对SpringJDBC的简单扩展

public <T> int save(T t) {
return batchSave(Collections.singletonList(t));
}

public <T> int batchSave(List<T> list) {
BeanBatchSavePSCC<T> pscc = new BeanBatchSavePSCC<>(list);
return getJdbcTemplate().execute(pscc, pscc);
}

public <T> int update(T t) {
return batchUpdate(Collections.singletonList(t));
}

protected <T> int update(T t, String where, Object... values) {
BeanBatchUpdatePSCC<T> pscc = new BeanBatchUpdatePSCC<>(Collections.singletonList(t), where, values);
return getJdbcTemplate().execute(pscc, pscc);
}

public <T> int batchUpdate(List<T> list) {
BeanBatchUpdatePSCC<T> pscc = new BeanBatchUpdatePSCC<>(list);
return getJdbcTemplate().execute(pscc, pscc);
}

public <T> List<T> list(Class clazz){
return getJdbcTemplate().query("select * from table", BeanRowMapper.createRowMapper(clazz));
}

public class BeanBatchSavePSCC<T> implements PreparedStatementCreator, PreparedStatementCallback<Integer> {

private Class clazz;
private PropertyDescriptor[] pds;
private Map<Integer, Method> methodMap;
private List<T> list;
private Method methodSetterPK;

public BeanBatchSavePSCC(List<T> list) {
this.list = list;
if (list == null || list.isEmpty()) {
throw new NullPointerException("");
}
this.clazz = list.get(0).getClass();
methodMap = new HashMap<>();
pds = BeanUtils.getPropertyDescriptors(clazz);
}

@Override
public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
PreparedStatement statement = con.prepareStatement(getInsertSql(), Statement.RETURN_GENERATED_KEYS);
for (T t : list) {
for (Map.Entry<Integer, Method> entry : methodMap.entrySet()) {
Object value = ReflectionUtils.invokeMethod(entry.getValue(), t);
statement.setObject(entry.getKey(), value);
}
statement.addBatch();
}
statement.executeBatch();
return statement;
}

/**
* 返回更新数量
*
* @param statement
* @return
* @throws SQLException
* @throws DataAccessException
*/
@Override
public Integer doInPreparedStatement(PreparedStatement statement) throws SQLException, DataAccessException {
ResultSet rs = statement.getGeneratedKeys();
int index = 0;
while (rs.next()) {
Object id = rs.getObject(1);
ReflectionUtils.invokeMethod(methodSetterPK, list.get(index), id);
index++;
}
JdbcUtils.closeResultSet(rs);
return list.size();
}

protected String getInsertSql() {
StringBuilder sql = new StringBuilder("INSERT INTO ");
sql.append(FieldUtils.underscoreName(clazz.getName()));
sql.append("(");
int index = 1;
for (PropertyDescriptor pd : pds) {
String name = pd.getName();
if (!name.equals("class")) {
Method method = pd.getReadMethod();
if (method.getAnnotation(PK.class) != null && methodSetterPK == null) {
methodSetterPK = pd.getWriteMethod();
}
methodMap.put(index, method);
sql.append("`").append(FieldUtils.underscoreName(name)).append("`,");
index++;
}
}
sql.deleteCharAt(sql.lastIndexOf(",")).append(")");
sql.append(" VALUES ").append("(");
for (int i = 1; i < index; i++) {
sql.append("?,");
}
sql.deleteCharAt(sql.lastIndexOf(",")).append(");");
System.out.println(sql.toString());
return sql.toString();
}
}

public class BeanBatchUpdatePSCC<T> implements PreparedStatementCreator, PreparedStatementCallback<Integer> {

private Class clazz;
private PropertyDescriptor[] pds;
private Map<Integer, Method> methodMap;
private List<T> list;
private Method pkReadMethod;
private String where;
private Object[] values;

public BeanBatchUpdatePSCC(List<T> list) {
this.list = list;
init();
}

public BeanBatchUpdatePSCC(List<T> list, String where, Object... values) {
this.list = list;
this.where = where;
this.values = values;
init();
}

private void init() {
if (list == null || list.isEmpty()) {
throw new NullPointerException("");
}
this.clazz = list.get(0).getClass();
methodMap = new HashMap<>();
pds = BeanUtils.getPropertyDescriptors(clazz);
}

@Override
public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
String sql = getUpdateSql();
PreparedStatement statement = con.prepareStatement(sql);
for (T t : list) {
int index = 1;
for (Map.Entry<Integer, Method> entry : methodMap.entrySet()) {
Object value = ReflectionUtils.invokeMethod(entry.getValue(), t);
statement.setObject(entry.getKey(), value);
index ++;
}
if (where != null) {
for (Object value : values) {
statement.setObject(index, value);
index++;
}
} else if (pkReadMethod != null) {
Object value = ReflectionUtils.invokeMethod(pkReadMethod, t);
statement.setObject(methodMap.size() + 1, value);
}
statement.addBatch();
}
statement.executeBatch();
return statement;
}

/**
* 返回更新数量
*
* @param statement
* @return
* @throws SQLException
* @throws DataAccessException
*/
@Override
public Integer doInPreparedStatement(PreparedStatement statement) throws SQLException, DataAccessException {
return list.size();
}

protected String getUpdateSql() {
StringBuilder sql = new StringBuilder("UPDATE ");
sql.append(FieldUtils.underscoreName(clazz.getName()));
sql.append(" SET ");
int index = 1;
String pkColumn = null;
for (PropertyDescriptor pd : pds) {
String name = pd.getName();
if (!name.equals("class")) {
Method method = pd.getReadMethod();
if (method.getAnnotation(PK.class) != null && pkColumn == null)
3ff0
{
pkColumn = FieldUtils.underscoreName(name);
pkReadMethod = method;
continue;
}
methodMap.put(index, method);
sql.append("`").append(FieldUtils.underscoreName(name)).append("`=?,");
index++;
}
}
sql.deleteCharAt(sql.lastIndexOf(","));
if (where != null) {
sql.append(" WHERE ").append(where).append(";");
} else if (pkColumn != null) {
sql.append(" WHERE `").append(pkColumn).append("`=?;");
} else {
throw new NullPointerException("");
}
System.out.println(sql.toString());
return sql.toString();
}
}

//用户查询后转换成pojo
public class BeanRowMapper extends BeanPropertyRowMapper {

public BeanRowMapper(Class clazz){
super(clazz);
}

/**
* java属性和数据库字段对应方法
*
* @param name
* @return
*/
@Override
protected String underscoreName(String name) {
return super.underscoreName(name);
}

public static BeanRowMapper createRowMapper(Class clazz) {
return new BeanRowMapper(clazz);
}
}

public class FieldUtils {

public static String underscoreName(String name) {
if (!StringUtils.hasLength(name)) {
return "";
}
name = name.substring(name.lastIndexOf(".") + 1);
StringBuilder result = new StringBuilder();
result.append(name.substring(0, 1).toLowerCase(Locale.US));
for (int i = 1; i < name.length(); i++) {
String s = name.substring(i, i + 1);
String slc = s.toLowerCase(Locale.US);
if (!s.equals(slc)) {
result.append("_").append(slc);
} else {
result.append(s);
}
}
return result.toString();
}

}