serverlet 返回json

1.web.xml

	<servlet>
		<servlet-name>serverlet名</servlet-name>
		<servlet-class>项目类路径</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name><span style="font-family: Arial, Helvetica, sans-serif; font-size: 12px;">serverlet名</span><span style="font-size: 12px; font-family: Arial, Helvetica, sans-serif;"></servlet-name></span>
		<url-pattern>/请求路径</url-pattern>
	</servlet-mapping>

2.java

package com.pul.sam.area;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;

import org.hibernate.SessionFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.orm.hibernate3.HibernateTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.DefaultTransactionDefinition;
import org.springframework.web.context.support.WebApplicationContextUtils;

public class AreaQuery extends HttpServlet{

	private static final long serialVersionUID = 1L;
	
	protected void doGet(HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {
		this.requestManage(req,res);;
	}
	
	protected void doPost(HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {
		this.requestManage(req,res);
	}
	/**
	 * 处理请求
	 * @throws IOException 
	 */
	private void requestManage(HttpServletRequest req, HttpServletResponse res) throws IOException{
		//配置编码类型
		res.setContentType("text/html;charset=UTF-8;pageEncoding=UTF-8");  //控制浏览器的编码行为
		res.setCharacterEncoding("UTF-8");//目的是用于response.getWriter()输出的字符流的乱码问题，如果是response.getOutputStream()是不需要此种解决方案的；因为这句话的意思是为了将response对象中的数据以UTF-8解码后发向浏览器；
		res.setHeader("content-type","text/html;charset=UTF-8");	
		req.setCharacterEncoding("UTF-8");	
		
		String type = req.getParameter("type");
		switch (type) {
			case "prov":
				this.queryProv(req, res);
				break;
			case "city":
				this.queryCity(req, res);
				break;
			case "area":
				this.queryArea(req, res);
				break;
			default:
				break;
		}
	}
	
	/**
	 * 省份查询
	 * @throws IOException 
	 */
	@SuppressWarnings("rawtypes")
	private void queryProv(HttpServletRequest req, HttpServletResponse res) throws IOException {
		System.out.println("111111111");
		
		//配置编码类型
		res.setContentType("text/json;charset=UTF-8;pageEncoding=UTF-8");  //控制浏览器的编码行为
		res.setCharacterEncoding("UTF-8");//目的是用于response.getWriter()输出的字符流的乱码问题，如果是response.getOutputStream()是不需要此种解决方案的；因为这句话的意思是为了将response对象中的数据以UTF-8解码后发向浏览器；
		res.setHeader("content-type","text/json;charset=UTF-8");	
		req.setCharacterEncoding("UTF-8");		
		
		PrintWriter out = res.getWriter();		
		
		// 配置与数据库链接的属性
		ServletContext sc = req.getSession().getServletContext();
		ApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(sc);
		SessionFactory sessionFactory=(SessionFactory) ac.getBean("sessionFactory");//创建工厂
		HibernateTransactionManager htm = new HibernateTransactionManager(sessionFactory);
		DefaultTransactionDefinition def = new DefaultTransactionDefinition();
		def.setReadOnly(false);
		def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
		TransactionStatus status = htm.getTransaction(def);
		HibernateTemplate ht=new HibernateTemplate(sessionFactory);//增删改查的模版		
		//查询数据库
		String hql = "select distinct _t1.provCode,_t1.prov from TArea _t1";
		List list = ht.find(hql);
		htm.commit(status);  //真正提交到后台数据库
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("result", list);
		JSONObject json = JSONObject.fromObject(map);
		out.print(json);
		out.close();
	}

	/**
	 * 城市查询
	 * @throws IOException 
	 */
	@SuppressWarnings("rawtypes")
	private List queryCity(HttpServletRequest req, HttpServletResponse res) throws IOException {
		
		//配置编码类型
		res.setContentType("text/json;charset=UTF-8;pageEncoding=UTF-8");  //控制浏览器的编码行为
		res.setCharacterEncoding("UTF-8");//目的是用于response.getWriter()输出的字符流的乱码问题，如果是response.getOutputStream()是不需要此种解决方案的；因为这句话的意思是为了将response对象中的数据以UTF-8解码后发向浏览器；
		res.setHeader("content-type","text/json;charset=UTF-8");	
		req.setCharacterEncoding("UTF-8");		
		
		PrintWriter out = res.getWriter();		
		
		// 配置与数据库链接的属性
		ServletContext sc = req.getSession().getServletContext();
		ApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(sc);
		SessionFactory sessionFactory=(SessionFactory) ac.getBean("sessionFactory");//创建工厂
		HibernateTransactionManager htm = new HibernateTransactionManager(sessionFactory);
		DefaultTransactionDefinition def = new DefaultTransactionDefinition();
		def.setReadOnly(false);
		def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
		TransactionStatus status = htm.getTransaction(def);
		HibernateTemplate ht=new HibernateTemplate(sessionFactory);//增删改查的模版		
		//查询数据库
		String hql = "select distinct _t1.provCode,_t1.prov from TArea _t1";
		List list = ht.find(hql);
		htm.commit(status);  //真正提交到后台数据库
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("result", list);
		JSONObject json = JSONObject.fromObject(map);
		out.print(json);
		out.close();		
		return list;
	}
	
	/**
	 * 区查询
	 * @throws IOException 
	 */
	@SuppressWarnings("rawtypes")
	private List queryArea(HttpServletRequest req, HttpServletResponse res) throws IOException {
		System.out.println("111111111");
		
		//配置编码类型
		res.setContentType("text/json;charset=UTF-8;pageEncoding=UTF-8");  //控制浏览器的编码行为
		res.setCharacterEncoding("UTF-8");//目的是用于response.getWriter()输出的字符流的乱码问题，如果是response.getOutputStream()是不需要此种解决方案的；因为这句话的意思是为了将response对象中的数据以UTF-8解码后发向浏览器；
		res.setHeader("content-type","text/json;charset=UTF-8");	
		req.setCharacterEncoding("UTF-8");		
		
		PrintWriter out = res.getWriter();		
		
		// 配置与数据库链接的属性
		ServletContext sc = req.getSession().getServletContext();
		ApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(sc);
		SessionFactory sessionFactory=(SessionFactory) ac.getBean("sessionFactory");//创建工厂
		HibernateTransactionManager htm = new HibernateTransactionManager(sessionFactory);
		DefaultTransactionDefinition def = new DefaultTransactionDefinition();
		def.setReadOnly(false);
		def.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
		TransactionStatus status = htm.getTransaction(def);
		HibernateTemplate ht=new HibernateTemplate(sessionFactory);//增删改查的模版		
		//查询数据库
		String hql = "select distinct _t1.provCode,_t1.prov from TArea _t1";
		List list = ht.find(hql);
		htm.commit(status);  //真正提交到后台数据库
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("result", list);
		JSONObject json = JSONObject.fromObject(map);
		out.print(json);
		out.close();		
		return list;
	}
}

3.js

	$.ajax({    
	     type:'post',    
	     url:'/logistic/queryArea?type=prov',    
	     cache:false,    
	     dataType:'json',    
	     success:function(data){ 
//	    	 alert("success");
	    	 console.log(data);
	    	 console.log(eval(data));//前台json字符串转换json数据
         },    
	     error:function(e){
	    	  console.log("失败");
	    	  console.log(e);
	     }    
	});