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http断点续传简单实现(java)

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/* &N7:k+E  
**SiteFileFetch.java ^R'!\m|FR  
*/ WmVw>.]@~  
package NetFox; n#4J]Z@  
import java.io.*; 0l1]QD+Gc5  
import java.net.*; :*Ggz|  
h7]]F{r5  
5WJkeG ba  
public class SiteFileFetch extends Thread { pvR& ~g  
bSmaE7  
Mjvso0zj  
SiteInfoBean siteInfoBean = null; //文件信息Bean -Lf6]5$2'  
long[] nStartPos; //开始位置 Y 6Qb_X:  
long[] nEndPos; //结束位置 >T*g'954xF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5GFnfc}  
long nFileLength; //文件长度 \\G6c4 fC  
boolean bFirst = true; //是否第一次取文件 g~H? l3v  
boolean bStop = false; //停止标志 ~m|?! ]n  
File tmpFile; //文件下载的临时信息 0?Wf\7  
DataOutputStream output; //输出到文件的输出流 SyVbCj  
LLHOWD C(2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) i|^`gly  
public SiteFileFetch(SiteInfoBean bean) throws IOException :lQjy@J  
{ .z>." `  
siteInfoBean = bean; UO!6&k>c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H$z+gbjJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f$W}d0(F;  
if(tmpFile.exists ()) rLVc<595  
{ !>@V#I  
bFirst = false; ;F(01  
read_nPos(); P"~T*Qq-R  
} g)D}p@>m  
else _r5Ild @n  
{ (@o />T  
nStartPos = new long[bean.getNSplitter()]; }qdJ8K  
nEndPos = new long[bean.getNSplitter()]; E0Y/N?  
} 9la~3L_g  
(dip Ks?K  
,h`D(,?X  
t RyGxqiG  
} V dOd:w  
$q$\GOQ 9  
>~>[}d;glw  
public void run() jTgh+j]AP  
{ n rB27  
//获得文件长度 RF2XJJ  
//分割文件 > ,Bu^] C  
//实例FileSplitterFetch Xl+a@Ggtq  
//启动FileSplitterFetch线程 5XUI7Q%  
//等待子线程返回 =l'_*B8  
try{ e CUcE(  
if(bFirst) ZWW8Hr  
{ &8i{'k,l  
nFileLength = getFileSize(); 9qy 9  
if(nFileLength == -1) 7CMgvH)O  
{ cH-Zj  
System.err.println("File Length is not known!"); CgKSK0/a  
} ?N*@o.  
else if(nFileLength == -2) p2vUt  
{ 0a%ui2k  
System.err.println("File is not access!"); 9S1V! Jp  
} % P)}(e6y  
else #=#$b_6*  
{ 4H? Ma|,  
for(int i=0;i<nStartPos.length;i++) CPeK0(7Zh  
{ HU+H0S~g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _rJ SkZO  
} Z_~DTO2Qg  
for(int i=0;i<nEndPos.length-1;i++) 0i `Zy!  
{  +5mkMZ  
nEndPos = nStartPos[i+1]; CscJy0dB  
} BmF>IQ`M?  
nEndPos[nEndPos.length-1] = nFileLength; 1O7ss_E  
} 2^M+s\p  
} ^ED>{UiNI  
jt r=8OiL  
h1o+7  
//启动子线程 "FIx^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  Ph{+uI  
for(int i=0;i<nStartPos.length;i++) $rYu4^  
{ 2`U&,,-Mf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V\hct$ 7Vm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 13kb~'+&r  
nStartPos,nEndPos,i); z))[Lg  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7uNI  
fileSplitterFetch.start(); +`3ZH9  
} -y*+G&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (UT*T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w>Sz^_ h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ( +hI   
nEndPos = " + nFileLength); 8N_rJ)f  
// fileSplitterFetch[nPos.length-1].start(); !`=?<Fl  
6e| 5qKr  
$*-L8An?  
//等待子线程结束 }0>/G?2Yp  
//int count = 0; PW4Wn`u  
//是否结束while循环 X}Z%@tL  
boolean breakWhile = false; .Q)"F /  
oA@^N4PD  
mXaUWgO  
while(!bStop) P`"DepeD  
{ .WE0T|qDX  
write_nPos(); 'B6H/d>  
Utility.sleep(500); bQjHQ"G  
breakWhile = true; 3*JybMo"  
:/l   
l'\b(3JF  
for(int i=0;i<nStartPos.length;i++) }rZ=j6Z  
{ :+!b8[?Z  
if(!fileSplitterFetch.bDownOver) ;rL$z;}8  
{ L-$g& -  
breakWhile = false; 6 74X)hB  
break; Qf]!K6eR  
} rWqA)j*!  
} m/nn}+*C  
if(breakWhile) $?{zV$r1  
break; CI'5JOqP  
 E/;YhFb[  
\c}r6xOr  
//count++; >C3 9`1  
//if(count>4) [1CxMk~"[  
// siteStop(); ;gV8f{X{Z  
} 9E?>B3t^  
L1i> %5:g  
O8o18m8UH  
System.err.println("文件下载结束!"); &W!@3O{~.  
} 0O4mA&&!oK  
catch(Exception e){e.printStackTrace ();} {HnOUc\4  
} o]U ==  
7S Zs/wWh%  
z\ pT+9&  
//获得文件长度 sTyGi1  
public long getFileSize() mIodD)?{  
{ ~vF o 0k(  
int nFileLength = -1; tH(#nx8  
try{ q% 9oGYjvQ  
URL url = new URL(siteInfoBean.getSSiteURL()); /WVMT]T6^,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V=~dgy ~@  
httpConnection.setRequestProperty("User-Agent","NetFox"); rzLl M  
mJ7kOQ-.$  
B=`!  
int responseCode=httpConnection.getResponseCode(); mH .I!  
if(responseCode>=400) +8I0.,'  
{ a!]%@A6p  
processErrorCode(responseCode); 7yl'!uz)9  
return -2; //-2 represent access is error 0fU>L^P_?  
} blv6  
a@J :*W  
e?WR={  
String sHeader; u*`GIRfWT  
(p!AX<=z  
-<=< T@,  
for(int i=1;;i++)  t m?  
{ 5{TF6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]S ,GHPEN  
//Utility.log(in.readLine()); -NeF6  
sHeader=httpConnection.getHeaderFieldKey(i); :Ej)A fS  
if(sHeader!=null) b\Ub<pE  
{ 1| DI'e[X  
if(sHeader.equals("Content-Length")) # 95/,k  
{ q%Pnx_RB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \gpKQt0  
break; |\t_I~de  
} HfPeR8I%i  
} "RA$Twhj  
else O~VUViS6$  
break; t:7jlD!d  
} k$!&3Rh  
} Rw`s O:eZ  
catch(IOException e){e.printStackTrace ();} Rim}DfO/  
catch(Exception e){e.printStackTrace ();} &YNhKm@"  
ZT#G:a  
_P:P5H8  
Utility.log(nFileLength); *p^MAk9=  
|t_2AV  
B#yyO>0k]  
return nFileLength; {r)M@@[  
} qFk(UazN  
is$d<Y&F  
JnDR(s4(E  
//保存下载信息(文件指针位置) add-]2`  
private void write_nPos() CjGI}t  
{ A )cb  
try{ H<"j3qt  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _guY%2% yR  
output.writeInt(nStartPos.length); (k~c]N)v  
for(int i=0;i<nStartPos.length;i++) +6*I9R  
{ t {}1 f  
// output.writeLong(nPos); w=$_',5#Z  
output.writeLong(fileSplitterFetch.nStartPos); RI=B(0 A  
output.writeLong(fileSplitterFetch.nEndPos); qxx.f5 8H  
} }f}&|Vap  
output.close(); RP9||PFS~~  
} |IvX7%*]~  
catch(IOException e){e.printStackTrace ();} F/Xhm91 ^  
catch(Exception e){e.printStackTrace ();} Zj;!7ZuT1  
} p\K5B,  
4dP_'0]9A:  
9^tyjX2  
//读取保存的下载信息(文件指针位置) t JP(eaqZ  
private void read_nPos() n9^zAcUbAW  
{ o%a$m9I  
try{ 3'wBX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M*N8p]3Cq  
int nCount = input.readInt(); )UJMmw\  
nStartPos = new long[nCount]; D[mYrWHpn  
nEndPos = new long[nCount]; mq L+W  
for(int i=0;i<nStartPos.length;i++) <#-ERQw  
{ )j]RFt  
nStartPos = input.readLong(); g2I@j3  
nEndPos = input.readLong(); :>k\uW  
} ilP&ctn6+c  
input.close(); sMx\WTyz  
} "`k[ 4C  
catch(IOException e){e.printStackTrace ();} .+<K-'&=  
catch(Exception e){e.printStackTrace ();} {`LV{ !  
} f8lww)^,v  
EA\~m*k  
79v&6Io  
private void processErrorCode(int nErrorCode) vuf|2!kh/  
{ ^&}Y>O,  
System.err.println("Error Code : " + nErrorCode); yT4|eHl  
} VWi-)  
:vjbuqN]  
{~SR>I3sv  
//停止文件下载 oaHBz_pg  
public void siteStop() ~EBZlTN  
{ 0U<9=[~q7@  
bStop = true; uD"Voh|]=  
for(int i=0;i<nStartPos.length;i++) So:89T  
fileSplitterFetch.splitterStop(); !v-(O"a  
#?9o A4Q  
Jj!T7f*-GX  
} T1E=<q4  
} - M]C-$  
//负责部分文件的抓取 9SPu 4i  
**FileSplitterFetch.java |Bid(`t.  
*/ 5>HI/QG  
package NetFox; PJLA^eC7>  
"7g: u-  
qv:WC TAn  
import java.io.*; Z+?j8(:n  
import java.net.*; 2+enRR~  
h5JXKR.1]c  
C9h8d   
public class FileSplitterFetch extends Thread { S(Pal/-"  
z)26Ahm TV  
o|+tRl  
String sURL; //File URL xASj w?  
long nStartPos; //File Snippet Start Position xiI!_0'  
long nEndPos; //File Snippet End Position y!#1A?|k  
int nThreadID; //Thread's ID Umqm5*P(  
boolean bDownOver = false; //Downing is over a4wh-35/  
boolean bStop = false; //Stop identical (n< xoV[e  
FileAccessI fileAccessI = null; //File Access interface 46vz=# ,6L  
<1y%ch;  
UX?_IgJh<"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ul=`]@]]  
{ Abl=Ev  
this.sURL = sURL; B 5?(gb"  
this.nStartPos = nStart; ]OVjq ?  
this.nEndPos = nEnd; &"BKue~q@p  
nThreadID = id; ,FTF@h-Cs  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8wBns)wy@  
} |^1eL I  
jkbz8.K  
yoH6g?!O  
public void run() 4avM:h  
{ X#J[Nn>  
while(nStartPos < nEndPos && !bStop) eRGip2^cq+  
{ Bpgl U=Qr  
,Yo In  
Gqs8$[o  
try{ SbB5J> >7J  
URL url = new URL(sURL); cIgF]My*D@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1G\ugLm  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~"-wSAm  
String sProperty = "bytes="+nStartPos+"-"; sB6UlX;b:  
httpConnection.setRequestProperty("RANGE",sProperty); qRU8uu   
Utility.log(sProperty); {M=tw  
a7+BAma<  
<Z vG&  
InputStream input = httpConnection.getInputStream(); =q._Qsj?fu  
//logResponseHead(httpConnection); o5)U3U1|  
kxKBI{L  
'K0Y@y  
byte[] b = new byte[1024]; `:8&m  
int nRead; W>"i0p  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Nk 7Q  
{ k8h$#@^  
nStartPos += fileAccessI.write(b,0,nRead); ?0%lB=qQ  
//if(nThreadID == 1) O6`@'N>6P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *P_TG"^{W  
} <_NF  
<'/+E4m  
f[.]JC+,  
Utility.log("Thread " + nThreadID + " is over!"); MZ{)`7acR\  
bDownOver = true; z_zr3XR9  
//nPos = fileAccessI.write (b,0,nRead); c<e$6:|xM  
} y"7?]#$9/  
catch(Exception e){e.printStackTrace ();} SO}Hc;Q1`  
}  bSmRo  
} ?vZ&CB  
oV*3Mec  
0n1y$*I4  
//打印回应的头信息 uy B ?-Y+  
public void logResponseHead(HttpURLConnection con) sI~{it#  
{ HMBxj($eR  
for(int i=1;;i++) r+) A)a,  
{ 6OVAsmE  
String header=con.getHeaderFieldKey(i); $ @^n3ZQ4  
if(header!=null) %DiZ&}^Ck  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %N!Y}$y  
Utility.log(header+" : "+con.getHeaderField(header)); bzZEwMc6  
else /$B<+;L!#  
break; vHao y  
} 50CU|  
} Chjth"  
;X\!*Loe  
NxNz(R $~  
public void splitterStop() )2\6 Fy0S  
{ N 4Dyec\  
bStop = true; u%&zY97/  
} w;X-i.%`  
nkv zv  
byd[pnI$H  
} GXsHc,  
x5{ zGv.j  
lT*Hj.  
/* %GAEZH,2sG  
**FileAccess.java n2$*Z6.G  
*//文件访问(定位,写) S9mj/GpL3  
package NetFox; e\/Lcng  
import java.io.*; 6tP^_9njy  
rNZN}g  
3C.bzw^  
public class FileAccessI implements Serializable{ P_w+p"@m  
f4uK_{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K^9!Qp  
RandomAccessFile oSavedFile; Vk[m$  
long nPos; 3EAu#c@q"  
Q~uj:A]n<  
G:f]z;Xdp  
public FileAccessI() throws IOException o-/Xa[yC  
{ 9!PJLI=D  
this("",0); l^&#fz  
} V7 c7(G  
2c}>} A4  
MA"DP7e?v  
public FileAccessI(String sName,long nPos) throws IOException M7En%sBp  
{ 7Sr7a {  
oSavedFile = new RandomAccessFile(sName,"rw"); w${=]h*2  
this.nPos = nPos; Cvq2UNz(R  
oSavedFile.seek(nPos); "M2HiV  
} AOeptv^k3}  
9QZ;F4 r  
!x|Ok'izDL  
public synchronized int write(byte[] b,int nStart,int nLen) *y7^4I-J  
{ h@l5MH=|%  
int n = -1; ]Y:|%rvVH  
try{ Haiuf)a  
oSavedFile.write(b,nStart,nLen); #m|AQr|  
n = nLen; 6f0 WN  
} NO"=\Zn6  
catch(IOException e) HJM-;C](  
{ ]*Zg(YA  
e.printStackTrace (); jF{zcYU  
} ,D>$N3;  
jFnq{L t  
9V("K  
return n; KI#),~n S  
} <T<?7SE+  
>OmY  
e<>(c7bF  
} ,+%$vV .g\  
u9QvcD^'z  
umK~K!i  
/* uQ. m[y  
**SiteInfoBean.java rs'~' Y  
*/ r6QNs1f~.  
package NetFox; #%Uk}5;-  
MHk\y2`/;  
X5'foFE'  
public class SiteInfoBean { T/UhZ4(V  
r( :"BQ  
r@^h,  
private String sSiteURL; //Site's URL mRFcZ.7  
private String sFilePath; //Saved File's Path  g&#.zJ[-  
private String sFileName; //Saved File's Name I[G<aI!  
private int nSplitter; //Count of Splited Downloading File D8qZh1w%A|  
5&\Q0SX(~  
#8QQZdC8`  
public SiteInfoBean() :J5xO%WA(  
{//nSplitter的缺省值为5 P$4G2>D8dg  
//default value of nSplitter is 5 n ;y<!L7  
this("","","",5); v|"Nx42  
} D`2Iy.|!  
Mq8jPjL  
NAlYfbp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) D~G24k6b3  
{ ?,O{,2}  
sSiteURL= sURL; D*I%=);B_  
sFilePath = sPath; 6m|j " m  
sFileName = sName; la[xbv   
this.nSplitter = nSpiltter; [0w @0?[  
`c ^2  
c4k3|=f  
} b<~\IPY  
f^Lw3|rq4  
=i4Ds  
public String getSSiteURL() z;x $tO  
{ 1nye.i~  
return sSiteURL; &ScADmZP^d  
} oyiEOC  
Jo1n>Mo-j  
X~T"n<:a>  
public void setSSiteURL(String value) Yw vX SA  
{ C2<!.l  
sSiteURL = value; cF7I  
} m\)z& hv<r  
D4?5 %s  
"}Of f  
public String getSFilePath() CD;C z*c  
{ KW ]/u  
return sFilePath; T&   
} 51u8.%{4  
!U/iY%NE  
]g2Y/\)a  
public void setSFilePath(String value) 9# IKb:9k  
{ al.~[T-O+  
sFilePath = value; y+hC !-  
} S~.:B2=5K  
nb9qVuAGU  
^w/_hY!4/  
public String getSFileName() lU`]yL  
{  K!VIY|U  
return sFileName; Po#;SG#Ee  
} yZE"t[q#O  
Z_.Eale^  
:,X,!0pWRp  
public void setSFileName(String value) &9g4/c-?$  
{ k4FxdX  
sFileName = value; `L/kwVl  
} o}C|N)'  
N{U``LV  
Xt %;]1n  
public int getNSplitter() e "5S ;  
{ \BOZhXfl'  
return nSplitter; '8R5?9"  
} wuSp+?{5k  
u=JI 1  
.H {  
public void setNSplitter(int nCount) FIG3P))  
{ Sp3?I2 o  
nSplitter = nCount; Av:5v3%  
} {{7%z4l  
} %]S~PKx  
0!!b(X(  
(vMC.y5  
/* 0wU8PZ Nj  
**Utility.java $@<qaR{t\  
*/ 8.3888  
package NetFox; B#9rqC  
Z[[ou?c  
-]\cUQ0  
public class Utility { (\}>+qS[  
^|M\vO  
TO7%TW{L  
public Utility() !*_5 B'  
{ z;yb;),  
Hg\+:}k&9  
&rj3UF@hb  
} }YH@T]O}  
=X6WK7^0  
//线程睡眠 ?9 hw]Q6r}  
public static void sleep(int nSecond) 1:%HE*r  
{ /R7qR#  
try{ GP6-5Y"8  
Thread.sleep(nSecond); }JyWy_Y  
} m&(yx| a4+  
catch(Exception e) `KBgVhS>  
{ l ps 6lnh  
e.printStackTrace (); {Hxvt~P  
} O&YX V  
} H. UwM  
 W|XTa  
//日志 E#?*6/  
public static void log(String sMsg) S(<r-bV<  
{ %upnXRzw  
System.err.println(sMsg); EkS7j>:  
} q|,cMPS3  
!m)P*Lw  
>Q':+|K}  
public static void log(int sMsg) jkw:h0hX  
{ <+ 0cQq=2  
System.err.println(sMsg); +Gv{Apd"  
} ,b!!h]t  
} =@$G3DM  
EooQLZ  
6yEYX'_  
/* (%*CfR:>  
**TestMethod.java 6) {jHnk)  
*/ AW3\>WC  
package NetFox; QB p`r#{I{  
v).V&":  
<\uz",e}  
public class TestMethod { /Qi;'h]  
3NRxf8  
mNS7/I\  
public TestMethod() o;bK 7D  
{ ///xx/weblogic60b2_win.exe JQ|qg\[  
try{ %H OMX{~}#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k{_ Op/k}V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ue8Cpn^M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z*?-*6W  
fileFetch.start(); $OOZ-+8  
} vpR^G`/  
catch(Exception e){e.printStackTrace ();} $t.i)wg +  
^3B)i=  
&<8Q/m]5  
} H{Tt>k  
|Y#KMi ~  
{.c(Sw}Eo  
public static void main(String[] args) *h6Lh]7  
{ g}HB|$P7  
new TestMethod(); #>~<rcE(  
} ?Ne@OMc  
} u%n6!Zx  
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