Java 对Oracle Clob（大字符串）格式的操作 增改查

package com.study.db;

import java.io.FileInputStream;

import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/*
连接数据库和常用数据库操作的类
*/
import oracle.sql.CLOB;

/**
连接数据库的类
最基础的类

*/
public class DBOracle {

/**
连接数据库常用的属性
*/
public String sDBDriver = "oracle.jdbc.driver.OracleDriver";// 设置驱动
public String url = "jdbc:oracle:thin:@192.168.1.0:1521:HPO";// 设置数据库信息
public String sHint = "";
public ResultSet rs = null;
public Connection conn = null;
public Statement stmt = null;
public String user = "study";
public String pwd = "ok";

/**
加载配置文件读取信息
*/
public DBOracle() throws IOException {

String userpath = System.getProperty("user.dir");
String filesparator = System.getProperty("file.separator");
String dbconfig = userpath + filesparator + "dbconfig.properties";
FileInputStream in;
in = new FileInputStream(dbconfig);
Properties dbp = new Properties();
dbp.load(in);
in.close();
this.url = dbp.getProperty("URL");
this.user = dbp.getProperty("USER");
this.pwd = dbp.getProperty("PASSWORD");
System.out.println("地址=" + dbconfig);
// System.out.println("真实="+this.url);

}

public String getSHint() {
return sHint;
}

public void setSDBDriver(String dbDriver) {
sDBDriver = dbDriver;
}

public String getSDBDriver() {
return sDBDriver;
}

public String getUrl() {
return url;
}

public void setUrl(String s) {
url = s;
}

public ResultSet getResultSet() {
return rs;
}

public boolean initialize(String url, String user, String pwd) {
this.url = url;
this.user = user;
this.pwd = pwd;
return initialize();
}

public boolean initialize() {// 默认构造方法
try {
Class.forName(sDBDriver);
sHint = "Initialization sucessfully";
return true;
} catch (ClassNotFoundException e) {
sHint = "Initialization Exception:" + e.getMessage();
return false;
}
}

/**
关闭数据库对象
*/
public boolean close() {// 关闭数据库连接
try {
if (rs != null)
{ rs.close();}
if (stmt != null)
{stmt.close();}
if (conn != null)
{conn.close();}
return true;
} catch (SQLException ex) {
sHint = "Close Exception:" + ex.getMessage();
return false;
}
}

/**
插入大字段方法
*/
public String insertClob(int userid, int courseware_Id, int Progress,
String CourseClob) {// 插入数据库clob字段
try {
// int testid = 77;
// System.out.println("113用户ID" + userid + "课件ID" + courseware_Id+
// "进度" + Progress + "value=" + CourseClob);
Class.forName(this.sDBDriver);
Connection conn = DriverManager.getConnection(this.url, this.user,
this.pwd);
conn.setAutoCommit(false);
/* 以下表User_CourseWare中的Report字段时CLOB类型的 */
// 插入一条数据，注意CLOB字段，需要先插入一个空的clob类型 empty_clob()，然后再单独更新clob字段
// String sql = "insert into
// User_CourseWare(User_Id,Courseware_Id,Progress,Report,Id)values(
// ?,?,?,empty_clob(),?)";
String sql = "insert into User_CourseWare(User_Id,Courseware_Id,Progress,Report ,id)values( ?,?,?,empty_clob(),  user_courseware_sq.nextval  )";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, userid);
pstmt.setInt(2, courseware_Id);
pstmt.setInt(3, Progress);
// System.out.println("sql insert=" + sql);
// pstmt.setInt(4, testid);
int i1 = pstmt.executeUpdate();
conn.commit();
pstmt = null;
if (i1 > 0) {
// System.out.println("用户ID" + userid + "插入" + courseware_Id+
// "课件成功");
}
ResultSet rs = null;
CLOB clob = null;
String sql1 = "select Report from User_CourseWare where  User_Id=? and Courseware_Id=? for update";
pstmt = conn.prepareStatement(sql1);
/*
* pstmt.setInt(1, testid); pstmt.setInt(2, userid); pstmt.setInt(3,
* courseware_Id);
*/
// System.out.println("sql1 select=" + sql1);
pstmt.setInt(1, userid);
pstmt.setInt(2, courseware_Id);

rs = pstmt.executeQuery();
if (rs.next()) {
clob = (CLOB) rs.getClob(1);
}
Writer writer = clob.getCharacterOutputStream();
writer.write(CourseClob);
writer.flush();
writer.close();
rs.close();
conn.commit();
pstmt.close();
conn.close();

} catch (Exception e) {

e.printStackTrace();
return "error";
}
return "success";

}

/*   获得大字段XML
获得大字符串格式
@param user_id
用户ID
@param courseware_id
课件ID
@return 大字符串

*/
public String getCourseClob(int user_id, int courseware_id) {// 根据课件ID和人ID查询课程ID
String content = "null";
try {
Class.forName(this.sDBDriver);
Connection conn = DriverManager.getConnection(this.url, this.user,
this.pwd);
conn.setAutoCommit(false);
ResultSet rs = null;
CLOB clob = null;
String sql = "";
sql = "select Report from User_CourseWare  where user_id=? and courseware_id=?  ";

PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, user_id);
pstmt.setInt(2, courseware_id);
rs = pstmt.executeQuery();
if (rs.next()) {
clob = (CLOB) rs.getClob(1);

if (clob != null && clob.length() != 0) {
content = clob.getSubString((long) 1, (int) clob.length());
content = this.Clob2String(clob);
}

}

rs.close();
conn.commit();
pstmt.close();
conn.close();

} catch (ClassNotFoundException e) {

e.printStackTrace();
// return "null";
content = "error";
} catch (SQLException e) {
e.printStackTrace();
// return "null";
content = "error";
}
return content;
}

/*
clob to string
大字符串格式转换STRING
@param clob
@return 大字符串

*/
public String Clob2String(CLOB clob) {// Clob转换成String 的方法
String content = null;
StringBuffer stringBuf = new StringBuffer();
try {
int length = 0;
Reader inStream = clob.getCharacterStream(); // 取得大字侧段对象数据输出流
char[] buffer = new char[10];
while ((length = inStream.read(buffer)) != -1) // 读取数据库 //每10个10个读取
{
for (int i = 0; i < length; i++) {
stringBuf.append(buffer[i]);
}
}

inStream.close();
content = stringBuf.toString();
} catch (Exception ex) {
System.out.println("ClobUtil.Clob2String:" + ex.getMessage());
}
return content;
}

/*

更新Clob(大字符串格式)内容
*/

public String updateClob(int userid, int courseware_Id, int Progress,
String CourseClob) {
this.updateUser_Course(userid, courseware_Id, Progress);// 调用更新进度
try {
Class.forName(this.sDBDriver);
Connection conn = DriverManager.getConnection(this.url, this.user,
this.pwd);
String sql = "update User_CourseWare set  Report=empty_clob() , Progress=? where User_Id = ? and  Courseware_Id =? ";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, Progress);
pstmt.setInt(2, userid);
pstmt.setInt(3, courseware_Id);
int i1 = pstmt.executeUpdate();
conn.commit();
// System.out.println("update sql="+sql);
pstmt = null;
if (i1 > 0) {

}

ResultSet rs = null;
CLOB clob = null;
String sql1 = "select Report from User_CourseWare where User_id=? and Courseware_id=?  for update";
pstmt = conn.prepareStatement(sql1);
// System.out.println("select sql="+sql1);
pstmt.setInt(1, userid);
pstmt.setInt(2, courseware_Id);
rs = pstmt.executeQuery();
if (rs.next()) {
clob = (CLOB) rs.getClob(1);
}

Writer writer = clob.getCharacterOutputStream();
writer.write(CourseClob);
writer.flush();
writer.close();
rs.close();
conn.commit();
pstmt.close();
conn.close();

} catch (Exception e) {
e.printStackTrace();
return "error";
}
return "success";
}

/*
参数：userid 用户ID courseware_Id 课件ID Progress 课件进度 返回值 课件进度不到100时不更新 到100时
更新 状态为2（已学）
*/
public String updateUser_Course(int userid, int courseware_Id, int Progress) {
String caseTest = "default";
if (Progress == 100) {
String sql = "update User_Course set  Status =2 where USER_ID =? and COURSE_ID =?   ";
try {
Class.forName(this.sDBDriver);
Connection conn = DriverManager.getConnection(this.url,
this.user, this.pwd);
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, userid);
pstmt.setInt(2, courseware_Id);

int i1 = pstmt.executeUpdate();
conn.commit();
pstmt = null;
if (i1 > 0) {
// System.out.println("更新成功!");
}
caseTest = "success";

} catch (Exception e) {
caseTest = "error";
e.printStackTrace();

}

}

return caseTest;
}

/*
@param sql
要执行的查询语句
@return 结果集
*/
public ResultSet executeQuery(String sql) {
rs = null;
try {

Class.forName(this.sDBDriver);

conn = DriverManager.getConnection(this.url, this.user, this.pwd);

stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
} catch (Exception ex) {
sHint = "Query Exception:" + ex.getMessage();
}

return rs;
}

/*   执行 更新删除等语句
@return 返回执行结果的boolean值
*/
public boolean executeUpdate(String sql) {
try {
Class.forName(this.sDBDriver);
conn = DriverManager.getConnection(this.url, this.user, this.pwd);
stmt = conn.createStatement();
stmt.executeUpdate(sql);
conn.commit();
return true;
} catch (Exception ex) {
sHint = "Update Exception :" + ex.getMessage();
return false;
}
}

}