JAVA中操作clob与blob大字段属性
相信很多朋友在oracle数据入库的时候经常会遇到大字段处理的问题，在经过多次的处理这个问题之后小编逐渐进行了总结，好啦不废话啦直接进击主题。（此处的数据库连接，朋友们可以去搜集其他资料，此处只是集中针对大字段的存储更新问题）。
其中blob的jar包是oracle.sql.BLOB，大家自行在网上搜索下载即可。
一、blob数据的处理
字段属性变动前都会使用empty_blob()进行该属性的初始化，之后再使用流的方式将需要变动的数据写入数据库。
1、插入方法
/*
* pidColumnName - 主键对应的列名
* pidColumnValue - 主键值
* blobColumnName - blob类型的列名
* blobColumnValue - blob的值
* tableName - 数据表的表名
* */
public boolean insertSqlByPid(Map param) {
String pidColumnName = param.get("pidColumnName").toUpperCase();
String pidColumnValue = param.get("pidColumnValue");
String blobColumnName = param.get("blobColumnName").toUpperCase();
String blobColumnValue = param.get("blobColumnValue");
String tableName = param.get("tableName").toUpperCase();
Connection con;
try {
con = DriverManager.getConnection(url, username, password);
con.setAutoCommit(false);
String sql1 = "insert into "+tableName+"("+pidColumnName+","+blobColumnName+") values('"+pidColumnValue+"',empty_blob())";
Statement statement = con.createStatement();
boolean b2 = statement.execute(sql1);
String sql2 = "select "+blobColumnName+" from "+tableName+" where "+pidColumnName+"='"+pidColumnValue+"' for update";
PreparedStatement stmt = con.prepareStatement(sql2);
ResultSet rs = stmt.executeQuery();
OutputStream outStream = null;
if (rs.next()) {
BLOB blob = (BLOB) rs.getBlob(1);
outStream = blob.getBinaryOutputStream();
outStream.write(blobColumnValue.getBytes(), 0,blobColumnValue.getBytes().length);
}
outStream.flush();
outStream.close();
con.commit();
con.close();
return true;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
} 2、更新方法
/*
* pidColumnName - 主键对应的列名
* pidColumnValue - 主键值
* blobColumnName - blob类型的列名
* blobColumnValue - blob的值
* tableName - 数据表的表名
* */
public boolean updateSqlByPid(Map param) {
String pidColumnName = param.get("pidColumnName").toUpperCase();
String pidColumnValue = param.get("pidColumnValue");
String blobColumnName = param.get("blobColumnName").toUpperCase();
try {
blobColumnName = new String(blobColumnName.getBytes(),"UTF-8");
} catch (UnsupportedEncodingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
String blobColumnValue = param.get("blobColumnValue");
String tableName = param.get("tableName").toUpperCase();
Connection con;
try {
con = DriverManager.getConnection(url, username, password);
con.setAutoCommit(false);
String sql1 = "update "+tableName+" set "+blobColumnName+" = empty_blob() where "+pidColumnName+" = '"+pidColumnValue+"'";
Statement statement = con.createStatement();
boolean b1 = statement.execute(sql1);
String sql2 = "select "+blobColumnName +" as BLOB_NAME from "+tableName+" where "+pidColumnName+"='"+pidColumnValue+"' for update";
PreparedStatement stmt = con.prepareStatement(sql2);
ResultSet rs = stmt.executeQuery();
OutputStream outStream = null;
if (rs.next()) {
BLOB blob = (BLOB) rs.getBlob("BLOB_NAME");
outStream = blob.getBinaryOutputStream();
outStream.write(blobColumnValue.getBytes("UTF-8"), 0,blobColumnValue.getBytes("UTF-8").length);
}
outStream.flush();
outStream.close();
con.commit();
con.close();
return true;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
} 3、查询方法
/*
* pidColumnName - 主键对应的列名
* pidColumnValue - 主键值
* blobColumnName - blob类型的列名
* blobColumnValue - blob的值
* tableName - 数据表的表名
* */
public String selectSqlByPid(Map param) {
String blobInfo = null;
String pidColumnName = param.get("pidColumnName").toUpperCase();
String pidColumnValue = param.get("pidColumnValue");
String blobColumnName = param.get("blobColumnName").toUpperCase();
String tableName = param.get("tableName").toUpperCase();
Connection con;
try {
con = DriverManager.getConnection(url, username, password);
con.setAutoCommit(false);
String sql3 = "select "+blobColumnName+" from "+tableName+" where "+pidColumnName+"='"+pidColumnValue+"' ";
PreparedStatement stmt2 = con.prepareStatement(sql3);
ResultSet rs2 = stmt2.executeQuery();
if (rs2.next()) {
BLOB blob = (BLOB) rs2.getBlob(1);
blobInfo = new String(blob.getBytes((long)1, (int)blob.length()),"UTF-8");
}
con.close();
return blobInfo;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return blobInfo;
}
} 二、clob数据的处理
此处clob 的处理与blob属性的处理是略不相同的，但是原理还是一样的，此处是通过reader流转为byte数组再转为String数据返回
1、查询方法
/*
* pidColumnName - 主键对应的列名
* pidColumnValue - 主键值
* clobColumnName - clob类型的列名
* clobColumnValue - clob的值
* tableName - 数据表的表名
* */
public String selectSqlByPid(Map param) {
String clobInfo = null;
String pidColumnName = param.get("pidColumnName").toUpperCase();
String pidColumnValue = param.get("pidColumnValue");
String clobColumnName = param.get("clobColumnName").toUpperCase();
String tableName = param.get("tableName").toUpperCase();
Reader inStream =null;
Connection con;
try {
con = DriverManager.getConnection(url, username, password);
con.setAutoCommit(false);
String sql = "select "+clobColumnName+" from "+tableName+" where "+pidColumnName+"='"+pidColumnValue+"' ";
PreparedStatement stmt = con.prepareStatement(sql);
ResultSet rs = stmt.executeQuery();
if (rs.next()) {
Clob clob = rs.getClob(1);
if(clob==null){
System.out.println("照片信息为空");
}else{
//clob解码编译为base64
String pic = clob.getSubString((long)1, (int) clob.length());
byte[] binary = (new sun.misc.BASE64Decoder()).decodeBuffer(pic.replaceAll(" ", ""));
//照片存到本地
String path = "D:/zhks/picture/temp/";
File temp = new File(path);
if(!temp.exists()) {
temp.mkdirs();
}
String filename = path+"/"+pidColumnValue+".jpg";
FileOutputStream fos = null;
fos = new FileOutputStream(filename);
fos.write(binary, 0, binary.length);
fos.close();
clobInfo = filename;
}
}
con.commit();
con.close();
return clobInfo;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return clobInfo;
}
} 2、更新方法
/*
* pidColumnName - 主键对应的列名
* pidColumnValue - 主键值
* clobColumnName - clob类型的列名
* clobColumnValue - clob的值
* tableName - 数据表的表名
* */
public boolean updateByPid(Map param) {
String pidColumnName = param.get("pidColumnName").toUpperCase();
String pidColumnValue = param.get("pidColumnValue");
String clobColumnName = param.get("clobColumnName").toUpperCase();
try {
clobColumnName = new String(clobColumnName.getBytes(),"UTF-8");
} catch (UnsupportedEncodingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
String clobColumnValue = param.get("clobColumnValue");
String tableName = param.get("tableName").toUpperCase();
Connection con;
try {
con = DriverManager.getConnection(url, username, password);
con.setAutoCommit(false);
String sql1 = "update "+tableName+" set "+clobColumnName+" = empty_clob() where "+pidColumnName+" = '"+pidColumnValue+"'";
Statement statement = con.createStatement();
boolean b1 = statement.execute(sql1);
String sql2 = "select "+clobColumnName +" as CLOB_NAME from "+tableName+" where "+pidColumnName+"='"+pidColumnValue+"' for update";
PreparedStatement stmt = con.prepareStatement(sql2);
ResultSet rs = stmt.executeQuery();
if (rs.next()) {
oracle.sql.CLOB clob = (oracle.sql.CLOB) rs.getClob("BLOB_NAME");
Writer outStream = clob.getCharacterOutputStream();
char[] c = clobColumnValue.toCharArray();
outStream.write(c, 0, c.length);
outStream.flush();
outStream.close();
}
con.commit();
con.close();
return true;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
}