数据库多表操作事务处理

一、主要思路

在需要同时插入多条数据时，这其中可能是同一个表的多条记录，也可能是多个不同表之间的数据同时更新。对此，我们需要保证其中的原子性和一致性，做到要么全部操作都能全部成功完成，否则全部不操作。

我们可以通过SQL的事务来对相关数据库操作进行处理，在开始conn.setAutoCommit(false);（conn是或得的连接）把本次运行的SQL操作改为非自动运行，在配置好各SQL语句之后，调用conn.commit();来运行，其中通过try{……}catch……来捕捉异常，如果遇到错误时，就调用conn.rollback();来对本次操作进行回滚到操作前的状态，防止存在错误数据和脏数据。

二、主要实现方法

/**
* 批量插入对象-同一个表多条记录
* <p>
* 注意：对象字段不能为数据库关键字
* @param list
* @return
* @throws SQLException
* @author lims
* @date 2015-08-28
*/
public int[] insertSameTable(List<Pojo> list) throws SQLException {
if (list == null || list.size() == 0) {
return null;
}
String sql = getInsertSql(list.get(0));
PreparedStatement ps = null;
String[] fields = null;
int[] result = null;
Connection conn=getConnection();
try {
ps = conn.prepareStatement(sql.toString());
this.startTransaction(conn);
for (Pojo obj : list) {
Map<String, String> pojo_bean = obj.listInsertableFields();
fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()]);
for (int i = 0; i < fields.length; i++) {
ps.setObject(i + 1, pojo_bean.get(fields[i]));
}
ps.addBatch();
}
result = ps.executeBatch();
this.commitTransaction(conn);
} catch(Exception e){
conn.rollback();
throw new RuntimeException(e);
} finally {
fields = null;
org.apache.commons.dbutils.DbUtils.closeQuietly(ps);
this.closeConnection(conn);
}
return result;
}

/**
* 批量插入对象-多表插入
* <p>
* 注意：对象字段不能为数据库关键字
* @param list
* @return
* @throws SQLException
* @author lims
* @date 2015-08-28
*/
public int insertMutilTable(List<Pojo> list) throws SQLException {
if (list == null || list.size() == 0) {
return 0;
}
String[] fields;
PreparedStatement ps = null;
int result = 0;
Connection conn=getConnection();
try {
this.startTransaction(conn);
for (Pojo obj : list) {
Map<String, String> pojo_bean = obj.listInsertableFields();
String sql = getInsertSql(obj);

ps = conn.prepareStatement(sql.toString());

fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()]);
for (int i = 0; i < fields.length; i++) {
ps.setObject(i + 1, pojo_bean.get(fields[i]));
}
result = ps.executeUpdate();
}
this.commitTransaction(conn);
} catch(Exception e){
conn.rollback();
throw new RuntimeException(e);
} finally {
fields = null;
org.apache.commons.dbutils.DbUtils.closeQuietly(ps);
this.closeConnection(conn);
}
return result;
}

/**
* 批量更新同一个表的多条记录
* @param list
* @return
* @throws SQLException
* @author lims
* @date 2015-08-28
*/
public int[] updateSameTable(List<Pojo> list) throws SQLException {
if (list == null || list.size() == 0) {
return null;
}
String[] fields;
PreparedStatement ps = null;
int[] result = null;
Connection conn=getConnection();
try {
this.startTransaction(conn);
for (Pojo obj : list) {
Map<String, String> pojo_bean = obj.listInsertableFields();
fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()]);
StringBuilder sql = new StringBuilder();
sql.append("update "+getTableName(obj.getClass())+" set ");
for (int i = 0; i < fields.length; i++) {
if (i > 0)
sql.append(',');
sql.append(fields[i]).append(" = ? ");
}
sql.append(" where id=?");
ps = conn.prepareStatement(sql.toString());

fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()+1]);
for (int i = 0; i < fields.length; i++) {
if(i==fields.length-1) {
ps.setObject(i + 1, obj.getId());
}
else {
ps.setObject(i + 1, pojo_bean.get(fields[i]));
}

}
ps.addBatch();
}
result = ps.executeBatch();
this.commitTransaction(conn);
} catch(Exception e){
conn.rollback();
throw new RuntimeException(e);
} finally {
ps.clearBatch();
fields = null;
org.apache.commons.dbutils.DbUtils.closeQuietly(ps);
this.closeConnection(conn);
}
return result;
}

/**
* 多表更新
* @param list
* @return
* @throws SQLException
* @author lims
* @date 2015-08-28
*/
public int updateMutilTable(List<Pojo> list) throws SQLException {
if (list == null || list.size() == 0) {
return 0;
}
String[] fields;
PreparedStatement ps = null;
int result = 0;
Connection conn=getConnection();
try {
this.startTransaction(conn);
for (Pojo obj : list) {
Map<String, String> pojo_bean = obj.listInsertableFields();
String sql = getUpdateSql(obj);

ps = conn.prepareStatement(sql.toString());

fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()+1]);
for (int i = 0; i < fields.length; i++) {
if(i==fields.length-1) {
ps.setObject(i + 1, obj.getId());
}
else {
ps.setObject(i + 1, pojo_bean.get(fields[i]));
}

}
result = ps.executeUpdate();
}
this.commitTransaction(conn);
} catch(Exception e){
conn.rollback();
throw new RuntimeException(e);
} finally {
fields = null;
org.apache.commons.dbutils.DbUtils.closeQuietly(ps);
this.closeConnection(conn);
}
return result;
}

/**
* 插入数据和更新多表数据
* @param list
* @return
* @throws SQLException
* @author lims
* @date 2015-08-28
*/
public int insertAndUpdateMutilTable(List<Pojo> saveList,List<Pojo> updateList) throws SQLException {
if (saveList == null || saveList.size() == 0 || updateList == null || updateList.size() == 0) {
return 0;
}
String[] fields;
PreparedStatement ps = null;
int result = 0;
Connection conn=getConnection();
try {
this.startTransaction(conn);
for (Pojo obj : saveList) {//插入操作
Map<String, String> pojo_bean = obj.listInsertableFields();
String sql = getInsertSql(obj);

ps = conn.prepareStatement(sql.toString());

fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()]);
for (int i = 0; i < fields.length; i++) {
ps.setObject(i + 1, pojo_bean.get(fields[i]));
}
result = ps.executeUpdate();
}
for (Pojo obj : updateList) {//更新操作
Map<String, String> pojo_bean = obj.listInsertableFields();
String sql = getUpdateSql(obj);

ps = conn.prepareStatement(sql.toString());

fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()+1]);
for (int i = 0; i < fields.length; i++) {
if(i==fields.length-1) {
ps.setObject(i + 1, obj.getId());
}
else {
ps.setObject(i + 1, pojo_bean.get(fields[i]));
}

}
result = ps.executeUpdate();
}
this.commitTransaction(conn);
} catch(Exception e){
conn.rollback();
throw new RuntimeException(e);
} finally {
fields = null;
org.apache.commons.dbutils.DbUtils.closeQuietly(ps);
this.closeConnection(conn);
}
return result;
}

三、相关调用方法

protected abstract Connection getConnection() throws SQLException;

protected abstract void closeConnection(Connection conn);

private void startTransaction(Connection conn) {
try {
if (conn != null) {
conn.setAutoCommit(false);
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}

private void commitTransaction(Connection conn) {
try {
if (conn != null) {
conn.commit();
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}

/**
* 获取Pojo对应的数据库表名
*
* @param c
* @return
*/
private static <T extends Pojo> String getTableName(Class<T> c) {
try {
String tn = tableNameCache.get(c.getSimpleName());
if (tn == null) {
tn = c.newInstance().tableName();
tableNameCache.put(c.getSimpleName(), tn);
}
return tn;
} catch (Exception e) {
log.error("Get " + c.getSimpleName() + " name exception.");
return null;
}
}

/**
* 获取Pojo的插入sql语句
*
* @param obj
* @return
*/
private static String getInsertSql(Pojo obj) {
try {
String insertSql = insertSqlCache.get(obj.getClass().getName());
if (insertSql == null) {
Map<String, String> pojo_bean = obj.listInsertableFields();
String[] fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()]);
StringBuilder sql = new StringBuilder("INSERT INTO ");
sql.append(obj.tableName());
sql.append('(');
for (int i = 0; i < fields.length; i++) {
if (i > 0)
sql.append(',');
sql.append(fields[i]);
}
sql.append(") VALUES(");
for (int i = 0; i < fields.length; i++) {
if (i > 0)
sql.append(',');
sql.append('?');
}
sql.append(')');
insertSql = sql.toString();
sql = null;
insertSqlCache.put(obj.getClass().getName(), insertSql);
}
return insertSql;
} catch (Exception e) {
log.error("Get " + obj.getClass().getSimpleName()
+ " insertSql exception.");
return null;
}
}

/**
* 获取Pojo的更新sql语句
*
* @param obj
* @return
* @author lims
* @date 2015-08-23
*/
private static String getUpdateSql(Pojo obj) {
try {
String updateSql = updateSqlCache.get(obj.getClass().getName());
if (updateSql == null) {
Map<String, String> pojo_bean = obj.listInsertableFields();
String[] fields = pojo_bean.keySet().toArray(
new String[pojo_bean.size()]);
StringBuilder sql = new StringBuilder();
sql.append("update "+getTableName(obj.getClass())+" set ");
for (int i = 0; i < fields.length; i++) {
if (i > 0)
sql.append(',');
sql.append(fields[i]).append(" = ? ");
}
sql.append(" where id=?");

updateSql = sql.toString();
sql = null;
updateSqlCache.put(obj.getClass().getName(), updateSql);
}
return updateSql;
} catch (Exception e) {
log.error("Get " + obj.getClass().getSimpleName()
+ " updateSql exception.");
return null;
}
}