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http断点续传简单实现(java)

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/* L5Urg*GNL  
**SiteFileFetch.java v9%nau4  
*/ yp=|7  
package NetFox; pC*BA<?Rg  
import java.io.*; ^ED"rMI  
import java.net.*; Bk@)b`WR  
2m_'z  
1"}B]5!  
public class SiteFileFetch extends Thread { br0u@G  
tM&n3MWQ  
\n#]%X5c  
SiteInfoBean siteInfoBean = null; //文件信息Bean Hqvc7-c6  
long[] nStartPos; //开始位置 QU:EY'2  
long[] nEndPos; //结束位置 pT4qPta,2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 NEA_Plt  
long nFileLength; //文件长度 79D=d'e A  
boolean bFirst = true; //是否第一次取文件 E{uf\Fc   
boolean bStop = false; //停止标志 !w q4EV  
File tmpFile; //文件下载的临时信息 42fprt  
DataOutputStream output; //输出到文件的输出流 Q[M (Wqg  
$+Vmwd;  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) '!!e+\h#  
public SiteFileFetch(SiteInfoBean bean) throws IOException R N@^j  
{  bRNK.[|  
siteInfoBean = bean; @ ]f3| >I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~<n(y-P^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >;)2NrJV  
if(tmpFile.exists ()) h$70H^r  
{ 9b1?W?"  
bFirst = false; <B!'3C(P  
read_nPos(); ##H;Yb  
} Y}ng_c  
else R|iEvt  
{ - yoAxPDW  
nStartPos = new long[bean.getNSplitter()]; [|4}~UV  
nEndPos = new long[bean.getNSplitter()]; N31?9GE  
} bFg*l$`5  
lR:?uZ$  
8O6_iGTBh  
j'+ELKQ  
} A t{U~^  
D?^540,b  
wa!zv^;N*  
public void run() #e/2C  
{ wf?u (3/%  
//获得文件长度 XYjcJ  
//分割文件 4r\*@rq  
//实例FileSplitterFetch eOt%xTx  
//启动FileSplitterFetch线程 .`,F  
//等待子线程返回 Uo2+:p  
try{ Vvyj  
if(bFirst) MM#i t=u  
{ mzGjRl=O  
nFileLength = getFileSize(); 1?(cmXj  
if(nFileLength == -1) ;7rd;zJ  
{ 4QE=f(u;h  
System.err.println("File Length is not known!"); 7{pIPmJ  
} /HkFlfPd  
else if(nFileLength == -2) bni) Qw  
{ Pp+~Cir  
System.err.println("File is not access!"); g<$. - g  
} (? \?it-  
else }taLk@T  
{ y}N&/}M:}8  
for(int i=0;i<nStartPos.length;i++) qe$33f*  
{ j$Nf%V 6Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (S|a 9#  
} QdDObqVdy  
for(int i=0;i<nEndPos.length-1;i++) 9~c~E/4!  
{ 1AF%-<`?s  
nEndPos = nStartPos[i+1]; >SoO4i8  
} /v|Onq1Y4  
nEndPos[nEndPos.length-1] = nFileLength; D+sQPymI  
} Lz@$3(2  
} :&qhJtGo  
k#C f})  
GAw(mH*  
//启动子线程 2ev*CX6.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @4drjT  
for(int i=0;i<nStartPos.length;i++) 1a$IrQE  
{ := <0=JE#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }_}KVI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TQf L%JT  
nStartPos,nEndPos,i); BC! 6O/kr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U]hF   
fileSplitterFetch.start(); hv>KX  
} ZjD)? 4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '^iUx,,ZQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v^SsoX>WMH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q8>t!rh<R  
nEndPos = " + nFileLength); @TzvT3\q  
// fileSplitterFetch[nPos.length-1].start(); #6=MKpR  
(wuaxo:  
*0y{ ~@  
//等待子线程结束 byGn,m  
//int count = 0; qsI^oBD"  
//是否结束while循环 QXVC\@  
boolean breakWhile = false; j13DJ.xu  
R>2IRvY(  
I{ ryD -!  
while(!bStop) 6Ps.E  
{ ?59'dGnz_  
write_nPos(); &gn-Wb?  
Utility.sleep(500); "uKFOV?j&  
breakWhile = true; Fi2xr<7"  
sN~\+_  
pJBg?D  
for(int i=0;i<nStartPos.length;i++) +C+<BzR~A.  
{ $6h*l T<  
if(!fileSplitterFetch.bDownOver) J;}3t!  
{ XF*.Jg]  
breakWhile = false; M;jcUX_{  
break; }D*yr3b  
} T\9~<"P^  
} :,S98z#  
if(breakWhile) z.oU4c  
break; gL3iw!7  
Pbn!KX~F~  
\X|sU:g  
//count++; yNCEz/4  
//if(count>4) Eectxyr?;N  
// siteStop(); h3!$r~T!a:  
} PFrfd_s{>\  
#%$28sxB  
WsI>n  
System.err.println("文件下载结束!"); };,/0Fu  
} 8'#/LA[uPe  
catch(Exception e){e.printStackTrace ();} jlqv2V7=/  
} .cDOl_z<:G  
g/~XCC^F?  
W)*p2 #l  
//获得文件长度 O o8qyW  
public long getFileSize() +=BAslk  
{ ;65D  
int nFileLength = -1; y(W|eBe  
try{ ZU{4lhe  
URL url = new URL(siteInfoBean.getSSiteURL()); z6*<V5<7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0 1V^L}  
httpConnection.setRequestProperty("User-Agent","NetFox"); iW%8/$  
R=]d%L8  
x Q4%e[/  
int responseCode=httpConnection.getResponseCode(); Kibr ]w  
if(responseCode>=400) Hfym30  
{ N&,]^>^u  
processErrorCode(responseCode); o!c] (  
return -2; //-2 represent access is error  ?K_ '@  
} +B}0=Ex$t  
][&9]omB  
YA:nOvd@O  
String sHeader; !bnyJA  
BU|#e5  
HKDID[d0  
for(int i=1;;i++) 9?<{_'  
{ aUU7{o_Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3g~'5Ao  
//Utility.log(in.readLine()); _S}A=hK'  
sHeader=httpConnection.getHeaderFieldKey(i); `aC){&AP(  
if(sHeader!=null) . pzC5Ah  
{ #,d I$gY  
if(sHeader.equals("Content-Length")) c;2#,m^  
{ YW/QC'_iC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Pe;Y1Qq>>  
break; 3qL>-%):*  
} vy9 w$ls  
} jszK7$]^  
else [ic870_  
break; O@V%Cu  
} f+_h !j  
} Z?5V4F:f  
catch(IOException e){e.printStackTrace ();} J aTp} #  
catch(Exception e){e.printStackTrace ();} 457\&  
kF"@Ngv.  
n+;6=1d7ZW  
Utility.log(nFileLength); T .FI'wy  
U1nw- Q+  
@.Ic z  
return nFileLength; 1KM`i  
} 9h4({EE2t  
aJ") <_+  
~ `M\Ir  
//保存下载信息(文件指针位置) 0'YG6(h  
private void write_nPos() ~\LCvcY"X  
{ ).^}AFta  
try{ ?iI4x%y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eqw0]U\pv  
output.writeInt(nStartPos.length); .Z:zZ_Ev  
for(int i=0;i<nStartPos.length;i++) ^T"vX  
{ VX LT^iX  
// output.writeLong(nPos); {(U %i\F\  
output.writeLong(fileSplitterFetch.nStartPos); {!t7[Ctb  
output.writeLong(fileSplitterFetch.nEndPos); ,I1 RV  
} 0j"8@<  
output.close(); npJt3 Y_I  
} D=m 'pL/pl  
catch(IOException e){e.printStackTrace ();} #P l~R  
catch(Exception e){e.printStackTrace ();} Ms~{9?  
} 8_<4-<}P:  
+LM#n#T  
bef_rH@`  
//读取保存的下载信息(文件指针位置) Oy U  
private void read_nPos() _8Kx6s%  
{ NS%WeAf  
try{ {M-YHX>*;g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?HF%(>M  
int nCount = input.readInt(); S}p4iE"n  
nStartPos = new long[nCount]; s<qe,' Y  
nEndPos = new long[nCount]; P9g en6  
for(int i=0;i<nStartPos.length;i++) V=:'SL*3|  
{ \7Jg7*  
nStartPos = input.readLong(); z9FfU  
nEndPos = input.readLong(); g35DV6  
} Tq]Sn]CSP  
input.close(); 1$M@]7e+!+  
} 79`AM X[b  
catch(IOException e){e.printStackTrace ();} \b%kf99  
catch(Exception e){e.printStackTrace ();} ^6_e=jIN  
} + s- lCz  
h4q|lA6!k8  
CC#;c1t  
private void processErrorCode(int nErrorCode) d ,4]VE  
{ ~HOy:1QhE=  
System.err.println("Error Code : " + nErrorCode); oE#d,Z  
} GrUCZ<S  
`c<;DhNO  
_%5R o6  
//停止文件下载 ='`/BY(m[  
public void siteStop() O8B\{T1  
{ &f ^,la  
bStop = true; S30?VG9U0f  
for(int i=0;i<nStartPos.length;i++) kS bu]AB  
fileSplitterFetch.splitterStop(); emCM\|NQg&  
+=O5YR!{  
7;KwLT9  
} zIh ['^3.n  
} T6 '`l?H`;  
//负责部分文件的抓取 bbrXgQ`s+w  
**FileSplitterFetch.java c-B cA  
*/ vI>>\ .ED  
package NetFox; .zi_[  
 o4|M0  
E[/\7 v\  
import java.io.*; SQX:7YF~  
import java.net.*; RhncBKm*M  
Ney/[3 A  
8C*c{(4  
public class FileSplitterFetch extends Thread { SHe49!RA'{  
z^'gx@YD*v  
S:h{2{  
String sURL; //File URL ~`aa5;Ab_  
long nStartPos; //File Snippet Start Position |Y?H A&  
long nEndPos; //File Snippet End Position zd @m~V  
int nThreadID; //Thread's ID 7Zlw^'q$:L  
boolean bDownOver = false; //Downing is over M7pOLP_1jB  
boolean bStop = false; //Stop identical WA+iYLx@H  
FileAccessI fileAccessI = null; //File Access interface u6AA4(  
`$ 6rz  
~_/(t'9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vN`klDJgW[  
{ ibj87K  
this.sURL = sURL; vX/T3WV  
this.nStartPos = nStart;  C uB`CI  
this.nEndPos = nEnd; !@}wDt  
nThreadID = id; I}1NB3>^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wOU_*uY@6'  
} kM,C3x{A  
C{U?0!^  
&5yV xL:  
public void run() H{Wu]C<@p  
{ A~)D[CV  
while(nStartPos < nEndPos && !bStop) &litXIvT>  
{ y*qVc E  
As'=tIro  
YNQY4\(  
try{ <0Xf9a8>  
URL url = new URL(sURL); \W~ N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =vX/{C  
httpConnection.setRequestProperty("User-Agent","NetFox"); sB7# ~p A  
String sProperty = "bytes="+nStartPos+"-"; Zy`m!]G]80  
httpConnection.setRequestProperty("RANGE",sProperty); h1de[q)  
Utility.log(sProperty); 16 =sij%A  
Sc;BCl{=|  
4K\G16'$v  
InputStream input = httpConnection.getInputStream(); 8Vr%n2M  
//logResponseHead(httpConnection); [_k1jHr48N  
pH9VTM.*  
\NPmym_ 6J  
byte[] b = new byte[1024]; .P8&5i)'P,  
int nRead; fp`;U_-&0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;ub;l h3  
{ +S o4rA*9  
nStartPos += fileAccessI.write(b,0,nRead); X $jWo@  
//if(nThreadID == 1) ZOh`(})hy  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b,7k)ND1F  
} EJMM9(DQ7  
=;Au<|  
B3 8]~'8  
Utility.log("Thread " + nThreadID + " is over!"); l9{hq/V  
bDownOver = true; GeH#I5y  
//nPos = fileAccessI.write (b,0,nRead); z&zP)>Pv  
} 8\+uec]k  
catch(Exception e){e.printStackTrace ();} H\ F :95  
} KcWN,!G  
} m| n  
5?{ r  
+^60T$  
//打印回应的头信息 TM%| '^)  
public void logResponseHead(HttpURLConnection con) ]cHgleHQ  
{ >g1~CEMN#  
for(int i=1;;i++) 9X}10u:  
{ ]_f_w 9]  
String header=con.getHeaderFieldKey(i); marQNZ  
if(header!=null) hOjk3 k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j#!IuH\]  
Utility.log(header+" : "+con.getHeaderField(header)); cr7 }^s  
else gb[5&> (#  
break; M?1Y,5  
} =^M/{51j  
} L/$H"YOv  
Ag-(5:  
8\&X2[oAD  
public void splitterStop() XO.jl"xu  
{ slCx w$  
bStop = true; }Y12  
} n(1l}TJy  
 -*1d!  
R0KPZv-  
} ?gA 8x  
)|ju~qbf  
P) Jgs  
/* L +b6!2O,  
**FileAccess.java X _q\Sg  
*//文件访问(定位,写) q+yQwX{  
package NetFox; f\|w '  
import java.io.*; n@<YI  
V'z1  
9}rS(/@ }  
public class FileAccessI implements Serializable{ 5TH~.^`Fi  
ejSji-Qd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZF!h<h&,  
RandomAccessFile oSavedFile; (nQ^  
long nPos; p $S*dr  
NVkV7y X]  
`KZm0d{H  
public FileAccessI() throws IOException 5'OrHk;u  
{ 3#LlDC_WC  
this("",0); 8I=2lK  
} =9H7N]*h  
Vr3Zu{&2  
KjD/o?JUr  
public FileAccessI(String sName,long nPos) throws IOException {&&z-^  
{ ?g_3 [Fk  
oSavedFile = new RandomAccessFile(sName,"rw"); )8a~L8oN  
this.nPos = nPos; =Qy<GeY  
oSavedFile.seek(nPos); \j$&DCv   
} G<L;4nA)  
yuh *  
ik)|{%!K]H  
public synchronized int write(byte[] b,int nStart,int nLen) X]ipI$'+C  
{ ?qb}?&1  
int n = -1; 2=*H 8'k  
try{ OAgniLv  
oSavedFile.write(b,nStart,nLen); 9SX +  
n = nLen; AP3a;4Z#  
} k R?qb6  
catch(IOException e) y6g&Y.:o  
{ >xN .F/[K  
e.printStackTrace (); M[NV )q/)  
} j * %  
'NWfBJm  
&h}#HS>l  
return n; \;,_S+Fz8  
} _P!m%34|  
bL0yuAwF2  
xVw9v6@`h  
} 2R[:]-b  
aS>u,=C  
K%t*8 4j  
/* Kew@&j~  
**SiteInfoBean.java y\/1/WjBn  
*/ ))qy;Q,  
package NetFox; x`mG<Yt  
oh4E7yN  
vx{}}/B]J  
public class SiteInfoBean { })'B<vq  
,V7nzhA2  
M`0V~P`^  
private String sSiteURL; //Site's URL S;Fi?M  
private String sFilePath; //Saved File's Path {B~QQMEow  
private String sFileName; //Saved File's Name 9=s<Ld  
private int nSplitter; //Count of Splited Downloading File ko!)s  
kXViWOXU^  
W~)}xy  
public SiteInfoBean() 21n?=[  
{//nSplitter的缺省值为5 v_yw@  
//default value of nSplitter is 5 t$`r4Lb9/  
this("","","",5); &j;wCvE4+  
} ___~D dq  
Mc)}\{J  
aEB_#1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <;lkUU(WT2  
{ [|v][Hwv  
sSiteURL= sURL; \P[Y`LYL  
sFilePath = sPath; kBS9tKBWg  
sFileName = sName; q9B$" n  
this.nSplitter = nSpiltter; }H53~@WP>  
Lw1Yvtn  
!n`fTK<$  
} &< z1k-&!  
8C40%q..  
BT !^~S%w  
public String getSSiteURL() YqscZ(L:y  
{ e+EQ]<M  
return sSiteURL; 5=-Q4d  
} @@f"%2ZR[  
yWmJ~/*lG  
8|gIhpO?^  
public void setSSiteURL(String value) Q3'llOx  
{ 6bg ;q(*7  
sSiteURL = value; ~g91Pr   
} aj='b.2)  
}{Pp]*I<A  
yxPazz  
public String getSFilePath() p T?}Kc  
{ 3Tcms/n  
return sFilePath; X0HZH?V+  
} \  #F  
hgG9m[?K  
ic:zsuEm  
public void setSFilePath(String value) '@v\{ l  
{ #~]zhHI  
sFilePath = value; @mCEHI{P  
} |"}FXa O  
yX>K/68  
u,ho7ht3(  
public String getSFileName() WCZjXDiwJ  
{ :U|1xgB  
return sFileName; B`)BZ,#p  
} e+7"/icK  
(TtkFo'!U  
NWESP U):w  
public void setSFileName(String value) /8'NG6"H`  
{ K8|r&`X0  
sFileName = value; q>_.[+6  
} I9A~Ye 5O&  
P8:dU(nlW  
$S6`}3  
public int getNSplitter() b#%hY{$j  
{ 7~h<$8Y(T  
return nSplitter; C^Yb\N}S  
} -m zIT4  
u {cW:  
P= BZ+6DS  
public void setNSplitter(int nCount) ?>:g?.+  
{ QE+g j8  
nSplitter = nCount; /KaZH R.  
} b~P`qj[  
}  \!X8   
VBlYvZ;$*  
t.y2ff<[U  
/* H7Rx>h_  
**Utility.java ?=msH=N<l  
*/ /U*C\ xMm  
package NetFox; J1U/.`Oy  
`g?Negt\v  
W+c<2?d:  
public class Utility { x j)F55e?  
HyQJXw?A:  
(S5R!lpO  
public Utility() u@) U"FZ  
{ a5"D@E  
C==hox7b  
M<Ncb   
} QVT5}OzMt  
@i_FTN  
//线程睡眠 ?zMHP#i  
public static void sleep(int nSecond) < NY^M!  
{ `$IK`O  
try{ fplow  
Thread.sleep(nSecond); ys^oG$lq  
} Lg+Ac5y}`  
catch(Exception e) +)om^e@.  
{ H|<[YYk  
e.printStackTrace (); eKgBy8tNS0  
} ?!:ha;n  
} \:'/'^=#|  
 DPxM'7  
//日志 B]wk+8SMY.  
public static void log(String sMsg) H2\;%K 2  
{ .VJMz4$]O  
System.err.println(sMsg); CsR$c,8X.  
} 1=c\Rr9]  
&{hL&BLr  
L#{S!P,"  
public static void log(int sMsg) re?,Wext\  
{ M)+H{5bt  
System.err.println(sMsg); /Iy]DU8  
} SM#]H-3  
} !Pvf;rNI1T  
VcYrK4  
ek\ xx  
/* rU:`*b<  
**TestMethod.java /t57!&  
*/ R?|.pq/Ln  
package NetFox; /SR*W5#s  
#Y`~(K47  
[({nj`  
public class TestMethod { %N6A+5H  
2#]#sZmk  
~$cV: O7  
public TestMethod() \ZFGw&yN  
{ ///xx/weblogic60b2_win.exe KP^V>9q  
try{ `2WFk8) F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )[6U^j4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ZY={8T@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <?6|.\&  
fileFetch.start(); #U4F0BdA  
} Gr'  CtO  
catch(Exception e){e.printStackTrace ();} bHYy}weZ  
34O `@j0-3  
nwe* BVp  
} 85$m[+md  
dr}`H,X"3  
6r0krbN  
public static void main(String[] args) |bHelD|  
{ -UEZ#Q  
new TestMethod(); TDKki(o=~  
} BLdvyVFx  
} ]i)c{y  
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