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http断点续传简单实现(java)

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/* 7t-*L}~WA  
**SiteFileFetch.java g)9JO6]  
*/ $]%<r?MUb-  
package NetFox; 4/2RfDp  
import java.io.*; 5&HT$"H :  
import java.net.*; &AQ;ze  
a(ux?V)E.  
%kZ~xbY  
public class SiteFileFetch extends Thread { l0caP(  
8 5%Pq:E  
u1;e*ty  
SiteInfoBean siteInfoBean = null; //文件信息Bean otz_nF;E  
long[] nStartPos; //开始位置 we\b]  
long[] nEndPos; //结束位置 2JA&{ch  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n4vXm  
long nFileLength; //文件长度 3j+=3n,  
boolean bFirst = true; //是否第一次取文件 nI*(a:  
boolean bStop = false; //停止标志 t?9 ;cS4  
File tmpFile; //文件下载的临时信息 ^3WIl ]  
DataOutputStream output; //输出到文件的输出流 %on9C`/  
9uw,-0*5  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) h nsa)@  
public SiteFileFetch(SiteInfoBean bean) throws IOException @0vC v  
{ Tw`c6^%^y  
siteInfoBean = bean; iM/*&O}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oDW<e'Jm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I(^jOgYU  
if(tmpFile.exists ()) d4p{5F7]^  
{ EtR@sJ<  
bFirst = false; })zB".  
read_nPos(); Jcalf{W6  
} J-, H6u  
else MdVCD^B  
{ m]0^  
nStartPos = new long[bean.getNSplitter()]; iM?I /\  
nEndPos = new long[bean.getNSplitter()]; 2H?I'<NoC  
} Bbl)3$`,  
PTzp;.  
'YZI>V*  
Y8J ;+h9  
} HzD>-f  
Sv7>IVC?@  
1H&?UP4=(  
public void run() r,u<y_YW  
{ 28T\@zi  
//获得文件长度 2vqmsl ?  
//分割文件 %A)-m 69  
//实例FileSplitterFetch h/ LR+XX!  
//启动FileSplitterFetch线程 RwAbIXG{0  
//等待子线程返回 Yg=E@F   
try{ Z:_m}Ya|  
if(bFirst) r/CEYEJ&X  
{ ><;l:RGK|  
nFileLength = getFileSize(); %aj7-K6:t  
if(nFileLength == -1) gx!*O<|e4  
{ f?=r3/AO  
System.err.println("File Length is not known!"); 1z})mfsh  
} CB*`  
else if(nFileLength == -2) O+G~Qp0b>  
{ vQ-i xh  
System.err.println("File is not access!"); 93Mdp9v+i  
} ^%n124  
else =bs.2aN&^  
{ Bs+c2R  
for(int i=0;i<nStartPos.length;i++) v>#Cg \  
{ F=oHl@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [2GXAvXsT  
} M1AZ}b c0]  
for(int i=0;i<nEndPos.length-1;i++) zW"~YaO%C  
{ @9OeC O  
nEndPos = nStartPos[i+1]; G 2%  
} o &BPG@n  
nEndPos[nEndPos.length-1] = nFileLength; OW+e_im}  
} QD$}-D[  
} [c&2i`C  
hl AR[]  
{l0,T0  
//启动子线程 /]ku$.mr\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {PN:bb  
for(int i=0;i<nStartPos.length;i++) `4VO&lRm  
{ &mh Ln4^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d^KBIz8$5l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^G}# jg.  
nStartPos,nEndPos,i); >Hdjsu5{N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vP3K7En  
fileSplitterFetch.start(); uz*d^gr}  
} E4Y "X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -'80>[}q/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xK$}QZ)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /a@ kS  
nEndPos = " + nFileLength); Y3-]+y%l  
// fileSplitterFetch[nPos.length-1].start(); q{a#HnZo"  
e{,!|LhpQ  
yJnPD/i  
//等待子线程结束 ]UK`?J=t2g  
//int count = 0; :&Qb>PH[  
//是否结束while循环 'n~fR]h}  
boolean breakWhile = false; sS C?io  
OI~}e,[2z  
]}BB/KQy^  
while(!bStop) Cf Qf7-  
{ y7CWBTH0>  
write_nPos(); 5B}3GBA  
Utility.sleep(500); ( FM4 ^#6  
breakWhile = true; @q,)fBZq  
Q 2*/`L}m\  
N1PECLS?  
for(int i=0;i<nStartPos.length;i++) O x{Q.l  
{ {J{1`@  
if(!fileSplitterFetch.bDownOver) ;!'qtw"CB  
{ m'd^?Qc  
breakWhile = false; ;xL67e%?  
break; h]qT1( I  
} F vj{@B!  
} + Qt[1Xq  
if(breakWhile) ]x1p!TSU  
break; ,,S9$@R  
K6E}";;  
!]yQ1@)*'  
//count++;  G]b8]3^  
//if(count>4) mj)PLZ]  
// siteStop(); L*P_vCC  
} }qG#N  
,aI,2U91  
d;{y`4p)s  
System.err.println("文件下载结束!"); qc3~cH.@  
} ])C>\@c6Gm  
catch(Exception e){e.printStackTrace ();} }xqXd%uz  
} $)Wb#B  
@\ }sb]  
TfL4_IAG.  
//获得文件长度 X&s7% ]n+  
public long getFileSize() :ztyxJv1  
{ w5,6$#  
int nFileLength = -1; RYt6=R+f  
try{ J=):+F=  
URL url = new URL(siteInfoBean.getSSiteURL()); 5lO^;.cS,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %8 qSv%_  
httpConnection.setRequestProperty("User-Agent","NetFox"); t')h{2&&!2  
`Z:3` 7c  
f7Zf}1|  
int responseCode=httpConnection.getResponseCode(); "MTWjW*6  
if(responseCode>=400) z4g+2f7h-X  
{ eO'xkm  
processErrorCode(responseCode); )`<6taKx@n  
return -2; //-2 represent access is error @YCv  
} zHV|-R  
~^x-ym5  
)U'yUUi  
String sHeader; IdF$Ml#[h  
4Hk6b09  
r ^MiRa  
for(int i=1;;i++) mk\i}U>`  
{ y<|)'(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h`lmC]X _  
//Utility.log(in.readLine()); lcCJ?!lsSW  
sHeader=httpConnection.getHeaderFieldKey(i); d Qai4e>[  
if(sHeader!=null) [yC"el6PM  
{ /tP7uVL R  
if(sHeader.equals("Content-Length")) Ae6("Oid  
{ ?ZaD=nh$mK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _-/x;C  
break; r sLc&2F  
} Q&gPa]z]}  
} @HvScg*Y  
else QNb>rLj52  
break; dhW<p 5  
} !_dR'  
} (`pNXQ0n  
catch(IOException e){e.printStackTrace ();} %@P``  
catch(Exception e){e.printStackTrace ();} [^M|lf   
_jmkl B  
"7d.i(vw  
Utility.log(nFileLength); a1|c2kT  
0V3gKd7  
EI\v  
return nFileLength; XCm\z9F  
} =-qf;5[|  
q`[K3p   
[fxuUmU  
//保存下载信息(文件指针位置) q3)wr%!k5D  
private void write_nPos() k}zd' /b  
{ \B&6TeR  
try{ lbS?/f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); e />:K' {  
output.writeInt(nStartPos.length); qOi5WX6F/  
for(int i=0;i<nStartPos.length;i++) GmbIFOT~  
{ # kEOKmO  
// output.writeLong(nPos); [sj VRW-  
output.writeLong(fileSplitterFetch.nStartPos); G'9{a'  
output.writeLong(fileSplitterFetch.nEndPos); /l6\^Xf{  
} H|`R4hAk  
output.close(); Yx),6C3  
} ?q!FG(  
catch(IOException e){e.printStackTrace ();} _88QgThb  
catch(Exception e){e.printStackTrace ();} Y\p $SN  
} 8R}K?+]  
@!<d0_dnC  
bDWeU}  
//读取保存的下载信息(文件指针位置) f05=Mc&)  
private void read_nPos() /$:U$JVb?l  
{ z]$>+MH_  
try{ 13a(FG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [4XC #OgA  
int nCount = input.readInt(); @KA1"Wb_  
nStartPos = new long[nCount]; ;v_V+t <$  
nEndPos = new long[nCount]; O:^'x*}  
for(int i=0;i<nStartPos.length;i++) l E^*t`+  
{ c#QFG1  
nStartPos = input.readLong(); qo_]ZKL44  
nEndPos = input.readLong(); JKy#j g:#  
} ue6d~8&  
input.close(); $KX[Zu%  
} EZib1g&:R/  
catch(IOException e){e.printStackTrace ();} 7~b!4x|Z  
catch(Exception e){e.printStackTrace ();} kaQ2A  
} 9tk" :ld  
9!}q{2j  
G52Z)^  
private void processErrorCode(int nErrorCode) `(DJs-xD  
{ MCU9O  
System.err.println("Error Code : " + nErrorCode);  s4$X  
} /.$L"u  
^PqMi:htc  
iCrxV{   
//停止文件下载 #6W,6(#^#  
public void siteStop() nU/;2=f<  
{ SY1GR n  
bStop = true; 0^#DNq*NQ  
for(int i=0;i<nStartPos.length;i++) p7C!G1+z  
fileSplitterFetch.splitterStop(); >vujZw_0>  
jK3\K/ob(  
,[`$JNc  
} *vnXlV4L  
} xmr|'}Pt[  
//负责部分文件的抓取 p)3nyN=|_  
**FileSplitterFetch.java :c7CiP  
*/ ?2ItB`<(  
package NetFox; ArzDI{1  
@B`Md3$7  
QU/3X 1W  
import java.io.*; tg85:  
import java.net.*; eN/G i<  
OVR?*"N_  
1h=D4yN  
public class FileSplitterFetch extends Thread { z(H?VfJo  
q4ipumy*  
=yqHC<8:  
String sURL; //File URL jPk c3dG +  
long nStartPos; //File Snippet Start Position vZkXt!%)  
long nEndPos; //File Snippet End Position |nY~ZVTt/  
int nThreadID; //Thread's ID [w+Q^\%bN  
boolean bDownOver = false; //Downing is over hNbIpi=  
boolean bStop = false; //Stop identical >]&X ^V%Q#  
FileAccessI fileAccessI = null; //File Access interface V=}1[^  
~R.dPUr  
eko]H!Ov(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `#6x=24  
{ |RhM| i  
this.sURL = sURL; B:9.e?t  
this.nStartPos = nStart; Sj-[%D*  
this.nEndPos = nEnd; IU!Ht>  
nThreadID = id; q*8lnk  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J%Mnjk^_\S  
} B~TN/sd  
@6&JR<g*t  
;h~er6&   
public void run() \%5MAQS  
{ r]LCvsVa  
while(nStartPos < nEndPos && !bStop) AhxGj+  
{ C1QV[bJK  
#w>~u2W  
7[KCWJ  
try{ "!L kp2\  
URL url = new URL(sURL); :a3 xvN-l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [B9;?G  
httpConnection.setRequestProperty("User-Agent","NetFox"); Gt~JA0+C)7  
String sProperty = "bytes="+nStartPos+"-"; nQ=aLV+'  
httpConnection.setRequestProperty("RANGE",sProperty); qLjT.7 .x  
Utility.log(sProperty); YG[w@u  
uLVBM]Qj  
'4u v3)P  
InputStream input = httpConnection.getInputStream(); !wh&>3~  
//logResponseHead(httpConnection); 'fY9a(Xt.  
HI!4  
({[,$dEa;  
byte[] b = new byte[1024]; #I%s 3  
int nRead; -Mf Q&U   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FtIa*j^G  
{ p2d\ZgWD=)  
nStartPos += fileAccessI.write(b,0,nRead); '*R%^RK  
//if(nThreadID == 1) 4%_M27bu[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R^8{bP  
} X9XI;c;b-  
[,g~m9  
sN/+   
Utility.log("Thread " + nThreadID + " is over!"); l [%lE  
bDownOver = true; (E!!pz  
//nPos = fileAccessI.write (b,0,nRead); Z'M`}3O  
} YYUe)j{T  
catch(Exception e){e.printStackTrace ();} #Ufo)\x  
} 213\ehhG<  
} >Ko[Xb-8^_  
`\b+[Nes  
*jCW.ZLY  
//打印回应的头信息 J(iV0LAZb  
public void logResponseHead(HttpURLConnection con) "2hh-L7ql  
{ |4C^$  
for(int i=1;;i++) LE;g 0s  
{ 6 hiC?2b{x  
String header=con.getHeaderFieldKey(i); h$fe -G#  
if(header!=null) vVVPw?Ww-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j[e,?!8;  
Utility.log(header+" : "+con.getHeaderField(header)); ;BBpN`T  
else lG"H4Aa>  
break; yV]xRaRr2  
} R$6qoqv{yG  
} }5bM1h#z  
+nU.p/cK+\  
3-x%wD.  
public void splitterStop() w*~Tm>U  
{ OJ,m1{9$}  
bStop = true; h?j_Ry  
} `X -<$x  
I3)Zr+  
5w<A;f  
} Yc#IFmC}  
UI?=]"  
J@#?@0]F  
/* c`kQvXx  
**FileAccess.java 2`Gv5}LfyR  
*//文件访问(定位,写) REA;x-u*  
package NetFox; KoHGweKl#  
import java.io.*; rt!r2dq"  
Ai kf|)D[  
$>w/Cy  
public class FileAccessI implements Serializable{ !j^&gRH  
bFGDgwe z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {o|k.zy  
RandomAccessFile oSavedFile; f/ahwz  
long nPos; "J19*<~  
, =y#m- 9  
ClQe4uo{  
public FileAccessI() throws IOException x';u CKWV  
{ CL9yEy"V  
this("",0); r"]'`qP,  
} W{Z^n(f4  
;l!`C':'  
yrr) y  
public FileAccessI(String sName,long nPos) throws IOException ?R'Y?b  
{ \}dyS8  
oSavedFile = new RandomAccessFile(sName,"rw"); ZYMw}]#((E  
this.nPos = nPos; s3 B'>RG}  
oSavedFile.seek(nPos); 6STp>@Ch]"  
} (Hp'B))2  
p>kq+mP2bc  
FFcB54ALTf  
public synchronized int write(byte[] b,int nStart,int nLen) hIU(P Dl4  
{ R7_VXvm>z  
int n = -1; D>#l-{d  
try{ npH?4S-8G  
oSavedFile.write(b,nStart,nLen); aC^$*qN-)  
n = nLen; ~5OL6Bi-q  
} ai-n z-;  
catch(IOException e) HW6.O|3  
{ ..qd,9H  
e.printStackTrace (); r>n" 51*  
} a.kbov(  
&ab|2*3?X  
K+d2m9C=  
return n; jRj=Awy  
} X6@wkrf-  
JUt7En;XE  
M+Uyb7  
} %1}6q`:w  
K-Mc6  
aMwB>bt  
/* i[nF.I5*f  
**SiteInfoBean.java X0$@Ik  
*/ MXZ>"G  
package NetFox; uA~slS Z  
B3 zk(RNZ  
:1aL ?  
public class SiteInfoBean { cxP&^,~  
y8 E}2/  
|g&ym Fc  
private String sSiteURL; //Site's URL [EZYsOr.  
private String sFilePath; //Saved File's Path s"~5']8  
private String sFileName; //Saved File's Name P LR0#).n  
private int nSplitter; //Count of Splited Downloading File s] au/T6b  
4IsG=7   
Pq p *  
public SiteInfoBean() w"zE_9I\  
{//nSplitter的缺省值为5 Q!'qC*Gyfn  
//default value of nSplitter is 5 Ew,T5GG  
this("","","",5); d8x%SQ!V  
} `8g7q 5  
WFv!Pbq,  
,.mBJ SE3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }iiHr|l3  
{ 0kDBE3i#  
sSiteURL= sURL; R: Z_g !h  
sFilePath = sPath; `jsEN ;<  
sFileName = sName; ERz;H!pU8  
this.nSplitter = nSpiltter; H[WQ=){  
lj[, |[X7`  
M\oVA=d\0  
} ?dq#e9  
dt,3"J  
&t}?2>:  
public String getSSiteURL() \~DM   
{ p]gT&[iJ  
return sSiteURL; `!4,jd  
} F4C!CUI  
+l 0g`:  
93Yn`Av;  
public void setSSiteURL(String value) M"Y0jQ(  
{ $P {K2"Oc  
sSiteURL = value; ]\c,BWC@e  
} + ,4" u  
e@]-D FG  
~)X[(T{  
public String getSFilePath() %w}gzxN^  
{ m,MSMw1p  
return sFilePath; dQ:cYNm  
} I9 64  
fg*@<'  
LJTo\^*  
public void setSFilePath(String value) 2YBIWR8z  
{ X_TiqV  
sFilePath = value; Lxe^v/LsT  
} ;sOsT?)7$  
w4};q%OBj  
\=e8%.#@J  
public String getSFileName() /bVZ::A&_  
{ YZwaD b  
return sFileName; x4kWLy7Sz  
} /@oLe[Mz$  
/DFV$+9  
}VCI=?-  
public void setSFileName(String value) ?UZ?NY  
{ Ao.\  
sFileName = value; 963aW*r  
} DVp5hR_$  
`C72sA{M.  
(/{aJV  
public int getNSplitter() z~oDWANP  
{ 4 gBp8*2  
return nSplitter; >)nS2b OE  
} t;q7t!sC]  
nvq3*  
X` r* ob  
public void setNSplitter(int nCount) :}}%#/nd  
{ iz^qR={bW  
nSplitter = nCount; IyUdZ,ba  
} Zj9c9  
} C*kK)6v `  
Kuw^qX"  
C"V%# K  
/* [3>GGX[Ic  
**Utility.java [0;buVU.  
*/ /R8p]  
package NetFox; yt0,^*t_  
V2d,ksKwn  
m@G i6   
public class Utility { <^R{U&Z@  
%:9oDK  
DC4C$AyW r  
public Utility() ^4Uw8-/9  
{ |`O5Xs1{B  
_F(P*[[&  
\_]En43mg  
} H=c`&N7E  
;O#g"8  
//线程睡眠 NTs7KSgZ  
public static void sleep(int nSecond) vp)Vb^K>  
{ /YKMKtE  
try{ OYL]j{  
Thread.sleep(nSecond); Z=z%$l  
} J >0b1  
catch(Exception e) 9q[;u[A8^  
{ W[''Cc.  
e.printStackTrace (); !7p}C-RZp  
} v syWm.E  
} |F$BvCg  
,_v|#g@{  
//日志 n.6T OF  
public static void log(String sMsg) `FF8ie8L  
{ D)b}f`  
System.err.println(sMsg); s'HD{W`  
} db72W x0>  
;@mRo`D`  
Sr Ca3PA  
public static void log(int sMsg) _'0 @%P%  
{ X"asfA[6K  
System.err.println(sMsg); },-*  
} Tenf:Hm/k  
} wEft4 o  
'o4p#`R:8  
{<$b Aj  
/* f'En#-?O  
**TestMethod.java aE VsU|  
*/ <O~WB  
package NetFox; \FmKJ\  
*s4\\Wb=  
a>mMvc"  
public class TestMethod { @\P4/+"9  
y*b3&%.ml  
;iYff N  
public TestMethod() u0s8yPA  
{ ///xx/weblogic60b2_win.exe T/r#H__`  
try{ p]G3)s@>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AC%JC+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MHj,<|8Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |pZUlQbb  
fileFetch.start(); m"2d$vro"  
} (K..k-o`.  
catch(Exception e){e.printStackTrace ();} E)N<lh  
8AFczeg[[  
3)Ac"nuyqH  
} O~Wt600{E  
)U t5+-UK  
T Eu'*>g  
public static void main(String[] args) MmTC=/j  
{ D1s4`V -  
new TestMethod(); .3qu9eP   
} .Nm su+s  
} T? ,P*l  
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