http断点续传简单实现（java)

/* gX-hYQrC  
**SiteFileFetch.java rev*G:  
*/ %yjD<2J;  
package NetFox; 34N~<-9AY  
import java.io.*; wYV>Qd Z  
import java.net.*; uPYH3<  
< FO=PM  
1kUlQ*[<|  
public class SiteFileFetch extends Thread { )u=W?5%=}  
y:Of~ ]9@  
79d(UG'O  
SiteInfoBean siteInfoBean = null; //文件信息Bean XpE847!soL  
long[] nStartPos; //开始位置 Suo$
wZ7J  
long[] nEndPos; //结束位置 7OG:G z+)x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gGMQRRq  
long nFileLength; //文件长度 s
0D4K  
boolean bFirst = true; //是否第一次取文件 jf)l; \u  
boolean bStop = false; //停止标志 \weg%
a  
File tmpFile; //文件下载的临时信息 tk=S4/VWv  
DataOutputStream output; //输出到文件的输出流 YOrq)_ l  
7:b.c  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） eMFxdtH  
public SiteFileFetch(SiteInfoBean bean) throws IOException { %]imf|g.  
{ |KS,k|).  
siteInfoBean = bean; U-m MKRV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,5ZQPICF  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =8<~pr-NO  
if(tmpFile.exists ()) 0jjtx'F  
{ %+Z*-iX  
bFirst = false; iI7ocyUv  
read_nPos(); h4F%lGot  
} Za3}:7`Gu  
else BL_0@<1X  
{ /T(9:1/G  
nStartPos = new long[bean.getNSplitter()]; > l0H)W  
nEndPos = new long[bean.getNSplitter()]; #qDm)zCM  
} !d!u{1Y&  
pPo xx"y  
cgQ6b.  
YC56]
Zp  
} 4G&dBH  
iT,7jd?6#  
2E!~RjxSY  
public void run() btq4diW  
{ nQ_{IO8/6W  
//获得文件长度 Rc1k_fZ}  
//分割文件 |}UkVLc_^  
//实例FileSplitterFetch CPRVSN0b{4  
//启动FileSplitterFetch线程 324XoMO  
//等待子线程返回 C}Kl!  
try{ "2sk1  
if(bFirst)
"UNFB3  
{ h3 XSt  
nFileLength = getFileSize(); pWJEFm  
if(nFileLength == -1) /9I/^i~  
{ ^ W?cuJ8  
System.err.println("File Length is not known!"); X<[ qX*  
} hp9U   
else if(nFileLength == -2) W [K.|8ho  
{
Y-YuY  
System.err.println("File is not access!"); E8}evi  
} }F_c0zM  
else zN
|k*}j1J  
{ X V;j6g  
for(int i=0;i<nStartPos.length;i++) !.$L=>:V  
{ er)I".|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0zq'Nf?#3  
} <TRhnz  
for(int i=0;i<nEndPos.length-1;i++) ;t\h"K<,|  
{ SNH 3C1  
nEndPos = nStartPos[i+1]; $%cc[[/U  
} {a:05Y  
nEndPos[nEndPos.length-1] = nFileLength; `/P/2{,~  
} >dt*^}*  
} _2hLc\#  
J}X{8Ds9  
UGhEaKH~R  
//启动子线程 &S*~EM.l8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d-UeItyW*  
for(int i=0;i<nStartPos.length;i++) 
V>'  
{ .w.:o2L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &P|[YP37_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :BF? r  
nStartPos,nEndPos,i); 2L^)k?9>g+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &oS$<  
fileSplitterFetch.start(); YzI;
)  
} x.?5-3|d$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5XZ!yYB?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %x$U(I}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `um,S  
nEndPos = " + nFileLength); "n!yK
  
// fileSplitterFetch[nPos.length-1].start(); 37/n"
\4  
~.m<`~u  
&[.`xZ(|  
//等待子线程结束 0Z9DewwP  
//int count = 0; 7Gc{&hp*  
//是否结束while循环 >d2Fa4u3  
boolean breakWhile = false; PLyity-L[7  
Iry$z^  
+T+@g8S  
while(!bStop) #@S%?`4,
 
{ KQdIG9O+6  
write_nPos(); Z'JS@dV  
Utility.sleep(500); o%$.8)B9F  
breakWhile = true; 5</$dcG  
@w[i%F,&`  
x *eU~e_jP  
for(int i=0;i<nStartPos.length;i++) >gk_klLh  
{ du3f'=q6|  
if(!fileSplitterFetch.bDownOver) >Jz9wo`  
{ Ey46JO"  
breakWhile = false; B`5<sW  
break; "s*-dZO  
} Aw o)a8e  
} ~C.*Vc?|  
if(breakWhile) h+f>#O+:  
break; > VG  
ly[LF1t  
rH+OXGoB  
//count++;
l>?c AB[  
//if(count>4) I2ek`t]  
// siteStop(); g,ZA\R~  
} C$
3*[  
%`vzQt`>  
yVd^A2  
System.err.println("文件下载结束！"); $`=p]  
} Wgq|Q*  
catch(Exception e){e.printStackTrace ();} E h%61/  
} S:\i M:  
]$ew 5%  
:QCL9QZ'  
//获得文件长度 ]Z JoC!u  
public long getFileSize() ,g`%+s7u  
{ #Ondhy%h[  
int nFileLength = -1; E-MPFL  
try{ }2A6W%^>]  
URL url = new URL(siteInfoBean.getSSiteURL()); TBhM^\z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bdUPo+  
httpConnection.setRequestProperty("User-Agent","NetFox"); $6Q
IYF""  
?Cq7_rq  
DA
=U=F  
int responseCode=httpConnection.getResponseCode(); snV*gSUH
 
if(responseCode>=400) jjpYg  
{ q^@*{H  
processErrorCode(responseCode); #c!:&9oU  
return -2; //-2 represent access is error D-3[#~MV  
} fGgt[f[  
R{hX--|j  
3JoY
-  
String sHeader; 'X~tt#T  
v1h(_NLI!  
@0`A!5h?u  
for(int i=1;;i++) yTaMlT|  
{ k<1yv$/mW  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BT_]=\zi  
//Utility.log(in.readLine()); ~{c ?-qb  
sHeader=httpConnection.getHeaderFieldKey(i); ?M2(80  
if(sHeader!=null) xQ?>72grP  
{ \?bV\/GBR  
if(sHeader.equals("Content-Length")) urp|@WZ  
{ wAMg"ImJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^Fk;t  
break; L aTcBcI  
} B|(g?  
} H$6RDMU  
else 0V%c%]PH  
break; &K[*vyD  
} $QX$rN  
} N'^>pSc4W|  
catch(IOException e){e.printStackTrace ();} 5Z=4%P*I  
catch(Exception e){e.printStackTrace ();} N_t,n^i9>*  
(1/Sf&2i  
OhF55,[  
Utility.log(nFileLength); DF%d/a{]  
;w{<1NH2+.  
#86N !&x  
return nFileLength; %cNN<x8  
} ;5a$OM  
7KT*p&xm  
On C)f  
//保存下载信息（文件指针位置） Pz]WT1J0  
private void write_nPos() yUoR6w  
{ ~f QrH%@  
try{ r}U6LE?>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C*`WMP*  
output.writeInt(nStartPos.length); yCX5 5:  
for(int i=0;i<nStartPos.length;i++) l\U Q2i  
{ 37bMe@W  
// output.writeLong(nPos); Iil2R}1  
output.writeLong(fileSplitterFetch.nStartPos); WR+j?Fcf  
output.writeLong(fileSplitterFetch.nEndPos); #-az]s|N  
} d[9,J?'OQ  
output.close(); s"L&y <?)  
} .Xg.,kW  
catch(IOException e){e.printStackTrace ();} >OG189O  
catch(Exception e){e.printStackTrace ();} z%&FLdXgW+  
} o$_0Qs$  
 /SvhOi  
g`EZLDjt  
//读取保存的下载信息（文件指针位置） w0QtGQ|  
private void read_nPos() rcnH^P  
{ _K5<)( )  
try{ bC&A@.g{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /"m s  
int nCount = input.readInt(); ZlV
 
nStartPos = new long[nCount]; e8,_"_1:F  
nEndPos = new long[nCount]; "tEp8m  
for(int i=0;i<nStartPos.length;i++) 1N5 E  
{ wl=tN{R  
nStartPos = input.readLong(); NP>v@jO  
nEndPos = input.readLong(); .EYL  
} ^Z (cVg  
input.close(); /E>;O47a  
} f5}afPk  
catch(IOException e){e.printStackTrace ();} Gz`Jzh j  
catch(Exception e){e.printStackTrace ();} X)g X9DA  
} cIug~ x>  
goM;Pf "<  
h'ik3mLH  
private void processErrorCode(int nErrorCode) =D zrM%  
{ WC_.j^sW  
System.err.println("Error Code : " + nErrorCode); G/x6zdk  
} 2"0VXtv6  
gI:g/ R  
pEB3qGA  
//停止文件下载 vgW(l2,@  
public void siteStop() ra^</o/  
{ 2BY|Cp4R  
bStop = true; b"g^Jm! j  
for(int i=0;i<nStartPos.length;i++) MmJMx  
fileSplitterFetch.splitterStop(); 3Vu}D(PJ  
];.5*a%*  
D5zc{) /  
} 92-Xz6Bo9  
} $W._FAAJ#  
//负责部分文件的抓取 -e_fn&2,Y  
**FileSplitterFetch.java &{)<Q(g  
*/ vuQA-w7  
package NetFox; hB?#b`i^  
;NP-tA)  
0jp].''RK\  
import java.io.*; AArLNXzVW  
import java.net.*; DpHubqWz  
LP3#f{U  
>^8O:.  
public class FileSplitterFetch extends Thread { kV-<[5AWW  
Z<U,]iZB  
8~y!X0Ov!  
String sURL; //File URL 6Ga'_P:  
long nStartPos; //File Snippet Start Position [[T7s(3  
long nEndPos; //File Snippet End Position ueg%yvO
 
int nThreadID; //Thread's ID \Y xG  
boolean bDownOver = false; //Downing is over l@Lk+-[D  
boolean bStop = false; //Stop identical +m_.?V6  
FileAccessI fileAccessI = null; //File Access interface V .Kjcy  
a$W O}g?  
AFt- V  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V``|<`!gd  
{ R6~6b&-8  
this.sURL = sURL; tbQY&TO1  
this.nStartPos = nStart; 5{ap  
this.nEndPos = nEnd; SiNgV\('U  
nThreadID = id; &zn|),  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F'~r?D  
} .]9`eGVWj  
cGE{dWz  
R;"$PHD  
public void run() PvKG
B01_  
{ {[uhIJD3g6  
while(nStartPos < nEndPos && !bStop) 2e6P?pX~2  
{ 8YSvBy  
`!8\
|/  
|\bNFnn(  
try{ AyJl
:aN^  
URL url = new URL(sURL); 5a |R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4lo
7yx  
httpConnection.setRequestProperty("User-Agent","NetFox"); 51:5rN(_  
String sProperty = "bytes="+nStartPos+"-"; #jbC@A9Pe  
httpConnection.setRequestProperty("RANGE",sProperty); l@4pZkdq  
Utility.log(sProperty); e"@r[pq-{u  
Z%#e* O0  
)~M@2;@L  
InputStream input = httpConnection.getInputStream(); ,]wab6sY  
//logResponseHead(httpConnection); W *0!Z:?  
uVYn,DB`  
:b9#e g  
byte[] b = new byte[1024]; <B%wq>4S  
int nRead; b'(AVA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ioe.[&o6B  
{ ]xf89[;0  
nStartPos += fileAccessI.write(b,0,nRead); \m
`IgP*  
//if(nThreadID == 1) ErN[maix#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ' !huU
 
} #h ud_  
,)
:aU  
_Q:ot'(~0-  
Utility.log("Thread " + nThreadID + " is over!"); P]"@3Z&w  
bDownOver = true; ?;=7{Ej  
//nPos = fileAccessI.write (b,0,nRead); 7L+Wj }m  
} *wAX&+);  
catch(Exception e){e.printStackTrace ();} E[hSL#0  
} do`'K3a"  
} }51QUFhL0  
^uo,LTq+  
padV|hF3(e  
//打印回应的头信息 ]:ca=&>  
public void logResponseHead(HttpURLConnection con) Fpo}UQQbc  
{ oVqx)@$
K  
for(int i=1;;i++) ?Gf'G{^}  
{ K*^'tltJ  
String header=con.getHeaderFieldKey(i); 
hgZvti  
if(header!=null) B^19![v3T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Zn1((J7  
Utility.log(header+" : "+con.getHeaderField(header));  H#F"n"~$  
else ks$5$,^T2o  
break; '>[ZfT  
} [1~3\-Y  
} %B&O+~  
4FnePi~i  
DKo6lP`  
public void splitterStop() qV=O;  
{ H94_ae  
bStop = true; OL=X&Vaf<  
} 4JBfA,  
oe6Ex5h  
/&?ei*z  
} va~:Ivl-)  
gy1kb,MO  
)YCH>Za  
/* r<]^.]3zj  
**FileAccess.java Y&VypZ"G>  
*//文件访问(定位，写) ~+6#4<M.~  
package NetFox; C&q}&=3r  
import java.io.*; Uq=Rz8hLM  
&WCVdZK:  
bil>;&h  
public class FileAccessI implements Serializable{ 7ey|~u2  
(3,7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2AqcabI9  
RandomAccessFile oSavedFile; Jbima>  
long nPos; m:EYOe,w  
+vFqHfmP  
-vT$UP  
public FileAccessI() throws IOException E=v4|/['N  
{ vr>J$(F  
this("",0); WOYZ  
} i(u zb<  
a"+/fC`  
CE183l\  
public FileAccessI(String sName,long nPos) throws IOException H
VC|0}  
{ 11$v~<M  
oSavedFile = new RandomAccessFile(sName,"rw"); 84(jg P  
this.nPos = nPos; Q1h v2*/U  
oSavedFile.seek(nPos); N9c#N%cu  
} T~>&m~} +  
U:/_T>f%  
v@X[0J_8  
public synchronized int write(byte[] b,int nStart,int nLen) Mc  
{ JjAO9j%  
int n = -1; r|jBKq~  
try{ qyIy xJ  
oSavedFile.write(b,nStart,nLen); 6{Bvl[mhI  
n = nLen; M~sP|Ha"+  
} gi A(VUwI>  
catch(IOException e) BZQJ@lk5  
{ ^J?2[(   
e.printStackTrace (); KE)^S [Da  
} j

{5oXW  
XF4NRs  
RvW>kATb_F  
return n; -mZ{.\9  
} 5o|u!#6  
 GwD"j]  
7 dG_E]&  
} F,5}3$  
P.|g4EdND  
m<9W#
 
/* 4.&et()}  
**SiteInfoBean.java =2wy;@f  
*/ Z=?qf$.}  
package NetFox; avv/mEf-f  
/3vj`#jD  
4p&SlJ  
public class SiteInfoBean { %ye4FwkRy  
B415{  
H%c{ }F  
private String sSiteURL; //Site's URL DB1
Y`l  
private String sFilePath; //Saved File's Path TLzcQ|  
private String sFileName; //Saved File's Name m+'X8}GC#O  
private int nSplitter; //Count of Splited Downloading File an?g'8! r:  
7w"YCRKh  
{'
|yb
  
public SiteInfoBean() T|nN.  
{//nSplitter的缺省值为5 qo;F]v*pkK  
//default value of nSplitter is 5 > cJX'U9  
this("","","",5); =>h~<88#5  
} w*N9p8hb]  
~R W6;  
_nnl+S>K  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p&\x*~6u  
{ (aH_K07  
sSiteURL= sURL; 7<ES&ls_  
sFilePath = sPath; q}R"  
sFileName = sName; |7T!rnr  
this.nSplitter = nSpiltter; /9yA.W;  
uRNc9  
'uOp?g'7  
} Ie;}k;?-  
seH#v  
:!EOg4%i  
public String getSSiteURL() WxLILh  
{ 0ID 8L [  
return sSiteURL; &"svt2  
} h:+>=~\  
ZjJEjw  
T+/Gz'  
public void setSSiteURL(String value) 2\!.w^7'^T  
{ xH8nn3U  
sSiteURL = value; :
U;ZBs3  
} ,Gd8 <  
93y.u<,2;  
~F]- +|  
public String getSFilePath() BO ^T :  
{ =l3*{ ?G  
return sFilePath; 3'6
>zp  
} #/1,Cv yj  
gasl%&  
"mE<r2=@  
public void setSFilePath(String value) Wc_Ph40C<_  
{ |3g:q  
sFilePath = value; C31SXQ  
} 1<qq69x  
^Q_0Zq^H  
*%cI,}%   
public String getSFileName() Pz+8u&~p  
{ sOW-GWSE<  
return sFileName; #H1yjJQ /x  
} cj<j*(ZZ  
vexQP}N0  
Hp":r%)  
public void setSFileName(String value) NLF{W|X  
{ |^@TA
=_  
sFileName = value; o0Hh&:6!M  
} L+QEFQ:r5  
$y>J=  
413r3/  
public int getNSplitter() >[Q(!Ai  
{ femAVx}go  
return nSplitter; aX1|&erI  
} #tBbvs+%  
F+A
Shh  
y#Ch /Jg?|  
public void setNSplitter(int nCount) .x1EdfHed/  
{ >UuLSF}  
nSplitter = nCount; $0K9OF9$
 
} I\DT(9 'E  
} rYq8OZLi  
4Kt?;
y ;  
'89D62\89  
/* x<=+RYz#^:  
**Utility.java Xf9VW}`*8  
*/ 8c3X9;a  
package NetFox; 2Sb~tTGz79  
Fu m1w  
^yu^Du  
public class Utility { f=J#mmHw$  
 c:~o e  
\aT._'=M+  
public Utility() <H E'5b  
{ Jo h&Ay  
K#";!  
,)Z^b$H]  
} WohK,<Or  
.'7o,)pJ<  
//线程睡眠 dmrM %a}W-  
public static void sleep(int nSecond) #ZGWU_l}  
{ TiF$',WMv  
try{ }kXF*cVg  
Thread.sleep(nSecond); Khw!+!(H  
} IEeh)aj[  
catch(Exception e) Q:kpaMA1P  
{ %r~TMU2"  
e.printStackTrace (); /5r[M=_ihr  
} E9226  
} .Fh5:WN  
vC J  
//日志 CWI(Q`((>  
public static void log(String sMsg) P
RX:*0  
{ <6n(a)L1  
System.err.println(sMsg); C2eei're  
} j|HOry1E&  
'n.eCdj  
8 s:sMU:Q  
public static void log(int sMsg) )Hlr 09t=]  
{ iAWPE`u4  
System.err.println(sMsg); &g@?{5FP  
} UwdcU^xt9  
}  D
[]vJ  
oOe5IczS(  
AytHnp\H  
/* 6eK18*j%H  
**TestMethod.java Fv5@-&y$W  
*/ XF{}St~(  
package NetFox; 31YzTbl[H  
)Cyrs~  
}QG6KJh_%  
public class TestMethod { HHoh//(\  
Z:9"7^+  
}L@!TWR-Qu  
public TestMethod() 0=(5C\w2  
{ ///xx/weblogic60b2_win.exe ?exV:OKLb  
try{ 1"~@UcJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P7"g/j""  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b^5rV5d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gnB%/g[_  
fileFetch.start(); 0$/wH#f  
} Alp9] 0(  
catch(Exception e){e.printStackTrace ();} kY4riZnm  
kV6T#RVob  
*]O[ZjyOY  
} t~ Q{\!  
,p>=WX  
.azdAq'r&\  
public static void main(String[] args) Y R#_<o  
{ S1;#58  
new TestMethod(); G4MNcy  
} PS!f&IY}[.  
} ShHm7+fV  
点击下载更多相关资料