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http断点续传简单实现(java)

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/* 1F&Trqq  
**SiteFileFetch.java czRFMYE  
*/ W+ko q*P  
package NetFox; Y^EcQzLw  
import java.io.*; dvJ M6W>^=  
import java.net.*; >_"an~Ss  
|Uh  
2)HuZda  
public class SiteFileFetch extends Thread { D!-g&HBTC  
V/I<g  
Ks`J([(W&  
SiteInfoBean siteInfoBean = null; //文件信息Bean T !WT;A  
long[] nStartPos; //开始位置 )"aV* "  
long[] nEndPos; //结束位置 PKg@[<g43  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *]/zc1Q4M  
long nFileLength; //文件长度 '^~{@~ ;%L  
boolean bFirst = true; //是否第一次取文件 A!WKnb_`  
boolean bStop = false; //停止标志 4-H+vNG{%  
File tmpFile; //文件下载的临时信息 "8jf81V*  
DataOutputStream output; //输出到文件的输出流 U7}yi$WT  
ieCEo|b  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) qL3;}R  
public SiteFileFetch(SiteInfoBean bean) throws IOException {dMsz   
{ ]tRu2Ygf  
siteInfoBean = bean; dufu|BL|}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ata:^qI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UJ7*j%XQz_  
if(tmpFile.exists ()) %oa-WmWm  
{ 3>`mI8 $t  
bFirst = false; }"%?et(  
read_nPos(); E GU 0)<  
} X296tA>C`  
else 9BBmw(M}  
{ kr:^tbJ  
nStartPos = new long[bean.getNSplitter()]; c"V"zg22  
nEndPos = new long[bean.getNSplitter()]; EF}\brD1  
} r 8rgY42  
J({Xg?  
RF4vtQC=  
-23w2Qt  
} tKx~1-  
:L@?2),  
ZWU)\}}_R  
public void run() n QZwC  
{ O#~yKqB  
//获得文件长度 /quc}"__  
//分割文件 `yXg{lk  
//实例FileSplitterFetch ][h%UrV  
//启动FileSplitterFetch线程 (WO]Xq<  
//等待子线程返回 {xB!EQ"  
try{ aPfO$b:  
if(bFirst) zFw s:_ i  
{ I%X6T@P  
nFileLength = getFileSize(); j2.|ln"!  
if(nFileLength == -1) O{G?;H$  
{ YPK(be_|I  
System.err.println("File Length is not known!"); K;Uvb(m{&  
} |5~#&v_  
else if(nFileLength == -2) j9 4=hJVKi  
{ BBRR)  
System.err.println("File is not access!"); KNpl:g3{<Q  
} +LZLy9iKt  
else g:D>.lKd  
{ -)]Yr #Q  
for(int i=0;i<nStartPos.length;i++) e~[/i\  
{ L Mbn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [{<`o5qR  
} [-k  
for(int i=0;i<nEndPos.length-1;i++) x_6[P2"PP  
{ ?o4C;  
nEndPos = nStartPos[i+1]; 2 %@4]  
} Tx=-Bb~;  
nEndPos[nEndPos.length-1] = nFileLength; wb5baY9  
} *,8^@(th  
} fg!__Rdi  
zrL$]Oy}x  
)c83/= <v  
//启动子线程 foF({4q7b^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %.Fi4}+O  
for(int i=0;i<nStartPos.length;i++) i,E{f  
{ w QH<gJE/:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rc>4vB_ha  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EZy)A$|  
nStartPos,nEndPos,i); YY((V@|K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zH4D8@[7O  
fileSplitterFetch.start(); ?{|q5n  
} 6?mibvK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +[AQUc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); % X+:o]T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RLynE V;]  
nEndPos = " + nFileLength); ~u!|qM  
// fileSplitterFetch[nPos.length-1].start(); J^nBdofP  
_8riUt  
]kG"ubHV?h  
//等待子线程结束 V2?=4mb  
//int count = 0; #ASz;$P  
//是否结束while循环 o]` *M|  
boolean breakWhile = false; djQH1^ (IU  
S)k*?dQ##R  
I<4Pur>"  
while(!bStop) >CgTs  
{ 1i"WDu*h3  
write_nPos(); 5k3n\sqZA  
Utility.sleep(500); 2LL'J7  
breakWhile = true; {3p4:*}  
tl4V7!U@^z  
F/bT)QT<f  
for(int i=0;i<nStartPos.length;i++) ,p@y] cr  
{ *,)Md[  
if(!fileSplitterFetch.bDownOver) FLCexlv^  
{ \H~T>j{N  
breakWhile = false; t#/YN.@r  
break;  ZrxD`1L  
} P[#e/qnXu|  
} b#Z{{eLny  
if(breakWhile) V>%rv'G8  
break; Ic:(Gi- %  
,I$`-$_'  
el<s8:lA  
//count++; WZejp}x  
//if(count>4) gJXq^~-hd  
// siteStop(); 9ni1f{k  
} SSg8}m5)Q  
dA`IEQJL  
E7 Ul;d  
System.err.println("文件下载结束!"); '&R2U_  
} @=Uh',F  
catch(Exception e){e.printStackTrace ();} d(x\^z  
} =:,g  
| y# Jx  
Uq,^Wy  
//获得文件长度 v ~?qz5:K~  
public long getFileSize() hh)`645=x  
{ B6nX$T4zP  
int nFileLength = -1; ' !cCMTj  
try{ (KD RkE|=  
URL url = new URL(siteInfoBean.getSSiteURL()); ksqQM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6V:U (g  
httpConnection.setRequestProperty("User-Agent","NetFox"); m 3hrb-  
2K6qY)/_  
c|B('3h  
int responseCode=httpConnection.getResponseCode(); )?n aN  
if(responseCode>=400) o>i4CCU+  
{ B6As,)RjD:  
processErrorCode(responseCode); 4*#18<u5  
return -2; //-2 represent access is error qI9z;_,gNz  
} V-2(?auZd  
|t&>5HM  
D~fl JR  
String sHeader; cJ n=  
sPQQ"|wU  
) 0W{]2  
for(int i=1;;i++) Apag{Z]^B  
{ L>NL:68yN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9r<J"%*Q  
//Utility.log(in.readLine()); "]x'PI 4J  
sHeader=httpConnection.getHeaderFieldKey(i); Y%aCMP9j~9  
if(sHeader!=null) l^-];|Y  
{ YQ)kRhFA  
if(sHeader.equals("Content-Length")) TG?brgW  
{ 1 ~*7f>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]BZA:dd.G  
break; *NaB#;+|k`  
} =tn)}Y.<e  
} 0c]/bs{}  
else vY}g<*  
break; t?&|8SId  
} I)6+6pm  
} 9dLV96  
catch(IOException e){e.printStackTrace ();} z`}qkbvi  
catch(Exception e){e.printStackTrace ();} *3FKt&v 0  
S-b/S5  
?V.cOR`6  
Utility.log(nFileLength); TR`U-= jH,  
8)3*6+D  
-%CP@dAk  
return nFileLength; tBWrL{xLe  
} P[ck84F/  
P {jbl!UD7  
{.|CdqwY  
//保存下载信息(文件指针位置) PO^ij2eS  
private void write_nPos() '<xXK@=KEI  
{ "ycJ:Xv49  
try{ 2r4Uh1D~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6=/F$|  
output.writeInt(nStartPos.length); A#<?4&  
for(int i=0;i<nStartPos.length;i++) RnE4<Cy  
{ gp?uHKsM  
// output.writeLong(nPos); 6ex/TySM  
output.writeLong(fileSplitterFetch.nStartPos); : /N0!&7  
output.writeLong(fileSplitterFetch.nEndPos); 9};8?mucr  
} yu|8_<bq  
output.close(); FUb\e-Q=  
} +Q)XH>jh   
catch(IOException e){e.printStackTrace ();} u@M,qo`  
catch(Exception e){e.printStackTrace ();} ]Sz:|%JP1  
} MYvY]Jx3  
n\'4  
yYYSeH  
//读取保存的下载信息(文件指针位置) B{#I:Rs9  
private void read_nPos() (gU!=F?#m  
{ T/~f~Zz  
try{ a0E)2vt4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lU\ [aNs  
int nCount = input.readInt(); ]^7@}Ce_  
nStartPos = new long[nCount]; h"Q8b}$^)  
nEndPos = new long[nCount]; wv1iSfW  
for(int i=0;i<nStartPos.length;i++) 5m 4P\y^a  
{ =R|HV;9 h  
nStartPos = input.readLong(); ]|a g  
nEndPos = input.readLong();  A,<E\  
} fOGFq1D  
input.close(); P>D)7 V9Hh  
} Pn1^NUMZJ  
catch(IOException e){e.printStackTrace ();} #A/  
catch(Exception e){e.printStackTrace ();}  'KL0@l  
} v$v-2y'%  
-f^tE,-  
6l x>>J!H  
private void processErrorCode(int nErrorCode) eJ-xsH*8  
{ p)-^;=<B3  
System.err.println("Error Code : " + nErrorCode); ,^< R{{{-A  
} & h)yro  
SHgN~ Um  
..5CC;B  
//停止文件下载 +GN(Ug'R  
public void siteStop() ]Q1yNtN  
{ _6hQ %hv8  
bStop = true; ;`{H!w[D  
for(int i=0;i<nStartPos.length;i++) 'GWN~5  
fileSplitterFetch.splitterStop(); |aS.a&vwR  
.! 3|&V'<  
P3=G1=47U  
} RSRS wkC  
} 3jU&zw9  
//负责部分文件的抓取 -d/ =5yxL  
**FileSplitterFetch.java d&Zpkbh"  
*/ yx[/|nZDC4  
package NetFox;  7xlkZF  
eC4[AX6e  
8kIksy  
import java.io.*; 2@],ZLa  
import java.net.*; ML 9' |  
I$G['` XX/  
J]'zIOQ  
public class FileSplitterFetch extends Thread { ^uc=f2=>,  
{}n^cq  
iWkWR"ys y  
String sURL; //File URL h,N?Ab'S  
long nStartPos; //File Snippet Start Position i1d'nxk6  
long nEndPos; //File Snippet End Position EME|k{W  
int nThreadID; //Thread's ID ]s'as9s9  
boolean bDownOver = false; //Downing is over Q3~H{)[Kq  
boolean bStop = false; //Stop identical a58H9w"u)  
FileAccessI fileAccessI = null; //File Access interface =y*IfG9b  
9W5lSX#^;  
;H*T^0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eo?bL$A[s  
{ ;igIZ$&  
this.sURL = sURL; |wMN}bq|T  
this.nStartPos = nStart; sl l\g  
this.nEndPos = nEnd; ]F~dlH1Wp  
nThreadID = id; ="H`V V_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :3Ox~o  
} 4p F*"B  
!;A\.~-!G  
;$|nrwhy  
public void run() \gaw6S>n}  
{ Wn2NMXK  
while(nStartPos < nEndPos && !bStop) ^^$s%{ep"  
{ IEi^kJflU  
U7F!Z( 9  
90rol~M&  
try{ =UQ3HQD  
URL url = new URL(sURL); \}b%E'+_T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vvMT}-!  
httpConnection.setRequestProperty("User-Agent","NetFox"); {JT&w6Jz  
String sProperty = "bytes="+nStartPos+"-"; 2%m BK  
httpConnection.setRequestProperty("RANGE",sProperty); &p@O _0nF  
Utility.log(sProperty); b8UO,fY q  
wn%A4-%{  
p6V0`5@t  
InputStream input = httpConnection.getInputStream(); $6 f3F?y7  
//logResponseHead(httpConnection); 1GcE) e!>  
TD0 B%  
W ac&b  
byte[] b = new byte[1024]; J*M>6Q.)  
int nRead; k4J+J.|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !F$6-0%  
{ gwMNYMI  
nStartPos += fileAccessI.write(b,0,nRead); F$]Pk|,  
//if(nThreadID == 1)  =:pJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d#FQc18v}k  
} ?:q*(EC<  
XRi8Gpg  
Q1 97mN+0  
Utility.log("Thread " + nThreadID + " is over!"); 73;GW4,  
bDownOver = true; CD~.z7,LC  
//nPos = fileAccessI.write (b,0,nRead); Xx:"4l.w.  
} L="}E rmK  
catch(Exception e){e.printStackTrace ();} >y 3=|  
} U5de@Y  
} h2R::/2.  
#\m<Sz5Gp#  
onzxx4bax  
//打印回应的头信息 f+!(k)GWd  
public void logResponseHead(HttpURLConnection con) k9!{IScq  
{ F JyT+  
for(int i=1;;i++) q_58;Bv  
{ (!WD1w   
String header=con.getHeaderFieldKey(i); n:!_  
if(header!=null) I efn$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); e\L8oOk#r  
Utility.log(header+" : "+con.getHeaderField(header)); YOO+R{4(  
else ?e 4/p  
break; x%B/  
} rx|pOz,:  
} G"t5nHY\.  
3!]rmZ-W  
^1];S^nD  
public void splitterStop() tWc Hb #  
{ bk[!8- b/a  
bStop = true; InI$:kJ  
} \9T7A&  
K$=zi}J W  
6'f;-2  
} #H~64/  
~t~|"u"P  
;2QP7PrSY  
/* T>W,'H  
**FileAccess.java ]Y&VT7+Z  
*//文件访问(定位,写) +ZP7{%  
package NetFox; i83OOV$1J  
import java.io.*; ?:0Jav  
BI@[\aRLQ  
v]UwJz3<  
public class FileAccessI implements Serializable{ /)O"l@ }U  
~k5W@`"W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 YoFxW5by  
RandomAccessFile oSavedFile; z F;K  
long nPos; Q"#J6@  
fk-RV>yr  
4*;MJ[|  
public FileAccessI() throws IOException K|=A:  
{ I&5!=kR  
this("",0); m1AJ{cs  
} om>KU$g  
8&dF  
<#4h}_xA%  
public FileAccessI(String sName,long nPos) throws IOException HZZn'u  
{ w0unS`\4  
oSavedFile = new RandomAccessFile(sName,"rw"); |R:'\+E  
this.nPos = nPos; wMN]~|z>  
oSavedFile.seek(nPos); |_U= z;Y  
} >9J:Uo1z  
Tlr v={  
Xch~ 1K  
public synchronized int write(byte[] b,int nStart,int nLen) .=; ;  
{ 9>#6*/Oa7  
int n = -1; u ^RxD^=L  
try{ LDa1X2N  
oSavedFile.write(b,nStart,nLen); GC'O[q+  
n = nLen; j'K/22  
} Ax}JLPz5'  
catch(IOException e) _@/8gPT*i  
{ j] [,J49L  
e.printStackTrace (); q@2siI~W  
} f*8DCh!r"  
/Z4et'Lo  
Dvln/SBk  
return n; e+K^A q  
} BJ(M2|VH  
hE-M$LmN@  
oP.7/*p  
} \l3h0R  
Ek}A]zC  
`r_/Wt{g  
/* TL#3;l^  
**SiteInfoBean.java +"VP-s0  
*/ )`D:F>p*  
package NetFox; 2J;g{95z  
/Ci<xmP  
;A[Q2(w+  
public class SiteInfoBean { $ME)#(  
IE~ |iQ?-  
>LuYHr  
private String sSiteURL; //Site's URL #_lDss  
private String sFilePath; //Saved File's Path e>7i_4(C  
private String sFileName; //Saved File's Name 4KrL{Z+}  
private int nSplitter; //Count of Splited Downloading File T6k0>[3xf  
3+bt~J0  
D1;QC  
public SiteInfoBean() <9 ;!3xG  
{//nSplitter的缺省值为5 ?z u8)U  
//default value of nSplitter is 5 ig &Y  
this("","","",5); E4xa[iZ  
} !f6(Zho  
PUX;I0Cf  
Y nZiT e@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BsJC0I(  
{ 4X|zmr:A  
sSiteURL= sURL; SX-iAS[<  
sFilePath = sPath; T]p-0?=4vv  
sFileName = sName; po7qmLq  
this.nSplitter = nSpiltter; v*yuE5{  
#3d(M  
sp`Dvqx0  
} @\I#^X5lv  
8Q+36!  
-Y;3I00(  
public String getSSiteURL() *uvQ\.  
{ Xn\jO>[Ef  
return sSiteURL; #R RRu2  
} :eLVC7'  
wec)Ctj+  
lb1Xsgm{  
public void setSSiteURL(String value) N,U8YO  
{ ;jTN | i'  
sSiteURL = value; 7"xd1l?zz  
} 6S\8$  
{FTqu.  
nt.y !k  
public String getSFilePath() WOf 4o  
{ 4v|W-h"K  
return sFilePath; u> / TE  
} 61 ~upQaR  
BL58] P84  
RzusNS  
public void setSFilePath(String value) $u6 3]rypm  
{ '[O;zJN;  
sFilePath = value; h`.&f  
} y18Y:)DkL  
&G$Ucc `  
KCDE{za  
public String getSFileName() NW)1#]gg%  
{ gv{ >`AN  
return sFileName; j 1HW._G  
} ^y4Z+Gu[  
/|&*QLy  
kz7(Z'pw  
public void setSFileName(String value) Fea(zJ_  
{ /JU.?M35  
sFileName = value; mlS$>O_aX  
} G<;*SYAb  
c_l"I9M#r  
9 JK Ew  
public int getNSplitter() HLHz2-lI  
{ 7})[lL`\s  
return nSplitter; cPc</[x[W  
} ]]j;/TiG  
{2 "zVt#h  
~.lPEA %%  
public void setNSplitter(int nCount) xA[mm  
{ Q.c\/&  
nSplitter = nCount; ROZF)|l  
} @!d{bQd,  
} *G 9V'9  
ef E.&]  
$]2vvr  
/* :S(ZzY Q  
**Utility.java R_S.tT!  
*/ ?#Q #u|~  
package NetFox; lCHO;7YHX  
*s iFj CN<  
-+-_I*(  
public class Utility { ges J/I  
'(jG[ry&T  
Lbb0_-']  
public Utility() QnX(V[  
{ %C_HXr@  
',5 ky{  
=zs`#-^8  
} _/<x   
j^2j& Ta  
//线程睡眠 {+Cy U!O  
public static void sleep(int nSecond) QoH6  
{ @49S`  
try{ X+]G-  
Thread.sleep(nSecond); 3%=~) 7cF  
} zT?D<XW>1  
catch(Exception e) DrK{}uM  
{ y Fq&8 x<X  
e.printStackTrace (); I ?.^ho  
} LvYB7<zk>  
} m/EFHS49  
4#hSJ(~7S  
//日志 cDkf qcC  
public static void log(String sMsg) dzrio-QU~  
{ r^ ZEImjc  
System.err.println(sMsg); D=&Me=$  
} K8Y=S12Ti  
mBON$sF|  
b<gr@WF  
public static void log(int sMsg) >!)DM]Ri  
{ Jma1N;d  
System.err.println(sMsg); P\)iZiGc  
} l_%6  
} g_COp "!~9  
<dhM\^ [  
Aj]V`B:65  
/* FH+s s!  
**TestMethod.java \v)+.m?n  
*/ gCY';\f!  
package NetFox; v0jgki4 t  
] {HI?V  
/%A*aGyIc  
public class TestMethod { ZbAcO/  
[Hh9a;.*}h  
x0:m-C  
public TestMethod() e'b(gD}  
{ ///xx/weblogic60b2_win.exe W-zP/]Dh  
try{ mF^v~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /J6rv((  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0}q uG^%_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aPbE;" f  
fileFetch.start(); mvT(.R ..s  
} O/(xj2~$ J  
catch(Exception e){e.printStackTrace ();} vTw>JNVI  
GYUn6P  
p,i[W.dy.'  
} jPW#(3hoE  
d)f :)Ew  
[RTs[3E^  
public static void main(String[] args) @@ %.t|=  
{ '}bgLv  
new TestMethod(); ;cN{a&  
} >[=^_8M  
} 9j:"J` '  
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