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http断点续传简单实现(java)

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/* GST#b6S  
**SiteFileFetch.java H=@KlSC ^  
*/ N>(w+h+  
package NetFox; U~D~C~\2;  
import java.io.*; 0B(s+#s  
import java.net.*; h/n(  
jfG of*  
wp@_4Iq1$  
public class SiteFileFetch extends Thread { (iq>]-=<  
9s<4`oa  
Cn/WNCzst&  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?9t4>xKn  
long[] nStartPos; //开始位置 u"&?u+1j  
long[] nEndPos; //结束位置 hEHd$tH06  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PIU@ }:}  
long nFileLength; //文件长度 H^|TV]^;N  
boolean bFirst = true; //是否第一次取文件 Ah1 9#0  
boolean bStop = false; //停止标志 t#"0^$l=  
File tmpFile; //文件下载的临时信息 joI)6c  
DataOutputStream output; //输出到文件的输出流 x/?ET1iGt  
36Lkcda[  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 1(@$bsgu2  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~vA{I%z5~  
{ !S=YM<Ad  
siteInfoBean = bean; \2kLj2!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &%rM|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Xr  <H^X  
if(tmpFile.exists ()) l_}d Q&R  
{ |RL#BKC`  
bFirst = false; t.8r~2(?  
read_nPos(); \96\!7$@O  
} QdgJNT<=H,  
else ;mEn@@{  
{ 4|K\pCw  
nStartPos = new long[bean.getNSplitter()]; UF7h{V})  
nEndPos = new long[bean.getNSplitter()]; f|,Kh1{e  
} {_N9<i{T  
wPM&N@Pf  
s)- ;74(  
wj6u,+  
} 5TJd9:\Af  
bY#BK_8 :  
Dy.i^`7\  
public void run() MS\vrq'_  
{ ?=9'?K/~a  
//获得文件长度 4`i8m  
//分割文件 41<~_+-@  
//实例FileSplitterFetch n725hY6}<l  
//启动FileSplitterFetch线程 +vy fhw4  
//等待子线程返回 d#E&,^@M  
try{ }gQ2\6o2g  
if(bFirst) 7(1`,Y  
{ %_W4\  
nFileLength = getFileSize(); XHU$&t`7>g  
if(nFileLength == -1) T [$-])iK  
{ -8^qtB  
System.err.println("File Length is not known!"); <-k!  
} SO6)FiPy!n  
else if(nFileLength == -2) ASHU0v  
{ '?Dxe B  
System.err.println("File is not access!"); 3tZIL  
} CFh9@Nx  
else jh oA6I  
{ #VrIU8Q7'  
for(int i=0;i<nStartPos.length;i++) I6 ?(@,  
{ B,\VLX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t}eyfflZ  
} %]Z4b;W[Y  
for(int i=0;i<nEndPos.length-1;i++) K ~mUO  
{ aG]>{(~cL  
nEndPos = nStartPos[i+1]; pA*C|g  
} w*6b%h%ww  
nEndPos[nEndPos.length-1] = nFileLength; -g~+9/;n  
} . f_ A%  
} \<pr28  
y;ElSt;S  
:C>7HEh-2_  
//启动子线程 'O(=Pz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Gt.'_hf Js  
for(int i=0;i<nStartPos.length;i++) wNHn.  
{ sm-[=d%@L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 83c2y;|8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QP%_2m>yhl  
nStartPos,nEndPos,i); o=YOn&@%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M?lh1Yu"  
fileSplitterFetch.start(); }R}+8  
} #Kb /tOp1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >S I'Q7k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M,fL(b;2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n.+'9Fj  
nEndPos = " + nFileLength); wS}c \!@<,  
// fileSplitterFetch[nPos.length-1].start(); o^/ #i`)  
|@AXW   
Y_CVDKdcY  
//等待子线程结束 V^,gpTyv*  
//int count = 0; nW)+-Wxq  
//是否结束while循环 /i"hViCrlG  
boolean breakWhile = false; &q>8D'  
6=;:[  
$/M-@3wro  
while(!bStop) Z i6s0Uck  
{ hty'L61\z  
write_nPos(); fLe~X!#HF  
Utility.sleep(500); Z oXz@/T  
breakWhile = true; z&gma Ywq  
(S!UnBb&  
`2 <:$]  
for(int i=0;i<nStartPos.length;i++) itzUq,T  
{ B2[f1IMI  
if(!fileSplitterFetch.bDownOver) }i!+d,|f  
{ .rK0C)  
breakWhile = false; geR :FO;\  
break; yq-~5ui  
} Q|)>9m!tt  
} %NQ%6 B  
if(breakWhile) ,LA'^I?  
break; R0=f`;  
`a& L  
<2)AbI+3  
//count++; .~o{i_JH  
//if(count>4) eaFkDl  
// siteStop(); hTDGgSG^  
} *5PQ>d G  
naaKAZ!S  
|<c9ZS+  
System.err.println("文件下载结束!"); ,7s>#b'  
} b23A&1X  
catch(Exception e){e.printStackTrace ();} n0=]C%wr  
} &|XgWZS5  
yF)J7a:U  
 zjUQ]  
//获得文件长度 Gt&yz"?D  
public long getFileSize() >.qFhO\1so  
{ iLnW5yy  
int nFileLength = -1; 4<($ZN8  
try{ +S{m!j%B  
URL url = new URL(siteInfoBean.getSSiteURL()); zls^JTE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zdwQpB,+^  
httpConnection.setRequestProperty("User-Agent","NetFox"); @m5J%8>k  
:=hL}(~]  
Yd3lL:M  
int responseCode=httpConnection.getResponseCode(); "zq'nV=  
if(responseCode>=400) )3CM9P'0  
{ b;VIR,2  
processErrorCode(responseCode); ''9]`B,:a0  
return -2; //-2 represent access is error G %sO{k7  
} 6vK`J"d{~D  
G Uu8 N  
R%3yxnM*  
String sHeader; Z@euO~e~  
fZ-"._9UyH  
%$ya>0?mq  
for(int i=1;;i++) b*Qd9  
{ IIAp-Y~B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W_wC"?A%  
//Utility.log(in.readLine()); \NNA"  
sHeader=httpConnection.getHeaderFieldKey(i); C)U4Fr ?E:  
if(sHeader!=null) M1eh4IVE?  
{ sR/Y v  
if(sHeader.equals("Content-Length")) -Hm"Dx  
{ .8QhJHwd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ug]2wftlQ  
break; fR[8O\U~  
} ;:=j{,&dl[  
} _AF$E"f@  
else FC+-|1?C  
break; Ou1kSG|kM  
} $?F_Qsy{d  
} d9JAt-6z2  
catch(IOException e){e.printStackTrace ();} RP2$(%  
catch(Exception e){e.printStackTrace ();} O.FTToh<  
g ba1R  
rCa]T@=  
Utility.log(nFileLength); 3YLK?X8  
P1OYS\  
drAJ-ii  
return nFileLength; :WWHEZK  
} h.?<( I  
ky|kg@n{  
B-LV/WJ_  
//保存下载信息(文件指针位置) UhJS=YvT  
private void write_nPos() lai@,_<GV  
{ eM!Oc$C8[  
try{ Ly(iq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0dwD ?GG2  
output.writeInt(nStartPos.length); ^JxVs 7  
for(int i=0;i<nStartPos.length;i++) 6/cm TT$i  
{ ED8{  
// output.writeLong(nPos); %S^ke`MhF  
output.writeLong(fileSplitterFetch.nStartPos); 5:38}p9`  
output.writeLong(fileSplitterFetch.nEndPos); 7d.H 8C2  
} U`) " ;WN  
output.close(); s>L-0vG  
} d1#lC*.Sg  
catch(IOException e){e.printStackTrace ();} cWnEp';.  
catch(Exception e){e.printStackTrace ();} ;L:UYhDbUx  
} oTvg%bX  
z@UH[>^gj  
1;m?:|6K{  
//读取保存的下载信息(文件指针位置) AM?ZhM  
private void read_nPos() \GHj_r  
{ gIweL{Pc  
try{ )r"R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z<|x6%  
int nCount = input.readInt(); B[mZQ&Gz`a  
nStartPos = new long[nCount]; vV"YgN:  
nEndPos = new long[nCount]; v3[ZPc;;  
for(int i=0;i<nStartPos.length;i++) Ew]&~:$Ki  
{ LntRLB'  
nStartPos = input.readLong(); +mG"m hF  
nEndPos = input.readLong(); T=w0T-[f  
} j 7);N  
input.close(); [|$C2Dhw=  
} GF@` ~im  
catch(IOException e){e.printStackTrace ();} ug}u>vQ>  
catch(Exception e){e.printStackTrace ();} :{eYm|2-  
} sz%]rN6$  
4NRj>y  
D+AkV|  
private void processErrorCode(int nErrorCode) !|9@f$Jv  
{ 0xi2VN"X  
System.err.println("Error Code : " + nErrorCode); `!X8Cn  
} I RLAsb3  
"$5cKbJ  
QX?moW6UW  
//停止文件下载 yz3=#  
public void siteStop() ^VzhjKSu  
{ 7lYf+&JZ  
bStop = true; fvta<  
for(int i=0;i<nStartPos.length;i++) }x6)}sz7  
fileSplitterFetch.splitterStop(); "w 4^i!\  
43=)akJi  
YpZuAJm<2_  
} ~2[kCuu  
} T g(\7Kq  
//负责部分文件的抓取 L5:1dF  
**FileSplitterFetch.java nCV7(ldmH  
*/ B{` K?e0  
package NetFox; +bso4 }rS  
q+qF;7dN@  
) F -8  
import java.io.*; wtL=^  
import java.net.*; uCt?(E>  
&n?RKcH}d  
Cw!tB1D  
public class FileSplitterFetch extends Thread { "KCG']DF  
J10/pS  
C5KUIOg  
String sURL; //File URL kg(}%Ih  
long nStartPos; //File Snippet Start Position asQ^33g z  
long nEndPos; //File Snippet End Position SPe%9J+  
int nThreadID; //Thread's ID cAx$W6S  
boolean bDownOver = false; //Downing is over ,ZYPffu<*  
boolean bStop = false; //Stop identical _^?_Vb  
FileAccessI fileAccessI = null; //File Access interface nql{k/6  
3 %BI+1&T_  
F1}d@^K 7d  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6%9 kc+ 9  
{ Rc93Fb-Zp  
this.sURL = sURL; u>] )q7s  
this.nStartPos = nStart; a$iDn_{  
this.nEndPos = nEnd; D0_CDdW%7  
nThreadID = id; =^zGn+@z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Fv(FRZ)  
} N3Q .4? z9  
Z>/ *q2  
W3('1  
public void run() ]T40VGJ:h  
{ o*~=NoR  
while(nStartPos < nEndPos && !bStop) O<AGAD  
{ <v\$r2C*  
wqjR-$c  
r~|7paX!  
try{ ^\S~rW.3_  
URL url = new URL(sURL); x'G_z_<V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q`O~f<a  
httpConnection.setRequestProperty("User-Agent","NetFox"); bO('y@)X  
String sProperty = "bytes="+nStartPos+"-"; );S8`V  
httpConnection.setRequestProperty("RANGE",sProperty); ^IvQdVB  
Utility.log(sProperty); E&"V~  
00>knCe6  
aU.!+e%_  
InputStream input = httpConnection.getInputStream(); EpT^r8I  
//logResponseHead(httpConnection); 8B "^}y\0  
&\ad.O/Q  
U.Z5;E0:  
byte[] b = new byte[1024]; 0Bkc93  
int nRead; 5)rN#_BKj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :Ez*<;pF'  
{ }0/l48G  
nStartPos += fileAccessI.write(b,0,nRead); WS@"8+re;  
//if(nThreadID == 1) osO\ib_%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B<.ZW}#v  
} EZp >Cf7  
]W`M <hEI  
8F$]@0v`%  
Utility.log("Thread " + nThreadID + " is over!"); BEAY}P(y3  
bDownOver = true; dtG>iJ  
//nPos = fileAccessI.write (b,0,nRead); gL@]p  
} O"X7 DgbC  
catch(Exception e){e.printStackTrace ();} [1Qg *   
} +'w6=qI  
} d&ff1(j(  
[_KOU2  
DHvZ:)aT}  
//打印回应的头信息 A&jR-%JG  
public void logResponseHead(HttpURLConnection con)  e?o/H  
{ p&2d&;Qo0  
for(int i=1;;i++) (_N(K`4#W  
{ U9\w)D|+eE  
String header=con.getHeaderFieldKey(i); D deKZ)8  
if(header!=null) ]Ee$ulJ02  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); eT2Tg5Etc  
Utility.log(header+" : "+con.getHeaderField(header)); s I0:<6W  
else `4Fw,:+e  
break; m,5?|J=  
} lG[j,MDs  
} qJ~fEX  
Da)_OJYE  
puh-\Q/P  
public void splitterStop() !@arPN$  
{ tu ;Pm4q7  
bStop = true; <a+ @4d;  
} B <G,{k  
w)R5@ @C*  
Zx: h)I  
} j(>xP*il  
ZP0D)@8  
+KTHZpp!c2  
/* .jbxA2  
**FileAccess.java CFoR!r:X  
*//文件访问(定位,写) r&F 6ZCw  
package NetFox; 4`o<e)c3  
import java.io.*; \0e`sOS`L  
Vkf{dHjW  
\zDs3Hp  
public class FileAccessI implements Serializable{ 5Z:qU{[  
7^d7:1M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \W\*'C8q\  
RandomAccessFile oSavedFile; 9pWSvalw9  
long nPos; *dC&*6Rx  
6y^GMlsI  
{lppv(U  
public FileAccessI() throws IOException Bob-qCBV  
{ >4+KEK  
this("",0); h$6~3^g:P  
} 0x^lHBYc  
5x,/p  
hL}ZPHA  
public FileAccessI(String sName,long nPos) throws IOException cT;Zz5  
{ t4hc X[  
oSavedFile = new RandomAccessFile(sName,"rw");  &Du S*  
this.nPos = nPos; T_9o0Qk  
oSavedFile.seek(nPos); m GJRCK_  
} "];@N!dA  
z'"Y+EWN  
1FT3d  
public synchronized int write(byte[] b,int nStart,int nLen) Pl2eDv-y  
{ bg)}-]u]  
int n = -1; g^\!> i  
try{ h7o.RRhK  
oSavedFile.write(b,nStart,nLen); $Fy >N>,E(  
n = nLen; eYu0")  
} :s-9@Yl|  
catch(IOException e) 9E[==2TO  
{ Ua=r24fy  
e.printStackTrace (); mwI7[I2q  
} $>+g)  
>Ml5QO$*.q  
*{\))Zmhd  
return n; (<e<Q~(  
} #nAq~@X  
jCIY(/  
[r'A8!/|[  
} ki1j~q  
&H+n0v  
' d?6 L  
/* 7lKatk+7K  
**SiteInfoBean.java "I9r>=  
*/ ~mMTfC~9  
package NetFox; >6)|># Wi  
lJT"aXt'M  
7;&,L H  
public class SiteInfoBean { Sn' +~6i  
L1y71+iqU  
Vobq|Rd/%  
private String sSiteURL; //Site's URL lWT`y  
private String sFilePath; //Saved File's Path <vD(,||  
private String sFileName; //Saved File's Name n.C5w8f  
private int nSplitter; //Count of Splited Downloading File H/={RuU  
sNP ;  
( 5uSqw&U  
public SiteInfoBean() (Fq:G) $  
{//nSplitter的缺省值为5 9b@yDq3hQ  
//default value of nSplitter is 5 tE-g]y3  
this("","","",5); 1xh7KBr,  
} Z/|=@gpw  
:3b02}b7  
Q( e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8.+ yZTg  
{ :fq4oHA#  
sSiteURL= sURL; Ps[#z@5{x  
sFilePath = sPath; %&q}5Y4!  
sFileName = sName; -~X[j2  
this.nSplitter = nSpiltter; 6E9/ z  
aUA)p}/:  
tCar:p4$  
} #3'M>SaoH  
kQQDaZ 8  
*v?kp>O  
public String getSSiteURL() 0'YJczDq:7  
{ 5}Xi`'g,  
return sSiteURL; NSH4 @x  
} ~-B+7  
1MT,A_L  
f*9O39&|  
public void setSSiteURL(String value) 7q 5 *grm  
{ Z&P\}mm   
sSiteURL = value; mVh;=>8K  
} BBv+*jj  
"^a"`?J  
)S/=5Uc  
public String getSFilePath() V w58w`e  
{ 8F@Sy,D  
return sFilePath; m7u`r(&  
} 0z4M/WrNt  
ItZYOt|Hn  
ju .pQ=PSX  
public void setSFilePath(String value) rPqM&&+  
{ a(D=ZKbVU  
sFilePath = value; 9 %i\)  
} ~131|e`C  
p8?v o ?^  
>}W[>WReI  
public String getSFileName() HXztEEK6  
{ bS954d/  
return sFileName; %\n|2*r  
} f fBd  
a7453s  
`(=Kp=b  
public void setSFileName(String value) 7mMMVz2  
{ cO 5zg<wF  
sFileName = value; +mzLOJed  
} $bFK2yx?=  
zNdkwj p+  
AS re@pW  
public int getNSplitter() kfT*G +l]  
{ s(J>yd=  
return nSplitter; FF! PmfF'  
} ela^L_NhF  
mtn^+*  
U V*Ruy-  
public void setNSplitter(int nCount) J%M [8  
{ 6)P.wW  
nSplitter = nCount; C H 29kQ  
} NY.* S6  
} ~(kqq#=s  
Ke?,AWfG  
KAI2[ gs  
/* 79exZ7|  
**Utility.java hpPacN  
*/ 8T6NG!/  
package NetFox; hh&$xlO)(v  
o ]z#~^w  
}u=Oi@~  
public class Utility { ^2+ Vt=*  
D&D6!jz  
) ba~7A  
public Utility() lv'WRS'}  
{ '?L^Fa_H  
kLZVTVSJt  
]+W){W=ai  
} O=(F46 M  
EwA*  
//线程睡眠 4gsQ:3  
public static void sleep(int nSecond) 7bihP@I !  
{ ZDgT"53   
try{ ,m5i(WL  
Thread.sleep(nSecond); p\lR1  
} UU MB"3e  
catch(Exception e) 6[c|14l  
{ !$oa6*<1  
e.printStackTrace (); %xOxMK@  
} |%v:>XEO  
} G 2)F<Y  
}X^MB  
//日志 ,aC}0t  
public static void log(String sMsg) :T G;W,`.V  
{ c {%mi  
System.err.println(sMsg); -OlrA{=c_  
} 10 *Tk 8  
XGH:'^o_  
AJxN9[Z!N  
public static void log(int sMsg) }9fch9>Zr  
{ jYRSV7d  
System.err.println(sMsg); nW7: ]  
} bS r"k  
} j9h fW'  
=2Yt[8';  
YZ4`b-  
/* KGg S"d  
**TestMethod.java "g&f:[a/  
*/ H~:oW~Ah  
package NetFox; -ZZJk-::  
?{J1Uw<  
3zD#V3 =  
public class TestMethod { GyN|beou  
c]aU}[s1  
t~/:St  
public TestMethod() 9$ ;5J  
{ ///xx/weblogic60b2_win.exe -oyA5Y x0  
try{ rSJ!vQo Cb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]B=*p0~j^n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T :X*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O& Sk}^  
fileFetch.start(); $jE<n/8  
} E OXkMr  
catch(Exception e){e.printStackTrace ();} <KU 0K  
hQm=9gS  
0't)-Pj+,  
} =CK%Zo  
 Jc ze.t  
M?" 4 {  
public static void main(String[] args) f/UU{vX(  
{ O0L]xr  
new TestMethod(); s)r !3HS  
} "I/05k K  
} K {v^Y,B  
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