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http断点续传简单实现(java)

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/* GuDD7~qxY  
**SiteFileFetch.java F+-MafN7Y  
*/ 2p.+C35c=j  
package NetFox; 8>+eGz|  
import java.io.*; [~JN n  
import java.net.*; >Nqkz?67  
@,$HqJ  
ky"7 ^  
public class SiteFileFetch extends Thread { fb=vO U  
5d;K.O  
4[j) $!l`  
SiteInfoBean siteInfoBean = null; //文件信息Bean w8Vzx8  
long[] nStartPos; //开始位置 md_s2d  
long[] nEndPos; //结束位置 p)] ^>-L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  0d)n} fm  
long nFileLength; //文件长度 @d9*<>@:  
boolean bFirst = true; //是否第一次取文件 3VgH* vAU}  
boolean bStop = false; //停止标志 I`lH6hHp  
File tmpFile; //文件下载的临时信息 ~%q e,  
DataOutputStream output; //输出到文件的输出流 <"9Z7" >  
P9~kN|  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [vJosbU;  
public SiteFileFetch(SiteInfoBean bean) throws IOException @WUCv7U  
{ 8u23@?  
siteInfoBean = bean; 2!`Z3>Oa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A[Xw|9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $S=OmdgR  
if(tmpFile.exists ()) cv&hT.1  
{ z`6KX93  
bFirst = false; "K]4j]yU  
read_nPos(); @}}1xP4Sr  
} a MD?^  
else $(hZw  
{ @g?z>n n  
nStartPos = new long[bean.getNSplitter()]; A#\X-8/  
nEndPos = new long[bean.getNSplitter()]; D^4V"rq  
} t*$@QO  
v0p EN\  
`Q[$R&\  
e=C,`&s z  
} \Bf{/r5x  
ON^u|*kO  
V6o,}o&-  
public void run() R'_[RHFC  
{ RAa1KOxZX  
//获得文件长度 -#hl& ^u$  
//分割文件 d@~)Wlje  
//实例FileSplitterFetch hTqJDP"&F  
//启动FileSplitterFetch线程 +%^xz 1m  
//等待子线程返回 EkPSG&6RZ  
try{ Xp@OIn  
if(bFirst) .- o,_eg1f  
{ E_#&L({|@  
nFileLength = getFileSize(); q9Wtu7/  
if(nFileLength == -1) tp0*W _<4  
{ =Ih_[$1dw  
System.err.println("File Length is not known!"); oWT0WS  
} 8A qe'2IH=  
else if(nFileLength == -2) ^Y!`wp2vn  
{ U$%w"k7^(  
System.err.println("File is not access!"); B.b)YE '  
} 3x$#L!VuU  
else O5"80z38[  
{ VzNH%  
for(int i=0;i<nStartPos.length;i++) ;* Jd#O  
{ hy rJu{p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m[rJFSpef  
} -A~<IyPt  
for(int i=0;i<nEndPos.length-1;i++) MsiSC  
{ n%hnL$!z  
nEndPos = nStartPos[i+1]; fz\Az-  
} ?z.`rD$}(n  
nEndPos[nEndPos.length-1] = nFileLength; q1j[eru  
} "5FeP;  
} ~M=`f{-$K  
(nG  
Si(?+bda0c  
//启动子线程 ^|2qD: ;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W*#/@/5  
for(int i=0;i<nStartPos.length;i++) jLU)S)  
{ xFh}%mwpt[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >U]. k8a)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qx NV~aK  
nStartPos,nEndPos,i); auU{I y   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /fEXAk  
fileSplitterFetch.start(); j(hC't-  
} [VH t#JuN,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GWsFW[T?~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `,z{70  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mE1*F'0a  
nEndPos = " + nFileLength); a'r\e2/e?H  
// fileSplitterFetch[nPos.length-1].start(); 2TO1i0  
Sr0mA M  
Smo'&x  
//等待子线程结束 tVwN92*J  
//int count = 0; #';r 0?|  
//是否结束while循环 Tbw8#[6AX  
boolean breakWhile = false; 1{qg@xlj  
Y2fs$emv  
A}o1I1+  
while(!bStop) H3b`)k sFr  
{ "7d_$.Z  
write_nPos(); K} @q+  
Utility.sleep(500); {1 mD(+pJ{  
breakWhile = true; v2^CBKZ+  
>{[J+f{~|  
y[# U/2  
for(int i=0;i<nStartPos.length;i++) Z~ (QV0}  
{ j&r5oD;  
if(!fileSplitterFetch.bDownOver) =6hf'lP  
{ gvX7+F=}B  
breakWhile = false; (uE_mEIsv  
break; uQ}kq7gd  
} 4_eq@'9-q  
} DuaOi1Gw  
if(breakWhile) )DW;Gc  
break; .$rcTZ  
_XN sDW4|  
!q?}[E2  
//count++; _[V 6s#Wk3  
//if(count>4)  zcc]5>  
// siteStop(); [F e5a  
} U3>G9g>^B  
>dO^pDSs  
{chl+au*l  
System.err.println("文件下载结束!"); g~]FI  
} W/+0gh7`,(  
catch(Exception e){e.printStackTrace ();} }5|uA/B  
} q>?oV(sF  
_nF_RpS  
JL1Whf  
//获得文件长度 M~v{\!S  
public long getFileSize() d] {^  
{ N 6eY-`4y  
int nFileLength = -1; 2gi`^%#k]  
try{ FTn[$q  
URL url = new URL(siteInfoBean.getSSiteURL()); 3Dy.mtP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5,A/6b  
httpConnection.setRequestProperty("User-Agent","NetFox"); *l}q,9iQ-  
cK""Xz&m  
z`W$/tw"  
int responseCode=httpConnection.getResponseCode(); ><Z2uJZ4x  
if(responseCode>=400) 8AK#bna~-  
{ gC?k6)p$N  
processErrorCode(responseCode); @jfd.? RK!  
return -2; //-2 represent access is error /Bc ;)~  
} rd6?;K0  
Ha<(~qf  
)7f:hg  
String sHeader; D`+'#%%x  
8"? t6Z;5  
7@:uVowQ  
for(int i=1;;i++) +%0+  
{ 8ARpjYZP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q~`n%uYg\{  
//Utility.log(in.readLine()); 9d v+u6)  
sHeader=httpConnection.getHeaderFieldKey(i); "&An9H'  
if(sHeader!=null) $WDa} ~j~^  
{ XWk^$"  
if(sHeader.equals("Content-Length")) Xln'~5~)  
{ o(}vR<tD\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TMbj]Mso  
break; ) Limt<S  
} yzYPT}t  
} w%kxY5q  
else `5 bHZ  
break; >-Jutr<I"~  
} ibh!8"[  
} E[ ,Ur`>:  
catch(IOException e){e.printStackTrace ();} \D0Pik@?  
catch(Exception e){e.printStackTrace ();} S%'t )tt,  
yB&s2J  
|[0|j/V%O  
Utility.log(nFileLength); 0nC%tCV'  
R/iXO~/"J  
SH"O<c Dp  
return nFileLength; jZ)1]Q2  
} &uC7W.|  
d+l@hgz~  
]R( =)  
//保存下载信息(文件指针位置) f"S^:F0  
private void write_nPos() [H!V  
{ ~R3@GaL1  
try{ |#"<{RS+w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rb?6N  
output.writeInt(nStartPos.length); 8^2Q ~{i  
for(int i=0;i<nStartPos.length;i++) Xfe,ZC)  
{ hH>t  
// output.writeLong(nPos); =MA$xz3  
output.writeLong(fileSplitterFetch.nStartPos); P@)z Nik[  
output.writeLong(fileSplitterFetch.nEndPos); lO[[iMHl<  
} >%t"VpvR  
output.close(); Y*0mC"n}  
}  ,_HVPE  
catch(IOException e){e.printStackTrace ();} -B'<*Y  
catch(Exception e){e.printStackTrace ();} M1^pf<!s  
} A^xD Axk  
+n7bbuxj(X  
cZi/bIh  
//读取保存的下载信息(文件指针位置) W2s6!_AN  
private void read_nPos() Y'wQ(6ok  
{ yi PMJ  
try{ THC34u]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;BsyN[bF  
int nCount = input.readInt(); }Til $TT%H  
nStartPos = new long[nCount]; x^&D8&4^  
nEndPos = new long[nCount]; ry0P\wY}  
for(int i=0;i<nStartPos.length;i++) !IF#L0z  
{ pxjb^GZ0  
nStartPos = input.readLong(); Bg {"{poy  
nEndPos = input.readLong(); -Z9e}$q$,  
} NvY%sx,  
input.close(); (V 5_q,2  
} D}OvD |<-  
catch(IOException e){e.printStackTrace ();} <7-3j{065  
catch(Exception e){e.printStackTrace ();} 4vC { G.  
} gy0l@ 5 N  
[BWA$5D)Ny  
=c:K(N qL  
private void processErrorCode(int nErrorCode) 1$H*E~  
{ Z$"E|nRN  
System.err.println("Error Code : " + nErrorCode); 7Rwn{]r  
} < j^8L^  
J4EQhuQ  
VG'M=O{)3  
//停止文件下载 EVX*YGxx6  
public void siteStop() jInI%  
{ yz.a Z  
bStop = true; 8R0Q-,'  
for(int i=0;i<nStartPos.length;i++) Z jLuqo  
fileSplitterFetch.splitterStop(); 0ZcvpR?G  
8cI<~|4_  
A%(t'z  
} &?59{B. mD  
} :(ni/,~Q  
//负责部分文件的抓取 TL'^@Y7X5  
**FileSplitterFetch.java g$+ $@~  
*/ j6}/pe*;;T  
package NetFox; O!xul$9  
N;gI %6  
}&!fT\4  
import java.io.*; u)J&3Ah%  
import java.net.*; GI']&{  
v"-@'qN'  
d|I?%LX0p  
public class FileSplitterFetch extends Thread { kzozjh%`9h  
"h58I)O  
2Tt^^Lb  
String sURL; //File URL 2z#gn9Wb  
long nStartPos; //File Snippet Start Position I8M^]+c  
long nEndPos; //File Snippet End Position 7 G37V"''  
int nThreadID; //Thread's ID D[#6jJ Ab  
boolean bDownOver = false; //Downing is over 4b5'nu  
boolean bStop = false; //Stop identical JlaT -j  
FileAccessI fileAccessI = null; //File Access interface H.-VfROi2  
J7a_a>Y  
rW),xfo0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oQ YmywY  
{ `0)'&HbLY  
this.sURL = sURL; |%\>+/j$  
this.nStartPos = nStart; /fh[_!qN  
this.nEndPos = nEnd; 'wA4}f  
nThreadID = id; @ (4$<><  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5=@q!8a*  
} K%i9S;~  
:$ qa  
+s$` kl  
public void run() A*b>@>2  
{ T*pcS'?'  
while(nStartPos < nEndPos && !bStop) N./l\NtZ  
{ :^bjn3b  
a]NH >d  
ZF@T,i9  
try{ dkUh[yo"H  
URL url = new URL(sURL); 8>4@g!9E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \A#YL1hh  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ah#bj8}  
String sProperty = "bytes="+nStartPos+"-"; #"&<^  
httpConnection.setRequestProperty("RANGE",sProperty); 0[L)`7  
Utility.log(sProperty); Wks?9 )Is  
^VL",Nt  
?xX9o  
InputStream input = httpConnection.getInputStream(); 0Tp,b (; n  
//logResponseHead(httpConnection); C] dK/~Z#r  
>n(Ga9E  
dAba'|Y  
byte[] b = new byte[1024]; 1[4 2f#  
int nRead; p#A{.6Pa:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OUM^ u*  
{ ^ s.necg0  
nStartPos += fileAccessI.write(b,0,nRead); vXI2u;=y  
//if(nThreadID == 1) pXap<T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YZ\a#s ,0  
} 4;;K1< 1  
`514HgR  
OK8|w]-A  
Utility.log("Thread " + nThreadID + " is over!"); 2WF7^$^:  
bDownOver = true; o W<Z8s;p  
//nPos = fileAccessI.write (b,0,nRead); zqJ0pDS  
} +5<]s+4T  
catch(Exception e){e.printStackTrace ();}  X<p'&  
} xQKRUHDc  
} -mfdngp3  
JbR;E`8  
XSBh+)0Ww  
//打印回应的头信息 -h%!#g  
public void logResponseHead(HttpURLConnection con) z\g6E/%%  
{ 9fhgCu]$  
for(int i=1;;i++) 8 o^ h\9I  
{ Fi3k  
String header=con.getHeaderFieldKey(i); P&kjtl68 Y  
if(header!=null) #t8{z~t3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )}3!iDA  
Utility.log(header+" : "+con.getHeaderField(header)); xPp\OuwK  
else 0YsBAfRG  
break; nm}wdel"  
} VC T~"T2R  
} n,l{1 q  
(^lw<$N  
j84g6;4Dv  
public void splitterStop() ps@;Z ?Q  
{ 1&2X*$]y  
bStop = true; ?7|6jTIs  
} ]ucz8('  
X}5}M+'~  
xtq='s8e  
} Ec4+wRWk85  
P/?'ea  
{3H)c^Q  
/* rY:A LA  
**FileAccess.java =G<i6%(^g  
*//文件访问(定位,写) 7SVq fWp  
package NetFox; K (!+l  
import java.io.*; ?7k%4~H t  
kD?lMA__  
]>_Ie?L)<  
public class FileAccessI implements Serializable{ v<u`wnt  
S9VD/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lO+6|oF0  
RandomAccessFile oSavedFile; \2U FJ  
long nPos; |A/)b78'u  
>0c4C< _  
:*<UCn""  
public FileAccessI() throws IOException N*$L#L$*  
{ .z6"(?~  
this("",0); bsosva+  
} .?^a|]  
9]]isE8r  
CtO;_ ;eD'  
public FileAccessI(String sName,long nPos) throws IOException 0; PV gO;9  
{ vCe]iB  
oSavedFile = new RandomAccessFile(sName,"rw"); ^|kqy<<X  
this.nPos = nPos; W? SFt z  
oSavedFile.seek(nPos); uKF)'gj  
} 1;FtQnvH  
jMUN|(=Y  
~u^MRe|`  
public synchronized int write(byte[] b,int nStart,int nLen) Jv[c?6He  
{ S#[w).7  
int n = -1; ^6kE tTO*  
try{ =F 9!)r  
oSavedFile.write(b,nStart,nLen); }:zTz% _K  
n = nLen; a?K3/0G  
} ZOIx+%/Vd#  
catch(IOException e)  O86[`,  
{ E|~)"=  
e.printStackTrace (); D.;iz>_}Y  
} fC<pCdsg  
x(r~<a[  
PYhRP00}M  
return n; 8G<{L0J%!  
} e]Q bC "  
kS)azV  
edZhI  
} eWw# T^  
;GF+0~5>  
o1^Rx5  
/* $AyE6j_1gX  
**SiteInfoBean.java 8H7=vk+  
*/ % Ix   
package NetFox; wUJ>?u9  
T-)lnrs^  
u,&[I^WK`C  
public class SiteInfoBean { |J+oz7l?-  
q7kE+z   
24b?6^8~k  
private String sSiteURL; //Site's URL U5!~ @XjG>  
private String sFilePath; //Saved File's Path tOT(!yz  
private String sFileName; //Saved File's Name p?idl`?^3  
private int nSplitter; //Count of Splited Downloading File ih\=mB  
ra]lC7<H  
L,7+26XV"B  
public SiteInfoBean() `"RT(` m  
{//nSplitter的缺省值为5 1/J3 9Y~+  
//default value of nSplitter is 5 f:u3fL  
this("","","",5); gF53[\w^v  
} |g1~-  
0E^6"nt7N  
chs] ,7R  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QTLGM-Z  
{ ww#]i&6  
sSiteURL= sURL; viXt]0  
sFilePath = sPath; @Lk!nP  
sFileName = sName; SpJIEw  
this.nSplitter = nSpiltter; hztxsvw  
jn,_Ncd#  
'5; /V  
}  U rL|r.  
LZ-&qh  
AdGDs+at,  
public String getSSiteURL() RIV + _}R  
{ n5s2\(  
return sSiteURL; 6*r#m%|   
} |SSe n#PYp  
!E.CpfaC  
t;/s^-}  
public void setSSiteURL(String value) b-Xc6f  
{ J *nWCL  
sSiteURL = value; /]>8V'e\  
} }_|qDMk+  
I;GbS`  
pr.+r?la]  
public String getSFilePath() 0hv}*NYd  
{ 45aFH}w:  
return sFilePath; ApSzkPv*  
} 4qvE2W}&  
ZgI?#e  
efX iZ  
public void setSFilePath(String value) #BhDC.CcW  
{ p"tCMB  
sFilePath = value; Wz&[ cj  
} Rn9e#_Az  
H7?Sd(U  
q<Z`<e  
public String getSFileName() c5- 56 Q  
{ E E^l w61  
return sFileName; DNu-Ce%  
} HD!2|b ~@  
 eo&^~OVT  
q .s'z}  
public void setSFileName(String value) L&LAh&%{2  
{ 9YEE.=]T  
sFileName = value; F9Co m}  
} r$WBEt,B  
cP2n,>:  
Cc}3@Nf{/  
public int getNSplitter() #w1E3ahaX  
{ z{wZLqG  
return nSplitter; E x )fXQ+  
} WWgJ !Uz  
%*a%F~Ss  
mV++7DY  
public void setNSplitter(int nCount) Lc! t  
{ cTa$t :K@  
nSplitter = nCount; 6R#.AD\  
} b-?d(-  
} ~jD~_JGp  
GWW#\0*Bn  
a%*W( 4=Y  
/* vf0 fa46  
**Utility.java (MzThGJK_  
*/ .Ge`)_e  
package NetFox; 5a%i%+;N  
]QSQr *  
k< $(  
public class Utility { ~@d4p|K  
g+%Pg@[  
,Fzuo:{uy  
public Utility() vn1*D-?  
{ .kc{)d*0K  
5b$QXO  
z`:tl7  
} (q}{;  
,buo&DT{L  
//线程睡眠 ]6;G#  
public static void sleep(int nSecond) * 3#RS  
{ @d_9NOmNT  
try{ ;MH_pE/m  
Thread.sleep(nSecond); ZLlAK?N  
} @pN6uDD}R  
catch(Exception e) yW@YW_2;4  
{ [Wn6d:  
e.printStackTrace (); #3}!Q0   
} yi:1cLq2  
} 1k!$#1d<  
=;{8)m  
//日志 D!rD-e  
public static void log(String sMsg) "Tnmn@  
{ rYO~/N  
System.err.println(sMsg); 'k9 Qd:a}  
} Z)!#+m83>-  
%TYe]^/'y  
1 EwCF  
public static void log(int sMsg) jhB+ ]  
{ |\T!,~  
System.err.println(sMsg); S.|%dz  
} }WnoI2  
} chXTFLC~  
UHS{X~CS e  
p+}eP|N  
/* d6ckvD[  
**TestMethod.java iJb-F*_y  
*/ >2ny/AK|  
package NetFox; O2S{*D={  
(".WJXB\  
qdxDR 2]U  
public class TestMethod { L8?;A9pc()  
plgiQr #  
7VW/v4n  
public TestMethod() IPk"{T3  
{ ///xx/weblogic60b2_win.exe C j:  
try{ 'tY y_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4\y>pXML-U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); DAQozhP8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [E;~Y_l  
fileFetch.start(); ;Swj`'7  
} Voo_ ?  
catch(Exception e){e.printStackTrace ();} N{?Qkkgx  
,U=7#Cf!  
VWW(=j  
} O#`y;%  
jBU!xCO  
e_dsBmTh  
public static void main(String[] args) Ns6C xE9  
{ \9k{h08s  
new TestMethod(); t'*2)U  
} /_i]bM7W  
} $!K,5^+  
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