http断点续传简单实现（java)

/* 8b[^6]rM  
**SiteFileFetch.java 28>gAz.#  
*/ 7b \HbgZ  
package NetFox; aXhgzI5]  
import java.io.*; ]B5qv6  
import java.net.*; rpQB# Pz  
L6J=m#Ld  
=K-B I  
public class SiteFileFetch extends Thread { m9a(f>C  
Ca0~K42~  
ZlUd^6|:3  
SiteInfoBean siteInfoBean = null; //文件信息Bean A"2k,{d  
long[] nStartPos; //开始位置 OB>Pk_eQK  
long[] nEndPos; //结束位置 gj0gs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 NYm2fFPc  
long nFileLength; //文件长度 q1.w8$  
boolean bFirst = true; //是否第一次取文件 y4w{8;Mh  
boolean bStop = false; //停止标志 b'3w.%^  
File tmpFile; //文件下载的临时信息 #\GWYWkR  
DataOutputStream output; //输出到文件的输出流 wtu WzHrF  
*"d"  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &CV%+  
public SiteFileFetch(SiteInfoBean bean) throws IOException ))K3pKyb  
{ ?MHVkGD  
siteInfoBean = bean; 4'cdV0]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c0sU1:e0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y9cW&rDH  
if(tmpFile.exists ()) BlF>TI%2  
{ kXFgvIpg<  
bFirst = false; b*+Od8r  
read_nPos(); %oJ_,m_(  
} se:]F/  
else /bjyV]N  
{ NldeD2~H  
nStartPos = new long[bean.getNSplitter()]; =6y4*f  
nEndPos = new long[bean.getNSplitter()]; $-Lk,}s.*  
} zWb
>y  
n,!PyJ  
@T0F }(k  
"t$c'`  
} AcqsXBKd  
O(2)A>}  
-NHA{?6r  
public void run() swss#?.se  
{
s5F,*<  
//获得文件长度 s2FJ^4  
//分割文件 z@R:~  
//实例FileSplitterFetch 8J-$+ ;  
//启动FileSplitterFetch线程 :G=N|3  
//等待子线程返回 "g;^R/sfq  
try{ b)"bX}  
if(bFirst) t:B~P,r  
{ Rf||(KC<  
nFileLength = getFileSize(); 7s+3^'  
if(nFileLength == -1) +&6R(7XC  
{ />=)=CGv;  
System.err.println("File Length is not known!"); ..`J-k  
} hK5BOq!y  
else if(nFileLength == -2) t
gCEz%  
{ se(ZiyHp  
System.err.println("File is not access!"); P~HzNC  
} Q(=}
PF  
else h;?=:(  
{ rtd&WkU rD  
for(int i=0;i<nStartPos.length;i++) d:cs8f4>  
{ 2+y<&[A8U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ];P$w.0  
} 1$2'N~`#U  
for(int i=0;i<nEndPos.length-1;i++) dtD)VNkBZ  
{ e"Kg/*Ji1  
nEndPos = nStartPos[i+1]; scZdDbL6+  
} E&ou(Q={  
nEndPos[nEndPos.length-1] = nFileLength; @0H}U$l  
} 1AiqB Rs  
} 8@pY:AY  
Y7g
^ ?6  
lf3QMr+  
//启动子线程 <Yif-9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E_ #MQ;n  
for(int i=0;i<nStartPos.length;i++) US3rkkgDO  
{ }q7rR:g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <mN.6@*{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `}<x"f7.z  
nStartPos,nEndPos,i); @Cg%7AF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KKB&)R  
fileSplitterFetch.start(); gx,BF#8}  
} ^oaFnzJdf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x$ z9:'U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o,}`4_N||  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HQqnJ;ns<  
nEndPos = " + nFileLength); V/xGk9L~  
// fileSplitterFetch[nPos.length-1].start(); .H;[s  
Vm\ly;v'R  
QCjC|T9  
//等待子线程结束 'e @`HG  
//int count = 0; TrA&yXXL  
//是否结束while循环 I2"
F2(>8K  
boolean breakWhile = false; ;>%@  
P|c[EUT  
g+'=#NS}  
while(!bStop) ai|d`:;  
{ D2<(V,h9  
write_nPos(); Lso4ZZ;  
Utility.sleep(500); BOqu$f+  
breakWhile = true; b7;`A~{9v  
"%^T~Z(_j  
jFAnhbbCE  
for(int i=0;i<nStartPos.length;i++) LcL|'S)  
{ m+&)eQ:  
if(!fileSplitterFetch.bDownOver) ~\HGV+S!g}  
{ N_<wiwI<  
breakWhile = false; bp"@vlv  
break; 21k^MZ  
} m][i-|@M  
} ,gYbi-E  
if(breakWhile) NHI(}Ea|]  
break; jNjm}8`t  
y$-;6zk\]  
fSR+~Vy  
//count++; x$p_mWC  
//if(count>4) M`m-@z  
// siteStop(); BF >678h  
} D=ZH? d  
V!^5#A<  
:&59N^So|  
System.err.println("文件下载结束！"); W#^W1j>_G  
} (tY0/s  
catch(Exception e){e.printStackTrace ();} uB&um*DP  
} 0Z{;sW  
|/!3N  
c-s A?q#|  
//获得文件长度 ^)wTCkH&y  
public long getFileSize() ONr}{T%@/  
{ 8Qm%T7]UFb  
int nFileLength = -1; k+nfW]UNF  
try{ ~6bf-Wg'X  
URL url = new URL(siteInfoBean.getSSiteURL()); IhRWa|{I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l:Hm|9UZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); .A6i?iROe  
IZw>!KYG  
VDnN2)
Km*  
int responseCode=httpConnection.getResponseCode(); wgETL|3-  
if(responseCode>=400) 98Dg[O  
{ o=%pR|  
processErrorCode(responseCode); 3kU4?D]  
return -2; //-2 represent access is error VgB
Z@*z(x  
} Ej;BI#gx=  
{`KRr:w  
!t.*xT4W  
String sHeader; 1\XR6q:2  
8Pgw_ 21N1  
PjxZ3O  
for(int i=1;;i++) s28t'  
{ &-e@Et`Pg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B_ x?s  
//Utility.log(in.readLine()); V DN@=/  
sHeader=httpConnection.getHeaderFieldKey(i); Gt|m;o  
if(sHeader!=null) OQ=0>;>  
{ cT&!_g#g  
if(sHeader.equals("Content-Length")) :_
0"t-  
{ 655OL)|cD6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IH2V.>h  
break; #?^%#"~4H  
} ].(l^W  
} GE S_|[Q  
else m,3H]  
break; x@aWvrL  
} eI#b%h  
} He1hgJ)N  
catch(IOException e){e.printStackTrace ();} tjId?}\  
catch(Exception e){e.printStackTrace ();} jeu|9{iTVu  
e]!`Cl-f80  
gt>k]0  
Utility.log(nFileLength); WR<,[*Mv^  
OZSM2~  
c04;2gR  
return nFileLength; +m>)q4e  
} s^vw]D  
y' r I1eF  
[t}@>@W|  
//保存下载信息（文件指针位置） Quts~Q  
private void write_nPos() pRez${f.(s  
{ .@`5>_  
try{ <Na .6P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z&Kh$ $)[  
output.writeInt(nStartPos.length); y$Rh$eK  
for(int i=0;i<nStartPos.length;i++) N"zg)MsX  
{ SJai<>k h  
// output.writeLong(nPos); ~!iZn  
output.writeLong(fileSplitterFetch.nStartPos); Acl?w
}Y  
output.writeLong(fileSplitterFetch.nEndPos); r:~q{  
} +U^H`\EUr  
output.close(); V/dL-;W;  
} 7.W$6U5  
catch(IOException e){e.printStackTrace ();} ahmxbv3f=5  
catch(Exception e){e.printStackTrace ();} t`!@E#VK  
} oQ{ X2\  
q L-Ni  
tmgZNg  
//读取保存的下载信息（文件指针位置） &`LR{7m  
private void read_nPos() ;JHR~ TV  
{ zu!#  
try{ l2h1CtAU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t}X+P`Ovq  
int nCount = input.readInt(); 12TX_0  
nStartPos = new long[nCount]; }
b/Xui9Q  
nEndPos = new long[nCount]; OTmw/#ug  
for(int i=0;i<nStartPos.length;i++) z[?
&bF<|  
{ G|eJ
ac>  
nStartPos = input.readLong(); G5T(  
nEndPos = input.readLong(); $*S&i(z  
} nYE''g+x  
input.close(); F5s`AjU  
} QP~Iz*J'  
catch(IOException e){e.printStackTrace ();} E 5N9.th  
catch(Exception e){e.printStackTrace ();} =#.qe=  
} xO0}A1t Wd  
<KEVA?0>  
1Pp2wpD4iC  
private void processErrorCode(int nErrorCode) " Z2D@l  
{ Gl]z@ZXWIw  
System.err.println("Error Code : " + nErrorCode); Bgf'Hm%r  
} g><itA?  
pm>$'z!.):  
dml,|k=  
//停止文件下载 >ca w :  
public void siteStop() Lyy:G9OV  
{
~RU-N%Kn  
bStop = true; mhv ;pM6  
for(int i=0;i<nStartPos.length;i++) jG^f_w  
fileSplitterFetch.splitterStop(); ^$x1~}D  
M'sq{K9  
ZQI;b0C  
} H9Dw#.em  
} CYn56eRK  
//负责部分文件的抓取 1F]jy  
**FileSplitterFetch.java 4V7=VZ,@3  
*/ iw=~j  
package NetFox; l<8+>W`_  
,\'E<O2T  
y.,li<  
import java.io.*; XQI!G_\+C  
import java.net.*; &S9O:>=*  
pp1kcrE\M  
\}EJtux q  
public class FileSplitterFetch extends Thread { q!Q*T^-rO  
i0g/'ZP  
I2^@>/p8\(  
String sURL; //File URL ?atHZLF  
long nStartPos; //File Snippet Start Position xO 6$:o-  
long nEndPos; //File Snippet End Position i@o'Fc  
int nThreadID; //Thread's ID <o"2
z~gv  
boolean bDownOver = false; //Downing is over YGsg0I't  
boolean bStop = false; //Stop identical ^EZ?wdL  
FileAccessI fileAccessI = null; //File Access interface
mXJ`t5v^l  
_`d=0l*8  
D`hg+64}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8\BYm|%aa  
{ =j^wa')  
this.sURL = sURL;  BRF4p:  
this.nStartPos = nStart; 9}<iS w[  
this.nEndPos = nEnd; l % 0c{E~  
nThreadID = id; 0kxe5*-|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iM +p{/bN  
} K[R.B!;N  
.gs:.X)TG9  
R&@NFin  
public void run() 8!|LJI  
{ LLU]KZhtY|  
while(nStartPos < nEndPos && !bStop) z *~rd2  
{ +OeoA{-W  

C%q]o  
4O>0gK{w  
try{ Z,:}H6Mj9  
URL url = new URL(sURL); #]}]ZE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B]wfDUG  
httpConnection.setRequestProperty("User-Agent","NetFox"); FKU)# Eo  
String sProperty = "bytes="+nStartPos+"-"; &.chqP(|  
httpConnection.setRequestProperty("RANGE",sProperty); ueu=$.^;g  
Utility.log(sProperty); ~^v*f  
/ 0y5/  
a'|/=$  
InputStream input = httpConnection.getInputStream(); n|Gw?@CU7  
//logResponseHead(httpConnection); &]jCoBj+_  
w|( ix;pK  
'~n=<Y  
byte[] b = new byte[1024]; 8ps1Q2|  
int nRead; >d<tcaB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <hB~|a<#  
{ 9HG"}CGZP  
nStartPos += fileAccessI.write(b,0,nRead); l
*]nvd_  
//if(nThreadID == 1) 3}x6IM2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RWdx)qj{  
} ^KjxQO6y3  
4R28S]Gb  
B/gI~e0  
Utility.log("Thread " + nThreadID + " is over!"); :r+F95e  
bDownOver = true; J 7]LMw7  
//nPos = fileAccessI.write (b,0,nRead); K?gO]T{6  
} #|;;>YnZ  
catch(Exception e){e.printStackTrace ();} 22gh,e2o  
} 6bd{3@   
} N7#,x9+E  
yq
,%<%+  
.v[!_bk8C  
//打印回应的头信息 (Z#j^}G_
l  
public void logResponseHead(HttpURLConnection con) {9|S,<9  
{ sV-UY!   
for(int i=1;;i++) Z1sRLkR^  
{ l^;=0UR_  
String header=con.getHeaderFieldKey(i); *$9Rb2}kK  
if(header!=null) KDu~,P]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *#
;  
Utility.log(header+" : "+con.getHeaderField(header)); Tk:%
YS;=  
else ~NBlJULS  
break; #waK^B)<a  
} f (ug3(j  
} WlRaD%Q  
#(1R:z\:  
`(VVb@:o  
public void splitterStop() S)W(@R+@4  
{ cW?~]E'<  
bStop = true; Qo])A6$IU  
} 3im2 `n  
)mE67{YJh~  
mL]5Tnc  
} eGi|S'L'  
Ep8 y  
MURHv3  
/* Z.3*sp0 yv  
**FileAccess.java $##
LSTA  
*//文件访问(定位，写) YfJQ]tt1  
package NetFox; D~r{(u~Ya  
import java.io.*; "= >8UR  
_2rxDd1#.  
e*hCf5=-  
public class FileAccessI implements Serializable{ 3TF'[(K=  
KK41I8Mw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 L]QBh\  
RandomAccessFile oSavedFile; ],w+4;+  
long nPos; m}GEx)Y D  
QR*{}`+l  
^s6C']q *O  
public FileAccessI() throws IOException % QI6`@Y"  
{ FXo{|z3  
this("",0); *>J45U(6:  
} g<5G#  
A=l1_8,`h  
=(Wl'iG   
public FileAccessI(String sName,long nPos) throws IOException _{48s8V  
{ 8e}8@[h  
oSavedFile = new RandomAccessFile(sName,"rw"); :B1a2Y^"  
this.nPos = nPos; 0=c:O  
oSavedFile.seek(nPos); 2hFj+Ay  
} /V f L(  
}W$}blbp  
xT;j_'9U;  
public synchronized int write(byte[] b,int nStart,int nLen) .R{
+Pz D  
{ Aj "SSX!L  
int n = -1; 15wwu} X  
try{ xqLIs:*  
oSavedFile.write(b,nStart,nLen); D0@d}N  
n = nLen; ]R6Z(^XT,E  
} vH/Y]Am  
catch(IOException e) O*-sSf   
{ 
^=Egf?|[  
e.printStackTrace ();  :IX_}|  
}  cvO;xR  
<G#z;]N  
V|G
[j\]E<  
return n; un(fr7NW  
} q($fl7}Y  
eW zyydl  
r!HB""w  
} Uiu9o]n  
V SUz+W  
2~q(?wY  
/* R4Si{J*O  
**SiteInfoBean.java i*ji   
*/ ?Qdp#K]WX  
package NetFox; ]WZi+  
.}DL%E`n  
4&'_~qU  
public class SiteInfoBean { k ks ?S',  
:j(D&?ao  
eKek~U&  
private String sSiteURL; //Site's URL "i/3m'<2  
private String sFilePath; //Saved File's Path S[L2
vM)  
private String sFileName; //Saved File's Name OCYC Dn  
private int nSplitter; //Count of Splited Downloading File ybgAyJ{J<  
AAld2"r  
IX y $  
public SiteInfoBean() qD/FxR-!  
{//nSplitter的缺省值为5 a@U0s+V&a0  
//default value of nSplitter is 5 v}-jls  
this("","","",5); {GM8}M~D&  
} SWM6+i p  
]#Q'~X W  
FAP1Bm  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hV>@qOl '  
{ ZeP3 Yjr3  
sSiteURL= sURL; }t9A#GOz  
sFilePath = sPath; 9G=Z
B^  
sFileName = sName; ky98Bz%  
this.nSplitter = nSpiltter; {;j@-=pV  
_
=68iDXm  
L}5IX)#gH
 
} ht@s!5\LK  
'c|Y*2@  

H-Z1i  
public String getSSiteURL() HnmByn\j  
{ <u85>x  
return sSiteURL; kFF)6z:2  
} W_z?t;  
^7&0Pm  
yyVv@  
public void setSSiteURL(String value) %Lwd1'C%  
{ JdW:%,sv  
sSiteURL = value; 60St99@O  
} Rooem dCM  
kVu-,OU  
B)`^/^7  
public String getSFilePath() &.t|&8-  
{ ;Z(~;D  
return sFilePath; hSyA;*)U  
} U?:<clh  
IRW%*W#  
J((
.zLvz  
public void setSFilePath(String value) 8{Id+Q>Vo,  
{ Sk 10"DB/  
sFilePath = value; Z/@%MEU[zl  
} (
" +/ :  
34P5[j!h  
9#AsSbBpf  
public String getSFileName() @43o4,  
{ >f*[U/{ K  
return sFileName; LYY|8)Nj2"  
} Kzd`|+?'`M  
dQ
4K^u  
^"d!(npw  
public void setSFileName(String value) ^v].mV/  
{ k$7@@?<  
sFileName = value; !B_?_ a  
} "nK(+Z  
&JpFt^IHi  
wbaXRvg  
public int getNSplitter() ceu}Lp^%/  
{ \4.U.pKY  
return nSplitter; ToHCS/J59  
} wGC)gW  
kGZ_/"iuO  
(]mh}=:KDg  
public void setNSplitter(int nCount) *0,?QS-a  
{ l&d 6G0  
nSplitter = nCount; c=T^)~$$  
} O/(qi8En  
} w*Gv#B9G
  
3 TN?yP)  
>Rbgg1^]5  
/* *YFe  
**Utility.java r4~Bn7j2  
*/ icf[.  
package NetFox; C||A[JOS  
G'<J8;B* t  
Q\~4J1  
public class Utility { [k9aY$baT^  
$z+iB;x  
[z:bnS~yiD  
public Utility() $3!j1  
{ ZL`G<Mo;.  
ul e]eRAG  
F%Lniv/N  
} Ha\q}~_  
!j)H!|R  
//线程睡眠 lq$1CI  
public static void sleep(int nSecond) gq6C6   
{ [Pdm1]":(  
try{ r'p;Nj.  
Thread.sleep(nSecond); ,0#5k
c*X  
} 26E"Ui5q  
catch(Exception e) .d5|Fs~B  
{ gnoV>ON0  
e.printStackTrace (); W.ud<OKP90  
} )T:{(v7 d`  
} ]rDf3_!m(  
h@72eav3+  
//日志 G^F4c{3c~  
public static void log(String sMsg) FhZ&^.:  
{ W9?Yzl  
System.err.println(sMsg); <4y1[/S  
} -0Q:0wU  
0:**uion  
:XMw="u=  
public static void log(int sMsg) aho;HM$hjP  
{ C9
/?B:  
System.err.println(sMsg); 8kih81tx"U  
} qphN  
} I~qS6#%r  
Fz16m7.  
8=7u,t  
/* 2;4Of~  
**TestMethod.java qeCx.Z  
*/ ]do0{I%\eq  
package NetFox; ";j/k9DE  
+b]g;  
6:B[8otQ  
public class TestMethod { cW,wN~  
*&B*/HAN  
:x97^.eW~  
public TestMethod() bG>pm|/  
{ ///xx/weblogic60b2_win.exe ^"ywltW>  
try{ ~fs{Ff'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f3-=?Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @.-g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,:-S<]fS{_  
fileFetch.start(); ;tI=xNre`1  
} FpfOxF6A3  
catch(Exception e){e.printStackTrace ();} !xMyk>%2  
I?"cEp   
m4ovppC  
} sRo%=7Z  
'@HWp8+  
[dsH0 D&T  
public static void main(String[] args) PBr-<J  
{ Y-n*K'  
new TestMethod(); YmHn*N}:U  
} DI9x]CR  
} HPpKti7g  
点击下载更多相关资料