常用工具类

package com.zys.training.util;


import com.fasterxml.jackson.databind.ObjectMapper;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;


/**
 * 向页面输出String
 * @author yushizhong
 */
public class HtmlUtil {

    /**
     * 输出string
     * @param response
     * @param jsonStr
     */
    public static void writerJson(HttpServletResponse response, String jsonStr) {
        writer(response, jsonStr);
    }

    public static void writerJson(HttpServletResponse response, Object object) throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        String jsonString = mapper.writeValueAsString(object)  ;
        writer(response,  jsonString);

    }

    private static void writer(HttpServletResponse response, String str)   {
        try {
            // 设置页面不缓存
            response.setHeader("Pragma", "No-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setHeader("Access-Control-Allow-Origin","*");
            response.setCharacterEncoding("UTF-8");
            PrintWriter out = null;
            out = response.getWriter();
            out.print(str);
            out.flush();
            out.close();
        } catch ( Exception ex){
            ex.printStackTrace();
        }
    }

    public static Map<String, String> getParameterMap(HttpServletRequest request) {
        // 参数Map
        Map properties = request.getParameterMap();
        // 返回值Map
        Map<String, String> returnMap = new HashMap<String, String>();
        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);
        }
        return returnMap;
    }

}

@RequestMapping("/get")
    public void get(HttpServletResponse response){
        response.setContentType("application/json");
        HtmlUtil.writerJson(response, "hello");
    }