Question

在一个应用程序中，我们有三个数据库服务器
1. db1 2. db2 3.db3 我们为上述连接配置了jndi 如果在db1中没有连接，那么从db2应用程序将建立连接，如果在db2中没有连接，应用程序将在db2.how中建立连接以实现这个spring jdbc模板。服务器的细节 tomcat 8.0 server，spring 4.0，oracle

Answer 1

这是您可以参考此来源的问题示例。

application.properties

spring.ds_items.driverClassName=org.postgresql.Driver 
spring.ds_items.url=jdbc:postgresql://srv0/test 
spring.ds_items.username=test0 
spring.ds_items.password=test0 


spring.ds_users.driverClassName=org.postgresql.Driver 
spring.ds_users.url=jdbc:postgresql://srv1/test 
spring.ds_users.username=test1 
spring.ds_users.password=test1

DatabaseItemsConfig.java

import javax.sql.DataSource; 

@Configuration 
@ConfigurationProperties(name = "spring.ds_items") 
public class DatabaseItemsConfig extends TomcatDataSourceConfiguration { 

    @Bean(name = "dsItems") 
    public DataSource dataSource() { 
        return super.dataSource(); 
    } 

    @Bean(name = "jdbcItems") 
    public JdbcTemplate jdbcTemplate(DataSource dsItems) { 
        return new JdbcTemplate(dsItems); 
    } 
}

DatabaseUsersConfig.java

import javax.sql.DataSource; 

@Configuration 
@ConfigurationProperties(name = "spring.ds_users") 
public class DatabaseUsersConfig extends TomcatDataSourceConfiguration { 

    @Bean(name = "dsUsers") 
    public DataSource dataSource() { 
        return super.dataSource(); 
    } 

    @Bean(name = "jdbcUsers") 
    public JdbcTemplate jdbcTemplate(DataSource dsUsers) { 
        return new JdbcTemplate(dsUsers); 
    } 

}

ItemRepository.java

import java.sql.ResultSet; 
import java.sql.SQLException; 

@Repository 
public class ItemRepository { 
    protected final Logger log = LoggerFactory.getLogger(getClass()); 

    @Autowired 
    @Qualifier("jdbcItems") 
    protected JdbcTemplate jdbc; 

    public Item getItem(long id) { 
        return jdbc.queryForObject("SELECT * FROM sb_item WHERE id=?", itemMapper, id); 
    } 

    private static final RowMapper<Item> itemMapper = new RowMapper<Item>() {
        public Item mapRow(ResultSet rs, int rowNum) throws SQLException { 
            Item item = new Item(rs.getLong("id"), rs.getString("title")); 
            item.price = rs.getDouble("id"); 
            return item; 
        } 
    }; 
}

UserRepository.java

   import java.sql.ResultSet; 
import java.sql.SQLException; 

@Repository 
public class UserRepository { 
    protected final Logger log = LoggerFactory.getLogger(getClass()); 

    @Autowired 
    @Qualifier("jdbcUsers") 
    protected JdbcTemplate jdbc; 

    public User getUser(long id) { 
        return jdbc.queryForObject("SELECT * FROM sb_user WHERE id=?", userMapper, id); 
    } 

    private static final RowMapper<User> userMapper = new RowMapper<User>() {
        public User mapRow(ResultSet rs, int rowNum) throws SQLException { 
            User user = new User(rs.getLong("id"), rs.getString("name")); 
            user.alias = rs.getString("alias"); 
            return user; 
        } 
    }; 
}

spring根据连接的可用性连接到数据库

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