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http断点续传简单实现(java)

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/* N;P/$  
**SiteFileFetch.java Z ]ZUK  
*/ fM:bXR2Y'  
package NetFox; kO^  
import java.io.*; 2,B^OZmw  
import java.net.*; pX>wMc+  
Ekrpg^3qp"  
ak3WER|f#  
public class SiteFileFetch extends Thread { 1 YtY=  
-V@ST9`  
7KRNTnd  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5oYeUy>N  
long[] nStartPos; //开始位置 X2| Z!  
long[] nEndPos; //结束位置 `LIlR8&@aX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WTt /y\'6  
long nFileLength; //文件长度 K^GvU0\  
boolean bFirst = true; //是否第一次取文件 iH]0 YT.E  
boolean bStop = false; //停止标志 1 rbc}e  
File tmpFile; //文件下载的临时信息 HlkjyD8  
DataOutputStream output; //输出到文件的输出流 &.z-itiV  
54TWFDmGi  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) F/p1?1M  
public SiteFileFetch(SiteInfoBean bean) throws IOException cMy?&  
{ FU}- .Ki  
siteInfoBean = bean; =8p[ (<F=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jamai8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  }l]r-  
if(tmpFile.exists ()) {O!;cI~  
{ r[kHVT8  
bFirst = false; "4smW>f:%  
read_nPos(); e 1bV&  
} e2;=OoBK  
else @N> rOA  
{ 2e ~RM2PQ  
nStartPos = new long[bean.getNSplitter()]; HQ4WunH2Y  
nEndPos = new long[bean.getNSplitter()]; rvnm*e,  
} WYCDEoqU2  
D,-L!P  
;tD?a7  
QiRx2Z*\  
} }!s$ / Kn  
[ CU8%%7  
55>+%@$,a  
public void run() c No)LF  
{ Pff-eT+~m  
//获得文件长度 .&^M Z8  
//分割文件 FuBUg _h  
//实例FileSplitterFetch +`m0i1uI3  
//启动FileSplitterFetch线程 u |$GOSD  
//等待子线程返回 /~<Przw  
try{ MD>E0p)  
if(bFirst) waV4~BdL  
{ }zeKf/?'  
nFileLength = getFileSize(); f'S0 "  
if(nFileLength == -1) #]}G{ P  
{ X)9|ZF2`  
System.err.println("File Length is not known!"); o+<hI  
} 4=* ml}RP  
else if(nFileLength == -2) ROfke.N\'  
{ 3i}$ ~rz]U  
System.err.println("File is not access!"); _1$+S0G;  
} | 8n,|%e  
else yAel4b/}  
{ 0b,{4DOD  
for(int i=0;i<nStartPos.length;i++) {`L,F  
{ 63i&e/pv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9B3}LVg\  
} *(*XNd||  
for(int i=0;i<nEndPos.length-1;i++) .8|5;!`WB  
{ FEA/}*2F  
nEndPos = nStartPos[i+1]; <@@@Pl!~  
} +w@/$datI  
nEndPos[nEndPos.length-1] = nFileLength;  _8z  
} ,(#n8|q4  
} #M[Cq= 2  
*K=me/ 3  
KiNluGNt  
//启动子线程 L=<,+m[!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I)G.tJZ e  
for(int i=0;i<nStartPos.length;i++) "r{ ^Y??  
{ z]i/hU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m%OX< T!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KR4RIJZ_t  
nStartPos,nEndPos,i); @|~D?&<\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `jDmbD +=  
fileSplitterFetch.start(); ;wr]_@<~  
} cXOb=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )jRaQ~Sm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T=cb:PD{%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nQ'AB~ Do  
nEndPos = " + nFileLength); Dw2$#d  
// fileSplitterFetch[nPos.length-1].start(); &\r_g!Mh  
Yg`z4 U'6~  
iJu$&u  
//等待子线程结束 C1~Ro9si  
//int count = 0; ,rQPs  
//是否结束while循环 Tj=g[)+K  
boolean breakWhile = false; GwlAEhP  
v#KE"m  
K~z9b4a>  
while(!bStop) H*dQT y,  
{ }KrZ6cG9#  
write_nPos(); kI$X~s$r  
Utility.sleep(500); NslaG  
breakWhile = true; v*e=oyx[  
LZ~$=<  
}*0*8~Q'5  
for(int i=0;i<nStartPos.length;i++) Yr+ghl/ V  
{ "[ ]72PC  
if(!fileSplitterFetch.bDownOver) af7\2 g3*  
{ ~E7=c3:"  
breakWhile = false; >E(IkpZ  
break; *W<g%j-a  
} P1QGfp0-J  
} UBy:W^\g  
if(breakWhile) hLLg  
break; JSiLG0  
QGd"Z lQ  
D&&11Iz&  
//count++; o//PlG~  
//if(count>4) jvos)$;L-  
// siteStop(); C0Ti9  
} ldm=uW  
NvlG@^&S  
 !.k  
System.err.println("文件下载结束!"); ~x}=lKN  
} .:s**UiDR  
catch(Exception e){e.printStackTrace ();} X*C4N F0  
} Fop "m/  
uBC*7Mkm  
l4Y}<j\;  
//获得文件长度 =zW.~(c{  
public long getFileSize() PfVjfrI[  
{ )Ikx0vDFQ  
int nFileLength = -1; ^?tF'l`  
try{ >U$,/_uMNW  
URL url = new URL(siteInfoBean.getSSiteURL()); [&FWR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M0%):P?x  
httpConnection.setRequestProperty("User-Agent","NetFox"); "%Eyb\V!  
/ZKO\q  
r@(hRl1k'  
int responseCode=httpConnection.getResponseCode(); 8>K2[cPD  
if(responseCode>=400) f8 M=P.jz  
{ ]"M4fA  
processErrorCode(responseCode); s?*MZC  
return -2; //-2 represent access is error A5gdZZ'x  
} C"ZCX6p+$  
} Pc6_#  
&wZ:$lK#o  
String sHeader; l2!4}zI2  
52#@.Qa  
`795 K8  
for(int i=1;;i++) QJ s /0iw  
{ P A9 ]L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2 }Q)&;u  
//Utility.log(in.readLine()); PRCr7f  
sHeader=httpConnection.getHeaderFieldKey(i); 9Kyr/6w4-k  
if(sHeader!=null) Re b^w,  
{ 8f|  
if(sHeader.equals("Content-Length")) 0Q5ua `U  
{ -K)P|'-?m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [0} ^w[  
break; ,saf"Ed=  
} > c7fg^@  
} C@L:m1fz  
else ?H3xE=<X  
break; 2,<!l(X  
} =GjxqIv  
} )vk$]<$  
catch(IOException e){e.printStackTrace ();} s?5(E}  
catch(Exception e){e.printStackTrace ();} Tl Z|E '_C  
\^3\_T&6  
#f@sq5pTO  
Utility.log(nFileLength); z>hG'  
4jrY3gyBX  
,.f GZ4  
return nFileLength; ]ba O{pJi  
} u<\/T&S  
^r$P&}Z\b  
mi3yiR  
//保存下载信息(文件指针位置) e p;_'  
private void write_nPos() C;;dCsiV5  
{ pFD L5  
try{ |k+Y >I&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y4Plm.  
output.writeInt(nStartPos.length); 6kKIDEX  
for(int i=0;i<nStartPos.length;i++) X4Eq/q"  
{ 4>>d "<}C  
// output.writeLong(nPos);  >kK  
output.writeLong(fileSplitterFetch.nStartPos); e ?H`p"l  
output.writeLong(fileSplitterFetch.nEndPos); w.Ft-RXA W  
} 6P!M+PO  
output.close(); mg*[,_3q33  
} Vo"\nj  
catch(IOException e){e.printStackTrace ();} \ey3i((L  
catch(Exception e){e.printStackTrace ();} t*^Q`V wQ  
} 6546"sU  
;e_n7>'#%  
*}0g~8Gp  
//读取保存的下载信息(文件指针位置) R b6` k^  
private void read_nPos() %Sfew/"R0  
{ hHdH#-O:4"  
try{ <D pi M`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qV.*sdS>  
int nCount = input.readInt(); +X0?bVT  
nStartPos = new long[nCount]; Jpws1~  
nEndPos = new long[nCount]; sL XQ)Ce  
for(int i=0;i<nStartPos.length;i++) ,`MUd0 n  
{ xO6)lVd  
nStartPos = input.readLong(); +dk}$w[ g  
nEndPos = input.readLong(); Yyby 1  
} W[: n*h  
input.close(); {KE858  
} 3j(GcR 9  
catch(IOException e){e.printStackTrace ();} z6b!,lp  
catch(Exception e){e.printStackTrace ();} N%:QaCZKw  
} Ylll4w62N  
9=~"^dp54%  
Y_)!U`>N?  
private void processErrorCode(int nErrorCode) /N7j5v(  
{ *K'(t  
System.err.println("Error Code : " + nErrorCode); `$7j:<c=  
} O!kBp(?]  
vWcU+GBZI  
; 7[5%xM  
//停止文件下载 `TOm.YZG  
public void siteStop() @%fNB,H`  
{ gyJ$ Jp  
bStop = true; &mKtW$K` q  
for(int i=0;i<nStartPos.length;i++) Q\Fgc ;.U  
fileSplitterFetch.splitterStop(); \;}F6g  
)&<BQIv9/  
me#VCkr#  
} KZ pqbI Z  
} a8FC#kfq  
//负责部分文件的抓取 xf?*fm?m  
**FileSplitterFetch.java dmW0SK   
*/ )VID ;l;4  
package NetFox; B_anO{3$4  
I8)x 0)Lx  
9^<t0oY  
import java.io.*; S v$%-x^t  
import java.net.*; k/?5Fs!#  
znzh$9tH  
@S yGj#  
public class FileSplitterFetch extends Thread { mTT1,|  
gh|TlvnA  
m@R!o  
String sURL; //File URL WrQe'ny  
long nStartPos; //File Snippet Start Position c%yhODq/  
long nEndPos; //File Snippet End Position t{| KL<d]  
int nThreadID; //Thread's ID 7 /w)^&8  
boolean bDownOver = false; //Downing is over c=K . |g,  
boolean bStop = false; //Stop identical [84ss;.$  
FileAccessI fileAccessI = null; //File Access interface MJd!J ]E6  
UYn5Pix  
J1T_wA_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oQ1>*[e<u  
{ KyK%2:  
this.sURL = sURL; ^+^#KC8]W  
this.nStartPos = nStart; anjU3j  
this.nEndPos = nEnd; x4Mq{MrWp  
nThreadID = id; ,&rlt+wE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;"$Wfy  
} a.#`>  
UR44 iA]  
Ds? @ LE|  
public void run() {M96jjiInf  
{ /qa{*"2Qo  
while(nStartPos < nEndPos && !bStop) N?TXPY  
{ lO! Yl:;m%  
//n$#c _}u  
{b6| wQ\  
try{ X]d;x/2  
URL url = new URL(sURL); A}v! vVg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L\)ssO uh  
httpConnection.setRequestProperty("User-Agent","NetFox"); )-%3;e<w  
String sProperty = "bytes="+nStartPos+"-"; 9&}$C]`  
httpConnection.setRequestProperty("RANGE",sProperty); 9AO`Zk{/Ez  
Utility.log(sProperty); &#^^UT(nj  
/]zn8 d  
S<H 2e{~  
InputStream input = httpConnection.getInputStream(); ^pruQp1X  
//logResponseHead(httpConnection); ,c<&)6FU]  
#$2 {l,>  
n]^zIe^6  
byte[] b = new byte[1024]; $ (/=Wn  
int nRead; _GS_R%b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L& ucTc =  
{ 7ESSx"^B  
nStartPos += fileAccessI.write(b,0,nRead); }W^%5o87{  
//if(nThreadID == 1) >zFk}/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GdHFgxI  
} r#rL~Rsd}  
A[:0?Ez=  
Ut.%=o;&[  
Utility.log("Thread " + nThreadID + " is over!"); m/@ ;N,K  
bDownOver = true; !Hq$7j_  
//nPos = fileAccessI.write (b,0,nRead); 4zyN>f|  
} OGW,[k= 2{  
catch(Exception e){e.printStackTrace ();} uF,F<%d  
}  |Hx#Uk#  
} 4eH:eCZze  
@h7)M:l  
P/i{_r  
//打印回应的头信息 hOZ:r =%  
public void logResponseHead(HttpURLConnection con) O*0%AjT6  
{ c\A 4-08  
for(int i=1;;i++) \PReQ|[ah  
{  +~xY}  
String header=con.getHeaderFieldKey(i); 'u@,,FFz[K  
if(header!=null) gQ90>P:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >NLG"[\  
Utility.log(header+" : "+con.getHeaderField(header)); rlxZ,]ul  
else wW &q)WOi  
break; hOFC8g  
} O0^m_  
} )Y4;@pEU  
9o%k [n  
e1cqzhI=nA  
public void splitterStop() HiAj3  
{ 7PTw'+{  
bStop = true; ) uM*`%  
} 6Qtyv  
jW]Q-  
BoJpf8e'-e  
} bu0i #  
zF: :?L~  
M%&1j >d  
/* +;r1AR1)x  
**FileAccess.java 0?V{u`*  
*//文件访问(定位,写) 0zQ~'x  
package NetFox; mIW8K ):  
import java.io.*; a]H&k$!c  
^IQtXae6M  
~mBY_[_s=  
public class FileAccessI implements Serializable{ g[G+s4Nv  
n_~u!Ky_P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 BD.&K_AW  
RandomAccessFile oSavedFile; arK(dg~S  
long nPos; 3Z0ez?p+5  
 4,g_$)  
RE._Ov>  
public FileAccessI() throws IOException z }3` 9  
{ t@X{qm:%Z  
this("",0); 8'WoG]E_  
} r:{;HM+  
oYx4+xH/  
Ml,~@} p  
public FileAccessI(String sName,long nPos) throws IOException --OAsbr  
{ ^8.s"4{  
oSavedFile = new RandomAccessFile(sName,"rw"); h`i*~${yg  
this.nPos = nPos; n4XEyCrD  
oSavedFile.seek(nPos); u@]rR&h`  
} b=@H5XTZyK  
w{8O$4 w  
g)dKXsy(F  
public synchronized int write(byte[] b,int nStart,int nLen) rX(Ol,&oP  
{ E!A+J63zsw  
int n = -1; c1tM(]&  
try{ >o:y.2yCe  
oSavedFile.write(b,nStart,nLen); KWS\iu  
n = nLen; (usFT_  
} Y{KN:|i.!  
catch(IOException e) QLxe1[qI  
{ D :)HK D.  
e.printStackTrace (); FPb4VJ|xm  
} lvOM1I  
s4uZ>  
<) cJz  
return n; &?@gCVNO,  
} [L>mrHqG  
r\A|fiL  
(N6=+dNY  
} C>A} e6o  
qrHCr:~  
A&N$=9.N1  
/* GvzaLEo  
**SiteInfoBean.java B/Js>R  
*/ 0VnRtLnqI  
package NetFox; ZAJ~Tbm[f  
kfY. 9$(d  
xLdkeuL[%  
public class SiteInfoBean { %MCJ%Ph  
lLur.f  
f4O}WU}l{s  
private String sSiteURL; //Site's URL g-pEt#  
private String sFilePath; //Saved File's Path |F4)&xN\  
private String sFileName; //Saved File's Name !_q=r[D\  
private int nSplitter; //Count of Splited Downloading File &E]<KbVx  
}0[<xo>K  
lFp:F5  
public SiteInfoBean() I)\{?LdHR  
{//nSplitter的缺省值为5 v4qpE!W27~  
//default value of nSplitter is 5 :x,dYJm  
this("","","",5); dUQ )&Hv  
} %H[~V f?d  
e/uLBZ  
}#q0K  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DzbcLg%:W  
{ `z^50Vh|  
sSiteURL= sURL; !q~f;&rg  
sFilePath = sPath; 1! j^  
sFileName = sName; hzk4SOT(  
this.nSplitter = nSpiltter; xyP 0haE  
},=ORIB B:  
u+9)B 6O1  
} 6<%b}q9Mo  
~Qd|.T  
au E8 ^|  
public String getSSiteURL() ,V9 r2QY  
{ HXN. ,[  
return sSiteURL; vA{DF{S 4  
} }tW1\@ =  
!gL1  
G?^w <  
public void setSSiteURL(String value) z5_jx&^Z  
{ \j<aFOT(  
sSiteURL = value; : sG/  
} ujn7DBE"  
6P T)  
a$EudD#+  
public String getSFilePath() r]'[qaP  
{ |.b&\  
return sFilePath; nf-6[dg  
} Y>{%,d#s_  
E#A}2|7,g  
[s+FX5'K  
public void setSFilePath(String value) _&N:%;9uD  
{ *Z+U}QhHD6  
sFilePath = value; , {}S<^?]  
} |kF"p~s  
5s%FHa  
8 .&P4u i  
public String getSFileName() /!_FE+  
{ J|@O4 g   
return sFileName; )h]tKYx  
} /uPMzl  
#3O$B*gV6  
&gP1=P,!  
public void setSFileName(String value) ;Za^).=  
{ 9 ge'Mo  
sFileName = value; lmIphOUoIw  
} u`XZtF<vf  
gk}.L E  
LWxP}? =  
public int getNSplitter() 7CCSG{k  
{ a *bc#!e  
return nSplitter; |}: D_TX  
} [fJxbr"  
+ jN)$Y3Ya  
z<s ~`  
public void setNSplitter(int nCount) 7H)tF&  
{ ?IDkDv!na~  
nSplitter = nCount; DG=_E\"#  
} ; m:I  
} qL$\[(  
!95Q4WH-@  
3W[Ps?G  
/* +3pfBE|  
**Utility.java MnQ 6 !1Z  
*/ ]>0$l _V  
package NetFox; >w1jfpQ@t$  
;p"#ZS7  
<^+&A7 Q-_  
public class Utility { V oyRB2t  
M2A3]wd2a  
oMxpdG3y-  
public Utility() S,s") )A1  
{ Va/}|& 9  
C@MJn)$4  
D7v.Xq|  
} wh3Wuh?x  
h  m(  
//线程睡眠 $wcV~'fM  
public static void sleep(int nSecond) 9Z:pss@  
{ W,%qL6qV  
try{ zB"y^g  
Thread.sleep(nSecond); "9RW<+  
} Zf?jnDA  
catch(Exception e) ZO\bCrk  
{ (DM8PtZg  
e.printStackTrace (); 2~)q080jh  
} _2<k,Dl;RY  
}  P!/:yWd  
UFE~6"t(  
//日志 I^QB`%v5  
public static void log(String sMsg) 'fIG$tr9X  
{ AVp"<Uv  
System.err.println(sMsg); ?o(Y\YJf  
} I -XkxDw  
,`(Qs7)Xx  
yiczRex%rq  
public static void log(int sMsg) Zk # C!]=  
{ ]r1Lr{7^S  
System.err.println(sMsg); Y2>*' nU  
} ?nozB|*>ut  
} )1&,khd/u  
SU4~x0  
AH ]L C6-  
/* 8 =3$U+  
**TestMethod.java rzKn5Z  
*/ a@-!,Hi  
package NetFox; e)4L}a  
jAD{?/RB}  
HF%)ip+  
public class TestMethod { (<yQA. M  
o&E2ds3  
<-|g>  
public TestMethod() j2:A@ a6  
{ ///xx/weblogic60b2_win.exe i^/D_L.  
try{ zQx7qx  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WtbOm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YifTC-Q;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1<f,>BQ+  
fileFetch.start(); ^^(4xHN  
} Xx=.;FYk  
catch(Exception e){e.printStackTrace ();} GnW_^$Fs  
-KCQ!0\F  
V7>{,  
} <V*M%YWs  
;<v9i#K5  
oFS)3.  
public static void main(String[] args) Z9lfd6MU,  
{ OSCeTkR  
new TestMethod(); MtK5>mhZI`  
} -MeO|HWm  
} 0Yc#fD  
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