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http断点续传简单实现(java)

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/* "B3&v%b  
**SiteFileFetch.java 3Eu;_u_  
*/ +\/1V`  
package NetFox; #[$zbZ(I>:  
import java.io.*; TQ&1!~L*  
import java.net.*; HBp$   
FBGe s[,  
aTU[H~dTU  
public class SiteFileFetch extends Thread { xN CU5  
jWjp0ii  
Uuq*;L  
SiteInfoBean siteInfoBean = null; //文件信息Bean [8v>jQ)  
long[] nStartPos; //开始位置 OLs<]0H  
long[] nEndPos; //结束位置 4Mck/i2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b<E+5;u  
long nFileLength; //文件长度 #Bo3 :B8  
boolean bFirst = true; //是否第一次取文件 A-*y[/  
boolean bStop = false; //停止标志 J_`a}ox  
File tmpFile; //文件下载的临时信息 u/ZV35z  
DataOutputStream output; //输出到文件的输出流 Q@0Zh, l  
]TX"BH"2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) WNo7`)Kx  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1<;RI?R[9  
{ X`Jo XNqm  
siteInfoBean = bean; U ljWBd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x +]ek  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |A,<m#C  
if(tmpFile.exists ()) XmAu n  
{ 4l rKU^-  
bFirst = false; VKMgcfbHr/  
read_nPos(); CEh!X=Nn  
} aE 2=  
else 0T2^$^g  
{ K3xt,g  
nStartPos = new long[bean.getNSplitter()]; w:nLm,  
nEndPos = new long[bean.getNSplitter()]; FxdWJ|rN9D  
} /1h ${mo~  
^ /ZNdwx  
f)1*%zg%  
\__xTL\  
} Hj97&C{Q^  
1A}#j  
zGaqYbQD  
public void run() T6nc/|Ot  
{ tUT:v K`  
//获得文件长度 (i;,D-  
//分割文件 ;Z.sK-NJ4  
//实例FileSplitterFetch p)Fi{%bc  
//启动FileSplitterFetch线程 'y&DOy/|  
//等待子线程返回 sv)4e)1  
try{ *-X`^R  
if(bFirst) 0iI|eE o  
{ !QlCt>{  
nFileLength = getFileSize(); t03T1.:(Mg  
if(nFileLength == -1) !:c_i,N  
{ q+2v9K@  
System.err.println("File Length is not known!"); F60?%gg  
} _%KRZx}  
else if(nFileLength == -2) p]rV\,Yss  
{ hMyN$7Z  
System.err.println("File is not access!"); 5}TTf2&Xo#  
} c)Ne/E{!0  
else 3,0b<vfSv  
{ k>F>y|m  
for(int i=0;i<nStartPos.length;i++) Nz>xilU'  
{ w1LZ\nA<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L),r\#Y(v  
} Ctbc!<@o  
for(int i=0;i<nEndPos.length-1;i++) LKgo(&mY  
{ U#`2~Qv/1  
nEndPos = nStartPos[i+1]; w\a6ga!xt"  
} qwq5y t?  
nEndPos[nEndPos.length-1] = nFileLength; xAr&sGMA  
} QB d4ok: R  
} ko"xR%Q  
&q +l5L"  
Z+_xX  
//启动子线程 xy4P_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <8^ws90Y  
for(int i=0;i<nStartPos.length;i++) "A0y&^4B@  
{ 0,B"p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h-\Ov{~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _<'?s>(U'  
nStartPos,nEndPos,i); T1%}H3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xT-`dS0u  
fileSplitterFetch.start(); OHt^e7\  
} TLq^5,qG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6?a z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Zr(eH2}0D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eQ*zi9na  
nEndPos = " + nFileLength); "q KVGd  
// fileSplitterFetch[nPos.length-1].start(); rDGrq9  
JAy-N bb\  
v6ei47-  
//等待子线程结束 n<1*cL:8B  
//int count = 0; D^6Q`o  
//是否结束while循环 jp|*kBDq\  
boolean breakWhile = false; 4I#@xm8)  
h]/3doP  
gA gF$H .  
while(!bStop) E=91k.  
{ \Nk578+AA  
write_nPos(); 3R)|DGql=1  
Utility.sleep(500); )4N1EuD6  
breakWhile = true; 7g:Lj,Z4L  
-@@ O<M^  
53>(2 _/[r  
for(int i=0;i<nStartPos.length;i++) s1tkiX{>  
{ 1jE {]/Y7&  
if(!fileSplitterFetch.bDownOver) !x! 1H5"  
{ bXA%|7*  
breakWhile = false; K"ly\$F  
break; @>&b&uj7T  
} /qFY $vj  
} = ?BhtW  
if(breakWhile) E{}J-_oS45  
break; #CcEI  
r;p@T8k  
o#WECs>  
//count++; (M<l}pl)  
//if(count>4) gf}*}8D  
// siteStop(); ^^< C9  
} yYrFk^  
Ibx\k  
<$ qT(3w<y  
System.err.println("文件下载结束!"); #fk1'c2  
}  ^Vf@J  
catch(Exception e){e.printStackTrace ();} .m.Ga|;  
} O8Z+g{  
Ai)>ot  
H?,Dv>.#*  
//获得文件长度 Z?'?|vM  
public long getFileSize() ,/kZt!  
{ nw#AKtd@x  
int nFileLength = -1; Nw(hN+_u  
try{ Qg0%r bE  
URL url = new URL(siteInfoBean.getSSiteURL()); U.h2 (-p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =uEpeL~d;+  
httpConnection.setRequestProperty("User-Agent","NetFox"); nW<nOKTnk_  
bjI3xAs~  
?H>^X)Ph  
int responseCode=httpConnection.getResponseCode(); &[SFl{fx>-  
if(responseCode>=400) brG!TJ   
{ *IIA"tC  
processErrorCode(responseCode); s3  fQGbU  
return -2; //-2 represent access is error ` TH\0/eE  
} !yr4B "kz  
f'*/IG  
(?TK P 7  
String sHeader; /F46Ac}I  
IusZYB  
:*^aSPlV  
for(int i=1;;i++) *.KVrS<B1  
{ eI-SWwmv/u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #f%fY%5q  
//Utility.log(in.readLine()); FA := )  
sHeader=httpConnection.getHeaderFieldKey(i); 947;6a%$  
if(sHeader!=null) vif)g6,  
{ w'XN<RWA  
if(sHeader.equals("Content-Length")) j\zlp  
{ Z9|A"[b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); s0:M'wA  
break; j@Pd" Z9  
} 7GS 4gSd3  
} 5Ar gM%  
else PKC0Dt;F.  
break; y%x:~.  
} r;"D>IM\  
} 4O.R=c2}7>  
catch(IOException e){e.printStackTrace ();} PgA1:i&'  
catch(Exception e){e.printStackTrace ();} 8aKS=(Z!j  
G B"Orm.  
!"&-k:|g  
Utility.log(nFileLength); bC98<if  
agE-,  
|=KzQY|u  
return nFileLength; 5 8 7;2  
} <Q"G aqZ  
fK *l?Hr  
w%..*+P  
//保存下载信息(文件指针位置) JYmYX-  
private void write_nPos() [zXC\)&!  
{ Gt _tL%  
try{ !^s -~`'\~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cP\z*\dS  
output.writeInt(nStartPos.length); @vXXf/  
for(int i=0;i<nStartPos.length;i++) ew~?&=  
{ U@CAQ?  
// output.writeLong(nPos); B}.:7,/0  
output.writeLong(fileSplitterFetch.nStartPos); nK)1.KVN  
output.writeLong(fileSplitterFetch.nEndPos); !uO@4]:Y  
} kjB'W zZ8  
output.close(); Qe-Pg^PS]  
} D~Ef%!&  
catch(IOException e){e.printStackTrace ();} KUK.;gG*Z  
catch(Exception e){e.printStackTrace ();} 1P'A*`!K  
} 'Bxj(LaV-  
0 f$96sl  
{2m F\A#.  
//读取保存的下载信息(文件指针位置) -84%6p2-  
private void read_nPos() R4P&r=?  
{ d:>'c=y  
try{ uK`gveY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R9Wr?  
int nCount = input.readInt(); J/:U,01  
nStartPos = new long[nCount]; Gqc6]{  
nEndPos = new long[nCount]; oylQCbT   
for(int i=0;i<nStartPos.length;i++) .MRN)p  
{ 5f?GSHA}  
nStartPos = input.readLong(); Di27=_J  
nEndPos = input.readLong(); )UpVGT)  
} ryw%0H18  
input.close(); !#WQ8s!?o  
} g5"I{ol5T~  
catch(IOException e){e.printStackTrace ();} TJZ/lJU  
catch(Exception e){e.printStackTrace ();} t'0&n3  
} w 4CcdpR  
BDzAmrO<  
=S\^j"  
private void processErrorCode(int nErrorCode) BfCnyL%  
{ GDe,n  
System.err.println("Error Code : " + nErrorCode); 4b((,u$  
} @"A 5yD5  
WT")tjVKA  
/$]S'[5uF  
//停止文件下载 4o;;'P   
public void siteStop() <DPRQhNW]  
{ jkta]#O  
bStop = true; 6<>1,wbq  
for(int i=0;i<nStartPos.length;i++) }{j@q~w>$  
fileSplitterFetch.splitterStop(); Mis B&Ok`k  
nTGZ2C)c<'  
Ha/Qz'^S;  
} ],[<^=|  
} ?e4H{Y/M  
//负责部分文件的抓取 U`8Er48X  
**FileSplitterFetch.java WagL8BpLx  
*/ XP0;Q;WF}  
package NetFox; rQGInzYp  
i+in?!@G:  
!Q_Wbu\U  
import java.io.*; q :~/2<o  
import java.net.*; je2"D7D  
K]Vp! G  
.0RQbc9  
public class FileSplitterFetch extends Thread { W)J5[p?  
nxBP@Td  
[tJn! cMs  
String sURL; //File URL u-s*k*VHoc  
long nStartPos; //File Snippet Start Position ,}@4@ >?K  
long nEndPos; //File Snippet End Position #NGtba  
int nThreadID; //Thread's ID On~KTt3Mp  
boolean bDownOver = false; //Downing is over WcS`T?Xa  
boolean bStop = false; //Stop identical d4ld-y  
FileAccessI fileAccessI = null; //File Access interface tKcC{  
G4P*U3&p  
K1A<m=If  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tP*GYWI48  
{ !sEhjJV^7  
this.sURL = sURL; 1 I.P7_/  
this.nStartPos = nStart; ~E y+  
this.nEndPos = nEnd; Wa.xm_4s2  
nThreadID = id; 8Dtpb7\o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 53ZbtEwhwr  
}  <82&F  
+WR?<*_  
oQ/T5cOj  
public void run() oIx|)[  
{ >`a^E1)  
while(nStartPos < nEndPos && !bStop) Vp~ cN  
{ ,dK)I1"C  
~|Ln9f-g  
, .~ k  
try{ _[rQt8zn  
URL url = new URL(sURL); dQ-shfTr]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j$XaO%y)  
httpConnection.setRequestProperty("User-Agent","NetFox"); v=hn# U  
String sProperty = "bytes="+nStartPos+"-"; 60$;Q,]o  
httpConnection.setRequestProperty("RANGE",sProperty); _h  \L6.  
Utility.log(sProperty); &Wb"/Hn2  
[q3zs_nz  
 $RRX-  
InputStream input = httpConnection.getInputStream(); }N(gP_?n  
//logResponseHead(httpConnection); %C qp88]  
Oso**WUOZ&  
Qc?W;Q+  
byte[] b = new byte[1024]; yvzH}$!]  
int nRead; yp^k;G?_d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^VG].6  
{ 1P1h);*Z  
nStartPos += fileAccessI.write(b,0,nRead); |39,n~"o&  
//if(nThreadID == 1) -P|claO0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W^xO/xu1 /  
} Cd=$XJ-b  
7}~w9jK"F  
IvkYM`%  
Utility.log("Thread " + nThreadID + " is over!"); ::#[lw  
bDownOver = true; N\Lu+ x5  
//nPos = fileAccessI.write (b,0,nRead); PX/{!_mM  
} 7=u Gf$/  
catch(Exception e){e.printStackTrace ();} +^esL9RG:  
} X0^@E   
} Ri_2@U-  
~CV.Ci.dG  
:;+_<pk  
//打印回应的头信息 ( >ze{T|  
public void logResponseHead(HttpURLConnection con) F <6(Hw#>  
{ }v|_]   
for(int i=1;;i++) \<`oW>  
{ XR7v\rd  
String header=con.getHeaderFieldKey(i); rFzj\%xa[  
if(header!=null) tN\I2wm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )D/ ,QWk  
Utility.log(header+" : "+con.getHeaderField(header)); w}OBp^V^  
else cUG^^3!  
break; F@q9UlfB-  
} 6s~B2t:Y  
}  dm=?o  
r"{jrBK$  
,<#Rk 'y$  
public void splitterStop() ys`oHS f  
{ 3T0-RP*  
bStop = true; fR@Cg sw  
} 0k16f3uI   
Lp(`m=;O  
bfoTGi  
} uHZ4 @ w:  
6.KEe^[-  
> K,QP<B  
/* ^W:a7cMw  
**FileAccess.java : Bo  
*//文件访问(定位,写) xxl|j$m  
package NetFox; e/:?9  
import java.io.*; hI*v )c  
0KgP'oWvY  
V?G%-+^  
public class FileAccessI implements Serializable{ _Y&.Nw  
6=$<R4B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]jVE  
RandomAccessFile oSavedFile; xl,% Z~[  
long nPos; |X A0F\  
1`L.$T,1!  
$"|r7n5[  
public FileAccessI() throws IOException 5m0lk|`  
{ 1~~GF_l?  
this("",0); a$Ud"  
} ?K:\WW  
0ElEaH1z  
-`\^_nVC  
public FileAccessI(String sName,long nPos) throws IOException e<1Ewml(]  
{ ?G',Qtz<K  
oSavedFile = new RandomAccessFile(sName,"rw"); tl!dRV92  
this.nPos = nPos; AQQa6Ce*  
oSavedFile.seek(nPos); gM;m{gXYK  
} /"k[T  
\ZV>5N3hS  
$3p48`.\  
public synchronized int write(byte[] b,int nStart,int nLen) [[<TW}  
{ uQdy  
int n = -1; =gJ{75tV3  
try{ nyR<pnuC'  
oSavedFile.write(b,nStart,nLen); 62'9lriQ  
n = nLen; 4Ps;Cor+  
} zw+wq+2"  
catch(IOException e) Hqs-q4G$  
{ A~nqSe  
e.printStackTrace (); sPW :[  
} uk$MQ v*D  
H3R{+7  
59j`Z^e  
return n;  {p/Yz#  
} +kYp!00  
]k]bLyz\J  
3>L5TYa  
} }MMKOr(  
[efU)O&  
b?iPQ$NyQ  
/* DDGDj)=`  
**SiteInfoBean.java 8VQ!&^9!U#  
*/ 5;/q[oXI  
package NetFox; }2RbX,0l9  
E+XS7':I  
LB]3-FsU+  
public class SiteInfoBean { K O\HH  
+l)t5Mg\  
JS m7-p|E  
private String sSiteURL; //Site's URL z)^.ai,:0  
private String sFilePath; //Saved File's Path j~ds)dW%`&  
private String sFileName; //Saved File's Name GEVDXx>@  
private int nSplitter; //Count of Splited Downloading File 'do2n/  
Uq'W<.v 5  
S{e3aqT#N  
public SiteInfoBean() 9<3}zwJ  
{//nSplitter的缺省值为5 dg#Pb@7a  
//default value of nSplitter is 5 C|Gk}  
this("","","",5); VV$#<D<)  
} j?o6>j  
W>+`e]z  
:PN%'~}n  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q~wS2f`)  
{ J`[jub  
sSiteURL= sURL; wI 7gHp  
sFilePath = sPath; #P}n+w_@  
sFileName = sName; w$iPFZC'  
this.nSplitter = nSpiltter; :qj^RcmVPL  
ydOG8EI  
Oj%5FUP~[%  
} jGkDD8K [  
v+g:0 C5 (  
x(EwHg>;  
public String getSSiteURL() mpk+]n@  
{ nTGf   
return sSiteURL; F?a 63,r  
} [+b8 !'|&  
Yh!k uS#<  
dB#c$1  
public void setSSiteURL(String value) pO)EYla9  
{ i;]0>g4  
sSiteURL = value; cj GN=|`u  
} *u|1Z%XO  
PPG+~.7  
|n;);T(  
public String getSFilePath() xa]yq%  
{ yId1J  
return sFilePath; Y[PC<-fyf  
} aLW3Ub{h  
{Z <`@\K3  
D[]0/+,  
public void setSFilePath(String value) ipGxi[Vav  
{ 9wf"5c  
sFilePath = value; ZZHQ?p-  
} v\G 7V  
0w TOdCvmb  
G!C }ULq  
public String getSFileName() H-e$~vEbP  
{ oKz! Xu%Hl  
return sFileName; ,']CqhL6=R  
} NA0Z~Ug>  
DEkv,e  
38X{>*  
public void setSFileName(String value) "v0bdaQH3  
{ ,m0 M:!hK  
sFileName = value; St!0MdCH  
} c}S<<LR  
+C7W2!I[G2  
l+y;>21sTu  
public int getNSplitter() sb_/FE5e  
{ ) 5Ij  
return nSplitter; $E;Tj|W  
}  ydY( *]  
+{;wOQ.  
^%Y-~yB-  
public void setNSplitter(int nCount) ps`j>vX*  
{ t&x\@p9  
nSplitter = nCount; 3jW&S  
} 4|cRYZj5  
} g#6R(  
FaWc:GsfB  
znWB.H  
/* TT3GGHR  
**Utility.java PvW4%A@0  
*/  6; )5v  
package NetFox; AG%[?1IXW  
$f+I#uJ  
+zDRed_]=_  
public class Utility { zHNBX Rx  
DS@Yto  
RTg\c[=w  
public Utility() S^D@8<6GJ  
{ oXk6,b"  
jvR(e"  
UB8n,+R  
} _~umE/tz  
An?#B4:  
//线程睡眠 2Rwd\e.z  
public static void sleep(int nSecond) `) ],FE*:  
{ sieC7raO  
try{ E&t8nlTx  
Thread.sleep(nSecond); Fx1FxwIJ  
} E^{!B]/oP  
catch(Exception e) *+6iXMwe  
{ (5:pHX`P  
e.printStackTrace (); >y#qn9rV1  
} pih 0ME}z  
} r.Z g<T  
e9Gu`$K  
//日志 I!kR:Z  
public static void log(String sMsg) RZnmia  
{ ]D,_<Kk  
System.err.println(sMsg); u+6D|  
} KC:6^h'.  
tfm3IX  
2g_mQT  
public static void log(int sMsg) 74 )G.!  
{ Tu}EAr  
System.err.println(sMsg); \=|=(kt)  
} vQ2{ +5!|  
} H!"TS-s`  
PX23M|$!  
^ )!eiM  
/* '+iLW~   
**TestMethod.java (IjM  
*/ km^ZF<.@  
package NetFox; SS _6VE*sI  
.ej+?QYwC  
k5Q1.;fW76  
public class TestMethod { jxhZOLG  
}?6;;d#  
pz/W#VN  
public TestMethod() !v%>W< 3Q  
{ ///xx/weblogic60b2_win.exe G8?Do+[  
try{ VhMVoW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }|M:MJ`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,(sE|B#s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `]4(Z"R  
fileFetch.start(); QKVOc,Fp7i  
} <u# 7K\:  
catch(Exception e){e.printStackTrace ();} @ %q>Jd  
ve.P{;;Ky  
~FXq%-J  
} 7\nXJ381  
S&[9Vb  
glROT@  
public static void main(String[] args) gzW{h0iRr  
{ 8*B+@`  
new TestMethod(); $txF|Fj]^A  
} uz$p'Q  
} rADzJ#CU \  
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