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http断点续传简单实现(java)

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/* BLf>_b Uk  
**SiteFileFetch.java g63(E,;;J  
*/ J7Hl\Q[D1  
package NetFox; @&3EJ1  
import java.io.*; i0kak`x0  
import java.net.*; `*cxH..  
b;W3j   
CMG&7(MR  
public class SiteFileFetch extends Thread { H0gbSd+  
t[;LD_  
 JWhdMU  
SiteInfoBean siteInfoBean = null; //文件信息Bean Val|n*%  
long[] nStartPos; //开始位置 %XoiVlT@:  
long[] nEndPos; //结束位置 { VfXsI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r Iu$pZO  
long nFileLength; //文件长度 7yH"l9Z  
boolean bFirst = true; //是否第一次取文件 y@:h4u"3  
boolean bStop = false; //停止标志 ^?7-r6  
File tmpFile; //文件下载的临时信息 CR`Q#Yi  
DataOutputStream output; //输出到文件的输出流 ):68%,  
Q4!_>YZ  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) n&;85IF1  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0$)>D==  
{ Ky!Y"   
siteInfoBean = bean; i$:*Pb3mV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p{ Yv3dNl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^Y>F|;M#  
if(tmpFile.exists ()) L~rBAIdD  
{ p;59?  
bFirst = false; m '|b GV  
read_nPos(); t?x<g<PJ4  
} ^T;*M_  
else iohop(LZ  
{ fF$<7O)+]  
nStartPos = new long[bean.getNSplitter()]; 0w \zLU  
nEndPos = new long[bean.getNSplitter()]; U9:zVy  
} ,]ma+(|  
D3Ig>gKo?m  
5T_n %vz  
Ic"ybj`  
} 'KS,'%  
EyD=q! ZVZ  
['X]R:3h  
public void run() 6 Z6'}BDP  
{ B:;pvW]  
//获得文件长度 ?wiC Q6*$  
//分割文件 b9KP( _  
//实例FileSplitterFetch  3s,g*  
//启动FileSplitterFetch线程 xd q?/^E  
//等待子线程返回 +j`5F3@  
try{ av}k)ZT_  
if(bFirst) e#L8X {f  
{ \ =?a/  
nFileLength = getFileSize(); w(*vj  
if(nFileLength == -1) TluW-S  
{ UqFO|r"M  
System.err.println("File Length is not known!"); h:b)Wr  
} R[h9"0Y^  
else if(nFileLength == -2) xjuN-  
{ xaq-.IQAM$  
System.err.println("File is not access!"); Cx(>RXVoJ,  
} $<dH?%!7  
else AW%#O\N  
{ <y2U3; t  
for(int i=0;i<nStartPos.length;i++) fn jPSts0  
{ _JzEGpeG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u<7/0;D#+  
} *KZYv=s,u  
for(int i=0;i<nEndPos.length-1;i++) ?yrX)3hyH  
{ =t#llgi~  
nEndPos = nStartPos[i+1]; iW]j9}t  
} q 6:dy  
nEndPos[nEndPos.length-1] = nFileLength;  &=@IzmA  
} 'Vzp2  
} '1P2$#  
="1Ind@w!  
%B2'~|g  
//启动子线程 *)$Uvw E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .;y.]Z/;  
for(int i=0;i<nStartPos.length;i++) m)ky*"(  
{ ^b4 9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #px+;k 5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1E[J%Rh\ l  
nStartPos,nEndPos,i); .KB^3pOpx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /kZebNf6H  
fileSplitterFetch.start(); O40?{v'  
} s [RAHU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G, }Yl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2RVN\?s:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {g'(~ qv  
nEndPos = " + nFileLength); IA fc T!{  
// fileSplitterFetch[nPos.length-1].start(); g+8OekzB5  
[SjqOTon{  
ttaM.  
//等待子线程结束 i^/T  
//int count = 0; MD}w Y><C  
//是否结束while循环 !j8FIY'[  
boolean breakWhile = false; @+&LYy72  
.Yamc#A-  
bWjc'P6rx  
while(!bStop) sNbxI|B  
{ NlA,'`,  
write_nPos(); a kkNI3  
Utility.sleep(500); fF!Yp iI"  
breakWhile = true; ]{;gw<T  
AwCcK6N1  
-mbt4w  
for(int i=0;i<nStartPos.length;i++) z 4e7PW|  
{ *^pR%E .  
if(!fileSplitterFetch.bDownOver) 3<e=g)F  
{ lB8-Z ow  
breakWhile = false; S^JbyD_yoh  
break; vO H4#  
} o@_q]/Mh  
} ^)470K`%)  
if(breakWhile) 0.Q Ujw  
break; RF?`vRZOe  
v8wq,CYV  
G~]Uk*M q  
//count++; #JqB ;'\  
//if(count>4) Zcey|m*|  
// siteStop(); cRC6 s8  
} ~V:\ _{mE  
(fhb0i-  
DcS+_>a\{l  
System.err.println("文件下载结束!"); n.}ZkG0`  
} A\*>TN>s  
catch(Exception e){e.printStackTrace ();} W Tcw4  
} `{8K.(])s!  
!K#qeY}  
%6t:(z  
//获得文件长度 `C,n0'PL.  
public long getFileSize() HRpte=`q  
{ xW+6qtG`  
int nFileLength = -1; 8%:Iv(UMk  
try{ [ XN={  
URL url = new URL(siteInfoBean.getSSiteURL()); 1wii8B6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9v#CE!  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mg+2. 8%  
YByLoM*  
wC"FDr+  
int responseCode=httpConnection.getResponseCode(); M^A48u{,"  
if(responseCode>=400)  X hR4ru`  
{ TbMW|0 #w  
processErrorCode(responseCode); 9FF0%*tGo  
return -2; //-2 represent access is error {aZ0;  
} xKbXt;l2  
v<k?Vu  
%q"%AauJR  
String sHeader; ?C]vS_jAh  
;2G*wR  
S*pGMuui  
for(int i=1;;i++) )Dm s  
{ HH`'*$]7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {.`vs;U  
//Utility.log(in.readLine()); )w em|:H  
sHeader=httpConnection.getHeaderFieldKey(i); "%)qRe  
if(sHeader!=null) SV4E0c>  
{ Z<oaK  
if(sHeader.equals("Content-Length")) vN}#Kc\  
{ W@>% {eE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xl{=Y< ;  
break; 7Y lchmd  
} \eTwXe]Pv  
} j\yjc/m  
else 0J*??g-n  
break; =<C: d  
} P-[-pi@  
} UhF-K#Z9  
catch(IOException e){e.printStackTrace ();} /*~EO{o  
catch(Exception e){e.printStackTrace ();} +SzU  
&/Z /Y ]  
f^3*)Ni  
Utility.log(nFileLength); a9e>iU  
+D6YR$_<  
2F[ q).  
return nFileLength; E#RDqL*J  
} sQ3 [<  
%jJG>T  
Xxj- 6i  
//保存下载信息(文件指针位置) z9f-.72"X  
private void write_nPos() #!B4 u?"m  
{ Ha#= (9.  
try{ >fG3K`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UsG~row:!  
output.writeInt(nStartPos.length); @ )F)S 7  
for(int i=0;i<nStartPos.length;i++) KRbvj  
{ !vi> U|rh  
// output.writeLong(nPos); `?H]h"{7Q  
output.writeLong(fileSplitterFetch.nStartPos); 2y\E[jA  
output.writeLong(fileSplitterFetch.nEndPos); umBICC]CU  
} J`Q>3] wL  
output.close(); &N9 a<w8+  
} Cl.x'v  
catch(IOException e){e.printStackTrace ();} ^S<Y>Nm]  
catch(Exception e){e.printStackTrace ();} u2 I*-K  
} BU)U/A8iS  
D>r&}6<  
Z3e| UAif  
//读取保存的下载信息(文件指针位置) &;6`)M{*}  
private void read_nPos() O^PKn_OJ  
{ J-:.FKf\5l  
try{ k8yEdi`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OF>mF~  
int nCount = input.readInt(); ?PxP% $hS  
nStartPos = new long[nCount]; .~db4d]  
nEndPos = new long[nCount]; Y|m +dT6  
for(int i=0;i<nStartPos.length;i++) *-WpZGh  
{ }v;V=%N+v  
nStartPos = input.readLong(); P;y45b  
nEndPos = input.readLong(); mM~qBrwL  
} Mexk~z A^  
input.close(); t,Lrfv])  
} T"Y+m-<%  
catch(IOException e){e.printStackTrace ();} ^#-l q)  
catch(Exception e){e.printStackTrace ();} o 11jca|  
} # +>oZWVc  
>=lC4Tu  
qbr$>xH  
private void processErrorCode(int nErrorCode) mUC)gA/  
{ H'5)UX@LP  
System.err.println("Error Code : " + nErrorCode); NX.6px17  
} je-!4r,  
%Xd[(Q)  
Y Uc+0  
//停止文件下载 JG. y,<xW  
public void siteStop() M^Yh|%M  
{ bP#:Oi0v`  
bStop = true; \w>y`\6mX  
for(int i=0;i<nStartPos.length;i++) "Y.tht H  
fileSplitterFetch.splitterStop(); 2|y"!JqE1  
m 0C@G5  
hag$GX'2k  
} @7c?xQVd$  
} 6wRd<]C  
//负责部分文件的抓取 l4YbKnp]  
**FileSplitterFetch.java N% B>M7-=  
*/ Es`Px_k  
package NetFox; F<1fX7c  
nAato\mM  
nPtuTySG  
import java.io.*; qwcD`HV,  
import java.net.*; iMh#TUlQEQ  
aK~8B_5k8  
[aLI '  
public class FileSplitterFetch extends Thread { ,Vax&n+J  
<=&`ZH   
I{&[[7H  
String sURL; //File URL QL/(72K  
long nStartPos; //File Snippet Start Position bWS&Yk(  
long nEndPos; //File Snippet End Position  A@('pA85  
int nThreadID; //Thread's ID xH,a=8&9  
boolean bDownOver = false; //Downing is over E=Bf1/c\  
boolean bStop = false; //Stop identical { uFO/  
FileAccessI fileAccessI = null; //File Access interface #z%fx   
fbvL7* (  
D) P._?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException # w4-aJ  
{ ^ +\dz  
this.sURL = sURL; `RW HN/U  
this.nStartPos = nStart;  }v{LRRi  
this.nEndPos = nEnd; MchA{p&Ol  
nThreadID = id; YP<ms  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^DLfY-F+j  
} |-ALklXr  
e%M;?0j  
d1T!+I  
public void run() ,qwuLBW  
{ R\f+SvE  
while(nStartPos < nEndPos && !bStop) cVpp-Z|s8  
{ j;r-NCBnz  
+`0k Fbx  
G_JA-@i%  
try{ Y@iS_lR  
URL url = new URL(sURL); XT*sGM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Tidn-2L73O  
httpConnection.setRequestProperty("User-Agent","NetFox"); pki%vRY  
String sProperty = "bytes="+nStartPos+"-"; S hWJ72c  
httpConnection.setRequestProperty("RANGE",sProperty); kZ:ZtE  
Utility.log(sProperty); 8,%^ M9zBP  
hfTY.  
B[Scr5|  
InputStream input = httpConnection.getInputStream(); ~~P5k:  
//logResponseHead(httpConnection); kD%( _K5  
l'qg8  
gD?l-RT>  
byte[] b = new byte[1024]; "k@/ 3  
int nRead; z<;HQX,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j$:~Rek  
{ uzPV To|=  
nStartPos += fileAccessI.write(b,0,nRead); qDIZJ h  
//if(nThreadID == 1) 3hH<T.@)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V!=,0zy~Z  
} 3"i-o$P  
N+xP26D8  
J@'wf8Ub  
Utility.log("Thread " + nThreadID + " is over!"); t{kG<J/l  
bDownOver = true; e T{ 4{  
//nPos = fileAccessI.write (b,0,nRead); 'H!Uh]!  
} m0SlOgRsk  
catch(Exception e){e.printStackTrace ();} \\qZl)P_  
} X_h}J=33Q  
} %> eiAB_b  
8<.Oq4ku  
{\5  
//打印回应的头信息 L2z[   
public void logResponseHead(HttpURLConnection con) n\53wh@+  
{ o.!Dq7 R  
for(int i=1;;i++) KpGhQdR#  
{ eMsd37J  
String header=con.getHeaderFieldKey(i); aFYIM`?(  
if(header!=null) GVn!O1jio  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); IJ"q~r$  
Utility.log(header+" : "+con.getHeaderField(header)); NLqzi%s  
else TJRCH>E[a  
break; 0h_|t-9j  
} cwg"c4V  
} 6_Y,eL]"  
Q2gq}c~  
/4Gt{yg Sr  
public void splitterStop() fZF@k5*\  
{ ez$(c  
bStop = true; %h@EP[\  
} :o3N;*o>)0  
8ib:FF(= u  
Nf\LN$ &8  
} #6=  
w?[upn:K  
&u !,Hp  
/* [W&T(%(W-  
**FileAccess.java O0.*Pmt  
*//文件访问(定位,写) ;=z:F<Y  
package NetFox; ZECfR>`x  
import java.io.*; 1qA;/-Zr<o  
xJe%f\UDu  
})%{AfDRF  
public class FileAccessI implements Serializable{ ]f_p 8?j"  
2>%=U~5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o]V^};B  
RandomAccessFile oSavedFile; W=?<<dVYD  
long nPos; a7opCmL  
g_bLl)g<  
'g\4O3&_  
public FileAccessI() throws IOException _[BP 0\dPW  
{ J&_n9$  
this("",0); PJ#,2=n~  
} ,P0) 6>  
wCBplaojJ  
TWTb?HP  
public FileAccessI(String sName,long nPos) throws IOException [a(#1  
{ 3v-~K)hl?  
oSavedFile = new RandomAccessFile(sName,"rw"); YmG("z  
this.nPos = nPos; pb,d'z\S  
oSavedFile.seek(nPos); tH4B:Bgj!  
} -9?]IIVb  
R=?[Nz  
n@3>6_^rwT  
public synchronized int write(byte[] b,int nStart,int nLen) ~W/z96' 5  
{ EU#^7  
int n = -1; (9)Q ' 'S  
try{ 6S #Cl>v  
oSavedFile.write(b,nStart,nLen); l[J8!u2Xp  
n = nLen; i6Gu@( 8Q  
} /-s6<e!  
catch(IOException e) r JB}qYD  
{ #-J>NWdt  
e.printStackTrace (); kx^/*~ex  
} ar,7S&s H  
j>kqz>3  
Zd+bx*rD  
return n; t{>q|0  
} wd6owr  
<UCl@5g&  
K sCyFp  
} hbn([+xY  
j<$2hiI/?&  
jEwIn1  
/* <VE@DBWyl~  
**SiteInfoBean.java !R$`+wZ62  
*/ F0# 'WfM#  
package NetFox; \2z>?i)  
[F7hu7zY8  
Ys7]B9/1O  
public class SiteInfoBean { ?7A>+EY  
d(K +);!  
PvL[e"p  
private String sSiteURL; //Site's URL a'T;x`b8U,  
private String sFilePath; //Saved File's Path 4M T 7`sr  
private String sFileName; //Saved File's Name i#O SC5ZI  
private int nSplitter; //Count of Splited Downloading File 7 8,n%=nG  
gG uO  
jiGTA:v  
public SiteInfoBean() y7<|_:00  
{//nSplitter的缺省值为5 E-FUlOG&  
//default value of nSplitter is 5 Gm`8q}<I  
this("","","",5); (k P9hcV  
} QGz|*]  
Nboaf  
4ppz,L,4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F"kAkX>3}  
{ V[V[~;Py  
sSiteURL= sURL; ~6gPS 13  
sFilePath = sPath; C# pjmT_  
sFileName = sName; D+c>F5  
this.nSplitter = nSpiltter; u&e~1?R  
s#MPX3itK  
=MWHJ'3-/  
} sos5Y}  
8CE = 4  
`@%LzeGz  
public String getSSiteURL() 7$#u  
{ (?];VG  
return sSiteURL; y>LBl]  
} 8,|kao:  
l"]V6!-U  
tBSW|0  
public void setSSiteURL(String value) YZ7.1`8  
{ _dU\JD  
sSiteURL = value; 62u4-}JzF  
} ABkl%m6xf  
sRfcF`7  
r<\u6jF  
public String getSFilePath() yQrD9*t&g  
{ .]Z"C&"N]  
return sFilePath; k=^xVQuI  
}  lRQYpc\  
2zpr~cB=  
HT@=evV  
public void setSFilePath(String value) M%#e1"n  
{ Va8&Z  
sFilePath = value; 6B-16  
} `h;[TtIX4  
-qoH,4w  
AwN!;t_0+N  
public String getSFileName() n!(F, b  
{ .^.z2 e  
return sFileName; nFn5v'g  
} ^Dx&|UwiZa  
z{>Rc"%\  
p[cX O=  
public void setSFileName(String value) Pz^544\~ou  
{ I:.s_8mH}  
sFileName = value; EK'!}OGCG  
} EV?z`jE9  
]f3>-)$*  
/tLVX} &  
public int getNSplitter() _*zt=zn>  
{  _4f;<FL  
return nSplitter; hOeRd#AQK  
} F!do~Z  
"5 A! jq  
f!"w5qC^  
public void setNSplitter(int nCount) Dzbz)Zst  
{ fR|A(u#9  
nSplitter = nCount; Ep}s}Stlr}  
} KTv$  
} {b{s<@?  
s@C}P  
`{Ul!  
/* -HuA \0J  
**Utility.java /( LL3cZK  
*/ <QvOs@i*  
package NetFox; Mfs?x a  
<}LC~B!  
j#6.Gq  
public class Utility { dRDnJc3  
=T_g}pu  
ME dWLFf  
public Utility() Ls%MGs9PI  
{ #b`k e/P  
If.r5z9  
n|;Im&,  
} ~m |BC*)  
BzzTGWq\  
//线程睡眠 % `3jL7|  
public static void sleep(int nSecond) M}Sv8D]I  
{ 26nx`w?j(  
try{ $^ P0F9~0  
Thread.sleep(nSecond); 4Up/p&1@  
} z@Y;r=v  
catch(Exception e) nR~(0G,H  
{ C]#,+q*  
e.printStackTrace (); SdWV3  
} 9iq_rd]  
} 6 r"<jh#  
 `]X>V,  
//日志 kl`W\tF  
public static void log(String sMsg) ,)XLq8  
{ PdCEUh\>y  
System.err.println(sMsg); TN.rrop`#g  
} ! z**y}<T  
xU vs:  
Zh,71Umz  
public static void log(int sMsg) P%6~&woF  
{ ]A"h&`Cvt  
System.err.println(sMsg); TO_e^A#  
} yLGRi^d#  
} q@&6#B  
xmX 4qtAL  
u"8yK5!  
/* '7/)Ot(  
**TestMethod.java OPi0~s  
*/ =WLY6)]A  
package NetFox; Gq6*SaTk  
\8 ":]EU  
R=dC4;  
public class TestMethod { JLYi]nZ  
U(Zq= M  
]yu:i-SfP  
public TestMethod() j [a(#V{  
{ ///xx/weblogic60b2_win.exe _&x%^&{  
try{ ;*N5Y}?j'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :Al!1BJQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @,}UWU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Bwrx*J  
fileFetch.start(); u!s2 BC0}N  
} ;`Z{7'^U  
catch(Exception e){e.printStackTrace ();} FlQGg VN  
7P T{lT  
==B6qX8T  
} G B^Br6  
edD)TpmE,  
so; ]&  
public static void main(String[] args) CAlCDfKW}  
{ ye97!nIg@  
new TestMethod(); Lr+$_ t}r  
} k!^{eOM  
} =%7-ZH9  
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