http断点续传简单实现（java)

/* X)3(.L  
**SiteFileFetch.java S`kOtZ_N n  
*/ Pxr/*X  
package NetFox; #^T`vTD-  
import java.io.*; z=>fBb>w7  
import java.net.*; d,^O[9UWo  
!UoA6C:  
nm5DNpHk  
public class SiteFileFetch extends Thread { &>\;4E.O5  
*V2;ds.~  
p~w
] ~\  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?06gu1z/  
long[] nStartPos; //开始位置 roQI;gq^  
long[] nEndPos; //结束位置 kSz+UMC-7:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Tw-NIT)  
long nFileLength; //文件长度 WGv47i  
boolean bFirst = true; //是否第一次取文件 |]< 3cW+  
boolean bStop = false; //停止标志 gy.UTAs N  
File tmpFile; //文件下载的临时信息 LSC[
S:  
DataOutputStream output; //输出到文件的输出流 Gn2{C%  
<wSJK  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @vl$[Z|  
public SiteFileFetch(SiteInfoBean bean) throws IOException !8G)`'  
{ NVMn7H}>  
siteInfoBean = bean; B'yjMY![  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M@.l# [@U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q5ASN"_  
if(tmpFile.exists ()) H^-Y]{7  
{ :+"4_f0  
bFirst = false; ;oOTL'Vu  
read_nPos(); 4t[7lL`Z  
} l2L
QV]l  
else E+/Nicn=  
{ FOG{dio  
nStartPos = new long[bean.getNSplitter()]; x$d[Ovw-  
nEndPos = new long[bean.getNSplitter()]; \foThLx  
} bN_e~z  
hL3up]pZ  
__g?xw  
$]DuO1H./  
} 6\7c:  
t<v.rb  
:`N&BV  
public void run() 5=?P6I_$G  
{ hQ|mow@Zmz  
//获得文件长度 m \)B=H!bz  
//分割文件 xrg"/?84  
//实例FileSplitterFetch eke[{%L  
//启动FileSplitterFetch线程 Cu+p!hV  
//等待子线程返回 {]dxFhe)  
try{ 3= =["hO  
if(bFirst) ,!{8@*!=s  
{ d~<$J9%  
nFileLength = getFileSize(); ;KQU% k$  
if(nFileLength == -1) S(PV*e8  
{ J@-'IJ  
System.err.println("File Length is not known!"); ??/bI~Sd  
} zx$YNjeV  
else if(nFileLength == -2) J
q0sZ0j  
{ M+&~sX*a  
System.err.println("File is not access!"); 3 `_/h' ~  
} Xe);LhDC  
else 1J!v;Y\\  
{ LLgw1 @-D  
for(int i=0;i<nStartPos.length;i++) B!+c74  
{ 9Kd=GL_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y[i}iT/~  
} c[-N A  
for(int i=0;i<nEndPos.length-1;i++) 7rdmj[vu  
{ AOg'4  
nEndPos = nStartPos[i+1]; &| (K#|^@  
} p6j-8ggL  
nEndPos[nEndPos.length-1] = nFileLength; ;T
^s&/>E  
} #mU\8M,  
} AW
r2Bv  
|5vJ:'`I  
w%\ nXJ  
//启动子线程 _#K|g#p5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .!4'Y}  
for(int i=0;i<nStartPos.length;i++) 25OQY.>bE  
{ KiXfR\S~C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4 ?BQ&d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h{)m}"n<R  
nStartPos,nEndPos,i); e`0C0GaP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F$8:9eL,T  
fileSplitterFetch.start(); ~u*4k:2H  
} [k 7HLn)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y^]n>
X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o`CM15d*7o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RFbf2s\t  
nEndPos = " + nFileLength); RJ?)O#}  
// fileSplitterFetch[nPos.length-1].start(); ~m fG Yk"  
Q9cSrU[$  
qXtC7uNj$  
//等待子线程结束 cpk\;1&t  
//int count = 0; !mK()#6  
//是否结束while循环 Sd6O?&(  
boolean breakWhile = false; W<q<}RSn  
%i?  
Py*WHHO  
while(!bStop) bg|$1ue  
{ j*QdD\)  
write_nPos(); S
5JMt;O  
Utility.sleep(500); )L&y@dy)  
breakWhile = true; H{=]94  
q&:7R .Ci  
4Y?fbb<  
for(int i=0;i<nStartPos.length;i++) &~eCDlX/  
{ 7NJl+
*u  
if(!fileSplitterFetch.bDownOver) d>Tv?'o`q  
{ <7y/)b@  
breakWhile = false; IS8 sJ6")  
break; V~PGmn[V  
} :NLY;B`  
} ?*V\ -7jg  
if(breakWhile) ?u2\*@C  
break; e^*&&  
S<(i/5Z+  
d
\qszYP[  
//count++; pq0Z<b;2  
//if(count>4) .+>fD0fW7Y  
// siteStop(); fmYx  
} /'8%=$2Kw  
/[ m7~B]QE  
iJOoO"Ai  
System.err.println("文件下载结束！"); xlZh(pf  
} yPmo1|'X>d  
catch(Exception e){e.printStackTrace ();} 3F,M{'q
 
} Ju>QQOxi|  
dk
g`T#}  
1a9' *[  
//获得文件长度 [`tOhL  
public long getFileSize() X(Af`KOg[  
{ Vw;iE=L  
int nFileLength = -1; G739
Ne[gL  
try{ G9xl-ag+z  
URL url = new URL(siteInfoBean.getSSiteURL()); iAe"oXK|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #TUm&2 +V  
httpConnection.setRequestProperty("User-Agent","NetFox"); #reR<qp&]  
n$ByTmKxv  
k|xmZA*  
int responseCode=httpConnection.getResponseCode(); DzhLb8k  
if(responseCode>=400) !ldE9 .  
{ '[6]W)f  
processErrorCode(responseCode); :&5u)  
return -2; //-2 represent access is error Rm3W&hQ  
} zecM|S_  
7r,GdP.  
!_Y
%+Rkp0  
String sHeader; &=t~_ Dc  
],AtR1k  
At>e4t2@  
for(int i=1;;i++) )[Rwc#PA;  
{ G l/3*J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qh bagw~  
//Utility.log(in.readLine()); .\H-?6R^  
sHeader=httpConnection.getHeaderFieldKey(i); 5[\g87\  
if(sHeader!=null) bLl ?!G.  
{ PUea`rE?R  
if(sHeader.equals("Content-Length"))
]l }v  
{ "LYhYkI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8;~,jZ s  
break; @/aJi6d"^E  
} MuO(%.H  
} j^/<:e c.  
else N]8/l:@  
break; Lm$KR!z  
} 1grcCL q  
} Y".?j5f?  
catch(IOException e){e.printStackTrace ();} F+c8 O
 
catch(Exception e){e.printStackTrace ();} ?b d&Av  
/slCK4vFc  
H^*[TX=#[  
Utility.log(nFileLength); CWZv/>,%  
tZ
) ,Z<  
Fu?_<G%Ynp  
return nFileLength; eOVln1a  
} c9g
m%  
s'/_0  
;U0w<>4L  
//保存下载信息（文件指针位置） J}Z\I Y,  
private void write_nPos() 0XE6Hw  
{ JWu0
VLo  
try{ Y)8 Py1}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XR=ebl  
output.writeInt(nStartPos.length); %N\45nYU:  
for(int i=0;i<nStartPos.length;i++) !*^+7M  
{ ;|=5)KE  
// output.writeLong(nPos); O&CY9 2)Lk  
output.writeLong(fileSplitterFetch.nStartPos); "kt7m  
output.writeLong(fileSplitterFetch.nEndPos); =H-BsX?P  
} Yk{4 3yw  
output.close(); mr>E'd.'  
} r"L:Mu  
catch(IOException e){e.printStackTrace ();} 1"A"AMZf  
catch(Exception e){e.printStackTrace ();} H(?+-72KX  
} (eT9N_W  
5!i\
S[:  
&6GW9pl[  
//读取保存的下载信息（文件指针位置） 4D.h~X4  
private void read_nPos() U2Siw  
{ ZdhA:}~^E  
try{ )fuAdG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4
,`t9f^:  
int nCount = input.readInt(); ZDK+>^A)  
nStartPos = new long[nCount]; FKtCUq,:  
nEndPos = new long[nCount]; q.hpnE~#lh  
for(int i=0;i<nStartPos.length;i++) W)2
k>cS  
{ {Y+e|B0  
nStartPos = input.readLong(); 4\U"e*  
nEndPos = input.readLong(); }P!:0w3  
} ?S)Pv53>}  
input.close(); $*fEgU% c  
} TD;u"  
catch(IOException e){e.printStackTrace ();} o|KmKC n>  
catch(Exception e){e.printStackTrace ();} Fyz1LOH[X  
} UZJs!#P  
m2
%
 
Q9X+H4`}y  
private void processErrorCode(int nErrorCode) it j&L <e  
{ 0 4ceDe  
System.err.println("Error Code : " + nErrorCode); !9S!zRy@  
} R-Tf9?)  
TY+Rol;!  
F{&0(6^p!  
//停止文件下载 x;&iLQZh  
public void siteStop() 2Zq_zvKUt  
{ ;k1VY I
e}  
bStop = true; #
3C]"  
for(int i=0;i<nStartPos.length;i++) /GP:W6:6z6  
fileSplitterFetch.splitterStop(); LqQ&4I  
V'N]u(^  
{f6~Vwf  
} gE&83i"  
} 1A7(s0J8 :  
//负责部分文件的抓取 1VXn`O?LW  
**FileSplitterFetch.java ]|Iczg-   
*/ #9(iu S+BU  
package NetFox; Y0Rk:Njc  
St3/mDtH  
e&pt[W}X%u  
import java.io.*; H"JzTo8u  
import java.net.*; ,7Q b24A  
{tXyz[;i1}  
Wh?
3vZ^  
public class FileSplitterFetch extends Thread { X5)].[d  
yEL5U{  
2reQd
47  
String sURL; //File URL t] G hONN  
long nStartPos; //File Snippet Start Position v00w GOpW  
long nEndPos; //File Snippet End Position J.,7d ,  
int nThreadID; //Thread's ID >{h/4T@  
boolean bDownOver = false; //Downing is over /a-OBU  
boolean bStop = false; //Stop identical 3jM+j_nR  
FileAccessI fileAccessI = null; //File Access interface $Ehe8,=fj  
]EvK
.ORy  
F$,i_7Z&6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DvBRK}'  
{ dJ,,yA*  
this.sURL = sURL; =eeZtj.  
this.nStartPos = nStart; 4^w`]m  
this.nEndPos = nEnd; /kFw(l_.  
nThreadID = id; T;Ra/H
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O1z
3(  
} $gcC}tX  
ESY\!X:|  
*edhJUT  
public void run() uWrvkLGN  
{ g/z7_Aq/  
while(nStartPos < nEndPos && !bStop) C1
(0jUz  
{ J+nUxF;EE  
V%w]HIhq  
$@ZrGT  
try{ 3B ;aoejHm  
URL url = new URL(sURL); '_M"yg6d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :&=`xAX-  
httpConnection.setRequestProperty("User-Agent","NetFox"); k 3oR:  
String sProperty = "bytes="+nStartPos+"-"; \yo)oIi[p  
httpConnection.setRequestProperty("RANGE",sProperty); 7,D6RP(b  
Utility.log(sProperty); &n2dL->*#  
R`>z>!)  
-W"w  
InputStream input = httpConnection.getInputStream(); 5PT*b}g@  
//logResponseHead(httpConnection); 5l /EZ\q  
w;DRC5V>  
~&8bVA= .  
byte[] b = new byte[1024]; sG k'G573  
int nRead; kKNrCv@64d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6tT*b@/_o  
{ y[~w2a&+  
nStartPos += fileAccessI.write(b,0,nRead); l%xjCuuhU  
//if(nThreadID == 1) ]n&Eb88  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d7!,  
} :J;*]o:  
{$qLMx';  
GPU,.s"&(  
Utility.log("Thread " + nThreadID + " is over!"); R(cM4T.a  
bDownOver = true; CoQ<Ky}*  
//nPos = fileAccessI.write (b,0,nRead); .hytn`+9  
} F*/J`l  
catch(Exception e){e.printStackTrace ();} =bl6:  
} #BwkbOgr  
} eQ eucmQd{  
4X:S#z  
J4^aD;j  
//打印回应的头信息 ]w9\q*S]  
public void logResponseHead(HttpURLConnection con) De:| T8&  
{ HF]|>1WV[  
for(int i=1;;i++) q5ja \  
{ LRmH@-qP  
String header=con.getHeaderFieldKey(i); 20k@!BNq  
if(header!=null) S,2{^X  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A\};^Y  
Utility.log(header+" : "+con.getHeaderField(header)); &0%x6vea  
else LIMPWw g  
break; GUdVsZjz(  
} vvcA-k?  
} zQyt1&!  
T!Eyq,]  
Pa\"l'!>^  
public void splitterStop() .7M:AS>  
{ u(g0Ob  
bStop = true; t73" d#+  
} M"<B@p]rk:  
u8i!Fxu  
QwgP+ M+  
} "1%YtV5R{  
EnnE@BJ"  
u40<>A  
/* YO`V'6\  
**FileAccess.java ?'r=>'6D  
*//文件访问(定位，写) |$a!Zx94^  
package NetFox; HmZ*  
import java.io.*; d{G*1l(X  
We*&\e+"T  
=^S1+B MY-  
public class FileAccessI implements Serializable{ "3X~BdH&J  
KO5! (vi@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3zuYN-;  
RandomAccessFile oSavedFile; jK9#. 0  
long nPos; a!Ht81gj  
7,&
M
6<~  
{ x/~gp
 
public FileAccessI() throws IOException ;7w4BJcq']  
{ rq_0"A  
this("",0); [,As;a*o  
} LP-_i}Kq  
i*ErxWzu  
68-2EWq  
public FileAccessI(String sName,long nPos) throws IOException l#k&&rI5x.  
{ 4<Q^/-W  
oSavedFile = new RandomAccessFile(sName,"rw"); Rx%SeM2  
this.nPos = nPos; T?V!%AqY:  
oSavedFile.seek(nPos); v[I
,N$:  
} $`Hb-  
Fl0 :Z  
:o+&>z  
public synchronized int write(byte[] b,int nStart,int nLen) 19.oW49Sw  
{ ;ro%Wjg`}  
int n = -1; ?kKr/f4N  
try{ v3/l=e?u  
oSavedFile.write(b,nStart,nLen); iW,fKXuo&y  
n = nLen; uKE?VNC]  
} , UiA?7k  
catch(IOException e) #Z>EX?VS:  
{ u[G`_Y{=EM  
e.printStackTrace (); WXX)_L$2  
} /7[X_)OG  
KR sY `[Y  
qxW^\u!<  
return n; "0]s|ys6<  
} \:@yfI@  
8JbN&C  
WG=~GDS>  
} Vp j[)W%L  
<Gkmk?x`A  
z)&ZoSXWc  
/* ^7>k:|7-t  
**SiteInfoBean.java IMtfi(Y%F  
*/ "D1u2>(  
package NetFox; i]M:ntB"  
* j]"I=D  

2GC{+*  
public class SiteInfoBean { 9qXKHro
 
}Z Nyd  
]p5]n*0X  
private String sSiteURL; //Site's URL h1+lVAQbT  
private String sFilePath; //Saved File's Path E[kf%\  
private String sFileName; //Saved File's Name
(Y>|P  
private int nSplitter; //Count of Splited Downloading File pRrokYM d  
wseb]=U  
k1HVvMD<  
public SiteInfoBean() dD.;P=AP  
{//nSplitter的缺省值为5 "Q
<  
//default value of nSplitter is 5 E\lel4ai  
this("","","",5); t],5{UF  
} jNu`umS  
Lx#CFrLQ*  
.R5(k'g?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) LOX}  
{ KKJ)BG?qZ  
sSiteURL= sURL; CE;J`;  
sFilePath = sPath; CP"   
sFileName = sName; 5KIlU78  
this.nSplitter = nSpiltter; t`oH7)nut  
q@0g KC&U  
*j"u~ NF  
} FQW{c3%qZ  
*p Q'w  
Vnvfu!>(  
public String getSSiteURL() vE<z0l  
{ GZCX
m+  
return sSiteURL; 0V[`zOO(o  
} #$;i 4a  
uXkc07 r'  
F\IJim-Rh  
public void setSSiteURL(String value) hF;TX.Y6  
{ 49d02AU%  
sSiteURL = value; QK0-jYG^  
} Oi-= Fp  
 A4  
cypb6Q_  
public String getSFilePath() S2,tv
  
{ [oS4WP  
return sFilePath; vn5O8sD  
} odaCKhdk  
_KZ&/  
wJ Qm7n-+  
public void setSFilePath(String value) h5^qo ^;g7  
{ $3c9iVK~_  
sFilePath = value; o7=#ye&P  
} aTU[H~dTU  
N6UPD11}6  
` 5lW  
public String getSFileName() @:%p#$V  
{ cf`g.9pjlx  
return sFileName; _ISaO C{2-  
} B57MzIZi]  
#WqpU.
  
5R}K8"d  
public void setSFileName(String value) 'Tbdo >y  
{ T;`2t;  
sFileName = value; 9^<Y~rkm  
} u|{(m_"H  
CEHtr90P  
B+r$_L&I  
public int getNSplitter() 0Q4i<4 XW  
{ qayM0i>>  
return nSplitter; "%E<%g  
} s9aa _Th  
u/ZV35z  
M,we9];N  
public void setNSplitter(int nCount) Q@0Zh,l  
{ 3]wV 1<K  
nSplitter = nCount; lv!8)GX|  
} V7(-<})8  
} wS+ekt5  
pgipT#_K  
(\$=de>?  
/* b9RJ>K  
**Utility.java +Z=%4  
*/ KJP}0|[  
package NetFox; qLWM,[Og  
6QM$aLLP?  
dng^#|X)?  
public class Utility { >i!y[F  
wmB_)`QNP  
Bk2j|7  
public Utility() cyTBp58  
{ cJLAP%.L  
s8V:;$ !  
/mG-g%gE  
} u?7^+z  
Y?#aUQc  
//线程睡眠 F!7\Za,  
public static void sleep(int nSecond) ?A]/ M~3B  
{ tV"Jh>Z  
try{ K3xt,g  
Thread.sleep(nSecond); w:nLm,  
} {!>'# F^e  
catch(Exception e) :`B70D8ku  
{ Dn[uzY6  
e.printStackTrace (); ~i UG24v  
} UZRN4tru6  
} 3-v&ktD&N'  
dJ.up*aR  
//日志 6`WI S4  
public static void log(String sMsg) '_B;e=v`  
{ ?*L{xNC#  
System.err.println(sMsg); AwtiV-w  
} `R 
m<1  
:j&-Lc  
e4LJ3y&z"  
public static void log(int sMsg) WX4f3Um  
{ vI \8@97  
System.err.println(sMsg); }uiD8b{I  
} 3g87ir  
} a[=;6!  
p\22_m_wd  
;pt.)5  
/* hV}C.- 6h  
**TestMethod.java C8
KV<k  
*/  {HbSty  
package NetFox; '37 <+N  
'OI(MuSn  
ib%'{?Q.  
public class TestMethod { k2/t~|5  
w0PAtu  
3R<
VpN){  
public TestMethod() 4w#:?Y _\[  
{ ///xx/weblogic60b2_win.exe =wznkqyhi  
try{ !CUM*<iV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xV"~?vD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8lFYk`|g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3w}ul~>
j  
fileFetch.start(); G * =>  
} w*\JA+  
catch(Exception e){e.printStackTrace ();} 2sYz$ZGC"#  
:u`gjj$:s  
,wZq~;2  
} 4ufT-&m};s  
KEjMxOv1  
"#P#;]\`  
public static void main(String[] args) tQE<'94A  
{ "2ZuI;w  
new TestMethod(); 7QdboEa  
} _'Rg7zHTp-  
} -ND1+`yD  
点击下载更多相关资料