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http断点续传简单实现(java)

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/* N1y,~Z  
**SiteFileFetch.java Xe`$SNM  
*/ ey<z#Q5+  
package NetFox; aRn""3[  
import java.io.*; t=:5?}J.Q$  
import java.net.*; $Sm iN'7;  
~k@{b&  
u@Ni *)p`  
public class SiteFileFetch extends Thread { 1:DA{ejS  
c*[aIqj  
ESIeZhXVH  
SiteInfoBean siteInfoBean = null; //文件信息Bean sy(bL _%  
long[] nStartPos; //开始位置 `\ nKPj  
long[] nEndPos; //结束位置 &432/=QSm0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J7EWaXGbz  
long nFileLength; //文件长度 O]="ggq&  
boolean bFirst = true; //是否第一次取文件 =NK'xPr  
boolean bStop = false; //停止标志 &jnBDr  
File tmpFile; //文件下载的临时信息 P()&?C  
DataOutputStream output; //输出到文件的输出流 rnMi >?  
D}ZPgt#   
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !q/Q2N(  
public SiteFileFetch(SiteInfoBean bean) throws IOException BdvpG  
{ y{P~!Yn|  
siteInfoBean = bean; 8<6@O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d[;&2Jz*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %[L/JJbP&Z  
if(tmpFile.exists ()) & R<K>i  
{ HDE5Mg "  
bFirst = false; ]d|M@v~c4  
read_nPos(); hf)R PG&  
} N/2WUp  
else CAA 3-"Cwi  
{ Y!(w.G  
nStartPos = new long[bean.getNSplitter()]; IY}GU 2#  
nEndPos = new long[bean.getNSplitter()]; %6V=G5+W  
} ,(hP /<  
vON7~KA  
#~|esr/wf  
Mac:E__G  
} `09[25?  
eXLdb-  
&=Y%4 vq  
public void run() 5Tidb$L;Du  
{ fo9V&NE  
//获得文件长度 `J{{E,y @  
//分割文件 h,fahbH -  
//实例FileSplitterFetch }U%E-:  
//启动FileSplitterFetch线程 `B3YP1  
//等待子线程返回 o/RGzPR  
try{ ^#w9!I{4.  
if(bFirst) S!R (ae^}  
{ `X =[ m>  
nFileLength = getFileSize(); s9u7zqCF  
if(nFileLength == -1) (r<F@)J  
{ & )-fC  
System.err.println("File Length is not known!"); S =sL:FC  
} hJ8B&u(  
else if(nFileLength == -2) IMy!8$\u  
{ "zIQ(|TL?d  
System.err.println("File is not access!"); )4YtdAV  
} 6UPGE",u  
else kZ^wc .  
{ UG]5Dxk  
for(int i=0;i<nStartPos.length;i++) W,t`DMC  
{ yS#D$q2_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5RSP.Vyx{  
} `;Fs  
for(int i=0;i<nEndPos.length-1;i++) sY}0PB  
{ 4]cr1K ^  
nEndPos = nStartPos[i+1]; D_w<igu!3  
} `V[ hE r|  
nEndPos[nEndPos.length-1] = nFileLength; q^[SN  
} 0|rdI,z  
} PXDJ[Oj7(0  
,;=is.h9  
<z wI@i  
//启动子线程  <j_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gX5.u9%C\  
for(int i=0;i<nStartPos.length;i++) # o\&G@e}  
{ bU4\Yu   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1eS@ihkP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fAT M?  
nStartPos,nEndPos,i); DK%@ [D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w*4sT+ P  
fileSplitterFetch.start(); sR$/z9w  
} aU] nh. a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c 8|&Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0gKSjTqo  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~Z97L  
nEndPos = " + nFileLength); 4Rl~7|  
// fileSplitterFetch[nPos.length-1].start(); Op iVQr:  
lYrW"(2  
<+`}: A  
//等待子线程结束 |e&hm ~R1  
//int count = 0; Hn?v  /3  
//是否结束while循环 xl@  
boolean breakWhile = false; &!8u4*K5j  
?)/H8n  
+|O& k  
while(!bStop) ?,!C0ts  
{ _^w^tfH]  
write_nPos(); tlmfDQD  
Utility.sleep(500); 4?7OP t6  
breakWhile = true; O~F8lQ  
%e=UYBj"  
l]P3oB}Yo  
for(int i=0;i<nStartPos.length;i++) *3y:Wv T>  
{ 1ZfhDtK(  
if(!fileSplitterFetch.bDownOver) -s6;IoG/  
{ Snas:#B!  
breakWhile = false; g6q67m<h  
break;  ] 2lh J  
} @p7*JLO  
} F[oTc^dr  
if(breakWhile) F:2V;  
break; </h}2x  
|H-zm&h>'  
t=r*/DxX=  
//count++; h4? 'd+K  
//if(count>4) 6\/(TW&  
// siteStop(); &28%~&L  
} 2-u9%  
 f(*^zga,  
)}R w@70L-  
System.err.println("文件下载结束!"); Q-f?7*>  
} Gn?<~8a  
catch(Exception e){e.printStackTrace ();} z_ia3k<  
} >z69r0)>  
cpBTi  
5!d'RBO   
//获得文件长度 oOy_2fwZPp  
public long getFileSize() j}@n`[V1  
{ ns !Mqcm  
int nFileLength = -1; 4VfZw\^  
try{ Q>>II|~;J  
URL url = new URL(siteInfoBean.getSSiteURL()); l=t$ XWh!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q{oppali  
httpConnection.setRequestProperty("User-Agent","NetFox"); \MFjb IL  
1mz72K  
!5[5l!{x  
int responseCode=httpConnection.getResponseCode(); 2z0 27P-Q  
if(responseCode>=400) x]jJ  
{ U>kL|X3 V  
processErrorCode(responseCode); *`wgqin  
return -2; //-2 represent access is error A;C)#Q/  
} G8!* &vR/  
7 a_99? J  
\TXCq@  
String sHeader; #R3|nL  
$2gZpO|  
=LMM]'no,  
for(int i=1;;i++) '#@tovr  
{ Oi4tG&q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "~/O>.p  
//Utility.log(in.readLine()); dgM@|&9*m  
sHeader=httpConnection.getHeaderFieldKey(i); ~5b^Gvb?  
if(sHeader!=null) q`^ T7  
{ E >lW'  
if(sHeader.equals("Content-Length")) d;O4)8 >  
{ O;?Nz:/q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uu+)r  
break; *.F4?i2D  
} use` y^c  
} 'Q F@@48  
else #Vi:-zyY  
break; Y|96K2BR  
} j?y_ H[Z  
} rRzc"W}K+  
catch(IOException e){e.printStackTrace ();} MF/@Efjn ]  
catch(Exception e){e.printStackTrace ();} &i?>mt  
zsuXN*  
Ub-q0[6  
Utility.log(nFileLength); 'PVxc %[  
Rk@xv;t;  
2VyJ  
return nFileLength; vX/("[  
} b;%>?U`>p  
:927y  
&pZn cm  
//保存下载信息(文件指针位置) tDIQ=  
private void write_nPos() d/Y#oVI  
{ wmnh7'|0u  
try{ MGE8S$Z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QNe siV0MI  
output.writeInt(nStartPos.length); wPrqFpf  
for(int i=0;i<nStartPos.length;i++) /[RO>Z9  
{ #[.aj2  
// output.writeLong(nPos); | )M>;q   
output.writeLong(fileSplitterFetch.nStartPos); o6T'U#7P  
output.writeLong(fileSplitterFetch.nEndPos); C6{\^kG^j2  
} 5>u,Qh  
output.close(); )7s(]~z  
} U/l3C(bc!  
catch(IOException e){e.printStackTrace ();} }*9mNE  
catch(Exception e){e.printStackTrace ();} \olYv!f  
} I$w:qS&:  
Iu|4QE  
X/' t1  
//读取保存的下载信息(文件指针位置) w=feXA3-S  
private void read_nPos() /@QPJ~%8Ud  
{ @pkQ2OM 2  
try{ Usz O--.C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ap|$8 G  
int nCount = input.readInt(); T_/ n#e  
nStartPos = new long[nCount]; 0l+[[ZTV  
nEndPos = new long[nCount]; ^^Te  
for(int i=0;i<nStartPos.length;i++) @K=C`N_22  
{ GZWU=TC2{2  
nStartPos = input.readLong(); GW;O35 m  
nEndPos = input.readLong(); #4BwYj(Sl  
} GLtd6;V  
input.close(); SA[wF c  
} iw\yVd^]:k  
catch(IOException e){e.printStackTrace ();} ^M6R l0  
catch(Exception e){e.printStackTrace ();} I)wc&>Lc  
} BH\!yxK  
_-5|"oJ  
]CxD m  
private void processErrorCode(int nErrorCode) zSo(+D &[  
{ o4F(X0  
System.err.println("Error Code : " + nErrorCode); Z b}U 4  
} r"xs?P&/$  
f 6 k=ew  
S}/5W  
//停止文件下载 !M@jW[s  
public void siteStop() PB(I3R9  
{ $QB/n63  
bStop = true; <kOdd)X  
for(int i=0;i<nStartPos.length;i++) @ q:S]YB   
fileSplitterFetch.splitterStop(); &5d~ODO  
;(r,;S_`0  
5u=>~yK+  
} X([p0W 9V(  
} :` >bh  
//负责部分文件的抓取 {j[a'Gb  
**FileSplitterFetch.java 92XG|CWX  
*/ oFL7dL  
package NetFox; Gw-y6e'|Y  
T7R,6 qt  
r%\%tz'`j  
import java.io.*; %i5tf;x6i  
import java.net.*; $q*hE&x Qd  
C8t;E`  
e82xBLxR%  
public class FileSplitterFetch extends Thread { x,M8NTb*  
A"i $.dR{  
ZgA+$}U)uW  
String sURL; //File URL .oH)eD  
long nStartPos; //File Snippet Start Position i[/`9 AK  
long nEndPos; //File Snippet End Position z07Xj%zX9  
int nThreadID; //Thread's ID 2$TwD*[  
boolean bDownOver = false; //Downing is over 8h,=yAn5  
boolean bStop = false; //Stop identical .s-*aoj  
FileAccessI fileAccessI = null; //File Access interface D=@bPB>  
7!/!a*zg  
e?_uJh"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException = P$Q;d  
{ W$xW9u8@+(  
this.sURL = sURL; O;+ sAt  
this.nStartPos = nStart; &lnM 1W  
this.nEndPos = nEnd; Ubm]V{7  
nThreadID = id; COA*Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Qv6-,6<  
} P:%r3F  
d.yATP  
of8 >xvE|  
public void run() ]w_JbFmT  
{ QD^q\9U[  
while(nStartPos < nEndPos && !bStop) [\-)c[/  
{ `*",_RO;  
>u+%H vzc  
|eI!wgQx  
try{ p^k*[3$0  
URL url = new URL(sURL); Zu /w[*;M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L$6W,D  
httpConnection.setRequestProperty("User-Agent","NetFox"); B$ jX%e{:S  
String sProperty = "bytes="+nStartPos+"-"; ^h!}jvqE  
httpConnection.setRequestProperty("RANGE",sProperty); 4Z.Dz@.c(  
Utility.log(sProperty); mJZB@m u?  
-QK- w>  
xX.kKEo"d  
InputStream input = httpConnection.getInputStream(); '*D>/hn|:]  
//logResponseHead(httpConnection); .iYp9?t  
W. BX6  
<:4b4Nl  
byte[] b = new byte[1024]; SZvp %hS0  
int nRead; ipyc(u6Z5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L)c]i'WZ  
{ a66Ns7Rb  
nStartPos += fileAccessI.write(b,0,nRead); _*ar\A`  
//if(nThreadID == 1) XhUVDmeUMb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XtqhK"f%  
} ,\T7{=ZG\!  
q $PO. #  
{F;"m&3Lt  
Utility.log("Thread " + nThreadID + " is over!"); {r%T_BfY  
bDownOver = true; '^`iF,rg  
//nPos = fileAccessI.write (b,0,nRead); wZVLpF+7  
} XT?wCb41R  
catch(Exception e){e.printStackTrace ();} Clb7=@f  
} 7(d#zu6n  
} *dN_=32u  
KM?w{ ~9  
-S#jOr  
//打印回应的头信息 3_8W5J3I  
public void logResponseHead(HttpURLConnection con) Qb|@DMq%  
{ .bUj  
for(int i=1;;i++) YJ|U| [  
{ p8FXlTk  
String header=con.getHeaderFieldKey(i); D$+g5u)  
if(header!=null) _nM 7SK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Hk'R!X  
Utility.log(header+" : "+con.getHeaderField(header)); /U} )mdFm  
else <G'M/IR a  
break; m d `=2l  
} zkquXzlgB  
} >qBJK)LHOv  
-]t>'Q?  
9/_~YY=/h  
public void splitterStop() :D4'x{#H  
{ ]FgKL0  
bStop = true; iBwM]Eyv.  
} r uIgoB  
Xzl$Qc  
Xck`"RU<xA  
} =;(L$:l~  
~E/=nv$  
v#EFklOP  
/* [8Fn0A  
**FileAccess.java ?aI. Z+#  
*//文件访问(定位,写) M:dH>  
package NetFox; !f]kTs]j~  
import java.io.*; BS ]:w(}[  
T;]Ob3(BpW  
(\'$$  
public class FileAccessI implements Serializable{ f[ KI T  
o/ 7[ G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [RY Rt/?Q  
RandomAccessFile oSavedFile; J=&}$  
long nPos; P| hwLM  
*s<cgPKJ @  
G1\F7A  
public FileAccessI() throws IOException vCXmu_S4^>  
{ w ^?#xU1.i  
this("",0); 2x<!>B  
} Fy0sn|  
pXvys] @  
T$<yl#FY  
public FileAccessI(String sName,long nPos) throws IOException 3.1%L"r[)  
{ ) 7X$um  
oSavedFile = new RandomAccessFile(sName,"rw"); RB6Q>3g  
this.nPos = nPos; $N Mu  
oSavedFile.seek(nPos); F`GXho[  
} *tv\5KW G  
G4rzx%W?  
hiEYIx  
public synchronized int write(byte[] b,int nStart,int nLen) mkhWbzD'S  
{ _8!x  
int n = -1; 0X4)=sJP  
try{ -2(?O`tZ  
oSavedFile.write(b,nStart,nLen); IMBjI#\  
n = nLen; R1/c@HQw?  
} =XK}eQ_d  
catch(IOException e) | KY-kRN7  
{ <LzxnTx=  
e.printStackTrace (); V%z?wDC  
} ens]?,`0  
t\}_WygN  
<EQaYZY=  
return n; z;y{QO  
} s;..a&C'  
B"zB=Aw  
Xk/iyp/  
} xcn~KF8  
z>\l%_w  
|>[qC O  
/* q]?)c  
**SiteInfoBean.java lHDZfwJ&C1  
*/ G0~Z|P  
package NetFox; 8};kNW^2m  
KVr9kcs  
GzBPI'C  
public class SiteInfoBean { ,k=8|=aF  
~#i2reG5  
/.=aA~|  
private String sSiteURL; //Site's URL CBF<53TshR  
private String sFilePath; //Saved File's Path lSlZ^.&  
private String sFileName; //Saved File's Name QnP?j&  
private int nSplitter; //Count of Splited Downloading File G+Bk!o  
cTS.yN({G  
\#WWJh"W  
public SiteInfoBean() jvAjnh#  
{//nSplitter的缺省值为5 ;]b4O4C\  
//default value of nSplitter is 5 TLp2a<Iy  
this("","","",5); a DXaQ  
} O!^ >YvOh  
KeRC8mYp  
xm1'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #"lb9. _ M  
{ /!^,+  
sSiteURL= sURL; *^Ges;5 $"  
sFilePath = sPath; 9bM kP2w>  
sFileName = sName; 4c95G^dZ  
this.nSplitter = nSpiltter; UCK;?]  
0[M2LF!m  
|Olz h63k:  
} `/'p1?Z"  
1G.?Y3DC<  
TnKv)%VF  
public String getSSiteURL() l qwy5#  
{ [z ]P5  
return sSiteURL; y.}{KQ"a*  
} ,msP(*qoI  
1G"ohosmF  
*S"RU~1_  
public void setSSiteURL(String value) dP(.l}O  
{ /d,u"_=l  
sSiteURL = value; ~*"ZF-c,  
} C:}1r  
T/2k2r4PD  
]jC{o,?s  
public String getSFilePath() h#KSKKNW  
{ bmK  
return sFilePath; 1#%H!GKvTU  
} ot[ZFF\  
AIY 1sSK  
c*.  
public void setSFilePath(String value) LT o5v  
{ F8dr-"G  
sFilePath = value; 8>W52~^fU  
} Du65>O  
8h }a:/  
*~shvtq  
public String getSFileName() U#S-x5Gn  
{ 2 oV6#!{Z  
return sFileName; sve} ent  
} D!! B4zt  
t!SxJ B e  
WeaT42*Q{  
public void setSFileName(String value) ~3M8"}X;L  
{ {6GX ?aw'  
sFileName = value; az:}RE3o  
} 1 :$#a  
)^AZmUYZ  
\8!CKnfs  
public int getNSplitter() {U$XHG  
{ R]e&JoY  
return nSplitter; yP"}(!~m  
} H"(#Tp ZTE  
=}Zl E  
s R>>l3H  
public void setNSplitter(int nCount) f S/:OnH  
{ M>Tg$^lm  
nSplitter = nCount; }2LWDQ;po  
} % &&)[  
} }4!}vkVx  
LKp;sV  
3<+ZA-2  
/* V0Oqq0\  
**Utility.java }BU%<5CQ  
*/ l0`bseN <  
package NetFox; 0m]QQGvJ{  
F~fBr  
T9& {s-3*  
public class Utility { }T(=tfv@  
~!~i_L\V  
u&uFXOc'  
public Utility() &g&,~Y/z;  
{ JygJ4RI%j  
3^% 2,  
,7bhUE/VB  
} M1Ff ,]w  
,cS#  
//线程睡眠 &'&)E((  
public static void sleep(int nSecond) +DX P &Q  
{ fX 1%I  
try{ KYw7Jx`l  
Thread.sleep(nSecond);  iY$iL<  
} E56  
catch(Exception e) 6'kQ(r>  
{ 0$c(<+D  
e.printStackTrace (); e ar:`11z  
} U)Hc 7% e  
} X>yDj]*4P  
)Jk$j  
//日志 "5<!   
public static void log(String sMsg) ><D2of|  
{ &8l?$7S"_/  
System.err.println(sMsg); aReJ@  
} 0C%IdV%CU  
lSaX!${R'T  
XXn3K BIf  
public static void log(int sMsg) xtD(tiqh.;  
{ T=u"y;&L  
System.err.println(sMsg); p*42 @1,  
} ,(Zxd4?y  
} BXU0f%"8U  
`<d.I%}  
G^nG^HTo5  
/* ^gx~{9`RR  
**TestMethod.java xBc|rqge  
*/ -O?HfQ  
package NetFox; C F','gPnc  
BK4S$B  
d3q.i5']G  
public class TestMethod { Qd YYWD   
u28$V]  
I50Ly sM  
public TestMethod() A|1xK90^XT  
{ ///xx/weblogic60b2_win.exe !9NF@e'&!  
try{ BWxJ1ENM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "1^tVw|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $Ugc:L<h+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #~/9cVm$  
fileFetch.start(); (0Br`%!F  
} )#M$ov  
catch(Exception e){e.printStackTrace ();} )#i"hnYpQ  
Y% \3N  
N}%AUm/L  
} *j]Bo,AC  
7L&,Na  
+C7E]0!r  
public static void main(String[] args) }JST(d&  
{ N atC}k  
new TestMethod(); v5\ALWy+p  
} GB}\7a  
} HAI) +J   
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