encoding/json: examples for Marshal and Unmarshal

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5493075

src/pkg/encoding/json/example_test.go

+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+)
+
+// {"ID":1,"Name":"Reds","Colors":["Crimson","Red","Ruby","Maroon"]}
+func ExampleMarshal() {
+	type ColorGroup struct {
+		ID     int
+		Name   string
+		Colors []string
+	}
+	group := ColorGroup{
+		ID:     1,
+		Name:   "Reds",
+		Colors: []string{"Crimson", "Red", "Ruby", "Maroon"},
+	}
+	b, err := json.Marshal(group)
+	if err != nil {
+		fmt.Println("error:", err)
+	}
+	os.Stdout.Write(b)
+}
+
+// [{Name:Platypus Order:Monotremata} {Name:Quoll Order:Dasyuromorphia}]
+func ExampleUnmarshal() {
+	var jsonBlob = []byte(`[
+		{"Name": "Platypus", "Order": "Monotremata"},
+		{"Name": "Quoll",    "Order": "Dasyuromorphia"}
+	]`)
+	type Animal struct {
+		Name  string
+		Order string
+	}
+	var animals []Animal
+	err := json.Unmarshal(jsonBlob, &animals)
+	if err != nil {
+		fmt.Println("error:", err)
+	}
+	fmt.Printf("%+v", animals)
+}