  
} Ux1j+}y  
-8l(eDm"m  
Gk+R, :  
public static void main(String[] args) |||m5(`S  
{ VXiU5n^  
new TestMethod(); )sW!s3>S>  
} pfu"vo(t_  
} |{(JUXo6K  
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