Spring JDBC + Postgres SQL + Java 8 - 从/到LocalDate的转换

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问题描述

我正在使用Postgres SQL 9.2，Spring JDBC版本4.0.5和Java 8.

Java 8引入了新的日期/时间API，我想使用它，但是我遇到了一些困难。
我创建了表TABLE_A：

I am using Postgres SQL 9.2, Spring JDBC with version 4.0.5, and Java 8.
Java 8 introduced new date/time API and I would like to use it, but I encountered some difficulties.I have created table TABLE_A:

CREATE TABLE "TABLE_A"
(
  new_date date,
  old_date date
)

我使用Spring JDBC与数据库通信。我创建了Java类，它对应于这个表：

I am using Spring JDBC to communicate with database. I have created Java class, which corresponds to this table:

public class TableA
{
    private LocalDate newDate;
    private Date oldDate;
    //getters and setters

}

这是我的可插入新行的代码：

this is my code which is reponsible for inserting new row:

public void create(TableA tableA)
{
    BeanPropertySqlParameterSource parameterSource = new BeanPropertySqlParameterSource(tableA);
    final String sql = "INSERT INTO public.TABLE_A (new_date,old_date) values(:newDate,:oldDate)";
    namedJdbcTemplate.update(sql,parameterSource);

}

当我执行此方法时，我得到了异常：

When I executed this method I got exception:

org.postgresql.util.PSQLException: Can't infer the SQL type to use for an instance of java.time.LocalDate. Use setObject() with an explicit Types value to specify the type to use.

所以我更新了BeanPropertySqlParameterSource的创建：

so I updated cretion of BeanPropertySqlParameterSource:

BeanPropertySqlParameterSource parameterSource = new BeanPropertySqlParameterSource(tableA);
parameterSource.registerSqlType("newDate", Types.DATE);

在更改后我能够插入行。但接下来，我想从数据库中获取行。这是我的方法：

after that change I was able to insert row. But next, I would like to fetch rows from database. Here is my method:

public List<TableA> getAll()
{
    final String sql = "select * from public.TABLE_A";
    final BeanPropertyRowMapper<TableA> rowMapper = new BeanPropertyRowMapper<TableA>(TableA.class);
    return namedJdbcTemplate.query(sql,rowMapper);
}

当然我得到例外：

...
at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:474)
at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:511)
at org.springframework.beans.BeanWrapperImpl.setPropertyValue(BeanWrapperImpl.java:1119)
at org.springframework.beans.BeanWrapperImpl.setPropertyValue(BeanWrapperImpl.java:902)
at org.springframework.jdbc.core.BeanPropertyRowMapper.mapRow(BeanPropertyRowMapper.java:255)
...
Caused by: java.lang.IllegalStateException: Cannot convert value of type [java.sql.Date] to required type [java.time.LocalDate] for property 'newDate': no matching editors or conversion strategy found.

所以我更新了我的代码，这次是BeanPropertyRowMapper，我已经为bean包装器添加了转换服务，这是能够执行从java.sql.Date到java.time.LocalDate的转换

So I updated my code, this time BeanPropertyRowMapper, I have added conversion service to bean wrapper, which is able to perform conversion from java.sql.Date to java.time.LocalDate

public List<TableA> getAll()
{
    final String sql = "select * from public.TABLE_A";
    final BeanPropertyRowMapper<TableA> rowMapper = new BeanPropertyRowMapper<TableA>(TableA.class)
    {
        @Override
        protected void initBeanWrapper(BeanWrapper bw) {
            super.initBeanWrapper(bw);
           bw.setConversionService(new ConversionService() {
               @Override
               public boolean canConvert(Class<?> aClass, Class<?> aClass2) {
                   return aClass == java.sql.Date.class && aClass2 == LocalDate.class;
               }

               @Override
               public boolean canConvert(TypeDescriptor typeDescriptor, TypeDescriptor typeDescriptor2) {
                   return canConvert(typeDescriptor.getType(), typeDescriptor2.getType());
               }

               @Override
               public <T> T convert(Object o, Class<T> tClass) {
                   if(o instanceof Date && tClass == LocalDate.class)
                   {
                       return (T)((Date)o).toLocalDate();
                   }

                   return null;


       }

           @Override
           public Object convert(Object o, TypeDescriptor typeDescriptor, TypeDescriptor typeDescriptor2) {
               return convert(o,typeDescriptor2.getType());
           }
       });
    }
}   ;

return namedJdbcTemplate.query(sql,rowMapper);

现在一切正常，但它很复杂。

更容易实现这一目标的方法？
一般来说，我想在我的Java代码中运行LocalDate，因为它更方便，并且能够将它持久化到数据库。我希望默认情况下应该启用它。

and now everything works, but it is quite complicated.
Is it easier way to achieve that?Generally speaking, I would like to operate on LocalDate in my Java code, because it is much more convenient, and be able to persist it to database. I would expect that it should be enabled by default.

BeanPropertySqlParameterSource

Spring JDBC + Postgres SQL + Java 8 - 从/到LocalDate的转换

问题描述

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