http断点续传简单实现（java)

/* +_`7G^U?%  
**SiteFileFetch.java D=$)n_F  
*/ >ef6{UR
y<  
package NetFox; 6LZCgdS{  
import java.io.*; H+#FSdy#  
import java.net.*; t7pFW^&  
C^){.UGmJ  
/}$+uBgJm  
public class SiteFileFetch extends Thread { hb-%_c"kq  
b$7 +;I;  
zqku e%^?-  
SiteInfoBean siteInfoBean = null; //文件信息Bean 7^285)UQA  
long[] nStartPos; //开始位置 NHt\ U9l'  
long[] nEndPos; //结束位置 rjP/l6 ~'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @CoIaUVP  
long nFileLength; //文件长度 3^ClAE"8  
boolean bFirst = true; //是否第一次取文件 7=uj2.J6  
boolean bStop = false; //停止标志 JT?h1v<H]  
File tmpFile; //文件下载的临时信息 WAqINLdX  
DataOutputStream output; //输出到文件的输出流 _g8yDfcLG  
J4'eI[73  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） y7{?Ip4[  
public SiteFileFetch(SiteInfoBean bean) throws IOException IBGrt^$M  
{ LD?sh
"?b  
siteInfoBean = bean; @iiT
<
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _aphkeqd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); / 1RpM]d  
if(tmpFile.exists ()) #Y!a6h+  
{ VUc%4U{Cti  
bFirst = false; ("@!>|H  
read_nPos(); }\f0 A-  
} <b.D&  
else #Z#-Ht  
{ X2_=agEP  
nStartPos = new long[bean.getNSplitter()];
}ZI
7J  
nEndPos = new long[bean.getNSplitter()]; V9v
Tsmo(  
} hPh-+Hb  
\['Cj*ek  
r%_djUd  
U:`Kss`  
} =I<R!ZSN  
aXVFc5C\  
Qrv<lE1V;  
public void run() wkq 
66?  
{ .}t e
>]A*  
//获得文件长度 9$t(&z=  
//分割文件 GdwVtqbX  
//实例FileSplitterFetch e.C)jv6qr  
//启动FileSplitterFetch线程 x2EUr,7  
//等待子线程返回 F [M,]?   
try{ +vH4MwG$.&  
if(bFirst) J,hCvm  
{ mw!F{pw  
nFileLength = getFileSize(); '91/md5  
if(nFileLength == -1) `uFdwO'DD  
{ {ax:RUQxy  
System.err.println("File Length is not known!"); wJ]d&::@h  
} oDR%\VY6T  
else if(nFileLength == -2) ^~dWU>  
{ H|*m$|$,  
System.err.println("File is not access!"); dM5-;  
} ,}PgOJZ  
else e(sk[guvX  
{ bOB\--:]  
for(int i=0;i<nStartPos.length;i++) 7/H)Az@i45  
{ uH]OEz\H'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _w{Qtj~s|  
} !VJoM,b8  
for(int i=0;i<nEndPos.length-1;i++) pRqx`5 }  
{ ixFi{_  
nEndPos = nStartPos[i+1]; .8R@2c`}Cs  
} m*pJBZxd  
nEndPos[nEndPos.length-1] = nFileLength; w(/S?d  
} 6<
]lW  
} 2iOV/=+  
M+>u/fldV  
3Ul*QN{6  
//启动子线程 S!UaH>Rh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3<!7>]A  
for(int i=0;i<nStartPos.length;i++) n]9$:aLZ  
{ ]'}L 1r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )UR7i8]!0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VRMXtQ*1Dm  
nStartPos,nEndPos,i); E.TAbD&5(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,2q-D&)\Z  
fileSplitterFetch.start();  &HW9Jn  
} O?2DQY?jT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tc! #wd+u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); uYN`:b8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WLT"ji0w2  
nEndPos = " + nFileLength); *VcJ= b 2Y  
// fileSplitterFetch[nPos.length-1].start(); *p U x8yB  
~a:  
vQCy\Gi  
//等待子线程结束 Pal=F0-Q\  
//int count = 0; &pRREu:[4L  
//是否结束while循环 %Zi} MPx  
boolean breakWhile = false; $I
=~S[p  

WE?5ehEme  
]/Pn EU[  
while(!bStop) fex@,I&  
{ f8~_E  
write_nPos(); Upe%r
C(  
Utility.sleep(500); u_enqC3  
breakWhile = true; QV!up^Zso  
2ESo2  
>A= f1DF  
for(int i=0;i<nStartPos.length;i++) r;{.%s7  
{ RP"kC4~1  
if(!fileSplitterFetch.bDownOver) aOp\91  
{ wT@og|M  
breakWhile = false; #mF"1QW  
break; K-4PI+qQ\  
} _b 0&!l<  
} n S=W1zf  
if(breakWhile)  e
p8  
break; 1#x0q:6  
F
%|h;+5  
D~m*!w*  
//count++; aUp g u"
 
//if(count>4) ]9CFIh  
// siteStop(); w:0E(z  
} ^W^OfY  
@dKTx#gZ  
7I}uZ/N  
System.err.println("文件下载结束！"); Y]>t[Lo%  
} eFgA 8kY)  
catch(Exception e){e.printStackTrace ();} 7
dWS  
} ax`o>_)  
wMn i  
Tk
}]Gev  
//获得文件长度 j%kncGS  
public long getFileSize() TH;
hO).u  
{ TOt dUO  
int nFileLength = -1; & 21%zPm  
try{ ZVBXx\{s  
URL url = new URL(siteInfoBean.getSSiteURL()); L0,'m
S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2G7Wi!J  
httpConnection.setRequestProperty("User-Agent","NetFox"); &d!GImcxQ  
b}`TLn  
[JiH\+XLPs  
int responseCode=httpConnection.getResponseCode(); f|5co>Hk  
if(responseCode>=400) 7.Op<  
{ ?9/G[[(  
processErrorCode(responseCode); sRs>"
zAg  
return -2; //-2 represent access is error dV_G1'  
} i5Ggf"![  
23PGq%R  
**%37  
String sHeader; kVgTGC"L=  
P pb\6|*  
fhiM U8(&  
for(int i=1;;i++) V gWRW7Se  
{ {)XTk&"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 79gT+~z  
//Utility.log(in.readLine()); N8jIMb'<  
sHeader=httpConnection.getHeaderFieldKey(i); <~)P7~$d?p  
if(sHeader!=null) k[xSbs'D  
{ 0mE 0 j  
if(sHeader.equals("Content-Length")) pBH
Ra?Y5  
{ ^qs $v06  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tQ)qCk07  
break; _6Sp QW  
} B\~}3!j  
} )9g2D`a4  
else |Cv!,]9:r  
break; (.:e,l{U%  
} ah"o~Cbj  
} /uc>@!F  
catch(IOException e){e.printStackTrace ();} >MZ/|`[M  
catch(Exception e){e.printStackTrace ();} r!v\"6:OM  
<'u'#E@"sl  
X'ag)|5ot  
Utility.log(nFileLength); BGSw~6  
y29m/i:  
{ 6il`>=C  
return nFileLength; *4'"2"  
} {7[Ox<Ho  
N2G{<>=  
)=+|i3]U  
//保存下载信息（文件指针位置） 5pX6t  
private void write_nPos() 6nn*]|7  
{ itz,mrP  
try{ &C}*w2]0S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =_CzH(=f#  
output.writeInt(nStartPos.length); rq{$,/6.  
for(int i=0;i<nStartPos.length;i++) }BEB1Q}L  
{ )0
`C@um  
// output.writeLong(nPos); 81F9uM0  
output.writeLong(fileSplitterFetch.nStartPos); vM={V$D&  
output.writeLong(fileSplitterFetch.nEndPos); yi[x}ffdE  
} Rq-ZL{LR7  
output.close(); -"x$ZnHU  
}  mh%VrAq  
catch(IOException e){e.printStackTrace ();} mH(:?_KrS-  
catch(Exception e){e.printStackTrace ();} zLQx%Yg!  
} }MySaL>  
w0. u\  
P \I|,  
//读取保存的下载信息（文件指针位置） Pz7XAcPQ(  
private void read_nPos() X$ D6Ey  
{ kh<2BOV  
try{ ctQ/wrkU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :jf3HG  
int nCount = input.readInt(); &{:-]g\  
nStartPos = new long[nCount];  " bG2:  
nEndPos = new long[nCount]; u8^lB7!e/  
for(int i=0;i<nStartPos.length;i++) `[A];]  
{ V`5O{Gg  
nStartPos = input.readLong(); +@UV?"d  
nEndPos = input.readLong(); 42{~Lhxt  
} gYj'(jB  
input.close(); (
7Qo
 
} hH.G#-JO  
catch(IOException e){e.printStackTrace ();} ~*7]r`6\@  
catch(Exception e){e.printStackTrace ();} GgU/!@  
} SbZ6t$"  
[g,}gyeS(  
/v}`l  
private void processErrorCode(int nErrorCode) *8q.YuZ  
{ +ZYn? #IQ  
System.err.println("Error Code : " + nErrorCode); !D6]J
PX  
} !-bB559Nv  
2wn2.\v M  
KvSG;  
//停止文件下载 4i bc  
public void siteStop() buC{r,  
{ %O<BfIZ  
bStop = true; x-c"%Z|  
for(int i=0;i<nStartPos.length;i++) bt *k.=p  
fileSplitterFetch.splitterStop(); =1! 'QUc  
_F{C\}  
~&O%N  
} reVgqYp{{-  
} }JfjX'  
//负责部分文件的抓取 ?2a$*(  
**FileSplitterFetch.java /reX{Y  
*/ u2I Cl  
package NetFox;
@HW*09TG  
Efe 7gE'  
:Tc^y%b0  
import java.io.*; iLT}oKF2N;  
import java.net.*; 'qi}|I  
^Cmyx
3O^  
9F
lb|G%  
public class FileSplitterFetch extends Thread { RSds8\tk  
)jj0^f1!j  
J,G lIv.A  
String sURL; //File URL )0MB9RMk1  
long nStartPos; //File Snippet Start Position GILfbNcd  
long nEndPos; //File Snippet End Position }G=M2V<L  
int nThreadID; //Thread's ID 9L9sqZUB
 
boolean bDownOver = false; //Downing is over TC. ,V_  
boolean bStop = false; //Stop identical (hsl~Jf  
FileAccessI fileAccessI = null; //File Access interface )"LJ hLg  
m|# y >4  
Cw%{G'O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException c,22*.V/  
{ zi:BF60]=  
this.sURL = sURL;
ax2B ]L2  
this.nStartPos = nStart; .hiSw  
this.nEndPos = nEnd; -di o5a  
nThreadID = id;
mmsPLv6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o K@"f9  
} VL^EHb7  
d _ e WcI  
Q\)F;:|  
public void run() Y7nvHU|+o  
{ _wcNgFx  
while(nStartPos < nEndPos && !bStop) BY*Q_Et  
{ |%wX*zaf  
v<;Md-<  
Jwp7gYZ  
try{ M2|is ~  
URL url = new URL(sURL); CARzO7b\w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l,:F  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q&&@v4L  
String sProperty = "bytes="+nStartPos+"-"; m*;ERK  
httpConnection.setRequestProperty("RANGE",sProperty); v:p}B$  
Utility.log(sProperty); 4YHY7J  
zQA`/&=Y  
H"KCK6  
InputStream input = httpConnection.getInputStream(); OB7hlW  
//logResponseHead(httpConnection); F?cK-.  
}Lv;

!  
2tLJU Z1  
byte[] b = new byte[1024]; y]imZ4{/  
int nRead; }
%z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
aT<q=DO  
{ eFAnFJ][L  
nStartPos += fileAccessI.write(b,0,nRead); $cR{o#  
//if(nThreadID == 1) i!cCMh8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p7Cs.2>M>S  
} yNc2@  
KG@8RtHsQ  
8f7>?BUS,  
Utility.log("Thread " + nThreadID + " is over!"); |3%8&@ho  
bDownOver = true; 2%>FR4a  
//nPos = fileAccessI.write (b,0,nRead); oE~RySX  
} OTp]Xe/  
catch(Exception e){e.printStackTrace ();} \1`O_DF~o  
} :jx4{
V  
} AEuG v}#  
Y~Ifj,\  
IAEAhqp  
//打印回应的头信息 Ug`djIL  
public void logResponseHead(HttpURLConnection con) ^&)|sP  
{ b2]Kx&
!  
for(int i=1;;i++) jIF |P-  
{ Bf:Q2slqI  
String header=con.getHeaderFieldKey(i); B:
QHwzd
 
if(header!=null) XM}hUJJW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q^I\cAIB  
Utility.log(header+" : "+con.getHeaderField(header)); a6H%5N  
else ,PZ ge  
break;  9akH  
} x:7IIvP  
} {|\.i  
bi:8(Q$w:`  
E e]-qN*8  
public void splitterStop() B;WCTMy}  
{ q9NoI(]e  
bStop = true; d1kJRJ   
} iCyfOh  
0g\(+Qg^  
[r-p]"R  
} SB7c.H,  
>Se,;cB'/]  
[:V$y1  
/* vI]N^j2%  
**FileAccess.java _~pbqa,  
*//文件访问(定位，写) 2JFpZU"1  
package NetFox; 2-b6gc7  
import java.io.*; &OBkevg  
MW{8VH6+  
XUw/2"D'?  
public class FileAccessI implements Serializable{ e|9A716x  
c"Sq~X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #[a*rD%m  
RandomAccessFile oSavedFile; |)81
Lz  
long nPos; {iLT/i%  
y?:.;%!E  
4X$Qu6#i  
public FileAccessI() throws IOException -^
57oU  
{ qw8Rlws%  
this("",0); n(|^SH4$b  
} g*"P:n71  
]:f%l mEy  
\L\b$4$d  
public FileAccessI(String sName,long nPos) throws IOException
0RK!/:'  
{ D0q":WvE  
oSavedFile = new RandomAccessFile(sName,"rw"); |I|fMF2K  
this.nPos = nPos; R$Q.sE  
oSavedFile.seek(nPos); p$>l7?h  
} @o6L6Y0Naa  
r9lR|\Ax2U  
X76e&~  
public synchronized int write(byte[] b,int nStart,int nLen) }T$p)"  
{ f {"?%Ku#  
int n = -1; 0LKRN|@  
try{ s0_nLbWwO  
oSavedFile.write(b,nStart,nLen); aATA9V  
n = nLen; 9E tz[`|  
} -]=@s  
catch(IOException e) ((I%'  
{ N!|wo:  
e.printStackTrace (); 2Gdd*=4z  
} n}V_,:Z  
`KQvJjA6  
TU7'J  
return n; rt|7h>RQ  
} ^KELKv,_  
'eX 
'  
pD74+/DD  
} h*Pc=/p  
&f;K}WO  
5^KWCS7@  
/* OC:T O|S:4  
**SiteInfoBean.java 3Hm/(C  
*/ 7`YEH2  
package NetFox; l
PJ\-/>$z  
l$'wDhN*  
EyLuO-5  
public class SiteInfoBean { .%OR3"9@  
-R6)ROGl  
TuYCR>P[  
private String sSiteURL; //Site's URL #!m.!? O  
private String sFilePath; //Saved File's Path (3&?wy_l  
private String sFileName; //Saved File's Name -)/$M(Pu"  
private int nSplitter; //Count of Splited Downloading File FkRo _?  
wuqJr:q*#  
}#E[vRf  
public SiteInfoBean() =kqt  
{//nSplitter的缺省值为5 :Lug7bUVD  
//default value of nSplitter is 5  JSg$wi8  
this("","","",5); Y)a^(!<H<  
} evJ.<{M  
8h4'(yGQQW  
Yir [!{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0{[,E.  
{ C{bgkzr  
sSiteURL= sURL; BV+ Bk+  
sFilePath = sPath; S/I/-Bp~  
sFileName = sName; (2 a`XwR  
this.nSplitter = nSpiltter; .-X8J t  
.y,0[i V N  
~| 6[j<ziL  
} K}
U-w:{  
WSY}d Vr  
Zoc0!84<z  
public String getSSiteURL() EUgs6[w 4  
{ zZC9\V}R  
return sSiteURL; ivz5H(b  
} -[DOe?T  
wg]LVW}  
@jlw_ob2g  
public void setSSiteURL(String value) bNoW?8bZ  
{ z%LIX^q9  
sSiteURL = value; 4
I?^t"  
} 5lT*hF  
4X(H;  
CC^'@~)?  
public String getSFilePath() }Ys>(w  
{ AZ}Xj>=  
return sFilePath; Bng@-#`/  
} d$AWu{y  
5-xX8-ElYz  
E1U",CMU  
public void setSFilePath(String value) Ezv Y"T@  
{ /_#q@r4ZQ  
sFilePath = value; 6qd\)q6T&x  
} G<^{&E+=  
MO <3"@/,  
NS6:yX,/  
public String getSFileName() AlW66YAuQ  
{ 9lDhIqx0~  
return sFileName; =+?7''{>  
} 9v!1V,`j"  
=6|&Jt  
g^ i&gNDx  
public void setSFileName(String value) ; p{[1  
{ 1q1jZqno  
sFileName = value; \A6B,|@  
} :'&brp3ii=  
|WdPE@P  
3J438M.ka  
public int getNSplitter() yD6[\'%  
{ hzbw>g+  
return nSplitter; Wh2tNyS  
} v+=BCyT  
'1)$'
 
Eue~Y+K*b  
public void setNSplitter(int nCount) }sO&. ME  
{ 2oRg 2R}  
nSplitter = nCount; B\:%ufd ~  
} )sp4Ie  
} x`IEU*z#  
%O;bAC_M  
n`&U~s8w  
/* ["e3Ez  
**Utility.java U\<?z Dw  
*/ 7y@Pa&^8  
package NetFox; WYYa/,{9.  
*lw_=MXSK  
3az&<Pqb  
public class Utility { be^6i:  
8rS:5:Hi  
gH7|=W  
public Utility() 5K?IDt7A]  
{ N;j)
k;  
s1=G;  
&<U0ZvrsH  
} `&sH-d4v  
BV upDGh3  
//线程睡眠 !*. -`$x  
public static void sleep(int nSecond) .oUTqki  
{ 6s/&BR  
try{ ?+a,m# Yx  
Thread.sleep(nSecond); !|S43i&p  
} 8-%TC\:  
catch(Exception e) sCb=5uI  
{ =k0_eX0  
e.printStackTrace (); ~-J]W-n  
} Z//+Gw<'  
} sAD}#Zw$  
|CZ@te)>  
//日志 r_6ZO&  
public static void log(String sMsg) QR0Q{}wbqU  
{ 0C6-GKbZ  
System.err.println(sMsg); %k?U9pj^  
} ;Q*or2"!  
2M'[,Xe  
A/KJqiag  
public static void log(int sMsg) 4 bH^":i(  
{ pF Rg?-  
System.err.println(sMsg); y)!5R3b  
} $LFYoo
vX  
} ssxzC4m  
y6,/:qm  
9!}8UALD  
/* GV69eG3bX#  
**TestMethod.java Q;JM$a?5iV  
*/ ^R Fp8w(  
package NetFox; 474SMx$  
#(JNn'
fzq  
4k_vdz  
public class TestMethod { .QJ5sgmh  
c~uKsU  
4f'V8|QM{  
public TestMethod() Y+*0~xm4  
{ ///xx/weblogic60b2_win.exe O-I[igNl  
try{ q):5JXql~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T<p !5`B1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EYEnN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h+&OQ%e=8  
fileFetch.start(); `FTy+8mw  
} DBD%6o>]K  
catch(Exception e){e.printStackTrace ();} &NoS=(s,  
D9 |n)f  
MET'
(m  
} 9Ujo/3,Ak  
[8,yF D_U  
^ ALly2
  
public static void main(String[] args) 8'nVwb8I  
{ t@N=kV  
new TestMethod(); @jSYB+D  
} sVv xHkt@  
} ime\f*Fg  
点击下载更多相关资料