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http断点续传简单实现(java)

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/* nO;*Peob  
**SiteFileFetch.java 44r@8HO1  
*/ h eR$j  
package NetFox; ' \8|`Zb  
import java.io.*; Bm e_#  
import java.net.*; h=a-~= 8  
J`I^F:y*  
'ptD`)^(  
public class SiteFileFetch extends Thread { 0aWy!d  
[\_#n5  
N'5AU (  
SiteInfoBean siteInfoBean = null; //文件信息Bean n "J+? ~9  
long[] nStartPos; //开始位置 B)L=)N  
long[] nEndPos; //结束位置 @3aI7U/I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Q:v9C ^7  
long nFileLength; //文件长度  <u=k X  
boolean bFirst = true; //是否第一次取文件 g %ZKn  
boolean bStop = false; //停止标志 :6T 8\W  
File tmpFile; //文件下载的临时信息 3oo Tn-`{  
DataOutputStream output; //输出到文件的输出流 Y-ZTv(<  
P&g.%8b~84  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5eL_iNqJM  
public SiteFileFetch(SiteInfoBean bean) throws IOException <jjn'*44f  
{ bP+b~!3  
siteInfoBean = bean; ,ve$bSp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [(81-j1v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !et[Rdbu  
if(tmpFile.exists ()) ^Gt9.  
{ RZL:k;}5  
bFirst = false; Q>QES-.l  
read_nPos(); _v\L'`bif  
} Shag4-*@hi  
else vR*TW   
{ Cju%CE3a  
nStartPos = new long[bean.getNSplitter()]; #q-7#pp  
nEndPos = new long[bean.getNSplitter()]; USrBi[_ci\  
} }i\U,mH0_&  
QRw/d}8l  
J;R1OJs S  
]A.tauSW  
} :}n\ r/i  
YT@D*\  
Pkq?tm$#  
public void run() I5$]{:L|9  
{ 2cu?2_,  
//获得文件长度 ^?Y x{r~9  
//分割文件 Jmcf9g  
//实例FileSplitterFetch ^ALR.N+<  
//启动FileSplitterFetch线程 HuRq0/"  
//等待子线程返回 x[m&ILr  
try{ ]hC6PKJU  
if(bFirst) {zmh0c; |  
{ *y@Xm~ld  
nFileLength = getFileSize(); (imaL,M-D  
if(nFileLength == -1) A])+Pe  
{ g UAx8=h  
System.err.println("File Length is not known!"); ] l@Mo7|w  
} '^# =,+ A  
else if(nFileLength == -2) %@Ow.7zh  
{ iQ7S*s+l5O  
System.err.println("File is not access!"); !h[xeLlU  
} -&UP[Mq  
else Oh]RIWL  
{ y<0RgG1qp  
for(int i=0;i<nStartPos.length;i++) fvH4<c5x  
{ %+F%C=GqI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #@^mA{Dt5  
} B*c@w~E  
for(int i=0;i<nEndPos.length-1;i++) [.[|rnil  
{ :IB@@5r1  
nEndPos = nStartPos[i+1]; a|5^4 J \%  
} r}%2;!T  
nEndPos[nEndPos.length-1] = nFileLength; O S%  
} KO''B or  
} 'Io2",~ M  
2]i>kV/,0  
552U~t  
//启动子线程 Z+EN]02|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !8ch&cr)o+  
for(int i=0;i<nStartPos.length;i++) eX0ASI9  
{  8-.jf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F&[MyXU4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Mb +  
nStartPos,nEndPos,i); Hp}dm93T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g6V>_|  
fileSplitterFetch.start(); 3`%U)gCT5  
} H-ewO8@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^.:dT?@R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G1z0q3< B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 079mn/8;  
nEndPos = " + nFileLength); tg|7\Z7i  
// fileSplitterFetch[nPos.length-1].start(); j7u\.xu9  
z!> H^v  
16Gp nb  
//等待子线程结束  FKpyD  
//int count = 0; >/eV4ma"  
//是否结束while循环 7!r)[2l  
boolean breakWhile = false; =T3O;i  
c!20(( 2|I  
uu`G<n  
while(!bStop) 9u%S<F"  
{ DI,8y"!5  
write_nPos(); s^6"qhTa  
Utility.sleep(500); S#g=;hD  
breakWhile = true; s;NPY  
x=jS=3$8  
2 ,bLEhu  
for(int i=0;i<nStartPos.length;i++) %*Aq%,.={  
{ S(MVL!Lm  
if(!fileSplitterFetch.bDownOver) |o0?u:  
{ %hO/2u  
breakWhile = false; s?-J`k~q  
break; C;BC@OE  
} W2-1oS~ma  
} m c q!_#{y  
if(breakWhile) qQ=\R1l  
break; =bDy :yY}  
U) B^R  
2C@s-`b   
//count++; 10`]&v]T  
//if(count>4) %g+*.8;"b  
// siteStop(); J3P )oM[  
} v$_YZm{!<  
pipO ,n  
fBZAO  
System.err.println("文件下载结束!"); E%tGwbi7  
} ER4j=O#  
catch(Exception e){e.printStackTrace ();} "oc&uj  
} {T2=bK~  
OqNtTk+  
@GrQ /F7  
//获得文件长度 g[ dI%  
public long getFileSize() nJ{vO{N  
{ !caY  
int nFileLength = -1; ?r"QJa>  
try{ FvTc{"w /  
URL url = new URL(siteInfoBean.getSSiteURL()); ,Q>Rt V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $lYy`OuC  
httpConnection.setRequestProperty("User-Agent","NetFox"); \n}@}E L  
t7 ].33%\  
.W/#$s|X\  
int responseCode=httpConnection.getResponseCode(); ay-M.J  
if(responseCode>=400) =k +nC)e  
{ ~n<U8cm O  
processErrorCode(responseCode); 7>sNjOt@M  
return -2; //-2 represent access is error /%4wm?(eA  
} -<MA\iSP  
M}c gVMW  
07FS|>DM'Z  
String sHeader; r iuG,$EX  
E]<Ce;Vj  
!Ic{lB   
for(int i=1;;i++) QhqXd  
{ B<}0r 4T}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); oI2YJ2?Je8  
//Utility.log(in.readLine()); t<%S_J\  
sHeader=httpConnection.getHeaderFieldKey(i); m.|__L  
if(sHeader!=null) Cvk n2T  
{ U|2*.''+Q  
if(sHeader.equals("Content-Length")) F[HMX4  
{ 1B#Z<p  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KOqp@K$  
break; Rfuq(DwD6  
} <.6bni )  
} |4lrVYG^K  
else 6%nKrK  
break; Frxim  
} SmR"gu  
} aOWfu^&H:  
catch(IOException e){e.printStackTrace ();} 0w24lVR.  
catch(Exception e){e.printStackTrace ();} D6wg^ 'Q:  
|#x]FNg  
&t0toEj  
Utility.log(nFileLength); T+9#&  
n@"h^-  
/ZcqKC  
return nFileLength; GLIe8T*ht  
} QL{{GQ_dn  
X Nm%O  
`VB]4i}u  
//保存下载信息(文件指针位置) fsr0E=nV  
private void write_nPos() &-s/F`  
{ icnc5G  
try{ _#2AdhCu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); l[)ZEEP  
output.writeInt(nStartPos.length); P{{pp<tX*&  
for(int i=0;i<nStartPos.length;i++) x9&{@ ?o  
{ liuF;*  
// output.writeLong(nPos); e?"XMY  
output.writeLong(fileSplitterFetch.nStartPos); k&kx%skz  
output.writeLong(fileSplitterFetch.nEndPos); nKP[U=ac  
} =@UgCu>=  
output.close(); E }*   
} JkiMrpkuk  
catch(IOException e){e.printStackTrace ();} pP`KI'aUN  
catch(Exception e){e.printStackTrace ();} n%"0%A  
} HRPNZ!B  
E(l'\q'.  
/M.@dW7 w  
//读取保存的下载信息(文件指针位置) tCw.wDq3=  
private void read_nPos() ,2I8,MOg  
{ ebuR-9  
try{ kN99(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); z 5T_  
int nCount = input.readInt(); svBT~P0x  
nStartPos = new long[nCount]; tBZ&h` V  
nEndPos = new long[nCount]; rTR4j>Ua~  
for(int i=0;i<nStartPos.length;i++) h.`U)6*?&N  
{ ?\eq!bu  
nStartPos = input.readLong(); o,#[Se*n  
nEndPos = input.readLong(); }.uB6&!:  
} H,F/u&O  
input.close(); *t,J4c  
} .Y?/J,Ch  
catch(IOException e){e.printStackTrace ();} &?-LL{W{  
catch(Exception e){e.printStackTrace ();} Ot]Y/;K  
} :4ndU:.L  
\; b)qB  
h7EKb-@  
private void processErrorCode(int nErrorCode) -RSPYQjz  
{ m _0D^e7#  
System.err.println("Error Code : " + nErrorCode); jf_0IE  
} N<xf=a+j  
UP@a ?w  
X C jYm  
//停止文件下载 }P5zf$  
public void siteStop() '}`|QJ  
{ Pmj]"7Vd[  
bStop = true; Y[A`r0  
for(int i=0;i<nStartPos.length;i++) Llf |fayq  
fileSplitterFetch.splitterStop(); d" "GG/  
31w9$H N  
&*I\~;1  
} :?Xd&u0){  
} =ZsM[wd  
//负责部分文件的抓取 3lyk/',  
**FileSplitterFetch.java FyZa1%Tv@  
*/ P(_wT:8C?  
package NetFox; Z=ayVsJ3  
uc% &g  
CvCk#:@HM  
import java.io.*; 6AZJ,Q\E@  
import java.net.*; RP 2MtP"M  
idm!6]  
C] <K s  
public class FileSplitterFetch extends Thread { 0hKF)b  
\iQD\=o  
+F &,,s"&  
String sURL; //File URL q;T3bxp+  
long nStartPos; //File Snippet Start Position RLypWjMx$  
long nEndPos; //File Snippet End Position U&fOsx?"  
int nThreadID; //Thread's ID 05(lh<C  
boolean bDownOver = false; //Downing is over C+r<DC3  
boolean bStop = false; //Stop identical 5Rv6+d  
FileAccessI fileAccessI = null; //File Access interface Kilq Jg1%C  
73$^y)AvY  
})V9d  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Gy9+-7"V  
{ la ~T)U7  
this.sURL = sURL; |kvom 4T  
this.nStartPos = nStart; ta>:iQ a  
this.nEndPos = nEnd; G<kslTPyq  
nThreadID = id; 10v4k<xb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Azx4+`!-  
} })Og sBk  
N[ %^0T$  
r5qp[Ss3F  
public void run() ]8(_{@ /  
{ )bZS0f-  
while(nStartPos < nEndPos && !bStop) iH& Izv  
{ j2T Z`Z?a^  
>9{Gdq[gyr  
g{@q  
try{ _B` '1tNx  
URL url = new URL(sURL); j]EeL=H<P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G#ov2  
httpConnection.setRequestProperty("User-Agent","NetFox"); |3f?1:"Z  
String sProperty = "bytes="+nStartPos+"-"; .jRp.U  
httpConnection.setRequestProperty("RANGE",sProperty); SxLu<  
Utility.log(sProperty); ql5NSQ>{  
Z 6^AO=3  
fYF\5/_  
InputStream input = httpConnection.getInputStream(); dxkq*  
//logResponseHead(httpConnection); d\}r.pD  
j  )6A  
F}P+3IaE  
byte[] b = new byte[1024]; ahNpHTPa  
int nRead; h#9X0u7j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q=lQy  
{ EnXNTat})  
nStartPos += fileAccessI.write(b,0,nRead); 8 /1 sy.R  
//if(nThreadID == 1) w-l:* EV8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [mKPOg-t  
} !6: kJL}U  
@K; 4'b~  
oJJ2y  
Utility.log("Thread " + nThreadID + " is over!"); 4QODuyl2H  
bDownOver = true; 5LU8QHj3  
//nPos = fileAccessI.write (b,0,nRead); (j;s6g0  
} V dp wZ  
catch(Exception e){e.printStackTrace ();} I/D (gY06<  
} v'(p."g  
} Lu!o!>b  
UU')V  
9 |v3lGK(  
//打印回应的头信息 J ylav:  
public void logResponseHead(HttpURLConnection con) 6qQdTp{i  
{ <U(wLG'XS  
for(int i=1;;i++) (055>D6  
{ Coz\fL  
String header=con.getHeaderFieldKey(i); };"-6e/9  
if(header!=null) K[JbQ30  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); vZ[wr@)  
Utility.log(header+" : "+con.getHeaderField(header));  }t}y  
else 'E FP/(2J  
break; k^ B<t'  
} KECo7i=e  
} Hd H,   
b_2bg>|;  
o NX-vN-  
public void splitterStop() LUSBRr8  
{ 34S0W]V  
bStop = true; ]t$wK  
} -?L~\WJAL  
/ i[F  
!Au'WJfE  
} tnL$v2e6q  
ASA ]7qyO  
?:DeOBAb  
/* z2'3P{#s  
**FileAccess.java r]JV !'R  
*//文件访问(定位,写) oD1rt>k  
package NetFox; fS9TDy  
import java.io.*; ;7,>2VTm  
?wM{NVt#-  
M&auA  
public class FileAccessI implements Serializable{ (R^X3  
#Bu W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *Ae> ,LyE  
RandomAccessFile oSavedFile; miWog8j  
long nPos; ZSWKVTi  
hb@,fgo!Q  
7dxTyn=  
public FileAccessI() throws IOException C8dC_9  
{ B?M&j  
this("",0); >~_oSC)E  
} 05 56#U&>  
E~]37!,\\9  
oUSv)G.zb  
public FileAccessI(String sName,long nPos) throws IOException (r Tn6[ *  
{ 3Lg)237&j  
oSavedFile = new RandomAccessFile(sName,"rw"); &Ul8h,qw  
this.nPos = nPos; /i:c!l9  
oSavedFile.seek(nPos); $W_sIS0\z  
} /O`<?aP%  
c+a"sx\  
<PMQ$s>KK  
public synchronized int write(byte[] b,int nStart,int nLen) RX])#=Cs  
{ kH4xP3. i  
int n = -1; 5`>%{ o  
try{ {wK| C<K  
oSavedFile.write(b,nStart,nLen); X0FTD':f  
n = nLen; A!GQ4.~%  
} 1@}s:  
catch(IOException e) H@|h Nn$@  
{ 1 r9.JS  
e.printStackTrace (); m7 $t$/g  
} Bjc<d,]  
_GW,9s^A  
cPp<+ ts  
return n; @sPuc.  
} k`(Cwp{Oc  
tS[@3h  
HI\V29 a  
} 8~!9bg6C  
bCfw,V{sce  
UlD]!5NO  
/* P9yg  
**SiteInfoBean.java jt?DogYx  
*/ &@U)  
package NetFox; l>D!@`><I  
wAA9M4  
LW#$%}  
public class SiteInfoBean { :jHDeF.A  
yM PZ}  
han S8  
private String sSiteURL; //Site's URL Va-.  
private String sFilePath; //Saved File's Path (dnaT-M3  
private String sFileName; //Saved File's Name E``\Jre@  
private int nSplitter; //Count of Splited Downloading File ir<K"wi(2  
8#h~J>u.  
^3O`8o  
public SiteInfoBean() ]w/%>  
{//nSplitter的缺省值为5 \R|qXB $  
//default value of nSplitter is 5 w:3CWF4q]  
this("","","",5); @.8FVF  
} [,TK"  
:zK\t5  
bH`r=@.:cu  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q]rqFP0C  
{ LB\+*P6QM  
sSiteURL= sURL; [J\! 2\Oo  
sFilePath = sPath; s$ZKd  
sFileName = sName; *wl&Zzx  
this.nSplitter = nSpiltter; XtftG7r9S  
bFB.hkTP  
I~T~!^}U  
} i~ITRi@  
E HH+)mlo  
'9tV-whw  
public String getSSiteURL() Lgrpy  
{ r 3FUddF'  
return sSiteURL; @$R^-_m  
} jn._4TQ*}  
U}c05GiQw  
9D{p^hd  
public void setSSiteURL(String value) zOn% \  
{ /|WBk}  
sSiteURL = value;  I#U)  
} JLh{>_Rr  
il~A(`+YO  
4YyVh.x  
public String getSFilePath() |*y'H*  
{ PwS7!dzH-  
return sFilePath; NxrfRhaU3  
} 0I7 r{T  
i/j eb*d0  
q 1~3T;Il  
public void setSFilePath(String value) m/p:W/0L  
{ !CUX13/0  
sFilePath = value; EeDK ^W8N  
} G~{#%i  
f19'IH$n{  
8^5@J) R8  
public String getSFileName() DpvMY94Qh  
{ VskdC?yIp  
return sFileName; >"<<hjKJ  
} _.+2sm   
Ybp';8V  
[_1K1i"m  
public void setSFileName(String value) QRz5eGpW  
{ cjc1iciZ  
sFileName = value; ;bYLQ  
} !b?`TUt   
kA{eT  
{"hyr/SKd  
public int getNSplitter() {LqahO*  
{ .Gn-`  
return nSplitter; 63T4''bwu  
} :0vKt 6>Sp  
]<:qMLg  
?7\$zn)v#  
public void setNSplitter(int nCount) 4C`p`AQqpQ  
{ *9|*21  
nSplitter = nCount; 8w9?n3z=}  
} g%%j"Cz1  
} !xz{X?  
*s6(1 S  
K yDPD'  
/* YTV|]xpR  
**Utility.java i1DJ0xC]  
*/ ;\rKkH"K8n  
package NetFox; (laVmU?I7  
Mo0pN\A}h  
ebIRXUF}>  
public class Utility { QRlrcauM  
*7^w}v+.  
z0xw0M+X  
public Utility() ?vV&tqnx%  
{ 6 u}c543  
xL\R-H^c]  
Ue!~|:  
} n--w-1  
,xuA%CF-S  
//线程睡眠 r"x/,!_E  
public static void sleep(int nSecond) ghDOz 3  
{ `m=u2kxY  
try{ y({EF~w  
Thread.sleep(nSecond); X$9 "dL  
} k/.a yLq  
catch(Exception e) #6F/:j;  
{ H* vd  
e.printStackTrace ();  d>}R3T  
} F8>J(7On  
} *."a>?D~  
+w9X$<?_  
//日志 BiCC72oig  
public static void log(String sMsg) /6nj 4.xxc  
{ g: ,*Y^T  
System.err.println(sMsg); z P=3B%$  
} (sL!nRw  
Pef$-3aP>E  
tP0!TkTo9  
public static void log(int sMsg) 4A\>O?\  
{  Mt   
System.err.println(sMsg); wH0Ks5  
} g"|Z1iy|9  
} ;SVAar4r  
I'a&n}j x  
+nm?+ F  
/* RAi]9`*7  
**TestMethod.java drW}w+ !  
*/ %xh A2  
package NetFox; dXewS_7  
,e!9WKJ B  
y-k]Tr  
public class TestMethod { Q|i`s=|  
U[WR?J4~LX  
K f}h{X  
public TestMethod() >TB Rp,;r  
{ ///xx/weblogic60b2_win.exe eO?@K$I  
try{ +RN|ZG&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Gz@/:dW^vZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5.X`[/]<r  
SiteFileFetch fileFetch = new SiteFileFetch(bean); NI33lp$V  
fileFetch.start(); HYWKx><   
} ~$:=hT1  
catch(Exception e){e.printStackTrace ();} bZ_vb? n  
{3R?<ET]mt  
z57|9$h}w  
} *7:HO{P>Y  
U1~6o"1H  
i\94e{uty[  
public static void main(String[] args) ^7$V>|  
{ r8Pdk/CW^  
new TestMethod(); Q~S3d  
} 0DgEOW9H  
} 6O# xV:Uc<  
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