需求

执行一个未知的SQL，将其导出。SQL中可能含有CLOB字段。

SQL Map

<select id="selectSomething" parameterType="map" resultMap="PageData">
  ${sql_script}
</select>

java

思路：重写java.util.HashMap，对CLOB字段进行处理。重写put()方法。

import java.io.BufferedReader;
import java.io.Reader;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.servlet.http.HttpServletRequest;

import com.alibaba.druid.proxy.jdbc.ClobProxyImpl;
/** 
 * 说明：参数封装Map
 * 创建人：
 * 修改时间：
 * @version
 */
public class PageData extends HashMap implements Map{
    
    private static final long serialVersionUID = 1L;
    
    Map map = null;
    HttpServletRequest request;
//  public PageData(HttpServletRequest request){
//      this.request = request;
//      Map properties = request.getParameterMap();
//      Map returnMap = new HashMap(); 
//      Iterator entries = properties.entrySet().iterator(); 
//      Map.Entry entry; 
//      String name = "";  
//      String value = "";  
//      while (entries.hasNext()) {
//          entry = (Map.Entry) entries.next(); 
//          name = (String) entry.getKey(); 
//          Object valueObj = entry.getValue(); 
//          if(null == valueObj){ 
//              value = ""; 
//          }else if(valueObj instanceof String[]){ 
//              String[] values = (String[])valueObj;
//              for(int i=0;i<values.length;i++){ 
//                   value = values[i] + ",";
//              }
//              value = value.substring(0, value.length()-1); 
//          }else{
//              value = valueObj.toString(); 
//          }
//          returnMap.put(name, value); 
//      }
//      map = returnMap;
//  }
    
    public PageData() {
        map = new HashMap();
    }
    
    @Override
    public Object get(Object key) {
        Object obj = null;
        if(map.get(key) instanceof Object[]) {
            Object[] arr = (Object[])map.get(key);
            obj = request == null ? arr:(request.getParameter((String)key) == null ? arr:arr[0]);
        } else {
            obj = map.get(key);
        }
        return obj;
    }
    
    public String getString(Object key) {
        return (String)get(key);
    }
    
    @SuppressWarnings("unchecked")
    @Override
    public Object put(Object key, Object value) {
        if(value instanceof ClobProxyImpl){             //读取oracle Clob类型数据
            try {
                ClobProxyImpl cpi = (ClobProxyImpl)value;
                Reader is = cpi.getCharacterStream();   //获取流
                BufferedReader br = new BufferedReader(is);
                String str = br.readLine();
                StringBuffer sb = new StringBuffer();
                while(str != null){                     //循环读取数据拼接到字符串
                    sb.append(str);
                    sb.append("\n");
                    str = br.readLine();
                }
                value = sb.toString();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return map.put(key, value);
    }
    
    @Override
    public Object remove(Object key) {
        return map.remove(key);
    }

    public void clear() {
        map.clear();
    }

    public boolean containsKey(Object key) {
        // TODO Auto-generated method stub
        return map.containsKey(key);
    }

    public boolean containsValue(Object value) {
        // TODO Auto-generated method stub
        return map.containsValue(value);
    }

    public Set entrySet() {
        // TODO Auto-generated method stub
        return map.entrySet();
    }

    public boolean isEmpty() {
        // TODO Auto-generated method stub
        return map.isEmpty();
    }

    public Set keySet() {
        // TODO Auto-generated method stub
        return map.keySet();
    }

    @SuppressWarnings("unchecked")
    public void putAll(Map t) {
        // TODO Auto-generated method stub
        map.putAll(t);
    }

    public int size() {
        // TODO Auto-generated method stub
        return map.size();
    }

    public Collection values() {
        // TODO Auto-generated method stub
        return map.values();
    }
    
}