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http断点续传简单实现(java)

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/* wZolg~dg  
**SiteFileFetch.java A7}|VV  
*/ 2yg'?tpj  
package NetFox; A=>6$L];'  
import java.io.*; Y+PxV*"a  
import java.net.*; f;I"tugO  
HAOrwJFqU  
kUBHK"}K  
public class SiteFileFetch extends Thread { LA(JA  
G5@@m-  
J~ rC  
SiteInfoBean siteInfoBean = null; //文件信息Bean W`rE\P  
long[] nStartPos; //开始位置 -CNv=vj 3  
long[] nEndPos; //结束位置 S 2` ;7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7 @Qlp$[F  
long nFileLength; //文件长度 CHSD 8D  
boolean bFirst = true; //是否第一次取文件 'Z%aBCM  
boolean bStop = false; //停止标志 = ft$j  
File tmpFile; //文件下载的临时信息 w4/)r-Z4I  
DataOutputStream output; //输出到文件的输出流 =|^W]2W$  
@MVZy  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) lY8Qy2k|  
public SiteFileFetch(SiteInfoBean bean) throws IOException    r3K:  
{ *8HxJ+[,[  
siteInfoBean = bean; 57%cN-v*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ",oUVl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X=}0+W  
if(tmpFile.exists ()) @)Y7GM+^  
{ ZjID<5#  
bFirst = false; k3eN;3#&  
read_nPos(); VZl0)YLK  
} / S^m!{  
else J*k=|+[  
{ >I ; #BE3  
nStartPos = new long[bean.getNSplitter()]; u8\QhUk'G  
nEndPos = new long[bean.getNSplitter()]; eJdQ7g[>  
} X'p%$HsMG  
[aUT #  
T7X2$ '  
u01^ABn  
} jYx(  
7q=xW6  
|#,W3Ik(l  
public void run() 2Nzcej  
{ 1e%Xyqb  
//获得文件长度 Vi~+C@96  
//分割文件 D*b|(Oi  
//实例FileSplitterFetch '\qr=0aW  
//启动FileSplitterFetch线程 FX%E7H  
//等待子线程返回 :jCaDhK  
try{ JG$J,!.\  
if(bFirst) vIv3rN=5vB  
{ rI$10R$+H  
nFileLength = getFileSize(); /v<8x?=  
if(nFileLength == -1) 2,`mNjHh  
{ ;hp; Rd  
System.err.println("File Length is not known!"); 5Uz(Bi  
} 1Ez A@3:{  
else if(nFileLength == -2) M#,+p8  
{ {[iQRYD0|  
System.err.println("File is not access!"); @K> Pw arl  
} |bUmkw  
else z<XS"4l?W  
{ RGOwm~a  
for(int i=0;i<nStartPos.length;i++) uQ)]g  
{ jl7-"V>j?;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |]^! 4[!U  
} \}c50}#0  
for(int i=0;i<nEndPos.length-1;i++) lsf?R'1  
{ eu/Sp3@v  
nEndPos = nStartPos[i+1]; s47"JKf"  
} ywBo9|%T  
nEndPos[nEndPos.length-1] = nFileLength; l;i u`  
} breVTY7 S  
} DSa92:M}  
Z 0^d o  
>eI(M $  
//启动子线程 epe}^Pl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Q4 S8NqE  
for(int i=0;i<nStartPos.length;i++) +[qy HTcG  
{ #{PNdINoU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /pEki g7M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $80/ub:R  
nStartPos,nEndPos,i); Wb$bCR#?<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HRh".!lxy  
fileSplitterFetch.start(); o$;x[US  
} 6jA Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4Yk (ldR~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OC.@C}u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M1\/ueOe  
nEndPos = " + nFileLength); 0}!lN{m?  
// fileSplitterFetch[nPos.length-1].start(); *?\Nioii  
<#Dc(VhT  
ppS`zqq $  
//等待子线程结束 J(GLPCO$K  
//int count = 0; l1-FL-1  
//是否结束while循环 MR: {Ps&,  
boolean breakWhile = false; C5?M/xj  
Nq3P?I(<  
6=D;K.!  
while(!bStop) 3._fbAN%e  
{ DO; 2)ZQ%  
write_nPos(); L"0L_G  
Utility.sleep(500); Fh;(1X75I  
breakWhile = true; '-_PO|}  
,y @3'~  
eA_4,"{  
for(int i=0;i<nStartPos.length;i++) 4v7RX  
{ ujedvw;sO  
if(!fileSplitterFetch.bDownOver) ^} #!?" Y  
{ KYaf7qy]  
breakWhile = false; D=$<E x^p  
break; ^TGHWCK!t  
} lw{|~m5`  
} c+c^F/  
if(breakWhile) Uyh#g^r  
break; VdgPb (  
7BnP,Nd"W  
P^ VNB  
//count++; b6ddXM\Z  
//if(count>4) 9#7z jrB  
// siteStop(); ~gD'up@$/  
} V8/o@I{U[  
nEYJ?_55  
[z9i v~  
System.err.println("文件下载结束!"); |SmN.*&(9  
} U;/ )V  
catch(Exception e){e.printStackTrace ();} @AFLFX]  
} J^T66}r[f,  
ub&1L_K  
L $~Id  
//获得文件长度 `y(3:##p  
public long getFileSize() n1|%xQBU@  
{ kW9STN  
int nFileLength = -1; bYfcn]N  
try{ B(5g&+{Lq~  
URL url = new URL(siteInfoBean.getSSiteURL()); 4$rO,W/&0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =/;(qy9.-R  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q\Eq(2p  
@{G(.S  
SzDi= lY  
int responseCode=httpConnection.getResponseCode(); *SZ<ori  
if(responseCode>=400) J.*=7zmw  
{ *4bV8T>0Z  
processErrorCode(responseCode); 7pNh|#Uv'  
return -2; //-2 represent access is error C*$/J\6xy  
} >4c 1VEi  
4^r}&9C ~  
ME.LS2'n  
String sHeader; }z[se)s  
Ic*Q(X  
sq%f%?(V  
for(int i=1;;i++) 0IZV4{  
{ vzU%5,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !Kis,e  
//Utility.log(in.readLine()); DbDpdC;  
sHeader=httpConnection.getHeaderFieldKey(i); /i<g>*82  
if(sHeader!=null) [3s~Z8 pP  
{ nz(OHh!}u  
if(sHeader.equals("Content-Length")) `'/8ifKz  
{ Z-p_hNb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \Z$*8z=  
break; n~h%K7 c  
} @AwH?7(b  
} |7argk+  
else j'W)Nyw$[  
break; rr*IIG&.5  
} E4{8 $:q=  
} \,WPFV  
catch(IOException e){e.printStackTrace ();} GM5::M]fS  
catch(Exception e){e.printStackTrace ();} mxIEg?r(  
m{g{"=}YR  
yC -4wn*  
Utility.log(nFileLength); C-M op,w  
xc!"?&\*  
\<5xf<{  
return nFileLength; o{qbbJBC  
} B`vV[w?  
tNjrd}8s  
1@am'#<  
//保存下载信息(文件指针位置) ~HELMS~-  
private void write_nPos() m4EkL  
{ ~[C m#c  
try{ ^^v!..V]J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .hvIq .vr  
output.writeInt(nStartPos.length); >7n(* M  
for(int i=0;i<nStartPos.length;i++) vXc<#X9  
{ /q=<OEC  
// output.writeLong(nPos); ^71sIf;+  
output.writeLong(fileSplitterFetch.nStartPos); qU"+0t4  
output.writeLong(fileSplitterFetch.nEndPos); d-Sm<XHu.  
} j8lbn|.  
output.close(); js{ RaR=  
} ]!/1qF  
catch(IOException e){e.printStackTrace ();} (qaY,>je]D  
catch(Exception e){e.printStackTrace ();} wm}i+ApK  
} A >e%rx  
H*Yy o ?  
<_D+'[  
//读取保存的下载信息(文件指针位置) j,~h:MT  
private void read_nPos() %l>^q`p  
{ D~-Ri`k.  
try{ P63f0 F-G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O@l`D`  
int nCount = input.readInt(); Z@1rs#  
nStartPos = new long[nCount]; 3+)i23[4=\  
nEndPos = new long[nCount];  z=!xN5  
for(int i=0;i<nStartPos.length;i++) [j5L}e!T  
{ Uu G;z5  
nStartPos = input.readLong(); N(D_*% 96  
nEndPos = input.readLong(); G,J$lT X  
} @Fo0uy\ G  
input.close(); o/Z?/alt4  
} O%)w!0  
catch(IOException e){e.printStackTrace ();} 6JJ%`Uojh  
catch(Exception e){e.printStackTrace ();} SW bwD/SN  
} ]86U -`p  
Ef#%4ky  
C\1Dy5  
private void processErrorCode(int nErrorCode) =!Ok079{[  
{ U5" C"+ 3  
System.err.println("Error Code : " + nErrorCode); / JlUqC  
} I(C_}I>Wb  
LNe- ]3wB  
!dZC-U~  
//停止文件下载 N/Z<v* i"  
public void siteStop() 4B) prQ3  
{ !bQ5CB  
bStop = true; zE<}_nA  
for(int i=0;i<nStartPos.length;i++)  MgA6/k  
fileSplitterFetch.splitterStop(); GR/ p%Y(  
90Q}9T\  
O4 [[9  
} 9Czc$fSSt  
} Ur_~yX]Mo  
//负责部分文件的抓取 m+CvU?)gJ  
**FileSplitterFetch.java [N{Rd[{QTL  
*/ z55P~p  
package NetFox; H1+G:TM  
sq*sbdE  
pm^[ve  
import java.io.*; NKO5c?ds  
import java.net.*; k5|h8%h8  
]  OR ]  
A07FjT5w8  
public class FileSplitterFetch extends Thread { 9"&HxyOfX  
z[l17+v  
;+cZS=  
String sURL; //File URL w J; y4  
long nStartPos; //File Snippet Start Position kZfO`BVL  
long nEndPos; //File Snippet End Position <wa}A!fu  
int nThreadID; //Thread's ID iB{O"l@w  
boolean bDownOver = false; //Downing is over i,,UD  
boolean bStop = false; //Stop identical ^IY1^x  
FileAccessI fileAccessI = null; //File Access interface \=1k29O  
=Bl#CE)X  
H~fZA)W 4Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $kg!XT{ V  
{ O]`CSTv'_  
this.sURL = sURL; j$BM$q/c  
this.nStartPos = nStart; F?3a22Zg#  
this.nEndPos = nEnd; #TRPq>XzD  
nThreadID = id; s<tdn[d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yo3'\I  
} FK0nQ{uB"  
RaKL KZn  
ob-y {x,R  
public void run() Q@nxGm  
{ 1jO/"d.8n  
while(nStartPos < nEndPos && !bStop) Za5*HCo  
{ Gw$U0HA[,  
o^biO!4,  
0fwo8NgX  
try{ T-uI CMEf  
URL url = new URL(sURL); 5_#wOz0u$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y ~xcJH  
httpConnection.setRequestProperty("User-Agent","NetFox"); c=h{^![$  
String sProperty = "bytes="+nStartPos+"-"; %\2 ll=p1  
httpConnection.setRequestProperty("RANGE",sProperty); Z#%4QIz ?  
Utility.log(sProperty); zN0^FXGD  
Y}Y2 Vx  
7C F-?M!  
InputStream input = httpConnection.getInputStream(); ?FxxH*>"  
//logResponseHead(httpConnection); M5CFW >T  
(ybKACx  
5l}v  
byte[] b = new byte[1024]; PohG y  
int nRead; ?=$a6o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,_D`0B6o  
{ %TP0i#J  
nStartPos += fileAccessI.write(b,0,nRead); <T,vIXwu+  
//if(nThreadID == 1) kO+Y5z6=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8 W79  
} zvL;.U  
]`b/_LJN$F  
M1-n  
Utility.log("Thread " + nThreadID + " is over!"); r1}YN<+,s  
bDownOver = true;  W^Wr  
//nPos = fileAccessI.write (b,0,nRead); =bi:<%"  
} g kT`C  
catch(Exception e){e.printStackTrace ();} c R*D)'/tl  
} ~K5eO-  
} X3 P~z8_  
Vr+X!DeY  
_Y?p =;  
//打印回应的头信息 Ys|tGU  
public void logResponseHead(HttpURLConnection con) .i) H1sD  
{ KY~p>Jmh  
for(int i=1;;i++) bx#GOK-  
{ qH1[Bs Ox  
String header=con.getHeaderFieldKey(i); 4$oNh)+/h  
if(header!=null) 40w,:$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N7v7b<6  
Utility.log(header+" : "+con.getHeaderField(header)); .y\j .p  
else HZX(kYV  
break; Kc$j<MRtv  
} kj{z;5-dl  
} J^m#984  
E_[|ZrIO&*  
~oWCTj-  
public void splitterStop() U-&dn%Sq  
{ |3<tDq@+  
bStop = true; W< _9*{|E;  
} R*|y:T,H  
q$L=G  
>x]b"@Hkw  
} CoO..  
gi\2bzWkbX  
hd0d gc  
/* 4jbqV  
**FileAccess.java <=[,_P6|  
*//文件访问(定位,写) FrT.<3  
package NetFox; 7Ko<,Kp2b  
import java.io.*; O9?t,1  
A/ZZ[B-  
WT;4J<O/  
public class FileAccessI implements Serializable{ E%8Op{zv_  
v'na{"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $a.fQ<,\X  
RandomAccessFile oSavedFile; k<(G)7'gm  
long nPos; #; ~`+[y?\  
?-C=_eZJ  
g?&_5)&  
public FileAccessI() throws IOException RdaAS{>Sk  
{ Jmg<mjq/G  
this("",0); Gmi ^2?Z(  
} R!{^qHb  
je LRS8];  
E}6q;"[  
public FileAccessI(String sName,long nPos) throws IOException H2[VZ&Pg  
{ 7~&  
oSavedFile = new RandomAccessFile(sName,"rw"); r*_z<^d  
this.nPos = nPos; !8YZ;l  
oSavedFile.seek(nPos); k@:M#?(F  
} Bu_/yKW  
t7#lRp&  
M:TN^ rA|  
public synchronized int write(byte[] b,int nStart,int nLen) 0> {&8:  
{  rG[iEY  
int n = -1; m-T@Og  
try{ >2v UFq`H  
oSavedFile.write(b,nStart,nLen); QiO4fS'~W  
n = nLen; r:N =?X`N  
} LL% Aw)Q`  
catch(IOException e) 1'Sr0 oEd3  
{ ZW+M<G  
e.printStackTrace (); {o>51fXc)  
} b^s978qn#  
>I*)0tE  
={g.Fn(_  
return n; t"# .I?S0  
} &k53*Wo  
Bk)E]Fk|  
}SD*@w  
} }Br=eaY  
hSkI]%  
k|uW~ I)  
/* 80m<OW1  
**SiteInfoBean.java ;[nomxu|?  
*/  vNWCv  
package NetFox; +|0f7RB+R  
IkWV|E  
oyw*Z_9~  
public class SiteInfoBean { a%nksuP3  
n1XJ uc~  
4C:-1gu7  
private String sSiteURL; //Site's URL LK>A C9ak<  
private String sFilePath; //Saved File's Path ?58,Ja  
private String sFileName; //Saved File's Name )\aCeY8o  
private int nSplitter; //Count of Splited Downloading File !m {d6C[  
1Jm'9iy3  
E^s<5BC;  
public SiteInfoBean() ~W/|RP7S  
{//nSplitter的缺省值为5 OKo)p`BX  
//default value of nSplitter is 5 Q H>e_  
this("","","",5); #!.26RM:P  
} wqnrN6$jf  
DjLSl,Z  
xVnk]:c  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ) t#>fnN  
{ ]`+J!G,  
sSiteURL= sURL; U3 t$h  
sFilePath = sPath; Z:(Zy  
sFileName = sName; ]&b>P ;j:  
this.nSplitter = nSpiltter; hnYL<<AA  
r'F)8%  
/`kM0=MMa  
} OK] _.v}  
rbt/b0ET  
DYf3>xh>xb  
public String getSSiteURL() HpKF7oJ'N  
{ 7jS`4,  
return sSiteURL; HuI?kLfj\  
} n9H4~[JiC  
ITssBB9  
w. c]   
public void setSSiteURL(String value) 2%Mgg,/~  
{ $-w&<U$E  
sSiteURL = value; "7z1V{ ;Y  
} /_(q7:<ZF  
e)M)q!nG  
TC* 78;r  
public String getSFilePath() mVsghDESJ)  
{ ` W} Bc  
return sFilePath; OF1fS\P<>  
} QKHAN{hJ  
1F,>siuh ,  
FW@(MIH  
public void setSFilePath(String value) zn)Kl%N^  
{ "?HDv WP=w  
sFilePath = value; "3;b,<0  
} 'eYM;\%('  
bXNM.K  
,9.-A-Yw  
public String getSFileName() }7HR<%< 7  
{ qdNt2SO  
return sFileName; ISDeLUihY  
} +1pY^#A  
5H^"  
rtn.^HF  
public void setSFileName(String value) &;2@*#,  
{ I .> SC  
sFileName = value; 5Tg[-tl  
} ozOvpi:k3%  
O<>cuW(l  
&_dM2lj{  
public int getNSplitter() #I9hKS{  
{ ""W*) rR   
return nSplitter; 1yd}F`{8UF  
} *l.tsICmbP  
@,Kl"i;  
|*5HNP  
public void setNSplitter(int nCount) efrVF5,y?  
{ xT8pwTO  
nSplitter = nCount; (x!Tb2mlk  
} ;r3Xh)k;  
} <$@*'i^7Ez  
YIn H8Ex  
vPce6 Cl*  
/* kn9e7OO##  
**Utility.java Yc3Rq4I'G  
*/ Wz+7CRpeP  
package NetFox; _ %gu<Ys  
EQ%,IK/  
De`p@`+<#~  
public class Utility { 5H79-QLd  
cVf}8qf)  
n\w2e_g;N  
public Utility() YwaWhBCIF  
{ ^W%#Elf)  
PBOZ^%k  
xe@11/F  
} Vo`,|3^  
8Cef ]@x  
//线程睡眠 rE?Fp  
public static void sleep(int nSecond) ]L/AW  
{ krMO<(x+  
try{ Ba#wW E  
Thread.sleep(nSecond); chakp!S=  
} ~5]%+G  
catch(Exception e) <,+nS%a  
{ &xLCq&j 1  
e.printStackTrace ();  Op5S'  
} ?2nF1>1  
} x2h5,.K  
}8eu 9~   
//日志 {?RVw`g&f  
public static void log(String sMsg) ;hb_jW-0W  
{ U["-`:>jfp  
System.err.println(sMsg); C8W4~~1S  
} 9D[Jn}E:  
/8Ru O  
0BrAgv"3a_  
public static void log(int sMsg) $_f"NE}  
{ 3%L@=q  
System.err.println(sMsg); ><wYk)0E  
} O6"S=o&  
} 6%a:^f]  
@8eQ|.q]Q  
*?3c2Jg=E  
/* Ku`u%5<  
**TestMethod.java $(fhO   
*/ .K`EflN  
package NetFox; u:w   
Ohn?>qQ  
d;hv_h  
public class TestMethod { s2`Qh9R  
H&So Vi_V  
o2rL&  
public TestMethod() S!8gy,7<J  
{ ///xx/weblogic60b2_win.exe G$A=Tu~  
try{ Sp/<%+2(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F[)5A5+:Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b6UpE`\z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YhQ%S}  
fileFetch.start(); N;S1s0FN  
} {1;R&  
catch(Exception e){e.printStackTrace ();} p6X-P%s  
!:wA\mAd  
l05'/duuJ  
} )skz_a}]8  
BcxALRWE  
"cz'|z`  
public static void main(String[] args) n?:%>Os$  
{ * zt?y  
new TestMethod(); -?p4"[  
} {Jc.49  
} Om_- #S  
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