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http断点续传简单实现(java)

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/* #[KwR\b{:+  
**SiteFileFetch.java B:mlBSH  
*/ yPQ{tS*t  
package NetFox; +'n1?^U  
import java.io.*; /pk; E$qv  
import java.net.*; e0$mu?wd-  
HJcZ~5jf  
OT *W]f  
public class SiteFileFetch extends Thread { aSF&^/j  
%[Ds-my2  
@H_LPn  
SiteInfoBean siteInfoBean = null; //文件信息Bean &pba~X.u  
long[] nStartPos; //开始位置 WX=+\`NyJ(  
long[] nEndPos; //结束位置 P)\f\yb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3\WES!  
long nFileLength; //文件长度 RsOK5XnQn  
boolean bFirst = true; //是否第一次取文件 " LxJPt\  
boolean bStop = false; //停止标志 @2$8o]et  
File tmpFile; //文件下载的临时信息 }`M6+.z3F  
DataOutputStream output; //输出到文件的输出流 M^[ jA](a  
qt:->yiq+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Wey\GQ`"8  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'P Yl%2  
{ 3)-#yOr  
siteInfoBean = bean; CTP%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cq=R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }>1E,3A:%G  
if(tmpFile.exists ()) eS.]@ E-T  
{ A"k,T7B  
bFirst = false; j?mJ1J5  
read_nPos(); _0f[.vN  
} <n:?WP~U  
else \c\=S  
{ ueg X  
nStartPos = new long[bean.getNSplitter()]; iB,*X[}EqG  
nEndPos = new long[bean.getNSplitter()]; U^YPL,m1  
} 5 O6MI4:  
FD-)nv2:  
b;O+QRa  
8&;dR  
} }dR *bG  
lz*2wGI9  
jFc{$#g-  
public void run() x!jhWX  
{ Lf:Z (Z>  
//获得文件长度 b7,qzh  
//分割文件 0IdD   
//实例FileSplitterFetch avz 4 &  
//启动FileSplitterFetch线程 ie ,{C  
//等待子线程返回 950b9Vn&  
try{ `^}9= Q'r  
if(bFirst) tp]|/cx4  
{ =@z"k'Vl`  
nFileLength = getFileSize(); eo80L  
if(nFileLength == -1) ( BGipX4  
{ w}i.$Qt  
System.err.println("File Length is not known!"); i,HAXPi  
} ,@;<u'1\G  
else if(nFileLength == -2) [y:LA ~q  
{ \'KzSkC8  
System.err.println("File is not access!"); QezK&iJg  
} L!G3u/  
else zN:752d^+r  
{ Cf N; `  
for(int i=0;i<nStartPos.length;i++) <>Im$N ai  
{ ,rdM{ r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G~]BC#nB_  
} 3 /e !7  
for(int i=0;i<nEndPos.length-1;i++) 1%+^SR72  
{ D5p22WY  
nEndPos = nStartPos[i+1]; FN R& :  
} k);!H+  
nEndPos[nEndPos.length-1] = nFileLength; 3YRzBf:h  
} r__M1 !3  
} %Fv)$ :b  
#?*jdN:  
h CiblM  
//启动子线程 6xe |L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ep!.kA=\  
for(int i=0;i<nStartPos.length;i++) (`p(c;"*C!  
{ /$=^0v +  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zyr6Tv61U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZZ(@:F  
nStartPos,nEndPos,i); 24Fxx9 g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *8p</Q  
fileSplitterFetch.start(); GM/1u fZH  
} |3L MVN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q'VS]n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rU O{-R  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7,zARWB!?  
nEndPos = " + nFileLength); On^#x]  
// fileSplitterFetch[nPos.length-1].start(); 8{YxUD  
 V("1\  
_biJch  
//等待子线程结束 D/WS  
//int count = 0; LcXMOT)s  
//是否结束while循环 OOCeZ3yF(  
boolean breakWhile = false; \abl|;fj  
S(6ZX>wv:  
"ir*;|  
while(!bStop) EHZSM5hu  
{ "Tv7*3>  
write_nPos(); ~-+Zu<  
Utility.sleep(500); LDsYr]  
breakWhile = true; FScQS.qF  
?>Aff`dHY  
KB = z{g  
for(int i=0;i<nStartPos.length;i++) f<wgZM  
{ Tt\w^Gv\d  
if(!fileSplitterFetch.bDownOver) [P/gM3*'  
{ v(iUo&Ge  
breakWhile = false; sfa'\6=O  
break; b5Pn|5AVj  
} Q6K)EwN  
} Ie"R,,c   
if(breakWhile) (4LLTf0  
break; 6{'6_4;Fv(  
2XHk}M|  
F0Hbklr  
//count++; &[kgrRF@HU  
//if(count>4) Kxn7sL$]=F  
// siteStop(); o3=kF  
} u $#7W>R  
{rZ"cUm  
WIm7p1U#V  
System.err.println("文件下载结束!"); <Xx\F56zp  
} I8?[@kg5b'  
catch(Exception e){e.printStackTrace ();} Kcl$|T  
} #A; Z4jK  
AX+d?M  
''uI+>Y  
//获得文件长度 ~\ f^L?m  
public long getFileSize() UsN b&aue  
{ lG9ARRy(=  
int nFileLength = -1; b U NYTF{  
try{ 7VcVI? ?  
URL url = new URL(siteInfoBean.getSSiteURL()); n^N]iw{G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >U?Bka!  
httpConnection.setRequestProperty("User-Agent","NetFox"); lWvd"Vlt  
^A`(  
M;qL)vf  
int responseCode=httpConnection.getResponseCode(); l #Q`f.  
if(responseCode>=400) 7h1gU  
{ jm\#($gl=  
processErrorCode(responseCode);  #Uh 5tc  
return -2; //-2 represent access is error I?>T"nV +'  
} )\vHIXnfJ1  
*a!!(cZZ  
dn_OfK  
String sHeader; 4-_lf(# i  
P-[K*/bPw  
sv"mba.J  
for(int i=1;;i++) I})t  
{ #~;8#!X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2< Bv=B  
//Utility.log(in.readLine()); @88i/ Z_  
sHeader=httpConnection.getHeaderFieldKey(i); Ky#B'Bh}`g  
if(sHeader!=null) ^z^e*<{WEl  
{ I!gj;a?R  
if(sHeader.equals("Content-Length")) X vMG09  
{ PU5mz.&0'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]0 RXo3  
break; Hs=N0Sk]j  
} 493i*j5r)l  
} 4iqmi<[("  
else DWQQ615i  
break; e oSM@Isu  
} |SKG4_wGe  
} SzX~;pFM0  
catch(IOException e){e.printStackTrace ();} R Sz[6  
catch(Exception e){e.printStackTrace ();} t<F]%8S  
bpa O`[*  
]31XX=  
Utility.log(nFileLength); D|j \ nQ  
u3mT l  
]fo^43rn{  
return nFileLength; 8G&+  
} E5G"QnxR>N  
vUe *  
,$zlw\  
//保存下载信息(文件指针位置) I0+wczW,^  
private void write_nPos() '<< ~wt  
{ Uy5!H1u  
try{ %@n8 ?l4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1Dp @n  
output.writeInt(nStartPos.length); _G #"B{7  
for(int i=0;i<nStartPos.length;i++) 'h>5&=r  
{ lc7a@qnw   
// output.writeLong(nPos); bDBO+qA  
output.writeLong(fileSplitterFetch.nStartPos); /1~|jmi(  
output.writeLong(fileSplitterFetch.nEndPos); 'QojSq   
} (0#F]""\e  
output.close(); 5;8B!%b  
} \K~fRUo]=c  
catch(IOException e){e.printStackTrace ();} 1]Q 2qs  
catch(Exception e){e.printStackTrace ();} #0hNk%X=  
} ]/Yy-T#@  
dyiEK)$h  
?%/u/*9rj  
//读取保存的下载信息(文件指针位置) 68<Z\WP  
private void read_nPos() ~X<cG=p~u  
{ 7[v@*/W@  
try{ V!77YFen %  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y%:0|utQC  
int nCount = input.readInt(); in #]3QGV  
nStartPos = new long[nCount]; m+2`"1IE[  
nEndPos = new long[nCount]; yISQYvSN  
for(int i=0;i<nStartPos.length;i++) aT:AxYn8  
{ L'XdX\5  
nStartPos = input.readLong(); |F@xwfgb  
nEndPos = input.readLong(); 3'*%R48P`  
} hr4ye`c j  
input.close(); Nv?-*&L  
} |"YA<e %  
catch(IOException e){e.printStackTrace ();} /CI%XocB  
catch(Exception e){e.printStackTrace ();} 1Uemsx%'k  
} q7f;ZK=f  
?Wg{oB@(  
*UBP]w  
private void processErrorCode(int nErrorCode) }"?nU4q;S  
{ Zxc7nLKF~  
System.err.println("Error Code : " + nErrorCode); $@_t5?n``F  
} <2O7R}j7v  
gZlw  
\D U^idp#  
//停止文件下载 (;pi"/x[  
public void siteStop() M ?xpwqu\  
{ zf3:<CRX5  
bStop = true; Va@6=U7c  
for(int i=0;i<nStartPos.length;i++) T3 9C lH  
fileSplitterFetch.splitterStop(); X')Zm+  
VP %i1|XZJ  
%7v@n+Q  
} kg: uGP9  
} ^+%tlX_+.  
//负责部分文件的抓取 9#&W!f*qO|  
**FileSplitterFetch.java l^ 0_> R  
*/ >*= =wlOB  
package NetFox; q)V1{B@  
twtkH~`"Q  
O5qW*r'  
import java.io.*; u-QO>3oY6  
import java.net.*; 2zKo  
z_Wm HB  
Yn4)Zhkk  
public class FileSplitterFetch extends Thread { [ .j]V-61  
#PslrA. E  
w3=)S\  
String sURL; //File URL FL`1yD^2  
long nStartPos; //File Snippet Start Position O~h94 B`  
long nEndPos; //File Snippet End Position (D>y6r> r  
int nThreadID; //Thread's ID Ni!;-,H+E  
boolean bDownOver = false; //Downing is over k%]DT.cE  
boolean bStop = false; //Stop identical M U?{?5  
FileAccessI fileAccessI = null; //File Access interface xaWGa1V'z  
h41$|lonU%  
NFY|^*bll  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cZe'!CQS  
{ tS (i711  
this.sURL = sURL; ESD<8 OR  
this.nStartPos = nStart; -VWCD,c  
this.nEndPos = nEnd; j,=*WG  
nThreadID = id; ?""\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M'umoZmW0  
} 4|6&59?pnc  
BbrT f"`  
Y9i9Uc.]  
public void run() }PI35i1!t  
{ ik2- OM  
while(nStartPos < nEndPos && !bStop) +ze}0lrEL  
{ =a)iVXSB]  
{_zV5 V  
\E$1lc  
try{ @7@e`b?  
URL url = new URL(sURL); W$" Y%^L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h L]8e>a?  
httpConnection.setRequestProperty("User-Agent","NetFox"); z;dcAdz9  
String sProperty = "bytes="+nStartPos+"-"; k,,!P""  
httpConnection.setRequestProperty("RANGE",sProperty); b JfD\  
Utility.log(sProperty); bQwdgc),s{  
{sC@N![  
)L |tn  
InputStream input = httpConnection.getInputStream(); bZ>&QM  
//logResponseHead(httpConnection); *o02!EYge  
H]_WFiW-9  
vWU%ST  
byte[] b = new byte[1024]; '7xxCj/*  
int nRead; $D QD$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xLx"*jyL  
{ K2cq97k,d  
nStartPos += fileAccessI.write(b,0,nRead); >|a\>UgC  
//if(nThreadID == 1) 7E$eN8H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3sZ,|,ueD  
} /Hv* K&}M  
,b<9?PM  
i8Fs0U4"  
Utility.log("Thread " + nThreadID + " is over!"); T3PX gL)o  
bDownOver = true; ^|wT_k\  
//nPos = fileAccessI.write (b,0,nRead); WP0 #i~3*  
} /M3y)K`^  
catch(Exception e){e.printStackTrace ();} i2$*}Cu  
} },DyU  
} bh6d./  
[ULwzjss#L  
4~O6$;!|~  
//打印回应的头信息 Zc-#;/b3T  
public void logResponseHead(HttpURLConnection con) "r8EC  
{ +XEjXH5K  
for(int i=1;;i++) K`hz t  
{ u_N\iCYp  
String header=con.getHeaderFieldKey(i); :T_'n,  
if(header!=null) |d $1wr  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .Y!;xB/  
Utility.log(header+" : "+con.getHeaderField(header)); $ZQ"({<w<g  
else F9MR5O"  
break; LeY+p]n~  
} q*L ]  
} 4,2(nYF  
1g1?zk8zO  
4P|$LkI  
public void splitterStop() 6|,e%  
{ i90}Xyt  
bStop = true; @l'G[jN5  
} (lb6]MtTHY  
R6`*4z S  
Sv7 i! j  
} Mx8Gu^FW.d  
@ ]f3| >I  
u7HvdLql  
/* >;)2NrJV  
**FileAccess.java h$70H^r  
*//文件访问(定位,写) 0Cl,8P  
package NetFox; <B!'3C(P  
import java.io.*; CoU3S,;*  
=HVfJ"vK  
Pg/T^n&  
public class FileAccessI implements Serializable{ N31?9GE  
bFg*l$`5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q xfLfgu^  
RandomAccessFile oSavedFile; 8O6_iGTBh  
long nPos; 4otl_l(`yv  
A t{U~^  
:q^R `8;(t  
public FileAccessI() throws IOException wa!zv^;N*  
{ !\^jt%e&  
this("",0); XYjcJ  
} +0J@y1  
ABc)2"i:*  
YZ+>\ x  
public FileAccessI(String sName,long nPos) throws IOException 6B#('gxO  
{ QC{u|  
oSavedFile = new RandomAccessFile(sName,"rw"); |8H_-n  
this.nPos = nPos; U;g S[8,p  
oSavedFile.seek(nPos); Sk\n;mL:  
} ahA{B1M)n  
7rcA[)<'  
^ Hg/P8q  
public synchronized int write(byte[] b,int nStart,int nLen) eIg+PuQD]  
{ f])M04<  
int n = -1; 3?2<W EYr  
try{ ?q _^Rj$  
oSavedFile.write(b,nStart,nLen); zG#wu   
n = nLen; Q&xjF@I  
} mQ}Gh_'ps  
catch(IOException e) ;WD,x:>blO  
{ f^p^Y F+  
e.printStackTrace (); EUy(T1Cl&&  
} xYI;V7  
.n`( X#,*l  
:?=Q39O9  
return n; XA)'=L!^  
} mG2VZ>  
N5? IpE  
~-_i  
} gWOt]D&#/  
#{$1z;i?f  
sw$2d  
/* H\E7o" m  
**SiteInfoBean.java %X>FVlPm  
*/ URA0ey`  
package NetFox; ]tB@kBi "  
f#$|t>  
R_1qn  
public class SiteInfoBean { ~U$":~H[  
+@ MPQv  
s\gp5MT  
private String sSiteURL; //Site's URL nO{ x^b <  
private String sFilePath; //Saved File's Path nA_%2F'W}  
private String sFileName; //Saved File's Name {,?ss$L  
private int nSplitter; //Count of Splited Downloading File iA'As%S1  
/[ K_ &  
m`y9Cuk  
public SiteInfoBean() S`m,S4-eD  
{//nSplitter的缺省值为5 j13DJ.xu  
//default value of nSplitter is 5 R>2IRvY(  
this("","","",5); I{ ryD -!  
} 6Ps.E  
?59'dGnz_  
Zw{MgoJ0Z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M0L&~p_F  
{ %2"J:0j  
sSiteURL= sURL; E!J=8C.:  
sFilePath = sPath; 8#X_#  
sFileName = sName; PLA#!$c7q  
this.nSplitter = nSpiltter; _c2WqQ-05  
m\ S\3n  
7Xg?U'X  
} WC*=rWRxF  
rrqQCn9  
gEwd &J  
public String getSSiteURL() Gb2L }  
{ 4^*,jS-9g}  
return sSiteURL; q .J sf+  
} ])w[   
|=6_ xRyr  
9b"MQ[B4#a  
public void setSSiteURL(String value) UDEj[12S  
{ tfYB_N  
sSiteURL = value; |3shc,7  
} 6>`c1 \8f  
TL0[@rr4  
WsI>n  
public String getSFilePath() };,/0Fu  
{ v.&>Ih/L  
return sFilePath; jlqv2V7=/  
} /,s[#J   
}Fa%%}  
W)*p2 #l  
public void setSFilePath(String value) 5~H#(d<oZ  
{ ZmEEj-*7s  
sFilePath = value; DyO$P#~?  
} ZU{4lhe  
=0 qpVFvU  
Y?K{(szo ?  
public String getSFileName() d2N:^vvvR  
{ 0w=R_C)s  
return sFileName; W!T"m)S  
} Jr;jRe`4c  
,7_4 z]jK  
h-#1U3d  
public void setSFileName(String value) LP];x3  
{ #8XL :I  
sFileName = value; k@dN$O%p  
} 7f{=w, U  
\ZI'|Ad  
;# uZhd  
public int getNSplitter() ?D`T7KSe~D  
{ ?6^|ZtB  
return nSplitter; T,%j\0  
} K`g7$r)U[  
n.}E5 %qK  
Cbm\h/PXl  
public void setNSplitter(int nCount) `aC){&AP(  
{ . pzC5Ah  
nSplitter = nCount; z (?=Iv3  
} m ci/'b Xt  
} Wb}c=hZv  
yQNV@T<o  
P"/G  
/* n>>Qn&ym  
**Utility.java k,yZ[n|`  
*/ 5=|hC3h  
package NetFox; j|4C\~i  
v\tEVhm  
'cix`l|^  
public class Utility { kF"@Ngv.  
@#g<IBG=*  
ar9]"s+'  
public Utility() ;r[@v347  
{ HlvuW(,x=  
W2FD+ wt  
_tTNG2  
} gKYfQ+  
$5D,sEC@  
//线程睡眠 E_e6^Sk5B(  
public static void sleep(int nSecond) . mLK`c6  
{ f y:,_#  
try{ myl+J;,]  
Thread.sleep(nSecond); +Z M)bbB  
} ="wzq+U  
catch(Exception e) y*pUlts<  
{ l*\y  
e.printStackTrace (); PYbVy<xc  
} i0$Bx>  
} *t[. =_v  
E :9"cxx  
//日志 #S&Tkip]"W  
public static void log(String sMsg) /DQaGq/Ld  
{ 2'EUy@0  
System.err.println(sMsg); CHrFM@CM  
} ,(8;y=wux  
( +pLA"xq  
aT>'.*\]  
public static void log(int sMsg) mGp.3{j  
{ if|+EN%  
System.err.println(sMsg); <Ln1pV~k  
} S}p4iE"n  
} |7yAX+  
P9g en6  
V=:'SL*3|  
/* \7Jg7*  
**TestMethod.java V-<GT ?  
*/ g35DV6  
package NetFox; Tq]Sn]CSP  
=jB08A  
[<DZ*|+  
public class TestMethod { At7>V-f}  
&l3iV88  
Oo"^%F~%  
public TestMethod() Ag{iq(X  
{ ///xx/weblogic60b2_win.exe d&ex5CU5  
try{ ^*P%=>zO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &boOtl^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zt.'K(]2h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y. ,Kl~  
fileFetch.start(); j@YU|-\qh  
} ZI=%JU(  
catch(Exception e){e.printStackTrace ();} "@?? Fw!  
$ s9Vrw0Z  
0T Q$C-%  
} uc;8 K,[t  
n4}B r;%  
?b(=1S\E'^  
public static void main(String[] args) !%"8|)CAr  
{ "jG}B.l=,  
new TestMethod(); G6T_O  
} xuqv6b.  
} a)wJT`xu  
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