map 转json数据并返给前端，前端可以用JSON.parse()序列化
import java.util.HashMap;
import java.util.Map
public class MapToJson {
public static String toJson(boolean success,String key,Integer val){
Map<String,Integer> jsonMap = new HashMap<String, Integer>();
jsonMap.put(key,val);
return toJson(success,jsonMap);
}
public static String toJson(boolean success,Map<String,Integer> jsonMap){
StringBuffer buffer = new StringBuffer();
if (success){
buffer.append("{\"success\":true,\"data\":[");
}else{
buffer.append("{success:false}");
}
if (jsonMap.size() >0){
for (String key:jsonMap.keySet()){
if(!key.equals(("class"))){
buffer.append("{"+'"'+key+'"' + ":"+jsonMap.get(key)+"},");
}
}
buffer.deleteCharAt(buffer.length()-1);
}
buffer.append("]}");
return buffer.toString();
}
}
在网上搜搜到一位老哥的方法，但是输出的前端解析不了，最后重新检查，发现返回的json格式不正确，所以重新改了格式，然后就能解析，下面是前端代码
let fragment = document.createDocumentFragment();
let total = 0;
Tools.ajax({
url:'/cart',
data:{id:1},
type:'post',
success:function (req) {
let rel = JSON.parse(req);
console.log(typeof (req));
console.log(req);
console.log(rel);
for(let i = 0; i < rel.data.length; i++){
for(key in rel.data[i]);
let div = document.createElement("div");
div.innerHTML = "<span>商品名称:"+key+"</span><span>商品数量:"+rel.data[i][key]+"</span>";
total+=rel.data[i][key];
fragment.appendChild(div)
}
let cart = document.querySelector(".cart");
cart.appendChild(fragment);
console.log(total);
}
})